Sulfur-containing compounds are the most abundant compounds in crude oil. Sulfur in liquid fuel oil leads to the emission of sulfur oxides and sulfate particulate matter which not only endangers health and community property but also reduces the life of the catalysts and engines due to corrosion. Various methods, with a high level of precision and sensitivity, have been developed to analyze sulfur-containing. On the other side, the removal and characterization of sulfur-containing compounds in crude oils and petroleum products have great importance, not only for the downstream refining process, control/optimization, and environmental compliance but also for upstream geochemical studies for exploration and production. This review summarizes the analytical strategies and some of the most important and promising technologies for the removal of sulfur from oil.

Water bodies cover approximately 70% of the earth´s surface, making them ecosystems with a high environmental value and the habitat for numerous species of flora and fauna. Emerging pollutants (EPs) are ubiquitous anthropogenic compounds of environmental concern that can be found at different concentration levels in matrices such as sediment, water and aquatic biota. In addition, EPs can be bioaccumulated and biomagnified, inducing adverse effects on biota, and posing a risk to humans when contaminated biota is consumed. Unlike abiotic matrices, the occurrence of EPs in aquatic biota has not been widely studied. This is probably because their complexity, due to the presence of lipids, proteins and other organic compounds, makes the extraction and analysis of EPs difficult. This review gathers the most relevant analytical methods published between 2014 and 2019, comparing them and evaluating their strengths and weaknesses. It is intended to provide a better understanding of the development of new and improved methods, and to be a reference for researchers who are looking for the best methodology for their studies.

In this article, we have critically overviewed some interesting articles published in 2015-2019 about the use of the nanosorbents for the extraction of emerging organic contaminants (EOCs) from various environmental samples. Properties, advantages, disadvantages, and the applicability of different categories of nanosorbents used for the extraction of EOCs are evaluated and discussed. The potential applications of these nanomaterials as adsorptive phase in solid-phase extraction (SPE) based techniques are reviewed.

Ultraviolet filters (UV Filters) are compounds that are widely employed in personal care products such as sunscreens to protect the skin from sun damage, but they are also added to other products, such as food packaging, plastics, paints, textiles, detergents, etc. The continuous use of these products causes the release of a substantial amount of these products into the marine environment through direct input or wastewater discharge, and thus they are becoming an important class of contaminants of emerging concern. A correlation between their occurrence and different negative effects on marine biota has been reported. Taking into account all the possible impacts on the environment, knowledge of their presence and distribution in the different compartments of the ecosystems, ranging from waters and sediments to aquatic organisms, which potentially suffer from bioaccumulation and biomagnification processes, is essential. High concentrations of ultraviolet filters have been found in samples collected from across the entire planet, even in polar regions, revealing their global distribution. Therefore, interest in the sensitive determination of ultraviolet filters in several marine matrices has increased. In this article, an overall review of the more recently reported analytical chemistry methods for identifying and quantifying these compounds in marine environmental samples is presented. We compare and discuss the potential advantages and disadvantages of every step involved in the analytical procedure, including the pre-treatment, treatment and extraction processes that are required to avoid matrix effects. Moreover, we describe the worldwide occurrence and distribution of those most important UV filters.

The application of nanotechnology has become inevitable in almost all sectors such as pharmaceuticals, food and beverages, electronics, transport, etc. The continuous development in the area has led to the emergence of the polymer nanocomposites. The polymer nanocomposites due to their improved mechanical, thermal, electrical, optical, and magnetic properties are widely used in various fields and slowly they have become an integral part of our life. As the application of polymer nanocomposite is going to be inexorable in the near future, this review aims to provide some insight on the need for the polymer nanocomposites, their basic classification, and their manufacturing methods. The study also outlines the analyses that are required to characterize the polymer nanocomposites. Further, the study discusses the existing application of polymer nanocomposites in various fields. As the polymer nanocomposites are going to play a major role in the field of waste water treatment for the years to come, the study has also attempted to shed some light on the application of nanocomposites in water purification.

