Assessing the stability of arsenic sulfide pigments and influence of the binding media on their degradation by means of spectroscopic and electrochemical techniques Microchem. J. (IF 3.034) Pub Date : 2018-01-06 Marc Vermeulen, Koen Janssens, Jana Sanyova, Vanoushe Rahemi, Chris McGlinchey, Karolien De Wael
In this paper, we used the semiconducting and lightfastness properties of synthetic and mineral arsenic sulfide pigments to study their stability by means of electrochemical and microfadometric techniques. A combination of these techniques shows that in the early stage of the degradation process, amorphous arsenic sulfides are more stable than both crystalline forms, while upon longer exposure time, amorphous pigments will fade more than both mineral pigments, making it less suitable. While the stability study was carried out on unbound pigments, the influence of the organic binder on the relative degradation of the arsenic sulfide pigments was investigated through a multi-analytical approach on pigment/binder mock-up paint samples. For this purpose, the formation of arsenic trioxide was assessed by micro Fourier transform infrared (μ-FTIR) spectroscopy while the influence of the binder on the formation of sulfates was studied by means of synchrotron radiation X-ray near edge structure (μ-XANES). Both techniques elucidate a higher stability of all pigments in gum arabic while the use of egg yolk as binder leads to the most degradation, most likely due to its sulfur-rich composition. In the context of the degradation of arsenic sulfide pigments, other binders such as animal glue, egg white or linseed oil show an intermediate impact.
Polyurethane foam functionalized with phenylfluorone for online preconcentration and determination of copper and cadmium in water samples by flame atomic absorption spectrometry Microchem. J. (IF 3.034) Pub Date : 2018-01-06 Juliana Menezes de Sousa, Marcos Tadeu Couto, Ricardo J. Cassella
In this work, a polyurethane foam (PUF) functionalized with phenylfluorone (PUF-PF) was packed in a minicolumn and used as an on-line preconcentration system for cadmium and copper determination in water samples. The experimental conditions (both chemical and physical) were optimized to achieve the highest sensitivity. A study of possible ion interference on the retention of cadmium and copper was also performed. The enrichment factors obtained were 14 and 16 for copper and cadmium, respectively, using a preconcentration time of 1 min. The proposed system allowed the determination of metals with limits of detection (3σ) of 0.8 and 0.3 μg L− 1 for Cu(II) and Cd(II), respectively. The precision of the procedures was also calculated as 7.6% for Cu(II) (at 25 μg L− 1) and 4.0% for Cd(II) (at 10 μg L− 1). The limits of quantification obtained were 2.6 and 0.8 μg L− 1 for Cu(II) and Cd(II), respectively. Cadmium and copper contents in water samples (from rivers and swimming pools) were determined by applying the proposed procedure. In these samples, recovery tests were conducted in order to evaluate the accuracy of the method; the recovery percentages varied between 83 and 109%.
Evaluation of minerals, toxic elements and bioactive compounds in rose petals (Rosa spp.) using chemometric tools and artificial neural networks Microchem. J. (IF 3.034) Pub Date : 2017-12-20 Ana Maria P. dos Santos, Emmanuelle F.R. Silva, Walter Nei L. dos Santos, Erik G.P. da Silva, Liz O. dos Santos, Bruna R. da S. Santos, Maria C. da S. Sauthier, Wagna P.C. dos Santos
Rose (Rosa spp.) petals have been used for the preparation of new cooking recipes, due to their sensory properties. In this paper were evaluated the micro (Co, Cu, Fe, Mn, Mo, Ni and Zn), macro (Ca, Mg, Na and P) and toxic elements (As, Cd and Cr) of organic cultivation rose by ICP OES and ICP-MS. The bioactive compounds (total phenolics, total flavonoids, total anthocyanins and antioxidant capacity in DPPH) were determined by UV-VIS spectrophotometry. Chemometric tools were used in method optimization, such as full factorial design for acid digestion and Box-Behnken design for total phenolics, in addition to the application of Artificial Neural Networks with Kohonen Neural Network for bioactive compounds. The application of PCA and HCA showed that the mineral composition of rose petal samples had differences between summer and winter. The accuracy of the method was confirmed by the analysis of three certified reference materials: apple leaves (1515), spinach leaves (1570a) and peach leaves (1547), from the National Institute of Standards and Technology (NIST). Digestion efficiency was evaluated by residual carbon content. The developed methods were promising to evaluate the minerals, toxic elements and bioactive compounds in rose petals, and the results indicate that they can be added as a potential nutritional supplement in the human diet.
Modern acrylic paints probed by optical coherence tomography and infrared reflectography Microchem. J. (IF 3.034) Pub Date : 2018-01-04 J. Striova, A. Dal Fovo, V. Fontani, M. Barucci, E. Pampaloni, M. Raffaelli, R. Fontana
Contemporary art is particularly delicate as the synthetic materials used for their realization are of poorer quality and durability than the traditional materials. It follows that the contemporary artworks often require imminent restorations as well as in-depth analytical studies of the constituting materials. The non-invasiveness of the scientific methods is a key issue in the diagnostics of contemporary art because it minimizes the need of sampling. In this respect, the potential of Optical Coherence Tomography (OCT) imaging to probe the internal structure of the commercial acrylic paint layers, as a function of their thickness, was investigated and compared with that of the near infrared (NIR) reflectography. In support of these measurements, micro-profilometry, an interferometric technique with micrometric depth resolution, was used to measure the paint layer thicknesses. We show that for some painted materials there is a limited possibility to visualize the underdrawings, when investigated by both OCT and NIR reflectography. This is owed to either the absorption of the illumination wavelength by the paint layer (Cobalt-based paints) or the multiple photon scattering effect (presence of TiO2).
Development of an electroanalytical method to control quality in fish samples based on an edge plane pyrolytic graphite electrode. Simultaneous determination of hypoxanthine, xanthine and uric acid ☆ Microchem. J. (IF 3.034) Pub Date : 2018-01-02 Gastón Darío Pierini, Sebastian Noel Robledo, María Alicia Zon, María Susana Di Nezio, Adrian Marcelo Granero, Héctor Fernández
Characterization of glaze ceramics from the archaeological site of La Alcazaba, Almería (Spain) Microchem. J. (IF 3.034) Pub Date : 2017-12-26 Inés Ortega-Feliu, Blanca Gómez-Tubío, Yasmina Cáceres, Miguel Ángel Respaldiza
The Alcazaba de Almería is one of the most impressive mediaeval remains in Al-Andalus. Its defensive walls are expression of the economic and strategic relevance of Almeria City during middle Ages. In the course of archaeological excavations in this monumental area, several glazed ceramic remains were found in the palatine area so-called second enclosure. They are dated back between the 10th and the 15th centuries and correspond to small fragments on which different decorative techniques can be identified: green and manganese, green glazed, cuerda seca total, Nazarí Black and White, lustreware and blue and lustre earthenware. Although only seven samples out of 35 selected samples have been analyzed, their interest lie on that they are the first analytical approach to the ceramics of this important archaeological site and the group is representative some of most typical decorative procedures employed in Al-Andalus. The combination of ion beam and nuclear non-destructive analytical techniques performed on these ceramics have allowed the discussion on several aspects of the production technology, as the use of raw materials, and the degradation processes suffered by them. Glaze composition is discussed first. It is characterized by high values of Pb, Sn, Na, K and Mg. Chromophores are identified and some raw materials are discarded (psilomelane for manganese black) or proposed (absolite, skutterudite and trianite for blue). Secondly, the most degraded samples are found to be characterized by high values of Cl, in an inverse relation with the content of Si. The surface of two samples with lustre decorations, one with Cu particles and one with Cu + Ag particles, are studied finding a progressive decrease of Pb in the surface. Finally, the pastes of the samples are characterized by high values of Ca with respect to other ceramics of the area. Similar values are found in ceramics from Manises and Sevilla. The case of a possible imported sample is also discussed.
Homemade 3-carbon electrode system for electrochemical sensing: Application to microRNA detection Microchem. J. (IF 3.034) Pub Date : 2017-12-29 Mariana C.C.G. Carneiro, Felismina T.C. Moreira, Rosa A.F. Dutra, Rúben Fernandes, M. Goreti F. Sales
The homemade production of carbon screen-printed electrodes (C-SPEs) with a three‑carbon electrode system is reported, along with its application in electrochemical sensing. It is highlighted herein as main novelty that a simple carbon ink may be employed in the preparation of the 3-electrode system, including the pseudo-reference electrode, thereby avoiding the addition of silver or other suitable metal and simplify the construction of such devices, reducing costs and time. Screen-printed technology was employed to produce the 3-electrodes and the corresponding electrical paths. This was achieved by the manual application of a commercial carbon ink into a polyvinyl chloride (PVC) substrate allowing the production of > 20 SPEs. The optimization of the SPE assembly was made by univariate mode, until the best electrical features of the electrode-solution interface were achieved. Several electrochemical techniques were used for this purpose, namely cyclic voltammetry (CV), square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS). Raman Spectroscopy and Thermogravimetric Analysis (TGA) were also used for materials and electrode surface characterization. The usefulness of such devices was tested by modifying the working electrode with a sensing layer for microRNA-107, a potential biomarker in Alzheimer's Disease (AD). For this purpose, the surface was functionalized with carboxylic groups, activated by carbodiimide reaction and bound to a suitable oligonucleotide probe containing the complementary sequence. Finally, the microRNA-107 sequence hybridized with its probe, proving the efficiency of the C-SPEs in electrochemical sensing. Overall, this study brings into light the possibility of preparing simple homemade electrodes with a 3‑carbon electrode system that stands out by the low cost, disposability and versatility of the presented platform, holding a great potential for application in point-of-care devices using electrochemical sensing.
