Quantifying C10-C13 Polychloroalkanes in Environmental Samples by High-Resolution Gas Chromatography/Electron Capture Negative Ion High-Resolution Mass Spectrometry

Document Type

Article

Publication Date

7-15-1997

Publication Title

Analytical Chemistry

Volume

69

Issue

14

First Page

2762

Last Page

2771

Abstract

A method for quantifying C10-C13 polychloroalkanes (PCAs) in environmental samples by high-resolution gas chromatography/electron capture negative ion high-resolution mass spectrometry in the selected ion monitoring (SIM) mode is presented. The molecular compositions of commercial PCAs and of PCA-containing extracts from environmental samples are first determined by monitoring [M - Cl]- ions of specific m/z value corresponding to formula groups present and by assuming that the integrated ion signals are proportional to molar concentration weighted by the number of chlorine atoms in the formula group. For quantitative measurement, one specific m/z peak is selected for each analyte and its SIM response is integrated. The integrated SIM responses have a linear dependence upon amount of PCA injected over the range 0.5-500 ng. An analytical protocol is then described. High-resolution (∼12 000 resolving power) mass spectrometry is shown to be desirable to eliminate self-interferences between PCAs at low resolving power (∼1000) and potential interferences from technical chlordane, toxaphene, PCBs, and other organochlorine pesticides. Extraction recoveries of PCAs from fish averaged >80%. The analytical detection limit is ∼60 pg of injected PCA, at a signal-to-noise ratio of 4:1, while the method detection limit was 23 ng/g. As illustrations of the application of the technique to "real world" problems, PCA levels in biota and sediment samples from the mouth of the Detroit River (MI) are reported to be in the 0.3-1.2 μg/g range.

DOI

10.1021/ac961244y

ISSN

00032700

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