Pollution of coastal areas play an important role in anthropocentric issues. Thus, several analytical tools were developed and optimized in recent years aiming to improve the acquisition of good quality chemical data. Despite these efforts, assessments of the environmental occurrence of hazardous chemicals in coastal regions are often biased by poorly planned sampling campaigns. In coastal zones, the influence of local contamination sources and environmental factors (such as coastal currents, tides, estuarine discharges, depth and luminosity) should be carefully considered before establishing a sampling grid. Moreover, the wrong selection of the environmental matrix to be analyzed, especially by multiresidue methods which include analytes with different physicochemical properties, has also been an important source of bias in many published papers. This critical review provides an overview of the key-factors to be considered during the planning and execution of sampling campaigns seeking to identify and quantify contaminants in environmental samples obtained in coastal areas. Further, a discussion on a more suitable and cost-effective sampling design, based in recent advances, is also presented.

In this review, we focus on the status of the monitoring of polycyclic aromatic hydrocarbons (PAHs) in ambient air as well as in living (indoor) and working environments in Africa from 2000 to 2018. This is important as PAHs are ubiquitous in the environment and are known to be potentially carcinogenic. Aspects of sampling such as collection media for particle bound and gaseous PAHs are discussed. The efficiency and basic quality assurance data of commonly employed extraction techniques for separating target PAHs from sampling media using conventional solvent-based and emerging solvent-free approaches were also evaluated. Polyurethane foam and quartz fiber filters are generally the most commonly used collection media for gaseous and particle bound PAHs, respectively. A wide range of total PAH concentrations in ambient air has been reported across the continent of Africa, with the highest levels found at sampling sites close to high density traffic and industrial areas. A rapidly increasing population, commercial and industrial development, poor urban transportation infrastructure and the use of low quality oil products were the main causes of high total gas and particulate PAH concentrations (1.6–103 μg/m3) in West African port cities such as Cotonou, Benin. With regards to indoor environments, gas phase PAHs were detected at the highest total concentrations in rural areas ranging from 1 to 43 μg/m3 in Burundi with naphthalene being the most prevalent. Firewood burning was the major emission source in most developing countries and resulted in benzo[a]pyrene concentrations above the European permissible risk level of 1 ng/m3.

Antiviral drugs are a therapeutic class of medicines that have garnered interest among the public around the globe. High prescription and consumption rates, seasonal peak emissions due to frequent outbreaks of influenza, and important spatial distribution in areas where a large part of the population suffers from HIV are reported. The environmental impact of several antiviral drugs, may be worrisome, given their high bioactivity, insufficient removal with conventional wastewater treatment methods, limited knowledge on their fate and behavior as well as uncontrolled landfill of waste especially in some developing countries. Antiviral drugs that are administered to several hundreds of milligrams in human to achieve the desired efficacy are even more intriguing. To date, antivirals are far less documented and lack systematic investigation, with the data about their occurrence, fate and ecotoxicological effects to be scarce. The number of single-class analytical methods focusing on antiviral drugs in environmental matrices is small, and the provided analytical characteristics such as the limits of detection/quantification are not always low enough to enable trace analysis. There is also an urgent need to expand the number of the antiviral drugs included in multi-residue analytical methods, since less than 50% of the approved ones have been investigated in the environment. Sensitive and reliable analytical methods should be applied in order to estimate the potential hazards posed by the environmental occurrence and persistence of antiviral drugs. This review aims to discuss the analytical strategies employed to determine antiviral drugs in wastewaters, surface waters, groundwater, and drinking water, after a thorough literature survey. The ultimate goal is to establish the state-of-the-art and future challenges, from an analytical point of view.

