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Feasibility of high-resolution continuum source flame molecular absorption spectrometry for silicon determination in organic solutions via the SiO molecule
Journal of Analytical Atomic Spectrometry ( IF 3.1 ) Pub Date : 2018-01-10 00:00:00 , DOI: 10.1039/c7ja00360a
Zofia Kowalewska 1, 2, 3, 4, 5
Affiliation  

In this work, for the first time, Si determination via absorption by its diatomic molecule is proposed. High-resolution continuum source flame molecular absorption spectrometry (HR-CS FMAS) was applied with SiO as a target molecule generated during aspiration of xylene solutions of organic Si compounds into an air–acetylene flame. The registered absorption spectra composed of many, primarily well-resolved, rotational lines that belong to various sequences of the X1Σ+ → A1Π electronic transition of the SiO molecule. To select the spectral range for analysis, sequential measurements in the area of the most intensive SiO molecule absorption were executed. Under the selected conditions (spectral range in the vicinity of the 230.150 nm rotational line, iterative background correction and 5 pixels for analyte signal evaluation) the characteristic concentration of Si determination is 14.9 mg L−1 for octamethylcyclotetrasiloxane and 3.2 mg L−1 for hexamethyldisiloxane, while the detection limit is 0.92 mg L−1 and 0.20 mg L−1, respectively. The integration of absorbance for selected pixels belonging to various rotational lines improves detectability only insignificantly. The option of integration of absorbance of pixels belonging to the single rotational line is preferable due to the lack of overlaps by lines from interferents (Ni, Fe, S). Under the selected conditions, no additional signals were distinguished for solutions containing N or P. The effect of chemical character due to the competition of S to form the SiS molecule was not observed. On the other hand, even though the investigated 230.150 nm line is located between two rotational CS lines, some overlapping of the spectra of SiO and CS molecules was observed. Least squares background correction (LSBC) was helpful to overcome the interference. The detectability of the proposed method of Si determination is about one order of magnitude worse than for the appropriate atomic absorption method. However, the possibility for usage of ordinary air–acetylene flame instead of N2O–C2H2 flame is very attractive. The achieved detectability of Si determination is better than in the case of literature data for all the other elements determined using HR-CS FMAS. Volatile organic compounds are recommended for the generation of reference spectra of diatomic molecules in HR-CS MAS.

中文翻译:

高分辨率连续谱源火焰分子吸收光谱法通过SiO分子 测定有机溶液中硅的可行性

在这项工作中,在第一次,硅判定经由通过其原子分子吸收提出。高分辨率连续体源火焰分子吸收光谱法(HR-CS FMAS)应用于SiO作为目标分子的过程中,该目标分子是在将有机Si化合物的二甲苯溶液吸入到空气-乙炔火焰中时产生的。许多构成的注册吸收光谱,主要是良好分辨属于X的各种序列,旋转线1 Σ + →A 1SiO分子的π电子跃迁。为了选择要分析的光谱范围,在最密集的SiO分子吸收区域进行了连续测量。在所选条件下(230.150 nm旋转线附近的光谱范围,迭代背景校正和5个像素用于分析物信号评估),Si的特征浓度对于八甲基环四硅氧烷为14.9 mg L -1,对于六甲基二硅氧烷为3.2 mg L -1,而检出限为0.92 mg L -1和0.20 mg L -1, 分别。属于各种旋转线的选定像素的吸光度积分仅微不足道地改善了可检测性。由于不存在来自干扰物(Ni,Fe,S)的线的重叠,因此优选选择属于单个旋转线的像素的吸收率的积分的选择。在选定的条件下,对于包含N或P的溶液,没有其他信号被区分。未观察到由于S竞争形成SiS分子而引起的化学特性影响。另一方面,即使所研究的230.150nm线位于两条旋转的CS线之间,也观察到了SiO和CS分子的光谱的一些重叠。最小二乘背景校正(LSBC)有助于克服干扰。所提出的硅测定方法的可检测性比适当的原子吸收法差约一个数量级。但是,可以使用普通的空气-乙炔火焰代替N2 O–C 2 H 2火焰非常吸引人。对于使用HR-CS FMAS测定的所有其他元素,实现的Si测定的可检测性优于文献数据的情况。建议在HR-CS MAS中使用挥发性有机化合物生成双原子分子的参考光谱。
更新日期:2018-01-10
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