title: Simultaneous determination of thyreostatic residues in animal tissues by matrix solid-phase dispersion and gas chromatography-mass spectrometry.
abstract: A method for determination of thyreostatic residues in animal tissues by matrix solid-phase dispersion (MSPD) and gas chromatography-mass spectrometry in selected ion detection mode was developed. Thyreostatic compounds in different matrices were extracted and purified by combination of MSPD and subsequent solid-phase extraction. Silica gel was selected as the solid support of both procedures and the conditions of the procedures were optimized. Thyreostats were derivatized with pentafluorobenzylbromide (PFBBr) in strong basic medium and then with N-methyl-N-(trimethylsilyl)-trifluoroacetamide (MSTFA), which can improve the yields of derivatization for thyreostats, the repeatability, and therefore the limits of detection (LOD) of thyreostats. The limits of detection reached 10 microg/kg (2-thiouracil, 6-methyl-2-thiouracil and 6-propyl-2-thiouracil), 20 microg/kg (6-phenyl-2-thiouracil) and 50 microg/kg (tapazole) with high recoveries (more than 70% for most of thyreostats) and relative standard deviations between 4.5% and 8.7%.
authors.affiliation: Analytical & Testing Center of Beijing Normal University, Xinjiekowaidajie 19, Beijing 100875, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Meng-Xia
authors.initials: MX
authors.lastname: Xie
authors.forename: Yue-Ming
authors.initials: YM
authors.lastname: Qiu
mesh_terms: D000081:Acetamides; D000818:Animals; D013956:Antithyroid Agents / Q000032:analysis* / Q000302:isolation & purification; D005463:Fluoroacetates; D005464:Fluorobenzenes; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D008713:Methimazole / Q000302:isolation & purification; D008779:Methylthiouracil / Q000302:isolation & purification; D011441:Propylthiouracil / Q000302:isolation & purification; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D058428:Silica Gel; D012822:Silicon Dioxide; D013552:Swine; D013889:Thiouracil / Q000302:isolation & purification; D014297:Trimethylsilyl Compounds; D005466:Fluorocarbons
chemical_list: D000081:Acetamides; D013956:Antithyroid Agents; D005463:Fluoroacetates; D005464:Fluorobenzenes; D008713:Methimazole; D008779:Methylthiouracil; D011441:Propylthiouracil; D058428:Silica Gel; D012822:Silicon Dioxide; D013889:Thiouracil; D014297:Trimethylsilyl Compounds; C025063:pentafluorobenzyl bromide; D005466:Fluorocarbons; C086665:N-methyl-N-(trimethylsilyl)trifluoroacetamide