TY - JOUR
AU1 - Zubaidi, Fathiah, A
AU2 - Choo,, Yeun-Mun
AU3 - Tan,, Guan-Huat
AU4 - Hamid, Hamimah, Abd
AU5 - Choy, Yap, Ken
AB - Abstract A novel mass spectrometry detection technique based on a multi-period and multi- experiment (MRM-EPI-MRM3) with library matching in a single run for fast and rapid screening and identification of amphetamine type stimulants (ATS) related drugs in whole blood, urine and dried blood stain was developed and validated. The ATS-related drugs analyzed in this study include ephedrine, pseudoephedrine, amphetamine, methamphetamine, MDMA (3,4-Methylenedioxymethamphetamine), MDA (3,4-Methylenedioxyamphetamine), MDEA (3,4-Methylenedioxy-N-ethylamphetamine) and phentermine. The relative standard deviation for inter and intraday was less than 15% while recoveries ranged from 80% to 120% for all three matrices, i.e., whole blood, urine and dried blood stain. All compounds gave library matching percentage of more than 85% based on the purity. This method was proven to be simple and robust, and provide high confident results complemented with library matching confirmation. ATS-related drugs, LC-MS/MS, MRM-EPI-MRM3, whole blood sample, urine sample, dried blood stain sample Introduction The word “stimulant” refers to agents that stimulate the central nervous system (CNS) and have marked effects on mental function and behavior (1). Amphetamine-type stimulants (ATS) as described by World Health Organization (WHO) refers to amphetamine and other similar drugs that made people awake, felt energized or alert (2). ATS was used during war times to keep soldiers on high alert and it was sometimes used in diet pill to keep people from feeling hungry, hence aiding in weight loss. Besides amphetamine and methamphetamine, there are a wide range of compounds which fall into the ATS group, including methcathinone, entactogenic/empathogenic amphetamines (3,4-Methylenedioxymethamphetamine, MDMA and its analogs), ephedrine and pseudoephedrine, and compounds employed in therapeutic approaches, such as phentermine, methylphenidate (MPH), amphepramone or diethylpropione (DIE), mazindol, and fenproporex (PPP) (3). The routes of administration are intranasal sniffing when in powder form, pulmonary inhalation and injection when in crystal or liquid form, and oral ingestion when in capsule or tablet form. ATS have a common phenethylamine structural backbone and typically causes (but not limited) central nervous system stimulation, hallucinations, anorexia and others. ATS abuse often results in addiction. Overdosage of these substances will lead to hypertension, arrhythmia, excitability, aggressiveness, psychoses, coma and death (4, 5). ATS are metabolized mainly in the liver, and typically the parent compounds are detected in urine together with the metabolites (6). The elimination rate from blood depends on dosage, frequency of use, tolerance, metabolic rate, body mass, age and health status (7). The North America and European Union reported to have steady consumption of ATS, specifically illicit drugs but the usage was on the rise in China, the Middle East region and East, South East and Middle East Asia (8). The 2016 World Drug Report stated that amphetamine type-stimulants (ATS) are among the on-demand drugs of abuse besides opiates, cocaine, cannabis, and new psychoactive substances (NPS) (9). The ATS is sometimes consumed together with other drugs in the trend known as “polydrug use.” Regulatory and law enforcement bodies around the world have increasingly demanded more ATS related developement in detection, identification and confirmation methodology especially in biological samples such as urine and blood samples with growing number abuse cases. Gas chromatography mass spectrometer (GCMS) techniques are routinely used for ATS analysis, however tedious and time consuming derivatization processes are often required in the procedures. In addition, false positive and misleading results were sometime obtained in GCMS analysis (10). Liquid chromatography tandem mass spectrometer (LC-MS/MS) techniques have been developed for ATS analyses, which involved simpler sample preparation procedures as well as lesser analytical concerns, while multiple reaction monitoring (MRM) is one of the most common detection mode used for identification and quantification in LC-MS/MS analysis. However, combining LC-MS/MS with MRM-EPI-MRM3 for the detection and identification of ATS in biological matrices is very rare. Hence, this provides a window of opportunity to develop a fast, robust and efficient LC-MS/MS method for the determination and confirmation of ATS in biological matrices. The purpose of the present investigation is to establish and validate an efficient and robust method for the analysis of ATS-related drugs in biological matrices, including dried blood stain (DBS). A unique multi-period and multi-experiment method is developed and employed with greater degree of confidence in identification using library matching confirmation and has applied succesfully for real sample monitoring. ATS-related drugs investigated in this study include amphetamine, methamphetamine, MDEA, MDA, MDMA, together with the