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Relatively little is known about the metabolism of areca nut in human saliva. We here describe the simultaneous quantification of areca nut metabolites: arecoline, arecaidine and N-methylnipecotic acid in saliva samples after chewing one 5 g areca nut by using liquid chromatography-tandem mass spectrometry (LC-MS-MS). Time courses of salivary areca nut metabolites in five adult male areca nut chewer volunteers were investigated. The limits of quantification were all 1.25 ng/mL for arecoline, arecaidine and N-methylnipecotic acid. Intra- and interday imprecisions were <4.2 and 13.6%, respectively. The within-day accuracy ranged from 82.2 to 116.7%, and the between-day accuracy ranged from 78.3 to 115.6%. Through areca nut chewing time course study, we found that salivary arecoline, arecaidine and N-methylnipecotic acid concentrations varied greatly over time between experiment individuals. Our findings suggest that arecoline might be metabolized slightly to arecaidine at 30 min after areca nut chewing and arecoline might be metabolized slightly to N-methylnipecotic acid at 25 min after areca nut chewing in the mouth. We first provide simultaneous quantification of human salivary arecoline, arecaidine and N-methylnipecotic acid levels using LC-MS-MS. This method may facilitate future research design in the pathogenic effects of areca nut exposure., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

To facilitate the analysis of targeted drugs under high sample volume testing environment, an extraction, derivatization and gas chromatographic-mass spectrometric analysis method was developed for simultaneously determination of amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), ketamine, and norketamine in urine. This method utilized solid-phase extraction in conjunction with derivatization using heptafluorobutyric anhydride (HFBA) as the derivatization reagent. Using a 1-mL sample, the limits of quantitation achieved for the analysis of AMP, MAMP, MDA, MDMA, MDEA, ketamine, and norketamine were 25, 15, 60, 60, 70, 25, and 30 ng/mL, respectively. Upper limits of quantitation were 8000 ng/mL for all amphetamines and 6000 ng/mL for ketamine and norketamine. Except for dehydronorketamine (DHNK), within-day and between-day precisions (as expressed in CV%) for quality control samples were ≤ 3.1% and ≤ 4.95%, respectively. Except DHNK, the within-day accuracy ranged between 96.0% and 110.7% and the between-day accuracy ranged between 96.9% and 108.7%. A group of 107 urine samples previously determined to contain the target analytes were analyzed by this new approach. Quantitative data produced by both methods agreed well. With this new approach, we were able to use a single analytical protocol to conduct the confirmation test for samples that preliminarily tested positive (by immunoassay) for amphetamines, ketamine, or both.