Fast derivatization procedure for the analysis of phytoestrogens in soy milk by gas chromatography tandem mass spectrometry Microchem. J. (IF 3.034) Pub Date : 2017-09-28 Barbara Benedetti, Marina Di Carro, Cristiana Mirasole, Emanuele Magi
Ancient and modern paper: Study on ageing and degradation process by means of portable NIR μ-Raman spectroscopy Microchem. J. (IF 3.034) Pub Date : 2017-12-29 Daniele Chiriu, Pier Carlo Ricci, Giancarlo Cappellini, Carlo Maria Carbonaro
For many centuries, paper was considered the main support for recording cultural achievements all over the world. Archives represent the historical memory of our past, and the book conservation represents one main concern since many books and documents kept in libraries and archives are at risk because of their fragility. The use of portable, not destructive technique like NIR μ-Raman spectroscopy represents a valid instrument for monitoring the documentary heritage. In the present study, we investigated the degradation process, associated to the polymers breaking, in order to propose a successful kinetic model for determining the ageing time of cellulose. We compared the calculated results with respect to both experimental samples and literature data, covering a period of seven centuries, from XV to XXI centuries. Proposed model starts directly from Raman spectra, in particular by monitoring the band at 1100 cm− 1 ascribed to C-O-C inter-monomers bond, whose relative intensity is related to the cellulose chain length. We obtained a very good agreement with the experimental data with 8% of accuracy. Finally, with the help of Density Functional Theory (DFT) simulations, we confirmed our model by studying the structure and the grade of cellulose crystallinity in the paper. In particular, the reverse trend of the band at 900 cm− 1, related to the crystallinity grade of the cellulose, and the band at 1100 cm− 1, as a function of the dimer unit cell structure, supported the kinetic model, suggesting a shear stress like effect as the origin of the cellulose chain length decrease.
Evaluating the exploitability of several essential oils constituents as a novel biological treatment against cultural heritage biocolonization Microchem. J. (IF 3.034) Pub Date : 2017-12-27 Marco Veneranda, Laura Blanco-Zubiaguirre, Graziella Roselli, Giuseppe Di Girolami, Kepa Castro, Juan Manuel Madariaga
This work aimed at evaluating the possible use of several organic compounds as novel conservation products against the biocolonization of cultural heritage materials. In a first step, the antifungal activity of 10 selected essential oil (EOs) constituents was tested against a strain of Aspergillus niger collected from a Roman mural painting (Pompeii, Italy). According to antifungal assays, thymol, eugenol and cinnamaldehyde provided a strong and enduring inhibition effect. These properties open the way to the possible exploitability of EOs constituents for middle and long-term protection applications. In this perspective, the three compounds were exposed to different light conditions with the purpose of assessing their stability under photo-oxidation conditions. After ageing, Fourier transform infrared spectroscopy (FTIR) analysis and in vitro antifungal assays were performed. The collected results proved that light exposure had a critical negative effect on the antifungal capability of cinnamaldehyde samples. On the contrary, composition and properties of eugenol and thymol were not affected by ageing, confirming their possible use in the future development of long-lasting conservation products.
Complementary use of Optical Coherence Tomography (OCT) and Reflection FTIR spectroscopy for in-situ non-invasive monitoring of varnish removal from easel paintings Microchem. J. (IF 3.034) Pub Date : 2017-12-17 Magdalena Iwanicka, Patrizia Moretti, Saskia van Oudheusden, Marcin Sylwestrzak, Laura Cartechini, Klaas Jan van den Berg, Piotr Targowski, Costanza Miliani
Although the solvent removal of unwanted layers (e.g. aged varnishes, overpaints, oxalate patinas, dirt) from easel paintings is one of the most frequently performed restoration treatments, it is questioned regarding its controllability and safety to the artwork. There is thus a need for developing suited diagnostic methodologies able to inform restorers on the chemical, optical and morphological effects of cleaning. To this aim, we have explored the possibility of complementary use of Optical Coherent Tomography (OCT) and reflection FTIR. On the one hand, the OCT technique provides cross-sectional images with varnish layers visible and thus permits for measurement of their thicknesses. Combining many cross-sections into 3D data provides insight into the varnish thickness distribution over a given area of the paintings. On the other hand, reflection FTIR allows for a chemical characterization of the surface compounds revealing the nature of the varnish and monitoring its removal. Artificially aged model samples and two historical paintings were investigated at different steps of solvent cleaning tests and the results of the two techniques compared highlighting the benefits of their combined exploitation.
A novelty for cultural heritage material analysis: Transmission Electron Microscope (TEM) 3D electron diffraction tomography applied to Roman glass tesserae Microchem. J. (IF 3.034) Pub Date : 2017-12-27 N. Zacharias, F. Karavassili, P. Das, S. Nicolopoulos, A. Oikonomou, A. Galanis, E. Rauch, R. Arenal, J. Portillo, J. Roque, J. Casablanca, I. Margiolaki
We present a novel electron diffraction technique (Automated precession 3D diffraction tomography - ADT) based on a Transmission Electron Microscope (TEM) to precisely determine unit cell parameters, Space Group symmetry and atomic structure of various pigment/opacifier crystallites of submicron dimensions and commonly present in colored Roman glass tesserae. Such technique can operate at nanometer scale and it is possible to distinguish even between mineralogical phases of similar/same chemical composition, but different crystal structures.
Characterization of natural and treated diatomite by Laser-Induced Breakdown Spectroscopy (LIBS) Microchem. J. (IF 3.034) Pub Date : 2017-09-19 D. Paules, S. Hamida, R.J. Lasheras, M. Escudero, D. Benouali, J.O. Cáceres, J. Anzano
Determination and in vitro bioaccessibility evaluation of Ca, Cu, Fe, K, Mg, Mn, Mo, Na, P and Zn in linseed and sesame Microchem. J. (IF 3.034) Pub Date : 2017-09-12 Laís A. Souza, Thaís L. Souza, Filipe B. Santana, Rennan G.O. Araujo, Leonardo S.G. Teixeira, Daniele C.M.B. Santos, Maria Graças A. Korn
Given the importance of knowing the real nutritional value of food, the main objective of this study was to evaluate the total elements concentrations and bioaccessibility of Ca, Cu, Fe, K, Mg, Mn, Mo, Na, P and Zn in linseed and sesame samples. A full 24 factorial design was applied to optimize the microwave assisted acid digestion of the samples. Total elements concentrations were obtained by inductively coupled plasma optical emission spectrometry (ICP OES). Extraction procedures were performed using the Unified Bioaccessibility Method (UBM) to evaluate the bioaccessibility. The highest total content, in μg g− 1, were observed for K (4526–9768), P (3418–7014) and Mg (2527–4633), whereas Mo (< 0.11–2.6), Cu (12 − 32) and Mn (12–61) presented the lowest concentrations. The highest bioaccessible fractions in gastric phase were observed for K (16–26%), Mg (22–28%), Mn (19–27%), P (25–36%) and Zn (16–25%). In addition, it was found through the application of in vitro simulated gastrointestinal digestion that only a minor fraction of total Fe and Cu was potentially bioaccessible in this samples.
Real-time preparation of surface enhanced Raman scattering substrate for on-line analysis of aromatic molecules in capillary Microchem. J. (IF 3.034) Pub Date : 2017-09-18 Yan Kang, Wanchao Chen, Han Zhang, Lin Sun, Ting Wu, Yiping Du
A new way of real-time preparation of surface enhanced Raman scattering (SERS) substrate was developed by laser photoreduction of AgNO3 mixed with probe molecules (aromatic amine, aromatic mercaptan or phenolic compound) in capillary. The preparation of Ag nanoparticle cluster and acquisition of SERS signal could be performed synchronously and finished within several seconds. Probe molecules were analyzed on line in capillary. It was proposed that the rapid photoreduction process was initiated by photoinduced electron transfer from electron donors aromatic molecule to Ag+ under laser illumination. The p electrons from N (S or O) and π electrons from aromatic ring could form p-π conjugated structure. These delocalized electrons assisted the rapid reduction of Ag+ in such a short time. Additionally, Raman maps with 8 μm increment in X–Y directions (35 spectral spots) demonstrated good point-to-point repeatability of the substrate with the relative standard deviation less than 9%. Under optimal condition, several probe molecules, including benzidine, bisphenol A and so on were determined on line in capillary by this new method.