precursors of pseudoephedrine and ephedrine, and isomeric compound of phentermine. Materials and methods Chemicals and methods All standards and internal standards: amphetamine (AMP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-methylamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), pseudoephedrine (PEP), ephedrine (EP), phentermine (PTM), methamphetamine-d14 (MA-d14) and 3,4-methylenedioxy-N-methylamphetamine-d5 (MDMA-d5) were purchased from Lipomed (Switzerland). Acetonitrile and methanol were HPLC grade (Merck, Darmstadt, Germany). Chlorobutane 99.8% was acquired from Fischer Chemical (Loughborough, Leicestershire, UK). Formic acid 98–100% was purchased from Sigma-Aldrich (St. Louis, MO, USA). Whatman® FTA® card was purchased from Merck (Darmstadt, Germany). Phosphate buffer (20 mM, pH 7.4) was prepared by dissolving monobasic sodium phosphate in water and pH adjusted using sodium hydroxide. Ultrapure water was from arium® pro UV Ultrapure Water (Sartorius, Goettingen, Germany) with a specific resistance at >18 MΩcm. Sample collection and pre-treatment: Blank blood samples were obtained from bull’s blood while blank urine samples were collected from laboratory personnel volunteers. Both blood and urine samples have been tested earlier and were used in the preparation of calibration solutions and matrix matched analysis. Calibration solutions for AMP, MA, MDA, MDMA, MDEA, PEP, EP and PTM were prepared in blank blood and blank urine at six different concentrations of 5, 10, 20, 50, 100 and 200 ng/mL. Seven replicates with concentration of 20 and 100 ng/mL were prepared in blood, DBS and urine samples for method validation. Whole blood and urine samples (n = 20), respectively, with positive identification of ATS-related drugs were obtained from various real cases submitted for forensic and medico-legal analysis from January 2016 until September 2017 to Forensic Division, Department of Chemistry Malaysia. The whole blood samples (n = 20) were individually stained onto Whatman FTA for DBS analysis. External quality controls (QC) consisted of whole blood sample tested for proficiency testing provided by College of American Pathologists (CAP), USA and internal proficiency testing by Proficiency Testing Unit, Research and Quality Assurance Division, Department of Chemistry, Malaysia. The QC for urine samples are obtained from previous UNODC external proficiency testing participated by the laboratory of Department of Chemistry, Malaysia. Whatman FTA Card was selected as DBS medium and all samples were stored at 4°C until the time of analysis. Instrument and HPLC condition The Exion LC SCIEX Binary SL Series System (Toronto, Canada) consisted of an autosampler, a binary pump and a column for chromatography. LC separation was performed by injecting 5 μL of samples on a reversed-phase C18 Luna Omega analytical column (100 × 2.1 mm; 1.6 μm; Phenomenex, USA). Autosampler was set at 20°C and column temperature was at 40°C. Chromatographic separation was achieved by gradient elution at a flow rate of 300 μL/min. The mobile phases used were 0.1% formic acid in water in ultrapure water (A) and 0.1% formic acid in acetonitrile (B), with a total of 10 min runtime (0–2 min: 5% B isocratic gradient; 2–4 min: 5–20% B; 4–5 min: 20–90% B; 5–6 min: 90% B isocratic gradient; 6–8 min: 90-5%; 8–10 min: 5% B isocratic gradient). Mass spectrometry conditions A SCIEX 5500 hybrid QTRAP tandem mass spectrometry system (Toronto, Canada) equipped with patented Turbo V source was used. Compound ionization was performed using electrospray ionization (ESI) and set at positive mode. Heating gas temperature was held at 550°C and ion spray (IS) voltage of 5,500 V. The nebulizing gas (GS1), heating gas (GS2) and curtain gas pressures were set at 40, 40 and 20 psi, respectively throughout the analysis. Purified nitrogen gas was used as collision and spray gas. Analyst software version 1.6.3 together with MultiQuant version 3.0 were used during method development, data acquisition, data processing and statistical analysis. Mass spectrometry scan modes of multiple reaction monitoring (MRM), enhanced product ion (EPI) and multiple reaction monitoring with multistage fragmentation (MRM3) experimental conditions for individual analytes were optimized by post-column infusion of working solution (100 ng/mL) using Analyst Software and the summary of the parameters is shown in Table I. Table I. Optimized LCMS/MS parameters Ephedrine and pseudoephedrine (period 1) MRM3 First precursor Second precursor AF2 Voltage Collision energy 166.2 148.2 0.07 15 166.2 148.2 0.07 15 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 166.2 50–200 80 35 166.2 50–200 80 35 MRM Precursor Ion Second precursor Declustering potential Collision energy 166.2 148.2 70 15 166.2 115.2 70 35 Amphetamine (period 2) MRM3 First precursor Second precursor AF2 voltage Collision energy 136.1 119 0.06 15 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 136.1 50–150 80 30 MRM Precursor Ion Second precursor Declustering potential Collision energy 136.1 119.1 70 11 136.1 91.1 70 21 MDA (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 180 163 0.07 25 