Browsing by Author "Liu, Ray H."

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Developing a UHPLC-QTOF-MS and Automated Library Search Method for Screening Drugs and Toxic Compounds in Postmortem Specimens
(2017-06-01)
Liu, Hsiu-Chuan
;
Yang, Chu-An
;
Liu, Ray H.
;
Lin, Dong-Liang
;
應用化學系
Screening and confirming the presence of drugs and toxic compounds in various matrices are important and challenging tasks routinely faced by forensic and clinical laboratories. Recent advances in the liquid chromatographic and mass spectrometric technologies have provided an opportunity for the development of more specific and effective approaches to achieve the "screening" and "confirmation" goals in a single analytical step. The objectives of this study are: (i) the establishment of an ultra-high performance liquid chromatographic, quadrupole time-of-flight mass spectrometric mass spectrometric and MS-MS spectral database, including 1,200 compounds of interest; and (ii) the development of an effective protocol, using this database and three searching algorithms, for general unknown screening of these compounds. The established database and protocol were evaluated through the analysis of 30 external proficiency test and 100 postmortem samples and found to be significantly more effective than the LC-IT-MS and GC-MS approaches previously established in our laboratory.
Simultaneous Quantitation of Methamphetamine, Ketamine, Opiates and their Metabolites in Urine by SPE and LC-MS-MS
(2017-10-01)
Yang, Chu-An
;
Liu, Hsiu-Chuan
;
Lin, Dong-Liang
;
Liu, Ray H.
;
Hsieh, You-Zung
Heroin, methamphetamine and ketamine have been the most commonly abused drugs in Taiwan. The presence of these drugs and their metabolites in postmortem specimens has been routinely monitored in our laboratory mostly by gas chromatographic-mass spectrometric methods. This study aimed to evaluate a more effective approach to simultaneously quantify these analytes (i.e., amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), morphine, codeine, 6-acetylmorphine, 6-acetylcodeine, ketamine and norketamine) in postmortem urine and blood specimens by liquid chromatography-tandem mass spectrometry (LC-MS-MS). Samples (1 mL) were extracted via solid-phase extraction, evaporated and reconstituted in the mobile phase for injection into the LC-MS-MS system. Respective deuterated analogs of these analytes were used as internal standards. Chromatographic separation was achieved by an Agilent Zorbax SB-Aq analytical column at 50 degrees C. Mass spectrometric analysis was performed by electrospray ionization in positive-ion dynamic multiple reaction monitoring mode with optimized collision energy for respective precursor ion selected for each analyte, and the monitoring of two transition ions. Performance characteristics were assessed using drug-free samples that were fortified with 50-1,000 ng/mL of the 10 analytes. Analytical parameters evaluated and resulting data are as follows: (i) average extraction recoveries (n= 3) were better than 80%, except for MDMA (71%) and morphine (74%); (ii) inter-day and intra-day precision ranges (%CV) were 1.59-8.80% and 0.57-3.89%, respectively; (iii) calibration linearity (r(2)), detection limit and quantitation limit for all analytes were > 0.999, 1 and 5 ng/mL, respectively; (iv) matrix effects (ion suppression) were observed for three analytes, but were satisfactorily compensated for by the deuterated internal standards adopted in the analytical protocol. This method was successfully applied to the analysis of specimens collected from unknown death cases from various district prosecutors' offices in Taiwan, and was also found helpful to understanding whether the detected opiates were derived from heroin or legal morphine/codeine-containing medications.