declustering potential
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Author(s):  
C Scholz ◽  
J Cabalzar ◽  
T Kraemer ◽  
M R Baumgartner

Abstract The aim of the present study was to quantify a large number of analytes including opioids, stimulants, benzodiazepines, z-drugs, antidepressants and neuroleptics within a single sample workup followed by a single analytical measurement. Expected drug concentrations in hair are strongly substance dependent. Therefore, three different calibration ranges were implemented: 0.5 to 600 pg/mg (group 1), 10 to 12,000 pg/mg (group 2) and 50 to 60,000 pg/mg (group 3). In order to avoid saturation effects, different strategies were applied for selected transitions including the use of parent mass ions containing one or two 13C-isotopes and detuning of the declustering potential and/or collision energy. Drugs were extracted from pulverized hair by a two-step extraction protocol and measured by liquid chromatrography-tandem mass spectrometry (LC-MS-MS) using Scheduled MRM™ Algorithm Pro. In total, 275 MRM transitions including 43 deuterated standards were measured. The method has been fully validated according to international guidelines. A MultiQuant™ software based tool for task-oriented data evaluation was established, which allows extracting selected information from the measured data sets. The matrix effects and recoveries were within the allowed ranges for the majority of the analytes. The lower limits of quantification (LLOQs) were for ∼72% of the analytes in the low-pg/mg range (0.5–5 pg/mg) and for ∼24% of the analytes between 10 and 50 pg/mg. These LLOQs considered cut-offs by the Society of Hair Testing (SoHT), if recommended. The herein established multi-analyte approach meets the specific requirements of forensic hair testing and can be used for the rapid and robust measurement of a wide range of psychoactive substances. The analyte-specific wide concentration ranges open up a wide field of applications.


2016 ◽  
Vol 52 (2) ◽  
pp. 85-94
Author(s):  
Barbara Potocka-Banaś ◽  
Krzysztof Borowiak ◽  
Tomasz Janus ◽  
Teresa Dembińska ◽  
Alicja Rak

The aim of the study was to evaluate the usefulness of liquid chromatography-tandem mass spectrometry for determination of cocaine and its metabolites (benzoylecgonine, ecgonine methyl ester) in biological material. Method. Cocaine and its metabolites were quantified using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). Results. The extraction repeated twice with smaller portions of solvent showed higher efficiency and lower values of standard deviation that is why it was applied to further analysis. To increase sensitivity of LC/MS/MS method optimization of declustering potential was performed over 0-300V range and DP=100V was chosen. Collision energy for cocaine and benzoylecgonine was 25V and for ecgonine methyl ester was 22V. High resolution of the apparatus allowed to select narrow signal range for each compound: 185,135±0.025 Da for cocaine-d3, 182,120±0.025 Da for cocaine, 168,105±0.025 Da for benzoylecgonine and 182,125±0.025 Da for ecgonine methyl ester. Results obtained from analysis of two series of cocaine, benzoylecgonine and ecgonine methyl ester samples allowed to plot calibration curves within the range of 1-100 ng/ml which showed linearity. Conclusion. Obtained results allowed for identification and quantitative determination of cocaine and its metabolites (benzoylecgonine and ecgonine methyl ester) in human serum. Liquid chromatography-tandem mass spectrometry can find application in both forensic and clinical toxicology.


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