This paper offers a critical review from classical to new perspectives of advanced oxidation processes (AOPs) coupled to two- and multi-way calibration strategies based on multivariate curve resolution – alternating least-squares (MCR-ALS) and parallel factory analysis (PARAFAC) with various analytical techniques to monitor the degradation of contaminants in environmental samples. It focuses on the generation of highly reactive hydroxyl (HO•) radicals (classical AOPs with emphasis on Fenton, photo-Fenton and ozonation processes) and emerging reactive sulphate (SO4•−) radicals (new perspectives of AOPs) for effective degradation of recalcitrant compounds. Other new perspectives of AOPs were also addressed, namely semiconductor photocatalysis (TiO2/UV), combination of processes involving at least one AOP (hybrid or single-step processes and sequential or two-step processes), novel advanced electrochemical oxidation technologies (electro-Fenton and electro-photo-Fenton) and nanocatalytic heterogeneous Fenton technology with high specific surface area. Literature reports since 2008 for real applications in the environmental remediation based on AOPs (from classical to new perspectives) coupled to PARAFAC and MCR-ALS with first-, second- and third-order data were reviewed and the improvements obtained were briefly discussed. The two- and multi-way calibration strategies allow one the successful decomposition of first-, second- and third-order data collected from different analytical techniques. Therefore, the respective profiles obtained allowed qualitative (spectral profiles) and quantitative (concentration profiles) analysis of complex samples during the degradation of contaminants through the second-order advantage. Finally, trends of future research directions for AOPs coupled to various analytical techniques and advanced chemometric models were provided.

Ammonia nitrogen, consisting of un-ionized ammonia and ammonium, is a key parameter for studying the nitrogen cycle and indicating water quality. The measurement of these parameter concentrations is vital for the adequate monitoring of aquatic environments. Here, we review studies that focus on analytical methods for determining ammonia nitrogen in natural waters that were published between 2014 to mid-2019. These methods include spectrophotometric, fluorometric and electrochemical methods, and the features of these different analytical methods are reviewed. In addition, the outlook for future development is discussed.

Polycyclic aromatic hydrocarbons (PAHs) are a large category of ubiquitous persistent environmental pollutants, some of them have strong carcinogenicity to human and animals. These pollutants can easily enter the river through multiple ways including rainfall, dry deposition and water washout, and deposit in the sediment. However, it is easy for them to re-enter the river water and pollute water sources, as well as aquatic animals and plants, bringing potential harm to human health. Therefore, it is requisite to accurately analyze the PAHs in sediment. In this review, the analytical methods of PAHs in sediment, focused on the methods of sample extraction, purification, concentration and determination, are summarized.

Atmospheric pressure chemical ionization (APCI) was primarily applied as the ion source for liquid chromatography-mass spectrometry (LC–MS). While APCI started to be used in gas chromatography-mass spectrometry (GC–MS) in 1970s, GC-APCI-MS was not widely used until recently. As a soft ionization technique, APCI provides highly diagnostic molecular ions, which is favored for the wide-scope screening. With the capability of tandem mass spectrometry (MS/MS), GC-APCI-MS methods with high sensitivity and selectivity have been developed and applied in the analysis of persistent organic pollutants (POPs) in environment and biological samples at trace levels. The present review introduces the history of the APCI source, with emphasis on mechanisms of ionization processes under the positive and negative ionization modes. Comparison between GC-APCI-MS and GC–MS with traditional electron ionization (EI) and chemical ionization (CI) are provided and discussed for selectivity, sensitivity and stability for the analyses of POPs. Previous studies found that the GC-APCI-MS methods provided limits of detection (LODs) around 10–100 times lower than other methods. An overview of GC-APCI-MS applications is given with the discussions on the advantages and drawbacks of various analytical methods applied for the analyses of POPs.

Off-target deposition is one of the major routes of pesticide entry into the environment. Several studies have been carried out employing different tracers in an attempt to estimate pesticide deposition in the environment. This paper, in contrast, reviews different off-target sampling methods using the pesticide active ingredient. A critical analysis has been conducted on the sampling methods as applied to (a) pesticides of different volatilities, (b) samplers constructed using different materials, and (c) global distribution of the studies carried out on different pesticides using these samplers. In the last twenty years, pesticide deposition sampling has been carried out using various samplers such as chromatography paper, glass and plastic petri dishes, glass microscope slides, stainless steel rods and discs, amongst others. Of these, most studies have reported the use of chromatography paper because of the numerous advantages that it possesses, including protecting the pesticides from photodegradation and volatilisation. Air dispersion software models applied to pesticide deposition have tended to either over-predict or under-predict the amount of surface deposition resulting from pesticide spray drift. In conclusion, more work needs to be done to standardise pesticide deposition monitoring methods, including the choice of the most appropriate sampler for a particular situation, in order to obtain comparable and accurate data.