Determination of Pb, Cu and Fe in ethanol fuel samples by high-resolution continuum source electrothermal atomic absorption spectrometry by exploring a combination of sequential and simultaneous strategies Microchem. J. (IF 3.034) Pub Date : 2017-09-13 Jorge S. Almeida, Odara C.C.O. Souza, Leonardo S.G. Teixeira
Determination of selected metals in alligator snapping turtle (Macroclemys temminckii) by inductively coupled plasma-optical emission spectrometry Microchem. J. (IF 3.034) Pub Date : 2017-09-19 Jesse P. Dupre, Carey J. Hardaway, Joseph Sneddon, Eddie Lyons, Omar E. Christian
Urbanization and the continued encroachment of human activity into green spaces often result in the decline of several animal species. Macroclemys temminckii (alligator snapping turtle) is particularly sensitive to human activity as it is an opportunistic scavenger and carnivore. The longevity of this species, as well as its dietary habits make it an excellent candidate for biomonitoring. In this preliminary study, twelve (12) shell samples were collected from individuals trapped at Fort Polk, LA and Sam Houston Jones State Park, LA. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to determine the presence of the toxic metals cadmium (Cd), chromium (Cr) and lead (Pb) in addition to other trace minerals and iron (Fe). The levels of the toxic metal were below the detection limit of the ICP-OES. This report represents the first study of this nature on Macroclemys temminckii.
Chromatographic characterization of bio-oils from fast pyrolysis of sugar cane residues (straw and bagasse) from four genotypes of the Saccharum Complex Microchem. J. (IF 3.034) Pub Date : 2017-09-18 Jamilly A.S. Barros, Maurício C. Krause, Eliane Lazzari, Thiago R. Bjerk, Adriane L. do Amaral, Elina B. Caramão, Laiza C. Krause
Residues of four different genotypes of sugarcane (Saccharum sp., Saccharum Robustum, Miscanthus sp. and Erianthus sp.), belonging to the Germplasm Bank of the Saccharum Complex (BAGCANA) from EMBRAPA, were subjected to a pyrolysis process and the bio-oils produced were analyzed by GC and GC × GC. The main objective was to start the studies in the integrated use of these residues (sugarcane straw and sugarcane bagasse) in view of a bio-refinery. The species Robustum, Miscanthus and Erianthus were compared with the cultivated variety of sugarcane (Saccharum sp.) because they are candidate to application as “energy-cane”, which is a sugarcane with higher amount of cellulose being cultivated for energetic purposes. The residues (straw and bagasse) are not adequately used and tend to be inadequately discarded, causing environmental impacts. However, if these residues be re-processed by pyrolysis, the produced bio-oil can be found many potential uses. The goal of this paper is to compare the amount and quality of bio-oils produced from these residues (bagasse and straw), intending to aggregate value to these materials and to indicate their best uses. The bio-oils were analyzed by GC × GC coupled to mass spectroscopy, allowing the detection and identification of their major constituents. Phenols were the main classes of identified compounds that can indicate the use of the bio-oil as alternative source of raw material for chemical industries. It is important to highlight that not only the straw but also the bagasse produced similar bio-oils, differing only in the relative amount of these compounds in the bio-oil, allowing an integrated utilization of these materials. The goal of this paper is to compare the amount and quality of bio-oils produced from these residues (bagasse and straw), intending to aggregate value to these materials and to indicate their best uses. The bio-oils were analyzed by GC × GC coupled to mass spectroscopy, allowing the detection and identification of their major constituents. Phenols were the main classes of identified compounds that can indicate the use of the bio-oil as alternative source of raw material for chemical industries. It is important to highlight that not only the straw but also the bagasse produced similar bio-oils, differing only in the relative amount of these compounds in the bio-oil, allowing an integrated utilization of these materials. The identified compounds are approximately the same in all the samples, differing only in the relative amount of these compounds in the bio-oils. The major compounds were slightly different in the studied bio-oils, but they can be represented by benzofuran-2,3-dihydro, 4-vinyl-guaiacol, syringol and 5-hydroxy-methyl-furfural. The aldehyde contents increased significantly in the Miscanthus and Erianthus bio-oils samples, mainly due to furfural derivatives, which are not found in the other samples. In addition, only the species Erianthus sp. presented yield in bio-oil superior to the commercial specie, which may indicate its use in the production of furfural and derivatives.
In situ study of Limoges painted enamels by portable X-ray fluorescence supported by laser ablation inductively coupled plasma mass spectrometry analysis of micro-samples Microchem. J. (IF 3.034) Pub Date : 2017-09-15 Olga Syta, Luiza Kępa, Anna Mistewicz, Catia Wesołowska, Barbara Wagner
Portable XRF (X-ray fluorescence spectrometry) was used during non-invasive measurements of Limoges enamels from the collection of the National Museum in Warsaw (Poland). Four tiny micro-samples with dimensions below 1 mm2 were collected from 3 objects and subjected to multi-elemental LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) investigations, including oxides quantification and data imaging approach. Comparison of the obtained LA-ICP-MS data and literature glass compositional information allowed for possible dating of the investigated plaques to 16th or the first half of 17th century. The XRF spectra revealed the unexpected presence of Pt in one of the analyzed objects within areas of evident intervention/restoration recognized by a conservator. These results were confirmed by LA-ICP-MS imaging of a tiny silvery foil fragment sampled from the restoration inserts. Probably the first or one of the first examples of identification of Pt foil in a repair on a Limoges enamel restoration is reported in this work.
The effect of adduction energy and intramolecular bonding in the mobility of dextromethorphan and diphenhydramine with 2-butanol in the buffer gas in ion mobility spectrometry Microchem. J. (IF 3.034) Pub Date : 2017-09-18 Dairo Meza-Morelos, Roberto Fernandez-Maestre
Direct analysis of benzo[a]pyrene metabolites with strong overlapping in both the spectral and lifetime domains Microchem. J. (IF 3.034) Pub Date : 2017-09-23 Bassam Alfarhani, Maha Al-Tameemi, Hector C. Goicoechea, Fernando Barbosa, Andres D. Campiglia
Rapid determination of salicylic acid at screen printed electrodes Microchem. J. (IF 3.034) Pub Date : 2017-09-19 Sean Rawlinson, Anna McLister, Prosper Kanyong, James Davis
The pain relief capabilities of salicylate are well established and a multitude of over the counter products populates pharmacy shelves. Over application of the preparations, through accidental or deliberate misuse, can all too often result in salicylate poisoning and, in severe cases, can be fatal. A novel detection strategy involving the quantification of the quinone byproducts arising from the electrochemical oxidation of salicylate is described. The approach has been adapted for use with a disposable screen-printed electrode and found to exhibit a high sensitivity towards salicylate which is free from the electroactive interferences that compromise the direct oxidative route. A linear range of 16 to 300 μM was observed with a limit of detection of 5.6 μM. The analytical applicability of the approach was demonstrated through recovery experiments of 100 μM salicylate in urine.
Synchrotron radiation total reflection X-ray fluorescence (SR-TXRF) and X-ray absorption near edge structure (XANES) of fractionated air particulates collected from Jeddah, Saudi Arabia Microchem. J. (IF 3.034) Pub Date : 2017-10-02 Abdallah A. Shaltout, Messaoud Harfouche, Sameh I. Ahmed, Mateusz Czyzycki, Andreas G. Karydas
Fractionated atmospheric aerosols with sizes ranged from 0.25 μm to > 16 μm have been collected on silicon wafers using a 7-stage cascade impactor from the centre location of Jeddah city, Saudi Arabia during May 2015. Two fractionated sizes were selected in the present work, namely 0.5–0.25 μm (PM0.5–0.25) and 2–1 μm (PM2.0–1.0), because their mass concentrations were the most dominant. Fractionated atmospheric aerosols were examined under ultra-high vacuum environment with synchrotron radiation total reflection X-ray fluorescence (SR-TXRF) and X-ray absorption near edge structure (XANES) spectroscopy techniques at the International Atomic Energy Agency (IAEA) experimental end station operating at Elettra Sincrotrone Trieste, Italy. The mass concentrations in PM2.0–1.0 were found greater than those within PM0.5–0.25 material and the mass concentration ratio of PM2.0–1.0/PM0.5–0.25 was reached to 2. The homogeneity in the spatial deposition of different elements in both PM0.5–0.25 and PM2.0–1.0 fractions was evaluated by the means of X-ray fluorescence (XRF) scanning. XANES showed us that Cr species exist mainly in the trivalent oxidation state, while for Mn the co-existence of both the divalent and trivalent oxidation states was determined. The results of the present study provide an improved understanding on the origin of Cr and Mn species in these two fractionated particulates and give an insight to their contribution to atmospheric and physicochemical processes.
Development and validation of high performance liquid chromatographic method for determination of gentisic acid and related Renal Cell Carcinoma biomarkers in urine Microchem. J. (IF 3.034) Pub Date : 2017-09-28 Ting-An Yen, Kaushalya Sharma Dahal, Barry Lavine, Zayed Hassan, Sanjeewa Gamagedara
A reversed phase liquid chromatographic (RPLC) method was developed to simultaneously detect and quantify creatinine, quinolinic acid, gentisic acid and 4-hydroxybenzoic acid in urine. These four bio-markers are present in relatively high concentrations in urine. Using a 5% methanol in water mobile phase with 0.6% acetic acid and a Zorbax C18 column, baseline resolution for all four biomarkers in synthetic urine was achieved. Better resolution was obtained for the separation of these four compounds when water rich mobile phases were used. Detection of the four biomarkers in urine using the proposed RPLC method is limited by background from the urine matrix for the later eluting compounds and from the dead marker for earlier eluting compounds.
