title: Simplified sample preparation method for triclosan and methyltriclosan determination in biota and foodstuff samples.
abstract: An improved method for the determination of triclosan (TCS) and methyltriclosan (MTCS) in fish and foodstuff samples is presented. Analytes were simultaneously extracted and purified using the matrix solid-phase dispersion (MSPD) technique, and then selectively determined by gas chromatography with tandem mass spectrometry (GC-MS/MS). Several combinations of dispersants, clean-up co-sorbents and extraction solvents were tested in order to obtain lipid-free extracts and quantitative recoveries for TCS and MTCS. Under optimised conditions, 0.5 g samples were dispersed using 1.5 g of neutral silica in a mortar with a pestle, and transferred to a polypropylene cartridge containing 3 g of silica impregnated with 10% of sulphuric acid (SiO2-H2SO4, 10%, w/w). Analytes were recovered with 10 mL of dichloromethane whereas lipids were oxidized in the layer of acidic silica. The extract was concentrated to dryness and re-constituted with 1 mL of ethyl acetate. Then, a fraction of 0.5 mL was mixed with 50 microL of N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and injected in the GC-MS/MS system. The developed method provided absolute recoveries between 77 and 120% for different samples spiked at the low ng g(-1) level, quantification limits in the range of 1-2 ng g(-1) and a considerable simplicity in comparison with previously developed sample preparation approaches. Experiments carried out placing sliced food samples in direct contact with TCS-treated kitchenware surfaces showed the capability of the biocide to migrate into foodstuffs.
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, Avda de las Ciencias s/n., Santiago de Compostela 15782, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Canosa
authors.forename: I
authors.initials: I
authors.lastname: Rodríguez
authors.forename: E
authors.initials: E
authors.lastname: Rubí
authors.forename: M
authors.initials: M
authors.lastname: Ramil
authors.forename: R
authors.initials: R
authors.lastname: Cela
mesh_terms: D053000:Analytic Sample Preparation Methods / Q000379:methods*; D000818:Animals; D005504:Food Analysis / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D008055:Lipids / Q000302:isolation & purification; D012822:Silicon Dioxide / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013464:Sulfuric Acids / Q000737:chemistry; D013997:Time Factors; D014260:Triclosan / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D008055:Lipids; D012997:Solvents; D013464:Sulfuric Acids; D014260:Triclosan; D012822:Silicon Dioxide; C033158:sulfuric acid