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 180 50–200 80 25 MRM Precursor ion Second precursor Declustering potential Collision energy 180 105 70 29 180 133 70 11 Methamphetamine (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 150.1 119.1 0.06 35 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 150.1 50–200 80 25 MRM Precursor ion Second precursor Declustering potential Collision energy 150.1 119.1 100 15 150.1 91 100 23 d14-Metamphetamine (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 164 130 0.04 20 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 164 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 164 98 80 25 164 130 80 15 d5-MDMA (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 199 165 0.06 14 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 199 50–250 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 199 165 70 16 199 135 70 20 MDMA (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 194 163.1 0.08 22 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 194 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 194 163.1 86 15 194 105.1 86 31 Phentermine (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 150 91.1 0.16 44 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 150 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 150 133 100 15 150 91 100 22 MDEA (period 5) MRM3 First precursor Second precursor AF2 voltage Collision energy 208.1 163 0.06 20 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 208.1 50–250 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 208.1 163 70 17 208.1 135 70 29 Ephedrine and pseudoephedrine (period 1) MRM3 First precursor Second precursor AF2 Voltage Collision energy 166.2 148.2 0.07 15 166.2 148.2 0.07 15 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 166.2 50–200 80 35 166.2 50–200 80 35 MRM Precursor Ion Second precursor Declustering potential Collision energy 166.2 148.2 70 15 166.2 115.2 70 35 Amphetamine (period 2) MRM3 First precursor Second precursor AF2 voltage Collision energy 136.1 119 0.06 15 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 136.1 50–150 80 30 MRM Precursor Ion Second precursor Declustering potential Collision energy 136.1 119.1 70 11 136.1 91.1 70 21 MDA (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 180 163 0.07 25 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 180 50–200 80 25 MRM Precursor ion Second precursor Declustering potential Collision energy 180 105 70 29 180 133 70 11 Methamphetamine (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 150.1 119.1 0.06 35 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 150.1 50–200 80 25 MRM Precursor ion Second precursor Declustering potential Collision energy 150.1 119.1 100 15 150.1 91 100 23 d14-Metamphetamine (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 164 130 0.04 20 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 164 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 164 98 80 25 164 130 80 15 d5-MDMA (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 199 165 0.06 14 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 199 50–250 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 199 165 70 16 199 135 70 20 MDMA (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 194 163.1 0.08 22 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 194 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 194 163.1 86 15 194 105.1 86 31 Phentermine (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 150 91.1 0.16 44 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 150 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 150 133 100 15 150 91 100 22 MDEA (period 5) MRM3 First precursor Second precursor AF2 voltage Collision energy 208.1 163 0.06 20 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 208.1 50–250 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 208.1 163 70 17 208.1 135 70 29 Open in new tab Table I. Optimized LCMS/MS parameters Ephedrine and pseudoephedrine (period 1) MRM3 First precursor Second precursor AF2 Voltage Collision energy 166.2 148.2 0.07 15 166.2 148.2 0.07 15 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 166.2 50–200 80 35 166.2 50–200 80 35 MRM Precursor Ion Second precursor Declustering potential Collision energy 166.2 148.2 70 15 166.2 115.2 70 35 Amphetamine (period 2) MRM3 First precursor Second precursor AF2 voltage Collision energy 136.1 119 0.06 15 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 136.1 50–150 80 30 MRM Precursor Ion Second precursor Declustering potential Collision energy 136.1 119.1 70 11 136.1 91.1 70 21 MDA (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 180 163 0.07 25 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 180 50–200 80 25 MRM Precursor ion Second precursor Declustering potential Collision energy 180 105 70 29 180 133 70 11 Methamphetamine (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 150.1 119.1 0.06 35 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 150.1 50–200 80 25 MRM Precursor ion Second precursor Declustering potential Collision energy 150.1 119.1 100 15 150.1 91 100 23 d14-Metamphetamine (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 