Analytical strategies for determining the sources and ecotoxicological risk of PAHs in river sediment Microchem. J. (IF 3.034) Pub Date : 2017-09-30 Ivanice F. dos Santos, Sérgio L.C. Ferreira, Carmem Domínguez, Josep M. Bayona
In this work, analytical strategies were applied aiming at determining sources and ecological risk of PAHs in river sediments. A total of 23 PAHs (16 EPA + 7 alkylated derivatives) were determined in sediment samples. The concentration of total PAH (∑23PAH) span from 0.260 to 2.10 μg g− 1 dw. The molecular ratios indicated a prevalence of pyrolytic pollution sources due to wood combustion processes and refined oil products. The ecological risk was assessed by considering the Sediment Quality Guidelines (SQGs). It was noted that all of the individual PAH concentrations are below the ERM (average variation effect). The ∑23PAH was also below the total of ERL (low variation effect) from 4.02 μg g− 1 dw. The synergy between individual PAHs was assessed using the indices of quality (mSQGq). Accordingly, the risk associated with the simultaneous contamination of the total PAH varied from low to moderate for the different sediments samples of river. The river is located in the state of Bahia, in a region that concentrates the first and largest integrated industrial complex of Brazil.
Investigation of deferiprone binding to different essential metal ions using microscale thermophoresis and electrospray ionization mass spectrometry Microchem. J. (IF 3.034) Pub Date : 2017-10-10 Mufarreh Asmari, Lenka Michalcová, Hassan A. Alhazmi, Zdeněk Glatz, Sami El Deeb
In this study, the microscale thermophoresis (MST) method was applied to investigate the interaction of deferiprone with Fe3 +, Cu2 +, Zn2 +, Co2 +, Ni2 +, Mn2 +, Mg2 +, and Ca2 +. Experiments were performed on a MST (Monolith NT.115 LabelFree®) system. Pretest scanning indicated good fluorescence intensity of deferiprone allowing the use of label-free MST experiments. Different concentrations of the intended metal ions in the range of 0.048 to 100.0 μM were titrated against 100 μM fixed concentration of deferiprone dissolved in 0.1 M Tris buffer pH 7.4. MST measurements were performed in standard capillaries at 50% excitation power and 20% MST power. The results indicated significant interactions of deferiprone with Fe3 +, Cu2 +, Zn2 +, Co2 +, and Ni2 +. The data fitted to the Hill model with Hill coefficients of 1.8, 1.5, 3.2, 1.6, and 1.5 for Fe3 +, Cu2 +, Zn2 +, Ni2 +, Co2 +, respectively, thus indicating more than 1:1 stoichiometry. EC50 values for the binding of deferiprone to Fe3 +, Cu2 +, Zn2 +, Co2 +, and Ni2 + were calculated to be 20.6 ± 3.34, 38.1 ± 3.39, 39.5 ± 4.90, 51.1 ± 6.86, and 101.1 ± 22.70 μM, respectively. No binding was observed for deferiprone with Mn2 +, Mg2 +, and Ca2 +. Electrospray ionization mass spectrometry was used as a complementary technique under similar conditions; however, Tris buffer was replaced by ammonium acetate buffer to be compatible with the mass system. Electrospray ionization mass spectrometry confirms the results obtained by MST indicating stable molecular ion peaks for the complexes of deferiprone with either Fe3 +, Zn2 +, Cu2 +, Co2 +, Ni2 +, and Mn2 +, but no binding was observed for deferiprone with either Ca2 + and Mg2 + under a gas phase state. MST shows a fast and simple approach to study the binding of deferiprone to different essential metal ions. Moreover, the complexes were stable for investigation by mass spectrometry under a soft ionization technique like used electrospray ionization, which aided to confirm binding stoichiometry.
Evaluation of novel Fmoc-tripeptide based hydrogels as immobilization supports for electrochemical biosensors Microchem. J. (IF 3.034) Pub Date : 2017-10-07 Giovanni Fusco, Laura Chronopoulou, Luciano Galantini, Andrea Zerillo, Zulkarnain M. Rasik, Riccarda Antiochia, Gabriele Favero, Andrea D'Annibale, Cleofe Palocci, Franco Mazzei
Combining Raman microspectrometry and chemometrics for determining quantitative molecular composition and mixing state of atmospheric aerosol particles Microchem. J. (IF 3.034) Pub Date : 2017-10-18 Damian Siepka, Gaëlle Uzu, Elżbieta A. Stefaniak, Sophie Sobanska
Determining quantitative molecular composition of atmospheric particles is required for assessing their environmental and health impacts. The presented algorithm was designed to analyse numerous Raman spectra of metal-rich atmospheric particles. Multivariate curve resolution-alternating least squares procedure (MCR-ALS) has been applied to resolve complex data from Raman microanalysis by means of a computer-assisted analytical procedure called Single Particle Analysis (SPA). The SPA – contrary to Raman mapping – provides data in which each single particle is assigned to a single spectrum, in the group with a statistically significant size. During the procedure, the relative contributions of individual compounds in the recorded Raman spectra have been specified. Grouping and relationship determination of the collected data have been performed by hierarchical cluster analysis (HCA) and principal component analysis (PCA). A new methodology is proposed to quantitatively determine the molecular composition and chemical mixing of single airborne particles based on the data from the automated Raman microspectrometry measurements.
Composition and estimate of daily mineral intake from samples of Brazilian rice Microchem. J. (IF 3.034) Pub Date : 2017-10-12 Iago José Santos da Silva, Ana Paula Silveira Paim, Maria José da Silva
Rice is one of the most produced and consumed cereals in the world, making the control of its chemical composition, especially of minerals, important. A method of rice digestion using nitric acid and hydrogen peroxide to determine metals (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn) using Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) was developed. The optimized conditions were established using a factorial design 23, obtaining the following digestion conditions as the most adequate: digestion time (20 min), concentration of HNO3 (8 mol L− 1) and H2O2 volume (2.5 mL). Recovery values ranging from 80 to 120% with RSD < 5.1% were obtained for most elements of interest and limits of detection of the method were in the range of 0.02 mg kg− 1 (Mn) to 5.6 mg kg− 1 (Ca). A table of metal composition for the different types of processed rice (white, parboiled and brown) was established through an analysis of 54 rice samples. Brown rice contributed significantly to the Recommended Dietary Allowances (RDA) of Mn (61%) and Mg (20%), parboiled rice with Cu (45%) and white rice with Mn (14%). In addition, the daily intake estimated through rice consumption, for all detected metals, was much lower than the Tolerable Upper Intake Level. The rice samples could be differentiated by their type of processing, based on their mineral composition using Principal Component Analysis (PCA).
Macro X-ray fluorescence scanning (MA-XRF) as tool in the authentication of paintings Microchem. J. (IF 3.034) Pub Date : 2017-10-16 Steven Saverwyns, Christina Currie, Eduardo Lamas-Delgado
Scanning macro X-ray fluorescence (MA-XRF) was evaluated as a means for the non-invasive study of two paintings to investigate their authenticity. The first painting, a still-life attributed to the 17th century Spanish painter Francisco de Zurbarán, was analysed both with point XRF analyses and MA-XRF. MA-XRF analyses facilitated the interpretation of the results, revealed a hidden painting and gave a clear answer on the question of authenticity. The second painting, attributed to the workshop or school of Pieter Paul Rubens, was investigated by MA-XRF alone. This revealed a hidden stamp of a canvas manufactory, which situated the painting a few hundred years later than originally supposed. In this last case MA-XRF results were supported by X-radiography and infrared reflectography (IRR). A brief comparison was made between MA-XRF and these traditional scientific imaging techniques, which were not able to detect the stamp. Moreover, it is suggested that in certain cases where for budgetary reasons X-radiographs cannot be made, MA-XRF images can sometimes suffice.
Cloud point extraction for simultaneous determination of 12 phenolic compounds by high performance liquid chromatography with fluorescence detection Microchem. J. (IF 3.034) Pub Date : 2017-10-03 Xingling Luo, Han Zheng, Zehua Zhang, Meixia Wang, Bingyi Yang, Limei Huang, Mei Wang
A sensitive method based on cloud point extraction was developed for the separation and preconcentration of 12 phenolic compounds (hydroquinone, resorcinol, catechol, phenol, β-naphthol, bisphenol A, α-naphthol, 4-tert-butylphenol, 4-tert-octylphenol, nonylphenol, octylphenol, and 4-n-nonylphenol) from environmental water samples for subsequent analysis by high performance liquid chromatography. The nonionic surfactant Tergitol 15-S-7 was chosen as the extractant. The analytes were detected using a fluorescence detector. Gradient elution was performed with a mobile phase mixture of acetonitrile and water at a flow rate of 1.0 mL min− 1. Various experimental parameters affecting the analytical performance were optimized in detail. Under the optimum conditions, the correlation coefficients were all above 0.997 and the limit of detection range for the analytes was 0.03 to 8.5 μg L− 1. The proposed approach was successfully applied to the determination of 12 analytes in environment water samples with good recoveries (88.7%–106%).
