Journal of chromatographic science
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A simple, rapid, and sensitive liquid chromatography-mass spectrometry (MS)-MS method for quantitating paclitaxel in rat plasma is developed. Liquid-liquid extraction with tert-butyl methyl ether is used for sample preparation, and docetaxel is used as the internal standard. Paclitaxel and docetaxel are separated on a C18 column and quantitated using a triple-quadrupole MS operating in positive ion electrospray selective reaction monitoring mode with a total run time of 6.0 min. ⋯ The method has high extraction recovery (> 90%) and accuracy (> 90%), with the intra- and interday precision < 15%. Frozen stability, freeze-and-thaw stability, extracted stability, and room temperature solution stability are also examined. This assay is used to support a pharmacokinetic study of paclitaxel self-assembled nanoliposome in rats.
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A small amount of green particulate material is encountered in a consumer complaint sample. The green particulates in the sample are identified as a bromethalin-containing rodenticide using high-performance liquid chromatographic (HPLC)-UV-vis spectrophotometric and HPLC-negative-ion atmospheric pressure chemical ionization (APCI)-mass spectrometric (MS) approaches, which are commonly used for the detection and confirmation of bromethalin in grain-based rodenticides. ⋯ The estimated detection limit with the UV-vis detector is 500 pg of bromethalin injected into the column. The extensive fragmentation of the bromethalin molecule under APCI conditions provides sufficient structural information for positive identification.
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A method incorporating solid-phase microextraction (SPME) and gas chromatography-mass spectrometry for the headspace analysis of selected volatile organic compounds present in cigarette tobacco is developed and evaluated. Quantitative information on methyl, ethyl, n-propyl, isopropyl, isopropenyl, vinyl, and butyl acetates present in 29 different flavor variants (full, light, and ultra-light) of the top ten selling brands in the United States is presented. The concentrations of the various acetate analytes range from the low nanaogram to microgram levels per cigarette. ⋯ The SPME technique provides a method that allows high sample throughput, requires little sample preparation, and yields useful analytical information. High precision is obtained on multiple measurements of cigarettes from an individual pack, but lower precision levels are observed in general when comparing results obtained on the analysis of cigarettes from different packs of the same brand. The higher pack-to-pack variations may be due in part to product aging with a proportionate amount of evaporative loss of the relatively volatile acetates.