Selective Gas Chromatography Mass Spectrometry Method for Ultratrace Detection of Selenocyanate

Abstract

The recent interest in the determination of selenocyanate (SeCN–) in wastewater systems has spurred the development of analytical methods for its determination at the ultratrace level. Since most of the current procedures require complex and costly instrumental configurations, we have developed a simple and rapid gas chromatography tandem mass spectrometry (GC/MS/MS) method able to detect SeCN– in water samples with a LOD of 0.1 ng/g Se. A 1 mL volume of aqueous sample was buffered with sodium bicarbonate and treated with triethyloxonium tetrafluoroborate for conversion of the analyte into volatile EtSeCN. The derivatization yield was higher than 90%, and it could tolerate concentrations of chloride or sulfate up to 2%. The EtSeCN was extracted in chloroform and could be detected in electron ionization and also in negative chemical ionization mode with a further gain in signal-to-noise ratio by a factor of 2. The method was applied for the analysis of natural waters with quantitation of SeCN– in the low ng/g region. The Se13C15N– internal standard could be used for isotope dilution. Quantitative spike recoveries of 1 ng/g Se were obtained from seawater and river water, and 1 ng/g Se could be quantified within a standard uncertainty of 15%.

Atomic spectrometry update – a review of advances in environmental analysis

“…The method LOD was 0.3 mg L À1 , sufficient to quantify Sn species in samples from the Caspian Sea, a local river and waste waters. Although GC-MS methods for the determination of elemental species in water samples have existed for many years, only recently has modern instrumentation been capable of LODs at the level routinely achievable by GC-ICP-MS. Selenocyanate was quantied 70 in waste water by GC-MS/MS aer derivatisation with triethyloxonium tetrauoroborate, to generate volatile ethylSeCN, and by back extraction into chloroform. The LOD for Se was 0.1 ng g À1 .…”

Single Molecule-Level Detection via Liposome-Based Signal Amplification Mass Spectrometry Counting Assay

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