A novel analytical method for sensitive determination of lead: Hydrogen assisted T-shape slotted quartz tube-atom trap-flame atomic absorption spectrometry Microchem. J. (IF 3.034) Pub Date : 2017-10-23 Hümeysa Uslu, Çağdaş Büyükpınar, Tuğçe Unutkan, Hakan Serbest, Nevin SAN, Fatma Turak, Sezgin Bakırdere
A non-invasive in situ methodology to characterise the lacquers and metals from the Edo period Japanese armour Microchem. J. (IF 3.034) Pub Date : 2017-10-18 Maite Maguregui, Héctor Morillas, Iker Marcaida, Cristina García-Florentino, Isabel Ortiz de Errazti, Cristina Aransay, Juan Manuel Madariaga
Japanese armour is thought to have evolved from the armour used in ancient China and Korea. Few are the works dealing with the characterisation of the materials used to create this appreciate artworks and most of them are focused on the characterisation of the helmet. In this work we present for the first time an in situ non-invasive methodology to characterise the composition of both metals/alloys and lacquers used to create a Japanese armour from the Edo period (1603–1869) property of the Armoury Museum of Alava (Basque Country, Spain). The armour was in situ investigated, without the necessity of taking any sample, for its later conservation in the Restoration Service from the Provincial Council of Alava (Basque Country, Spain). Firstly, by means of the use of a hand-held energy dispersive X-ray fluorescence spectrometer (HH-ED-XRF), the elemental composition of the metals/alloys of the armour was evaluated. This analysis determined that the kabuto (helmet) and the dō (cuirass) were made of at least seven different materials including their main body and decorations. Apart from the elemental characterisation and by using a portable Fourier Transform infrared spectrometer, which implements a Diffuse Reflectance sampling interface (DRIFT), the nature of the lacquer used in the armour was also determined (urushi). Thanks to the penetrating analysis that can be achieved using the HH-ED-XRF the nature of the substrate used to lacquer the armour was also approached. Moreover, portable Raman spectroscopy also assisted DRIFT results in the identification of later interventions (nitrocellulose) done in the lacquered areas avoiding any sampling process and further analysis in the laboratory.
Optimum polyphenol and triterpene contents of Hedera helix (L.) and Scrophularia nodosa (L.): The role of powder particle size Microchem. J. (IF 3.034) Pub Date : 2017-10-21 Ali Zaiter, Loïc Becker, Elie Baudelaire, Amadou Dicko
The total polyphenolic and flavonoid contents, as well as the antioxidant free radical scavenging activity (DPPH test) of different sieved powders of Hedera helix (L.) and Scrophularia nodosa (L.), were assessed. Polyphenolic compound content varied significantly between different particle sizes (20–50; 50–100; 100–180; 180–315; > 500 μm). The intermediate classes (between 100 μm and 315 μm) exhibited the highest total polyphenol content with 28.3 mg gallic acid eq./g dry matter (DM), total flavonoid content (8.6 mg catechin eq./g DM) and antioxidant activity (23.5 Trolox eq. mg/g DM). The lowest values were observed for the unsieved powder of Hedera helix (L.), and > 500 μm classes of Scrophularia nodosa (L.). Liquid chromatography coupled with UV detector and mass spectrometry (LC-PDA-ESI/MS) allowed identifying and quantifying polyphenols, flavonoids, iridoids, and triterpene saponins. These latter were exclusively identified by mass spectrometry; unusable signals being recorded by UV measurements. Results showed that most of the compounds presented maximal concentrations in intermediate particle sizes (100 μm–315 μm).
Analysis of Serra d'Alto figuline pottery (Matera, Italy): Characterization of the dark decorations using XRF Microchem. J. (IF 3.034) Pub Date : 2017-10-27 L. Angeli, S. Legnaioli, C. Fabbri, E. Grifoni, G. Lorenzetti, J. Guilaine, V. Palleschi, G. Radi
During the Middle Neolithic (between 5000 and 4500 cal. BCE) the Serra d'Alto Culture was particularly widespread in Matera's territory and in Apulia region. Serra d'Alto pottery wares consist both of a very fine yellow paste—called figuline—decorated with patterns in black, and of a medium/coarse paste. In this paper, the X-ray Fluorescence (XRF) analyses of 102 samples of black painted decorated figuline pottery are reported. We analyzed sherds from six archaeological sites of Matera's area: Serra d'Alto, Trasano, Setteponti, Tirlecchia and Pipistrelli's cave, and Funeraria cave. The results show that a black pigment based on manganese has been used for the decoration of each of the Serra d'Alto samples. The exclusive presence of this material suggests a deliberate technological choice and defines a regular characteristic of Serra d'Alto pottery manufacturing. This study is part of an interdisciplinary project on painted pottery in the central and southern Italy, from Early to the Middle Neolithic period.
Environmental geochemical and spatial/temporal behavior of total and speciation of antimony in typical contaminated aquatic environment from Xikuangshan, China Microchem. J. (IF 3.034) Pub Date : 2017-10-21 Wenjing Guo, Zhiyou Fu, Hao Wang, Fanhao Song, Fengchang Wu, John P. Giesy
Since environmental geochemical behavior of antimony (Sb), especially Sb speciation in aquatic system were largely unknown, studies were conducted in various waters and sediments from the world's largest antimony mine area at Xikuangshan (XKS). Based on samples collection, total and speciation of Sb and several aquatic environmental parameters were determined in waters from river, well, reservoir, wastewater and sediments. Sb(V) was found as the predominant speciation in the waters and sediments. The environmental geochemical behavior of Sb speciations were mainly controlled by the process of oxidation and adsorption/combination with environmental matrix, mainly as Fe/Al (hydr)oxide, and oxidation may has higher priority than adsorption in the aquatic system. Spatial distribution of decreased Sb concentrations in some surface waters resulted from the dilution effect of river/reservoir/tributary water and adsorption of environmental matrix. The declined temporal distributions of Sb in waters compared with previous studies were attributed to several restoration measures and less mining/smelting activities in XKS. Results suggested that tailings heaps in mining region should arouse much attention for its potential release of Sb.
GC–MS and HPLC-ESI-QToF characterization of organic lipid residues from ceramic vessels used by Basque whalers from 16th to 17th centuries Microchem. J. (IF 3.034) Pub Date : 2017-11-05 Laura Blanco-Zubiaguirre, Erika Ribechini, Ilaria Degano, Jacopo La Nasa, Jose Antonio Carrero, Javier Iñañez, Maitane Olivares, Kepa Castro
This work is focused on the chemical characterization of the organic residues preserved in ceramic fragments that are suspected to have been used by the Basque whalers in the period from 16th to 17th Century to store whale oil. The lipid profiling along with the identification of biomolecular markers, makes possible to obtain information on the contents of the vessels and on the transformations undergone by the organic substances during the burial process. To achieve this goal, two complementary analytical techniques, High-Performance Liquid Chromatography - Electrospray Ionization - Quadrupole Time-of-Flight Mass Spectrometry (HPLC-ESI-QToF) and Gas Chromatography-Mass Spectrometry (GC–MS), were used not only to study the archaeological materials but also fresh whale oil products used as reference materials with the aim to detect potential diagnostic biomarkers. HPLC-ESI-QToF was used to identify triacylglycerols (TAGs) and study their distribution in the various samples, whereas GC–MS after suitable derivatization provided the fatty acid (FA) profile together with the detection of degradation compounds (dicarboxylic and dihydroxy fatty acids) and biomarkers related to marine commodities (isoprenoid acids). Samples of blubber from 5 different whale species belonging to the genus Balaenoptera (fin, sei and minke whale), Megaptera (Humpback whale) and Phocoena (harbour porpoise) were used as reference materials together with a sample of whale oil of unknown origin. The chemical results confirm the archaeological data regarding the vessels use as containers to store whale oil and indicate the whales from Balaenoptera genus as the most probable source of the oil.
Quantification of paramagnetic ions in solution using time domain NMR. PROS and CONS to optical emission spectrometry method Microchem. J. (IF 3.034) Pub Date : 2017-10-22 Flávio V.C. Kock, Maiara P. Machado, Geisamanda P.B. Athayde, Luiz A. Colnago, Lúcio L. Barbosa
Solutions containing paramagnetic ions (PMIs) have been widely used in several industrial and agricultural applications. Although the concentrations of these ions in solutions are very important, they are rarely checked due to the high cost of the measurements. In this paper, we demonstrate the viability of 2 MHz time-domain nuclear magnetic resonance (TD-NMR) relaxometer to quantify PMIs in solution. The method was used to quantify the concentration of Co2 +, Cr3 +, Cu2 +, Fe3 + and Mn2 + and is based on linear correlation between the transverse relaxation rate (T2− 1) of the hydrogens of water and PMIs concentration. The method was validated using inductively coupled plasma optical emission spectrometry (ICP-OES), which is the standard method for quantitative elemental analyses. The concentration of PMIs were analyzed between 0.5 and 10 mg·L− 1, with r2 ≥ 0.99 between the two methods. Although the limits of detection (LOD) and quantification (LOQ) of TD-NMR are several orders of magnitude higher than those of ICP-OES, they are in the range of concentration normally found in commercial applications. Therefore, this work demonstrate that TD-NMR can be an affordable alternative for certificate the concentration of PMIs concentration in small laboratory in industrial or agricultural facilities.