164 130 0.04 20 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 164 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 164 98 80 25 164 130 80 15 d5-MDMA (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 199 165 0.06 14 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 199 50–250 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 199 165 70 16 199 135 70 20 MDMA (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 194 163.1 0.08 22 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 194 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 194 163.1 86 15 194 105.1 86 31 Phentermine (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 150 91.1 0.16 44 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 150 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 150 133 100 15 150 91 100 22 MDEA (period 5) MRM3 First precursor Second precursor AF2 voltage Collision energy 208.1 163 0.06 20 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 208.1 50–250 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 208.1 163 70 17 208.1 135 70 29 Ephedrine and pseudoephedrine (period 1) MRM3 First precursor Second precursor AF2 Voltage Collision energy 166.2 148.2 0.07 15 166.2 148.2 0.07 15 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 166.2 50–200 80 35 166.2 50–200 80 35 MRM Precursor Ion Second precursor Declustering potential Collision energy 166.2 148.2 70 15 166.2 115.2 70 35 Amphetamine (period 2) MRM3 First precursor Second precursor AF2 voltage Collision energy 136.1 119 0.06 15 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 136.1 50–150 80 30 MRM Precursor Ion Second precursor Declustering potential Collision energy 136.1 119.1 70 11 136.1 91.1 70 21 MDA (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 180 163 0.07 25 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 180 50–200 80 25 MRM Precursor ion Second precursor Declustering potential Collision energy 180 105 70 29 180 133 70 11 Methamphetamine (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 150.1 119.1 0.06 35 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 150.1 50–200 80 25 MRM Precursor ion Second precursor Declustering potential Collision energy 150.1 119.1 100 15 150.1 91 100 23 d14-Metamphetamine (period 3) MRM3 First precursor Second precursor AF2 voltage Collision energy 164 130 0.04 20 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 164 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 164 98 80 25 164 130 80 15 d5-MDMA (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 199 165 0.06 14 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 199 50–250 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 199 165 70 16 199 135 70 20 MDMA (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 194 163.1 0.08 22 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 194 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 194 163.1 86 15 194 105.1 86 31 Phentermine (period 4) MRM3 First precursor Second precursor AF2 voltage Collision energy 150 91.1 0.16 44 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 150 50–200 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 150 133 100 15 150 91 100 22 MDEA (period 5) MRM3 First precursor Second precursor AF2 voltage Collision energy 208.1 163 0.06 20 EPI Precursor ion Fragment mass scan range Declustering potential Collision energy 208.1 50–250 80 30 MRM Precursor ion Second precursor Declustering potential Collision energy 208.1 163 70 17 208.1 135 70 29 Open in new tab Sample preparation Whole blood and urine sample Whole blood and urine samples were subjected to liquid-liquid extraction (LLE). An aliquot (30 μL) of the mix internal standard; MA-d14 and MDMA-d5 solution was added into 1 mL of the samples, followed by 0.5 mL of phosphate buffer solution and 3 mL of 1-chlorobutane. The samples were then equilibrated on a roller mixer for approximately 1 hour followed by centrifugation at 2,000 rpm for 10 min. The upper organic solvent layer was transferred to a clean tube and dried using rotary evaporator. The dried extract was reconstituted in 80 μL of 50% aqueous-methanol solution and transferred for LC-MS/MS analysis. Dried blood stain Blood stains were prepared by spotting 100 μL aliquot of blood onto Whatman FTA Card, which were subsequently dried at room temperature overnight. For the extraction part, the stained FTA Card was put into test tubes followed by adding 30 μL of the mix internal standard; MA-d14 and MDMA-d5 solution. LLE also performed by adding 1 mL of water followed by 0.5 mL phosphate buffer and 3 mL of 1-chlorobutane. The next steps followed whole blood and urine samples accordingly for LC-MS/MS analysis. Method validation The method validation followed the Scientific Working Group for Forensic Toxicology (SWGTOX) Standard Practices for Method Validation in Forensic Toxicology (11) and UNODC Guidance for the Validation of Analytical Methodology and Calibration of Equipment used for Testing of Illicit Drugs in Seized Materials and Biological Samples (12), including linearity, specificity/selectivity and matrix effect, limit of detection (LOD) and limit