A sensitive gas chromatographic-mass spectrometric method for the determination of 5-chloro-7-iodo-8-hydroxyquinoline (chinoform, clioquinol) in biological fluids and nervous tissues is described. Chinoform was converted into the pentafluorobenzyl ether, which was separated on a 10% Dexsil 300GC column and determined by the use of chinoform-d4 as an internal standard. The clean-up of chionoform in plasma and urine was efficiently achieved by extracting with benzene, while the drug in the tissue was pretreated successively by extraction with 12.5% v/v pyridine-benzene, separation on a Clin-Elut cartridge and adsorption on alumina. The quantitation limit of chinoform was 100 pg, and the recovery rates of chinoform added to plasma and tissue were 98% and 92%, respectively. The chinoform levels in biological fluids and tissues in dogs after prolonged administration of the drug at a dose of 400 mg/kg/day were measured by the proposed method. The plasma level and tissue distribution of chinoform are also discussed.
GC/MS with selected ion monitoring ((GC/MS (SIM)) has been developed as a screening method for the determination of 14 pesticides residues including cyhexatin and 2, 4, 5-T in nuts. The pesticides were extracted with acetone from nuts, and then partitioned between n-hexane and acetonitrile.Clean-up was conducted by solid-phase extraction (SPE) with a Bond Elut Florisil column. Most of the pesticides were eluted in a mixture of n-hexane and acetone (17: 3) from the column, and the eluate was examined by GC/MS (SIM). Cyhexatin and 2, 4, 5-T were analyzed after derivatization and SPE clean-up. Recoveries of 14 pesticides from 6 kinds of nuts were mostly over 80%. This method is effective for multi-residue analysis of pesticides in nuts.
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