title: Determination of total cyanide in soil by isotope dilution GC/MS following pentafluorobenzyl derivatization.
abstract: 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 (F5Bn-Br) followed by quantitation with gas chromatography mass spectrometry in negative chemical ionization mode. The reaction between CN-and F5Bn-Br resulted in the identification of several derivatives such as F5Bn-CN, (F5Bn)(F5Ph)CH-CN, and (F5Bn)2(F5Ph)C-CN. 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% F5Bn-Br in acetone, the tri-alkylated derivative was the most abundant. In such conditions a detection limit of 0.5 ng/g of CN-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 H3PO4to produce HCN which was then trapped in 0.1% NaOH in a sealed double vial system, followed by reaction with F5Bn-Br. 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.
authors.affiliation: Università di Pisa, Dipartimento di Chimica e Chimica Industriale, via Moruzzi 13, 56124 Pisa, Italy; Consiglio Nazionale delle Ricerche (CNR), Istituto di Chimica dei Composti Organometallici, UOS di Pisa, via Moruzzi 1, 56124 Pisa, Italy. Electronic address: beatrice.campanella@pi.iccom.cnr.it.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Campanella
authors.affiliation: Università di Pisa, Dipartimento di Chimica e Chimica Industriale, via Moruzzi 13, 56124 Pisa, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Biancalana
authors.affiliation: National Research Council of Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6, Canada.
authors.forename: Lucia
authors.initials: L
authors.lastname: D'Ulivo
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR), Istituto di Chimica dei Composti Organometallici, UOS di Pisa, via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Onor
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR), Istituto di Chimica dei Composti Organometallici, UOS di Pisa, via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Emilia
authors.initials: E
authors.lastname: Bramanti
authors.affiliation: National Research Council of Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6, Canada.
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Mester
authors.affiliation: National Research Council of Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6, Canada.
authors.forename: Enea
authors.initials: E
authors.lastname: Pagliano
keywords: Cyanide; Gas chromatography-mass spectrometry; Isotope dilution; Pentafluorobenzyl bromide; Soil