Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5130987 | Analytica Chimica Acta | 2017 | 8 Pages |
â¢A cost-effective, fast and simple method for determination of total cyanide in soil is presented.â¢A new micro-distillation strategy was developed overcoming the problems of a conventional distillation.â¢Negative chemical ionization-mass spectrometer has been exploited to obtain a high sensitivity and specificity.â¢High accuracy was attained for the analysis of certified reference materials with quadruple isotope dilution technique.
The high toxicity of cyanide, along with its widespread industrial use, has fuelled interest in the development of analytical methods for its determination in complex matrices. In this study, we propose a novel approach for the measurement of total cyanide in soil samples based on single-step derivatization with pentafluorobenzyl bromide (F5BnâBr) followed by quantitation with gas chromatography mass spectrometry in negative chemical ionization mode.The reaction between CNâ and F5BnâBr resulted in the identification of several derivatives such as F5BnâCN, (F5Bn)(F5Ph)CHâCN, and (F5Bn)2(F5Ph)CâCN. The relative proportion between such compounds was dependent on experimental conditions. When a 100 μL aliquot of an alkaline-aqueous extract was reacted with 700 μL of 1.3% F5BnâBr in acetone, the tri-alkylated derivative was the most abundant. In such conditions a detection limit of 0.5 ng/g of CNâ was attained.Soil samples were initially spiked with an alkaline solution of K13C15N internal standard and suspended in 7.5% aqueous NaOH. Determination of total cyanide was achieved by digestion of the alkaline extract with H3PO4 to produce HCN which was then trapped in 0.1% NaOH in a sealed double vial system, followed by reaction with F5BnâBr. Isotope dilution calibration was chosen for quantitation, and the validity of the novel method was demonstrated by analysis of soil Certified Reference Materials (CRMs) and by spike recovery tests.
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