Showing papers by "Kenji Hara published in 2006"

Two simple methods for enantiomeric analyses of urinary amphetamines by GC/MS using deuterium-labeled l-amphetamines as internal standards

Abstract: Two simple methods for enantiomeric analyses of amphetamines in urine by gas chromatography-mass spectrometry (GC-MS) using l-amphetamine-d 3 and l-methamphetamine-d 6 as internal standards are presented. One method (method A) employs extractive derivatization on a diatomaceous column with (S)-(-)-N-(trifluoroacetyl)prolyl chloride (TPC) followed by separation with a conventional capillary column. The second method (method B) uses headspace solid-phase microextraction (HD-SPME) after derivatization with heptafluoro-n-butyryl chloride (HFB), followed by separation with an enantiomeric capillary GC column. By the two methods, all enantiomers were well separated in each chromatogram, and good linearity was obtained in practical concentration ranges (0.1–1.6μg/ml for method A and 0.05–1μg/ml for method B) for every compound by selected-ion monitoring. The precision studies indicated satisfactory coefficients of variation (<5%) for every enantiomer at 0.1μg/ml by both methods. Both methods were also evaluated by applying them to an actual poisoning case. Both methods are recommended for use in forensic analysis, because of their simplicity, high precision, and sufficient sensitivity.

Rapid analysis of acetaminophen in serum by gas chromatography-mass spectrometry with extractive derivatization using a diatomaceous earth tube

Abstract: A new analytical method for acetaminophen (ACAP) in serum was developed by modifying an existing method used for amphetamines, which used extractive derivatization followed by gas chromatographymass spectrometry. After a serum sample was adjusted to pH 12.8, it was applied onto a diatomaceous earth tube; the analyte was simultaneously extracted and heptafluorobutyrylated during elution with a solvent containing a derivatizing reagent. Three internal standard (IS) candidates were tested: N-acetyl-d3-paminophenol, N-acetyl-m-aminophenol, and N-acetyl-4-amino-m-cresol. All ISs gave good linear relationships (r2 > 0.999) for ACAP in the concentration range from 1 to 200μg/ml. The detection limit for ACAP using each IS was estimated to be 0.05–0.1μg/ml. Intraday precision was satisfactory with a coefficient of variation of less than 8.3%. The use of this method with any of the three ISs is recommended in forensic and clinical toxicology because of its rapidity and good reproducibility.