Large-volume sample stacking for the analysis of low molecular mass amines in steam water by CE using novel highly absorbing probe for indirect UV detection Microchem. J. (IF 3.034) Pub Date : 2017-10-28 Julia Malinina, Mikhail Kamencev, Kirill Tkach, Nina Yakimova, Irina Kuchumova, Leonid Moskvin
A rapid, simple, sensitive and ultrafast capillary electrophoretic method – large-volume sample stacking (LVSS) without a polarity switching step has been developed in this study for determining ammonia and 9 amines, including ethanolamine, cyclohexylamine, hydrazine, morpholine, triethanolamine, and dimethylamine in steam water and their degradation products, such as methylamine, ethylamine, diethanolamine, and ammonia. The background electrolyte (BGE) containing acridine as a probe was firstly used for indirect UV detection. Acridine was shown to be very beneficial for the determination of low molecular mass amines due to its high electrophoretic mobility and at the same time high molar absorption coefficient (ε252) of 1.7 ∗ 105. No laborious sample preparation was needed. Separation and detection was achieved in about 8.5 min for BGE containing acridine per sample. Limits of detection (LOD) using acridine were as low as 0.003 mg/L. The calibration plots showed good linearity over the concentration range from 0.01 to 1 mg/L for ammonia and the amines of interest for nuclear and thermal power plants. The proposed method was successfully applied to the determination of ethanolamine and cyclohexylamine in steam water samples obtained from thermal power plant and the analytical results were in good agreement with those obtained by reference ion chromatography (IC) method.
Determination of thallium in water samples using inductively coupled plasma optical emission spectrometry (ICP-OES) after ultrasonic assisted-dispersive solid phase microextraction Microchem. J. (IF 3.034) Pub Date : 2017-10-31 N. Raphael Biata, K. Mogolodi Dimpe, James Ramontja, Nomvano Mketo, Philiswa N. Nomngongo
A rapid and effective ultrasonic assisted-solid phase micro-extraction (UA-DSPME) was developed for the preconcentration of thallium in real water samples. The ZnO-ZrO2@AC composite functionalized with 1-(2-Pyridylazo)-2-naphthol (PAN) was used as an adsorbent and the target analyte was quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). The morphological, crystalline physical and chemical properties of the composite were characterized by scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscope (TEM) and X-ray powder diffraction (XRD). The two-level fractional factorial design and response surface methodology were used to optimize experimental parameters affecting the preconcentration procedure. Under optimum conditions, the enrichment factor (EF), limits of detection (LOD) and quantification (LOQ) were found to be 112, 0.25 ng L− 1, and 0.84 ng L− 1, respectively. Furthermore, intra-day and inter-day precisions expressed in terms of relative standard deviation (RSD) were found to be 2.4% and 4.3%, respectively. Moreover, the linear dynamic range was between LOQ and 350 μg L− 1 with the correlation coefficient of 0.9966.
Compositional study of Byzantine glass bracelets discovered at the Lower Danube Microchem. J. (IF 3.034) Pub Date : 2017-10-26 R. Bugoi, I. Poll, Gh. Mănucu-Adameşteanu, C. Pacheco, P. Lehuédé
Twenty three glass bracelets fragments of different colors and appearances excavated at Păcuiul lui Soare, Dobrogea, Romania and dated to the 10th–11th century AD were analyzed for their chemical composition using Particle-Induced X-ray Emission (PIXE) and Particle-Induced Gamma-ray Emission (PIGE) techniques at AGLAE accelerator of Centre de Recherche et de Restauration des Musées de France (C2RMF), Paris. Analytical data showed that all bracelets are soda-lime-silica glass of intermediate recipes, with compositional patterns between the natron and plant ash ranges, indicating practices of extensive glass recycling. Păcuiul lui Soare glass bracelets turned out to be similar in composition with the ones found in other nearby coeval sites, but also with bangles discovered in more remote Byzantine sites. The analyses revealed that the same technological choices have been made to produce the bracelets, namely they have been produced in workshops that had access to vitreous artefacts of different compositions, i.e. produced using distinct types of fluxes. Recycling seem to be a characteristics for all glass bangles produced in the Byzantine Empire at the end of the first millennium AD, regardless of their finding place and dating. As concerning the glass color, blue hues in Păcuiul lui Soare were induced by the presence of small amounts of cobalt (hundreds of ppm), while the green and black colors were correlated to high concentrations of iron. Opaque red glass stripes turned out to be rich in copper. The most likely candidate for the pale yellow pigment decorating the outer surfaces of several bracelets was identified as lead tin yellow. Producing these bangles by apparently indiscriminate procedures of glass re-melting involves a certain degree of ease and this might explain the discovery of such an outstanding number of glass bracelets in all the Byzantine sites from the Lower Danube.
Geometric optimisation of electrohydrodynamic fluid flows for enhanced biosensing Microchem. J. (IF 3.034) Pub Date : 2017-10-21 Alain Wuethrich, Christopher B. Howard, Matt Trau
New insights into the composition of Indian yellow and its use in a Rajasthani wall painting Microchem. J. (IF 3.034) Pub Date : 2017-11-03 Diego Tamburini, Charlotte Martin de Fonjaudran, Giovanni Verri, Gianluca Accorsi, Angela Acocella, Francesco Zerbetto, Amarilli Rava, Samuel Whittaker, David Saunders, Sharon Cather
The widespread occurrence of Indian yellow on an early 17th-century wall painting in Rajasthan (India) was initially indicated by photo-induced luminescence imaging of the painted scheme in the Badal Mahal within the Garh Palace (Bundi). The presence of the organic pigment was subsequently confirmed by HPLC-ESI-Q-ToF. The results of a multi-analytical study focusing on two samples from the wall painting and two reference pigments from the British Museum and National Gallery (London, UK) are presented here. The research focused on the possible causes for the different yellow/orange hues observed in the painting samples. Analysis of cross-sections with SEM-EDS revealed similar elemental composition for the Indian yellow paint layers, but different underlying layers, indicating a variation in painting technique. The composition of the Indian yellow samples was investigated by HPLC-ESI-Q-ToF with both positive and negative ionisation. In addition to euxanthic acid and euxanthone, a sulphonate derivative of euxanthone was found to be present in all samples, while relative amounts of the three components varied. Flavonoid molecules—morin, kaempferol, quercetin and luteolin—were also detected in one wall painting sample (characterised by a brighter yellow colour) and not in the sample that was more orange. The optical properties of the samples were characterised by photoluminescence spectroscopy in both solid state and aqueous solution. The contribution of each organic compound to the emission spectrum of Indian yellow in solution was also investigated by time-dependent density functional theory (TDDFT) calculations. Small differences in terms of spectral shift were observed in solid state experiments, but not in solution, suggesting that the spectral differences in the emission spectrum were mostly due to different contributions of solid-state arrangements, most likely driven by π-π stacking and/or hydrogen bonds. However, a slight difference at high energies was observed in the spectra acquired in solution and TDDFT calculations permitted this to be ascribed to the different chemical composition of the samples. Time-resolved measurements highlighted di-exponential lifetime decays, confirming the presence of at least two molecular arrangements. Py(HMDS)-GC–MS was also used for the first time to characterise Indian yellow and the trimethylsilyl derivative of euxanthone was identified in the pyrograms, demonstrating it to be a suitable marker for the identification of the pigment in complex historic samples.
Micro-Raman spectroscopy of rock paintings from the Galb Budarga and Tuama Budarga rock shelters, Western Sahara Microchem. J. (IF 3.034) Pub Date : 2017-11-03 Mercedes Iriarte, Antonio Hernanz, José María Gavira-Vallejo, Andoni Sáenz de Buruaga, Santiago Martín
Rock paintings of two recent discovered rock shelters, Galb Budarga and Tuama Budarga, from the southeastern area of the Western Sahara, Sahrawi Arab Democratic Republic, have been studied by micro-Raman spectroscopy and scanning electron microscopy coupled with energy dispersive X-ray spectrometry in order to characterize the composition of the materials present in the painting panels. An unusual white pigment has been used in the zoomorphic pictographs of the Galb Budarga shelter which main components are the anhydrite (CaSO4) polymorphs I and II. Red and orange zoomorphic figures and ancient Berber scripts have been painted in the Tuama Budarga rock shelter. Haematite (α-Fe2O3) is the main component of the paints used; amorphous carbon and different manganese oxides have also been detected. Accretions of gypsum (CaSO4·2H2O) and anhydrite have been observed on the shelter wall used to paint. α-Quartz (α-SiO2), albite (NaAlSi3O8), dolomite, CaMg(CO3)2, calcite (CaCO3) and traces of hydroxylapatite (Ca10(PO4)6(OH)2) have been identified in the rocks supporting the paintings of both sites. Layers of calcium oxalates, whewellite (CaC2O4·H2O) and weddellite (CaC2O4·(2 + x)H2O, x ≤ 0.5) cover the pictorial panels of these rock shelters. A microestratrigraphic study of the paint used in the Tuama Budarga shelter revealed that the pigment layer is bracketed between oxalate layers.