of quantification (LOQ), accuracy and precision (within the laboratory repeatability and/or within the laboratory reproducibility conditions) to determine robustness and carry over. Calibration curves (six levels concentration: 5, 10, 20, 50, 100 and 200 ng/mL) were constructed using peak area ratio of analyte and internal standard with 1/x weighting factor linear regression. The reagent-only calibration standards and matrix-matched calibration standards were used to assess the matrix effects. The LOD and LOQ were performed to establish method sensitivity. LOD is defined as the lowest concentration of the analyte that resulted in signal-to-noise ratio of 3:1 while the LOQ is defined as the lowest concentration of the analyte that resulted in signal-to-noise ratio of 10:1. Specificity of the proposed method was assessed by analysing the response in both blank and control samples. The accuracy of the method was expressed in terms of average recoveries of spiked blank matrix at 20 and 100 ng/mL concentration levels. Precision of the method was represented as relative standard deviation (RSD%) of within-laboratory reproducibility analyses. Seven (7) replicates for each set were analyzed during each working day to test the intra-day precision and subsequently during three consecutive days for inter-day precision. Robustness was assessed by making deliberate variations to the method (duration of manual shaking, vortex shaking and centrifugation), and the subsequent effects on method performance (accuracy, precision) were investigated. According to the SWGTOX guidelines, evaluation of analyte’s carry over is needed for confirmation unless a laboratory is constantly addressing carryover in the QA/QC practices. The carry-over into subsequent sample may lead to inaccurate qualitative or quantitative results and may lead to false positive result when using instrumental methods. Blank samples were analyzed immediately after a high concentration of spiked standard of drugs. For this evaluation, blank sample with ISTD and blank solvents were analyzed after injection of 200 ng/mL calibrator and after each of three replicates injection of 100 ng/mL in a batch run. Application to real samples In order to evaluate the applicability of the method for routine applications, 20 samples of each whole blood and urine that previously analyzed using routine MRM mode of LC-MS/MS in the laboratory were re-analyzed using this method. The method was subsequently applied to dried blood stain (DBS) to investigate the potential of the validated method in forensic toxicology study. The external quality controls (QC) consisted of whole blood sample tested for proficiency testing provided by College of American Pathologists (CAP), USA and internal proficiency testing by Proficiency Testing Unit, Research and Quality Assurance Division, Department of Chemistry, Malaysia as well as the urine sample from UNODC Proficiency Testing also been tested for the study. Results and discussion Method development of multiperiod and multi-experiment MRM-EPI-MRM3 analysis with library search In this study, all compounds were separated chromatographically for multi-period and multi-experiment workflow. Each of the five periods (period 1: ephedrine and pseudoephedrine; period 2: amphetamine; period 3: methamphetamine, MDA and methamphetamine-d14 ISTD; period 4: MDMA, phentermine and MDMA-d5 ISTD; period 5: [MDEA]) consists of the MRM, EPI experiment and MRM3 (or MS3) experiment (Figure 1). Figure 1. Open in new tabDownload slide Five- period experiment in a single chromatogram of targeted compounds. Figure 1. Open in new tabDownload slide Five- period experiment in a single chromatogram of targeted compounds. The determination of precursor and product ions were performed by continuous direct infusion method using a syringe pump at 5 μL/min flowrate. The proton adduct of the molecular ion [MH]+ was chosen as the precursor ion for all analytes. An enhanced product ion (EPI) scan was conducted to obtain the product mass spectra of the precursor ion for subsequent analysis. The first transition corresponds to the most abundant product ion was used for identification and quantification, while the second transition was used for confirmation purpose. Manual optimization of the declustering potential (DP), collision energy (CE), entrance potential (EP) and collision exit potential (CXP) was performed for each analyte using 0.1 μg/mL solution of individual compounds in methanol for maximum sensitivity. The presence of precursor and product ions was investigated using the multiple reaction monitoring (MRM) experiments mode with a dwell time between 50 and 150 ms. The MRM experiment protocols were developed under a multi period experiments workflow for enhanced compounds identification and confirmation. Two additional experiments were added in a single experiment run under the multi-period multi-experiment workflow, i.e., the enhanced product ion scan (EPI) experiment and the MRM3 or MS3 multistage fragmentation experiment. The EPI experiment was set with a collision energy spread (CES), averaging three MS/MS spectrum at three different collision energies (low, medium and high), while the declustering potential, entrance potential and collision cell exit potential were set at default value. The unique fingerprint MS/MS spectra of each analyte obtained under EPI was compared with a library for identification. Spectra obtained the MS3 experiment was also compared with the MS3 library which further dimension on the interpretation and identification analytes (Table II). The optimized parameters are summarized in Table I. Table II. % Purity matching and instrument’s LOD and LOQ Compound % Purity matching with standards LOD (ng/mL) LOQ (ng/mL) EPI MRM3 EP 87 94 0.005 0.005 PEP 90 97 0.017 0.017 AMP 92 97 0.006 0.021 MA 96 100 0.156 0.521 MDA 96 99 0.15 0.50 MDMA 94 95 0.15 0.50 PTM 92 96 0.15 0.50 MDEA 84 98 0.003 0.009 Compound % Purity matching with standards LOD (ng/mL) LOQ (ng/mL) EPI MRM3 EP 87 94 0.005 0.005 PEP 90 97 0.017 0.017 AMP 92 97 0.006 0.021 MA 96 100 0.156 0.521 MDA 96 99 0.15 0.50 MDMA 94 95 0.15 0.50 PTM 92 96 0.15 0.50 MDEA 84 98 0.003 0.009 Open in new tab Table II. % Purity matching and instrument’s LOD and LOQ Compound % Purity matching with standards LOD (ng/mL) LOQ (ng/mL) EPI MRM3 EP 87 94 0.005 0.005 PEP 90 97 0.017 0.017 AMP 92 97 0.006 0.021 MA 96 100 0.156 0.521 MDA 96 99 0.15 0.50 MDMA 94 95 0.15 0.50 PTM 92 96 0.15 0.50 MDEA 84 98 0.003 0.009 Compound % Purity matching with standards LOD (ng/mL) LOQ (ng/mL) EPI MRM3 EP 87 94 0.005 0.005 PEP 90 97 0.017 0.017 AMP 92 97 0.006 0.021 MA 96 100 0.156 0.521 MDA 96 99 0.15 0.50 MDMA 94 95 0.15 0.50 PTM 92 96 0.15 0.50 MDEA 84 98 0.003 0.009 Open in new tab Linearity, LOD, LOQ and carry over The method was validated for linearity, sensitivity, specificity and matrix effects, accuracy, precision, robustness and carry over. A standard curve of six points was constructed by determining the best fit of peak-area ratios (peak area ratio of the analyte to internal standard) versus the analyte concentration with 1/x weightage linear regression analysis. Dynamic linear ranges, LOD, LOQ and calibration results are summarized in Table III. The results showed good linear relationships with correlation coefficients greater than 0.994 for all the target analytes. Table III. Method LOD and LOQ, and calibration curve dynamic range Compound LOD (ng/mL) LOQ (ng/mL) Slope Intercept R2 Whole blood (20 ppb)  AMP 3.42 10.26 0.03483 0.01040 0.9975  MA 4.43 13.31 0.03530 0.17505 0.9975  MDA 4.35 13.05 0.63843 0.63416 0.9955  MDMA 3.74 11.22 1.25822 −2.15486 0.9945  MDEA 5.15 15.45 0.03197 0.08349 0.9943  PEP 3.63 10.89 0.00748 0.03595 0.9997  EP 3.69 11.07 0.00632 0.03404 0.9959  PTM 3.90 11.71 0.00282 −0.01069 0.9973 Dried blood stain (20 ppb)  AMP 3.54 10.62 0.01877 0.01811 0.9991  MA 5.32 15.97 0.01827 0.14028 0.9957  MDA 2.18 6.54 0.10358 0.30267 0.9985  MDMA 5.22 15.66 0.21535 −0.00576 0.9973  MDEA 2.44 7.33 0.00506 0.02609 0.9975  PEP 4.74 14.22 0.00475 0.02673 0.9975  EP 1.51 4.53 0.00376 0.02496 0.9976  PTM 5.37 16.11 0.00131 −0.00446 0.9946 Urine (20 ppb)  AMP 4.18 12.56 0.00610 0.00342 0.9990  MA 7.29 21.87 0.00343 0.07763 0.9951  MDA 3.65 10.97 0.02010 0.03152 0.9972  MDMA 5.13 15.39 0.03320 0.05804 0.9964  MDEA 1.86 5.58 0.00950 0.0529 0.9952  PEP 3.35 10.07 0.17882 0.61049 0.9968  EP 3.12 9.36 0.12496 0.29508 0.9954  PTM 4.89 14.68 0.01835 −0.10540 0.9994 Compound LOD (ng/mL) LOQ (ng/mL) Slope Intercept R2 Whole blood (20 ppb)  AMP 3.42 10.26 0.03483 0.01040 0.9975  MA 4.43 13.31 0.03530 0.17505 0.9975  MDA 4.35 13.05 0.63843 0.63416 0.9955  MDMA 3.74 11.22 1.25822 −2.15486 0.9945  MDEA 5.15 15.45 0.03197 0.08349 0.9943  PEP 3.63 10.89 0.00748 0.03595 0.9997  EP 3.69 11.07 0.00632 0.03404 0.9959  PTM 3.90 11.71 0.00282 −0.01069 0.9973 Dried blood stain (20 ppb)  AMP 3.54 10.62 0.01877 0.01811 0.9991  MA 5.32 15.97 0.01827 0.14028 0.9957  MDA 2.18 6.54 0.10358 0.30267 0.9985  MDMA 5.22 15.66 0.21535 −0.00576 0.9973  MDEA 2.44 7.33 0.00506 0.02609 0.9975  PEP 4.74 14.22 0.00475 0.02673 0.9975  EP 1.51 4.53 0.00376 0.02496 0.9976  PTM 5.37 16.11 0.00131 −0.00446 0.9946 Urine (20 ppb)  AMP 4.18 12.56 0.00610 0.00342 0.9990  MA 7.29 21.87 0.00343 0.07763 0.9951  MDA 3.65 10.97 0.02010 0.03152 0.9972  MDMA 5.13 15.39 0.03320 0.05804 0.9964  MDEA 1.86 5.58 0.00950 0.0529 0.9952  PEP 3.35 10.07 0.17882 0.61049 0.9968  EP 3.12 9.36 0.12496 0.29508 0.9954  PTM 4.89 14.68 0.01835 −0.10540 0.9994 Open in new tab Table III. Method LOD and LOQ, and calibration curve dynamic range Compound LOD (ng/mL) LOQ (ng/mL) Slope Intercept R2 Whole blood (20 ppb)  AMP 3.42 10.26 0.03483 0.01040 0.9975  MA 4.43 13.31 0.03530 0.17505 0.9975  MDA 4.35 13.05 0.63843 0.63416 0.9955  MDMA 3.74 11.22 1.25822 −2.15486 0.9945  MDEA 5.15 15.45 0.03197 0.08349 0.9943  PEP 3.63 10.89 0.00748 0.03595 0.9997  EP 3.69 11.07 0.00632 0.03404 0.9959  PTM 3.90 11.71 0.00282 −0.01069 0.9973 Dried blood stain (20 ppb)  AMP 3.54 10.62 0.01877 0.01811 0.9991  MA 5.32 15.97 0.01827 0.14028 0.9957  MDA 2.18 6.54 0.10358 0.30267 0.9985  MDMA 5.22 15.66 0.21535 −0.00576 0.9973  MDEA 2.44 7.33 0.00506 0.02609 0.9975  PEP 4.74 14.22 0.00475 0.02673 0.9975  EP 1.51 4.53 0.00376 0.02496 0.9976  PTM 5.37 16.11 0.00131 −0.00446 0.9946 Urine (20 