Feasibility of high-resolution continuum source flame molecular absorption spectrometry for silicon determination in organic solutions via SiO molecule

Zofia Kowalewska

Abstract

In this work, for the first time, Si determination via absorption by its diatomic molecule has been proposed. The high-resolution continuum source flame molecular absorption spectrometry (HR-CS FMAS) has been 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 compose of many, mainly well-resolved, rotational lines, which belong to various sequences of the X1+→A1electronic transition of the SiO molecule. To select 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) characteristic concentration of Si determination is 14.9 mg L-1 for octamethylcyclotetrasiloxane and 3.2 mg L-1 for hexamethyldisiloxane, while 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 interferents lines (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 competition of S to form SiS molecule was also not observed. On the other hand, even though the investigated 230.150 nm line is located between two rotational CS lines, some overlapping of SiO and CS molecules spectra was stated. Least square 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 of 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 can be recommended for generation of reference spectra of diatomic molecules in HR-CS MAS.
Author Zofia Kowalewska IB
Zofia Kowalewska,,
- Insitute of Civil Engineering
Journal seriesJournal of Analytical Atomic Spectrometry, ISSN 0267-9477
Issue year2018
Vol33
Pages260-273
Publication size in sheets0.5
Keywords in Polishoznaczanie krzemu; wysoko-rozdzielcza absorpcyjna spektrometria cząsteczkowa z ciągłym źródłem promieniowania; HR-CS; HR-CS MAS; tło strukturalne; LSBC; interferencje spektralne; płomień.
Keywords in EnglishSilicon determination; High-resolution continuum source molecular absorption spectrometry; HR-CS; HR-CS MAS; Structured background; LSBC; SiO; Spectral interferences; Flame.
DOIDOI:10.1039/C7JA00360A
Languageen angielski
Score (nominal)35
ScoreMinisterial score [Punktacja MNiSW] = 35.0, 17-01-2018, ArticleFromJournal
Ministerial score (2013-2016) [Punktacja MNiSW (2013-2016)] = 35.0, 17-01-2018, ArticleFromJournal
Publication indicators WoS Impact Factor [Impact Factor WoS]: 2016 = 3.379 (2) - 2016=3.205 (5)
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