Metalloprotein and multielemental content profiling in serum samples from diabetic and hypothyroid persons based on PCA analysis Microchem. J. (IF 3.034) Pub Date : 2017-11-03 Ernesto R. Verni, Keaton Nahan, Alicia V. Lapiere, Luis D. Martinez, Raúl A. Gil, Julio A. Landero-Figueroa
Rapid determination of indium in water samples using a portable solution cathode glow discharge-atomic emission spectrometer Microchem. J. (IF 3.034) Pub Date : 2017-11-03 Wenchuan Zu, Yin Yang, Yu Wang, Xiaotao Yang, Cong Liu, Min Ren
Direct determination of calcium and phosphorus in mineral supplements for cattle by wavelength dispersive X-ray fluorescence (WD-XRF) Microchem. J. (IF 3.034) Pub Date : 2017-11-06 Diego Victor Babos, Vinícius Câmara Costa, Marco Aurelio Sperança, Edenir Rodrigues Pereira-Filho
The current study describes a simple and rapid method for the direct determination of Ca and P in mineral supplements for cattle by wavelength dispersive - X-ray fluorescence (WD-XRF). For calibration, solid standards obtained through a set of reference materials (RMs) of mineral supplements for cattle with concentrations of Ca ranged from 120 to 223 g kg− 1 (r = 0.9809) and P ranged from 29 to 95 g kg− 1 (r = 0.9957) were used. For Ca, the matrix-matching using the RM 18/03 diluted in Na2CO3: NaCl (1:1 w/w) in the range of 0–204 g kg− 1 (r = 0.9975) was also used as calibration strategy. The proposed method presented limits of detection of 47 mg kg− 1 for Ca and 36 mg kg− 1 for P using calibrations with RMs and 61 mg kg− 1 to Ca using matrix-matching calibration strategy. Accuracy was assessed by the analysis of four RM of mineral supplements for cattle. A statistical evaluation using student's t-test showed that there is no significant difference between the value obtained with the proposed method and the certified value, at 95% confidence level. The method was successfully applied and is a good alternative to conventional acid digestion routine analysis for determination of Ca and P in mineral supplements for cattle.
From macro to micro: An advanced macro X-ray fluorescence (MA-XRF) imaging approach for the study of painted surfaces Microchem. J. (IF 3.034) Pub Date : 2017-11-07 G. Sciutto, T. Frizzi, E. Catelli, N. Aresi, S. Prati, R. Alberti, R. Mazzeo
Fabric fiber sorbent extraction for on-line toxic metal determination by atomic absorption spectrometry: Determination of lead and cadmium in energy and soft drinks Microchem. J. (IF 3.034) Pub Date : 2017-11-14 Viktoria Kazantzi, Abuzar Kabir, Kenneth G. Furton, Aristidis Anthemidis
A novel simple and sensitive on-line flow injection (FI) fabric fiber sorbent extraction (FFSE) system adapted to flame atomic absorption spectrometry (FAAS) for automatic trace metal determination has been established. The FFSE platform is based on polyester fabric fibers coated with sol-gel poly-dimethylsiloxane (PDMS) packed into a microcolumn as sorbent packing material. The potentials of this new scheme were assessed for direct Pb(II) and Cd(II) determination in energy and soft drink samples. The on-line retention of target analytes on sol-gel coated fibers was carried out with sodium diethyl dithiocarbamate (DDTC), while elution was performed with methyl isobutyl ketone (MIBK). The effect of the main chemical and flow parameters on the sensitivity of the method was thoroughly studied. For a loading time of 90 s with a sampling frequency of 30 h− 1, enhancement factors of 167 and 40 and detection limits (3σ) of 1.6 and 0.3 μg L− 1 were obtained for Pb(II) and Cd(II) determination, respectively. The trueness of the developed method was estimated by analyzing a certified reference material and spiked tap water.
Determination of common ginsenosides in Kang'ai injection by aqueous two-phase extraction with deep eutectic solvents and HPLC-UV/DAD Microchem. J. (IF 3.034) Pub Date : 2017-11-14 Peng Li, Pengyun Zhao, Weijie Liu, Yifu Jiang, Wenjiao Wang, Longyue Bao, Yongri Jin, Xuwen Li
In this work, four kinds of deep eutectic solvents (DESs), composed of choline chloride (ChCl) and several alcohols, were synthesized and characterized by 1H NMR and FT-IR spectra. Based on DES (ChCl and 1,4-butanediol) and inorganic salt solution (dipotassium phosphate, K2HPO4), aqueous two-phase system (ATPS) coupled with high-performance liquid chromatography has been developed and applied. This method was used for the efficient extraction and determination of eight common ginsenosides (including ginsenoside Rg1, Re, Rf, Rg2, Rb1, Rc, Rb2 and Rd) in the traditional Chinese medicine injection named Kang'ai injection. To achieve optimum extraction performance, the experimental conditions were optimized, including type and amount of DES and salt, ultrasound time, temperature and pH value. In the dynamic linearity range, experimental results showed satisfactory recoveries of analytes ranging from 92.7–110.8% with the relative standard deviations (RSDs) ranging from 1.2–3.9%. It has been proved that DES-ATPS has great potential for determination of active ingredients in traditional Chinese medicine injection as well as samples in other analytical science field.
Elemental analysis as statistical preliminary study of historical musical instruments Microchem. J. (IF 3.034) Pub Date : 2017-11-14 G.V. Fichera, T. Rovetta, G. Fiocco, G. Alberti, C. Invernizzi, M. Licchelli, M. Malagodi
The history of bowed string instruments includes centuries of experimentation performed by violin makers with different manufacturing processes and several natural materials. The characterization of the material components can therefore often help researchers to identify the construction period of an instrument, its geographical origins or, if possible, the name of the violin maker. In a few cases, musical instruments, especially bowed ones, that were played frequently over time suffered severe damage (e.g. cracks, woodworms), and some parts of the instruments needed to be replaced to repair such damage. Gaetano Sgarabotto (1878–1959) and his son Pietro (1903–1990), two of the most eminent violin makers and restorers of the 20th century, collected many replaced parts in a group of fragments from musical instruments manufactured between the 16th and the 19th century by some of the most important Italian and European violin makers. In this work, non-invasive and micro-destructive analyses could be combined through portable X-ray fluorescence spectrometry (PXRF) and scanning electron microscopy (SEM) with an EDAX spectrometer (SEM-EDX) on 24 fragments of the Sgarabotto collection. Principal Component Analysis was applied to classify relics, highlighting the most relevant and particular elements in the dataset. The principle of transformation is the extraction of maximum variance for each successive new variable. This procedure leads to the separation of valuable information from noise and to the selection of a small number of influential and statistically significant variables. The application of this analytical procedure leads to (i) assessing the existence of elemental markers of specific historical periods and/or manufacturing areas; (ii) characterizing the materials that the layers of a selected group of fragments are composed of; (iii) identifying any correlations between different fragments.
Comparing chemometric and Langmuir isotherm for determination of maximum capacity adsorption of arsenic by a biosorbent Microchem. J. (IF 3.034) Pub Date : 2017-11-14 J.C. Vieira, L.C. Soares, R.E.S. Froes-Silva
Comparative study of magnesium and calcium in Codonopsis pilosula samples detected by CF-LIBS and LCGD-AES Microchem. J. (IF 3.034) Pub Date : 2017-11-20 Yongqiang Wang, Maogen Su, Duixiong Sun, Chao Wu, Xiaomin Zhang, Quanfang Lu, Chenzhong Dong
Emission spectra of Codonopsis pilosula samples from nine habitats were measured using calibration-free laser-induced breakdown spectroscopy (CF-LIBS) and liquid cathode glow discharge-atomic emission spectrometry (LCGD-AES). Based on the measured spectra, the elements in the samples and the corresponding compositions were determined, and the results were compared with those from inductively coupled plasma mass spectrometry (ICP-MS) by using the Mg/Ca ratios. In addition, an estimation of the plasma parameters was considered and the stability of the results from both analytical methods was discussed.