ppb)  AMP 4.18 12.56 0.00610 0.00342 0.9990  MA 7.29 21.87 0.00343 0.07763 0.9951  MDA 3.65 10.97 0.02010 0.03152 0.9972  MDMA 5.13 15.39 0.03320 0.05804 0.9964  MDEA 1.86 5.58 0.00950 0.0529 0.9952  PEP 3.35 10.07 0.17882 0.61049 0.9968  EP 3.12 9.36 0.12496 0.29508 0.9954  PTM 4.89 14.68 0.01835 −0.10540 0.9994 Compound LOD (ng/mL) LOQ (ng/mL) Slope Intercept R2 Whole blood (20 ppb)  AMP 3.42 10.26 0.03483 0.01040 0.9975  MA 4.43 13.31 0.03530 0.17505 0.9975  MDA 4.35 13.05 0.63843 0.63416 0.9955  MDMA 3.74 11.22 1.25822 −2.15486 0.9945  MDEA 5.15 15.45 0.03197 0.08349 0.9943  PEP 3.63 10.89 0.00748 0.03595 0.9997  EP 3.69 11.07 0.00632 0.03404 0.9959  PTM 3.90 11.71 0.00282 −0.01069 0.9973 Dried blood stain (20 ppb)  AMP 3.54 10.62 0.01877 0.01811 0.9991  MA 5.32 15.97 0.01827 0.14028 0.9957  MDA 2.18 6.54 0.10358 0.30267 0.9985  MDMA 5.22 15.66 0.21535 −0.00576 0.9973  MDEA 2.44 7.33 0.00506 0.02609 0.9975  PEP 4.74 14.22 0.00475 0.02673 0.9975  EP 1.51 4.53 0.00376 0.02496 0.9976  PTM 5.37 16.11 0.00131 −0.00446 0.9946 Urine (20 ppb)  AMP 4.18 12.56 0.00610 0.00342 0.9990  MA 7.29 21.87 0.00343 0.07763 0.9951  MDA 3.65 10.97 0.02010 0.03152 0.9972  MDMA 5.13 15.39 0.03320 0.05804 0.9964  MDEA 1.86 5.58 0.00950 0.0529 0.9952  PEP 3.35 10.07 0.17882 0.61049 0.9968  EP 3.12 9.36 0.12496 0.29508 0.9954  PTM 4.89 14.68 0.01835 −0.10540 0.9994 Open in new tab No analyte was detected in both blank sample and solvent injected immediately following analysis of 200 ng/mL calibrator and after each of three replicates injection of 100 ng/mL in a batch run indicating the absence of carry over effect. Recoveries accuracy and precision The results revealed good precisions and accuracies, and established the robustness of the method. Method validation results (Table IV) indicated the recoveries for all analytes were within ± 20% error, with acceptable intra-day and inter-day precision results of less than 15% RSD. Table IV. Method accuracy and precision Analyte Mean Accuracy Standard Deviation % CV 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL Whole blood  AMP 19.81 91.58 99.07 91.58 1.14 4.416 5.75 4.82  MA 22.24 102 111.22 101.96 1.479 4.708 6.65 4.62  MDA 18.89 95.49 94.43 95.49 1.451 7.729 7.68 8.09  MDMA 18.22 106.5 91.08 106.49 1.247 1.039 6.85 9.76  MDEA 22.97 108.2 114.85 108.2 1.717 6.222 7.47 5.75  PEP 20.21 96.79 101.07 96.79 1.21 7.545 5.98 7.8  EP 19.45 90.69 97.25 90.69 1.233 5.406 6.34 5.96  PTM 17.24 85.19 86.19 85.19 1.302 4.019 7.55 4.72 Dried blood stain  AMP 21.98 99.19 109.93 99.2 1.182 5.089 5.37 5.13  MA 21.8 108.69 109 108.7 1.775 6.942 8.14 6.39  MDA 22.18 100.58 110.94 100.59 0.727 8.753 3.27 8.7  MDMA 20.42 108.96 102.13 108.97 1.747 9.141 8.55 8.39  MDEA 21.6 106.64 108.04 106.64 0.815 6.487 3.77 6.08  PEP 19.31 95.94 96.58 95.95 1.581 2.943 8.19 3.07  EP 18.55 94.34 92.75 94.34 0.504 3.538 2.71 3.75  PTM 18.41 93.09 92.07 93.09 1.79 8.269 9.72 8.88 Urine  AMP 19.02 102 95.12 102.01 1.396 3.765 7.34 3.69  MA 19.52 115.3 97.59 115.34 2.43 2.664 12.45 2.31  MDA 17.93 103.4 89.66 103.42 1.219 2.794 6.8 2.7  MDMA 18.95 105.6 94.74 105.56 1.718 7.776 9.07 7.37  MDEA 24.51 93.83 122.54 93.83 0.62 12.04 2.53 12.83  PEP 19.44 85.22 97.21 85.22 1.119 4.329 5.75 5.08  EP 20 102.3 100.01 102.28 1.04 2.581 5.2 2.52  PTM 16.95 82.25 84.76 82.25 1.632 8.643 9.63 10.51 Analyte Mean Accuracy Standard Deviation % CV 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL Whole blood  AMP 19.81 91.58 99.07 91.58 1.14 4.416 5.75 4.82  MA 22.24 102 111.22 101.96 1.479 4.708 6.65 4.62  MDA 18.89 95.49 94.43 95.49 1.451 7.729 7.68 8.09  MDMA 18.22 106.5 91.08 106.49 1.247 1.039 6.85 9.76  MDEA 22.97 108.2 114.85 108.2 1.717 6.222 7.47 5.75  PEP 20.21 96.79 101.07 96.79 1.21 7.545 5.98 7.8  EP 19.45 90.69 97.25 90.69 1.233 5.406 6.34 5.96  PTM 17.24 85.19 86.19 85.19 1.302 4.019 7.55 4.72 Dried blood stain  AMP 21.98 99.19 109.93 99.2 1.182 5.089 5.37 5.13  MA 21.8 108.69 109 108.7 1.775 6.942 8.14 6.39  MDA 22.18 100.58 110.94 100.59 0.727 8.753 3.27 8.7  MDMA 20.42 108.96 102.13 108.97 1.747 9.141 8.55 8.39  MDEA 21.6 106.64 108.04 106.64 0.815 6.487 3.77 6.08  PEP 19.31 95.94 96.58 95.95 1.581 2.943 8.19 3.07  EP 18.55 94.34 92.75 94.34 0.504 3.538 2.71 3.75  PTM 18.41 93.09 92.07 93.09 1.79 8.269 9.72 8.88 Urine  AMP 19.02 102 95.12 102.01 1.396 3.765 7.34 3.69  MA 19.52 115.3 97.59 115.34 2.43 2.664 12.45 2.31  MDA 17.93 103.4 89.66 103.42 1.219 2.794 6.8 2.7  MDMA 18.95 105.6 94.74 105.56 1.718 7.776 9.07 7.37  MDEA 24.51 93.83 122.54 93.83 0.62 12.04 2.53 12.83  PEP 19.44 85.22 97.21 85.22 1.119 4.329 5.75 5.08  EP 20 102.3 100.01 102.28 1.04 2.581 5.2 2.52  PTM 16.95 82.25 84.76 82.25 1.632 8.643 9.63 10.51 Open in new tab Table IV. Method accuracy and precision Analyte Mean Accuracy Standard Deviation % CV 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL Whole blood  AMP 19.81 91.58 99.07 91.58 1.14 4.416 5.75 4.82  MA 22.24 102 111.22 101.96 1.479 4.708 6.65 4.62  MDA 18.89 95.49 94.43 95.49 1.451 7.729 7.68 8.09  MDMA 18.22 106.5 91.08 106.49 1.247 1.039 6.85 9.76  MDEA 22.97 108.2 114.85 108.2 1.717 6.222 7.47 5.75  PEP 20.21 96.79 101.07 96.79 1.21 7.545 5.98 7.8  EP 19.45 