title: Determination of thiocyanate in saliva by headspace gas chromatography-mass spectrometry, following a single-step aqueous derivatization with triethyloxonium tetrafluoroborate.
abstract: A novel method for the determination of salivary thiocyanate is presented. Thiocyanate was converted into ethyl thiocyanate by single-step aqueous derivatization based on triethyloxonium tetrafluoroborate and measured by gas chromatography-mass spectrometry (15 min runtime). The ethyl thiocyanate derivative is volatile and can be sampled from the headspace. The derivatization chemistry proposed allows for separation of the analyte from saliva matrix whose introduction in the measurement system is avoided. Quantitation of the analyte was obtained by isotope dilution, employing a (13)C-enriched thiocyanate as internal standard. Technical details and fundamental aspects of derivatization chemistry and calibration strategy are presented. The method was validated by comparison with a standard method based on ion chromatography. The two independent methodologies produced results in agreement within 3%. Also a three level spike recovery test was carried out for validation purpose and quantitative recoveries were attained. The method is fast, simple, safe, and sensitive. Measurement of a 1 mL volume 50 ng/g of thiocyanate standard produced a signal-to-noise ratio of 250 for the analytical peak. This method is therefore suitable for ultra-trace determination of thiocyanate (low part-per-billion range). For the application described the full detection potential of the method was not required and the sample preparation presented has been designed for quantitation of saliva samples containing 1-400 μg/g of thiocyanate with a combined standard uncertainty of 2% relative for saliva samples containing 25 μg/g of thiocyanate. This method was applied for the determination of thiocyanate in human saliva samples.
authors.affiliation: C.N.R., Institute of Chemistry of Organometallic Compounds, UOS of Pisa, Via Moruzzi, 1, 56124 Pisa, Italy; University of Pisa, Department of Chemistry and Industrial Chemistry, Via Risorgimento, 35, 56125 Pisa, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Ammazzini
authors.affiliation: C.N.R., Institute of Chemistry of Organometallic Compounds, UOS of Pisa, Via Moruzzi, 1, 56124 Pisa, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Onor
authors.affiliation: National Research Council of Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6, Canada. Electronic address: enea.pagliano@nrc.ca.
authors.forename: Enea
authors.initials: E
authors.lastname: Pagliano
authors.affiliation: National Research Council of Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6, Canada.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Mester
authors.affiliation: C.N.R., Institute of Chemistry of Organometallic Compounds, UOS of Pisa, Via Moruzzi, 1, 56124 Pisa, Italy; University of Pisa, Department of Chemistry and Industrial Chemistry, Via Risorgimento, 35, 56125 Pisa, Italy.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Campanella
authors.affiliation: C.N.R., Institute of Chemistry of Organometallic Compounds, UOS of Pisa, Via Moruzzi, 1, 56124 Pisa, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Pitzalis
authors.affiliation: C.N.R., Institute of Chemistry of Organometallic Compounds, UOS of Pisa, Via Moruzzi, 1, 56124 Pisa, Italy.
authors.forename: Emilia
authors.initials: E
authors.lastname: Bramanti
authors.affiliation: C.N.R., Institute of Chemistry of Organometallic Compounds, UOS of Pisa, Via Moruzzi, 1, 56124 Pisa, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: D'Ulivo
mesh_terms: D001881:Borates / Q000737:chemistry*; D002138:Calibration; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007201:Indicator Dilution Techniques; D007554:Isotopes / Q000032:analysis; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D013861:Thiocyanates / Q000032:analysis*
chemical_list: D001881:Borates; D007554:Isotopes; D013861:Thiocyanates; C031760:thiocyanate; C005142:triethyloxonium tetrafluoroborate
keywords: GC/MS; Isotope dilution; Saliva; Smokers and nonsmokers; Thiocyanate; Triethyloxonium tetrafluoroborate derivatization