Non-aqueous phase hydride generation and determination of trace bismuth by atomic fluorescence spectrometry Microchem. J. (IF 3.034) Pub Date : 2017-11-21 Luqiong Chen, Zirong Lei, Kan Hu, Shengchun Yang, Xiaodong Wen
Hydride generation (HG) of bismuth was accomplished in non-aqueous media by using solid reductant of potassium borohydride (KBH4) as a derivation reagent. The riched micelle phase of surfactant Triton X-114 was used as the non-aqueous media for the chemical vapor generation (CVG), and atomic fluorescence spectrometry (AFS) was used for the elemental determination. The analyte ions were firstly extracted into the non-aqueous media from the bulk aqueous phase of analyte/sample solution via a rapid cloud point extraction (RCPE) process and then directly mixed with the solid reductant KBH4 to generate volatile bismuth hydride in a specially designed reactor, which was then rapidly transported to a commercial atomic fluorescence spectrometer for detection. Under the optimal conditions, the limit of detection (LOD) for bismuth was 0.08 μg/L. Compared to conventional HG-AFS, the efficiency of non-aqueous phase HG accomplished using solid reductant and the analytical performance of the developed method was considerably improved.
Experimental evaluation of the detection methods of thermal ionization mass spectrometry for isotopic analysis of ultra-trace level uranium Microchem. J. (IF 3.034) Pub Date : 2017-11-20 Jong-Ho Park, Kahee Jeong
Thermal ionization mass spectrometry (TIMS)-based isotopic analysis of various amounts of uranium was performed to experimentally evaluate three detection methods: multi-dynamic, dynamic, and static. The analytical performances of the detection methods in terms of accuracy, precision, and measurement uncertainty were not significantly different for the analysis of 1 ng and 100 pg of uranium, whereas using ion counters for detecting 238U+ signal intensity slightly enhanced the performance for analyzing 30 pg of uranium. The static detection method improves the analysis performance for 5 pg and 1 pg of uranium due to the higher detection sensitivity of ion counters than faraday cups, elimination of ion signal drift, and increased number of valid data sets in a measurement. The experimental evaluation of the detection methods provides a basis for optimizing the detector configuration of TIMS in terms of the amount of uranium in samples. The uranium isotope ratios in microparticles measured by the static method agreed well with the certified values; this verified the applicability of the static detection method to particle analysis of environmental samples required for nuclear safeguards.
Evaluation of time-gated Raman spectroscopy for the determination of nitric, sulfuric and hydrofluoric acid concentrations in pickle liquor Microchem. J. (IF 3.034) Pub Date : 2017-11-20 Bryan Heilala, Ari Mäkinen, Ilkka Nissinen, Jan Nissinen, Anssi Mäkynen, Paavo Perämäki
The focus of this study was to assess the feasibility of time-gated Raman spectroscopy for stainless steel pickle liquor acid quantification. Pickle liquor is used for dissolving metal surface impurities during the pickling process. The pickle liquor samples consisted mainly of 11–89 g/L HNO3, 20–160 g/L H2SO4, 5–57 g/L HF and stainless steel residue. Raman peaks correlating with the different acids were identified in both aqueous and pickle liquor solutions. The linearity between Raman scattering intensity and acid concentration was studied. Multivariate PLSR calibration for pickle liquor HNO3, H2SO4 and HF quantification was also investigated. Time-gated Raman spectroscopy was found to be a promising technique for pickle liquor HNO3 and H2SO4 quantification.
Elucidation of mechanism involved in adsorption of Pb(II) onto lobeira fruit (Solanum lycocarpum) using Langmuir, Freundlich and Temkin isotherms Microchem. J. (IF 3.034) Pub Date : 2017-11-16 Cleide S.T. Araújo, Ione L.S. Almeida, Hélen C. Rezende, Suzana M.L.O. Marcionilio, José J.L. Léon, Túlio N. de Matos
This manuscript entitled “Elucidation of adsorption mechanism of Pb(II) onto lobeira fruit (Solanum lycocarpum) using a Langmuir, Freundlich and Temkin isotherms” by Cleide Sandra Tavares Araújo et al. describes the sorption potential of lobeira fruit (Solanum lycocarpum) for removing Pb(II) from aqueous solution using a factorial experimental design as optimization strategy and Langmuir, Freundlich and Temkin models have been used to fit adsorption isotherms. The Solanum lycocarpum known popularly as “lobeira-do-cerrado”, wolf fruit or “jurubebão”, is a lignocellulosic typical species of the “cerrado” (kind of Brazilian savannah), with wide distribution, mainly in anthropized areas, has been little explored for adsorption studies. The optimization using a factorial design enabled the optimization of the procedure to be carried out with a reduced number of experiments, thus requiring a lower quantity of reagents and showed has advantages, such as, the low cost of sorbent, high efficiency and the minimization of chemical sludge. So allowed the adsorption of lead by lobeira fruit an inexpensive and easily available raw material may be used for different industrial applications to lower the cost of wastewater treatment and has potential applications for the removal of Pb(II) from wastewater. The sorbent is an alternative material for chemical remediation and is economic and environmental friendly.
Determination of iodine in plants by ICP-MS after alkaline microwave extraction Microchem. J. (IF 3.034) Pub Date : 2017-10-13 Ana Jerše, Radojko Jaćimović, Nina Kacjan Maršić, Mateja Germ, Helena Šircelj, Vekoslava Stibilj
Iodine is an essential element, important for normal thyroid function. Due to the frequency of health problems associated with its insufficient intake, new or additional sources of iodine have to be investigated. One of them could be iodine enriched plants. Before introduction into the human diet, the iodine content must be known as precisely as possible. A method of iodine determination in various plant samples by inductively coupled plasma mass spectrometry (ICP-MS) after alkaline microwave extraction was optimized. Among the tested ratios between TMAH and water, the ratio 1:5 was found to be optimal, using the following temperature program: 20 min ramp to 200 °C and 5 min hold on 200 °C. For measurements, 0.1% TMAH solution was chosen as optimal, using helium in the collision cell. A calibration line, for which standards were prepared in 0.1% TMAH, can be used for quantitative determination of iodine content. Measurement uncertainty was estimated to be around 30% for samples with low iodine content (around 0.2 μg I/g) and below 7% for samples with higher iodine content (0.7 μg I/g). Detection limits were 20 ng/g of sample or less and good repeatability of the measurements and linearity over a wide concentration range were found. The results obtained by the optimized method were compared to those obtained with an independent method (k0-INAA), and they showed very good agreement, proving the accuracy of the determination by ICP-MS. Finally, iodine content was determined in samples with different matrices: pea seeds, pumpkin seeds and buckwheat achenes, from plants foliar sprayed with iodide or iodate solutions at the time of blooming.
Dynamic reaction cell inductively couple plasma-mass spectrometry optimization for seawater analysis Microchem. J. (IF 3.034) Pub Date : 2017-11-21 Eva Soriano, Vicent Yusà, Agustín Pastor, Miguel de la Guardia
A direct method for dynamic reaction cell inductively coupled plasma- mass spectrometry (DRC-ICP-MS) trace mineral elements determination in seawater was optimized by Experimental Statistical Design. Five instrumental parameters, such as radiofrequency, sample, nebulizer and reaction gas flows, rejection parameter q and axial field voltage were studied. A Plackett-Burman design was used for screening the most important parameters and the most significant ones were optimized with a Central composite design. Fifteen elements and different isotopes for some of these were considered through the study. The optimization was achieved by using three different reaction gases (NH3, CH4 and O2). The optimized method was used for the quantification of trace minerals in a certified seawater sample. The standard mode was adequate for the quantification of those elements that have a reduced number of interferences like 111Cd and 238U. However, the best results were obtained employing ICP-MS in NH3-DRC mode which allowed the simultaneous determination of elements like 51V, 55Mn, 58Ni, 68Zn and 238U, which can be determined in the reference sample with an accuracy error lower than 10% and 95Mo determined with an accuracy error of 15%. The use of CH4-DRC was restricted to quantify 111Cd with an error of 16%. The use of O2-DRC was suitable for determining 55Mn, 66Zn with errors lower than 3% and 51V, when monitored it in oxide form 67VO, with an accuracy error of 2%. O2-DRC is the single DRC mode that allowed a satisfactory quantification of 75As, with an error of 33% for a very low concentration, compared to other analysis mode in the direct analysis of seawater. Additionally Pb can be quantitatively recovered from spiked samples using NH3 and O2-DRC modes.
Enrichment of scandium by carbon nanotubes in the presence of calcium matrix Microchem. J. (IF 3.034) Pub Date : 2017-11-21 Mateusz Pęgier, Krzysztof Kilian, Krystyna Pyrzyńska
The sorption behavior of Sc(III) on oxidized carbon nanotubes (CNTs) for the separation and preconcentration of trace amounts of scandium ions from aqueous solutions was investigated. The mechanism of separation and the effects of pH, flow rate, sample volume and interferences, with special focus on calcium, on the recovery of Sc were systematically studied and optimized. Generally, the sorption of scandium increases with increasing pH. For pH in the range of 2.5–5.5 the sorption of Sc(III) onto CNTs is quantitative, but its removal in the pH range of 1–3.5 is mainly attributed to sorption, while at pH > 4 there is overlap with the precipitation curve, indicating insignificant sorption. The adsorbed amount of Sc(III) at pH 2.0 was 42.0 mg g− 1. The procedure was applied to the enrichment of scandium with ICP-OES detection for natural water analysis with a preconcentration factor of 250 and a detection limit (3σ) of 0.05 μg L− 1.
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