90.69 97.25 90.69 1.233 5.406 6.34 5.96  PTM 17.24 85.19 86.19 85.19 1.302 4.019 7.55 4.72 Dried blood stain  AMP 21.98 99.19 109.93 99.2 1.182 5.089 5.37 5.13  MA 21.8 108.69 109 108.7 1.775 6.942 8.14 6.39  MDA 22.18 100.58 110.94 100.59 0.727 8.753 3.27 8.7  MDMA 20.42 108.96 102.13 108.97 1.747 9.141 8.55 8.39  MDEA 21.6 106.64 108.04 106.64 0.815 6.487 3.77 6.08  PEP 19.31 95.94 96.58 95.95 1.581 2.943 8.19 3.07  EP 18.55 94.34 92.75 94.34 0.504 3.538 2.71 3.75  PTM 18.41 93.09 92.07 93.09 1.79 8.269 9.72 8.88 Urine  AMP 19.02 102 95.12 102.01 1.396 3.765 7.34 3.69  MA 19.52 115.3 97.59 115.34 2.43 2.664 12.45 2.31  MDA 17.93 103.4 89.66 103.42 1.219 2.794 6.8 2.7  MDMA 18.95 105.6 94.74 105.56 1.718 7.776 9.07 7.37  MDEA 24.51 93.83 122.54 93.83 0.62 12.04 2.53 12.83  PEP 19.44 85.22 97.21 85.22 1.119 4.329 5.75 5.08  EP 20 102.3 100.01 102.28 1.04 2.581 5.2 2.52  PTM 16.95 82.25 84.76 82.25 1.632 8.643 9.63 10.51 Analyte Mean Accuracy Standard Deviation % CV 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL 20 ng/mL 100 ng/mL Whole blood  AMP 19.81 91.58 99.07 91.58 1.14 4.416 5.75 4.82  MA 22.24 102 111.22 101.96 1.479 4.708 6.65 4.62  MDA 18.89 95.49 94.43 95.49 1.451 7.729 7.68 8.09  MDMA 18.22 106.5 91.08 106.49 1.247 1.039 6.85 9.76  MDEA 22.97 108.2 114.85 108.2 1.717 6.222 7.47 5.75  PEP 20.21 96.79 101.07 96.79 1.21 7.545 5.98 7.8  EP 19.45 90.69 97.25 90.69 1.233 5.406 6.34 5.96  PTM 17.24 85.19 86.19 85.19 1.302 4.019 7.55 4.72 Dried blood stain  AMP 21.98 99.19 109.93 99.2 1.182 5.089 5.37 5.13  MA 21.8 108.69 109 108.7 1.775 6.942 8.14 6.39  MDA 22.18 100.58 110.94 100.59 0.727 8.753 3.27 8.7  MDMA 20.42 108.96 102.13 108.97 1.747 9.141 8.55 8.39  MDEA 21.6 106.64 108.04 106.64 0.815 6.487 3.77 6.08  PEP 19.31 95.94 96.58 95.95 1.581 2.943 8.19 3.07  EP 18.55 94.34 92.75 94.34 0.504 3.538 2.71 3.75  PTM 18.41 93.09 92.07 93.09 1.79 8.269 9.72 8.88 Urine  AMP 19.02 102 95.12 102.01 1.396 3.765 7.34 3.69  MA 19.52 115.3 97.59 115.34 2.43 2.664 12.45 2.31  MDA 17.93 103.4 89.66 103.42 1.219 2.794 6.8 2.7  MDMA 18.95 105.6 94.74 105.56 1.718 7.776 9.07 7.37  MDEA 24.51 93.83 122.54 93.83 0.62 12.04 2.53 12.83  PEP 19.44 85.22 97.21 85.22 1.119 4.329 5.75 5.08  EP 20 102.3 100.01 102.28 1.04 2.581 5.2 2.52  PTM 16.95 82.25 84.76 82.25 1.632 8.643 9.63 10.51 Open in new tab Selectivity and matrix effects The reagent-only and matrix-matched calibration standards were used to assess the matrix effects. A typical double blank control (free of analytes and internal standard) was analyzed and no interfering peaks from endogenous compounds were observed at retention times correspond to the analytes or internal standards. Matrix effect was evaluated using the below equation (13), %Matrixeffect=Post-extractedspikedsampleresponseNon-extractedneatsampleresponse×100 where the post-extracted spiked sample contains the analytes added into the blank blood matrix, and the non-extracted neat sample contains the analytes added to the mobile phase. The experiment was performed in seven replicates (n = 7) and the experimental % matric effect and coefficient variation (CV) are 80–110% and <10%, respectively, within the acceptable range (% matric effect = 75–125%; CV = 15%) (14). Application on forensic toxicology cases in Malaysia The developed method was applied to whole blood, urine and dried blood stain (DBS) as well as the proficiency testing (PT) samples. The measured and intended responses (determined previously from real forensic toxicology cases in Malaysia) are listed in Table V. The accuracies were calculated by comparing the measured with the intended/reported concentrations and ranged from 83.3–106.7% for the entire tested analytes. The accuracy results also indicated that the use of bull’s blood as blank sample does not have significant impacts in the method. Table V. Measured response and accuracy for ATS-related drugs in whole blood sample, dried blood stain and urine samples Sample Whole blood sample Dried blood stain Urine* Intended response (ng/mL) Measured response (ng/mL) Accuracy (%) Measured response (ng/mL) Accuracy (%) Intended response (ng/mL) Measured response (ng/mL) 1 MDMA (600.0), MDA (50.0) MDMA (591.2), MDA (48.6) MDMA (98.5), MDA (97.2) MDMA (585.3), MDA (48.0) MDMA (97.5), MDA (96.0) PTM PTM 2 MDMA (200.0), MDA (35.4), MA (40.1) MDMA (190.4), MDA (31.2), MA (33.4) MDMA (95.2), MDA (88.1), MA (83.3) MDMA (192.6), MDA (30.1), MA (33.4) MDMA (96.3), MDA (85.0), MA (83.3) PTM, PEP PTM, PEP 3 MA (105.8), AMP (16.8) MA (100.5), AMP (14.2) MA (95.0), AMP (84.5) MA (98.8), AMP (13.6) MA (93.3), AMP (81.0) MDMA, MDA MDMA, MDA 4 PEP (350.6) PEP (352.3) PEP (100.4) PEP (348.6) PEP (99.4) MA, AMP, EP MA, AMP, EP 5 MDMA (635.2), MDA (56.3) MDMA (621.3), MDA (52.1) MDMA (97.8), MDA (92.5) MDMA (612.5), MDA (48.7) MDMA (96.4), MDA (86.5) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 6 PTM (485.6), PEP (205.8) PTM (451.0), PEP (215.2) PTM (92.8), PEP (104.5) PTM (447.9), PEP (216.0) PTM (92.2), PEP (104.9) PEP PEP 7 PTM (151.2) PTM (130.4) PTM (86.2) PTM (132.2) PTM (87.4) MDEA MDEA 8 MDMA (1130.2), MDA (60.8) MDMA (1100), MDA (65.8) MDMA (97.3), MDA (108.2) MDMA (1020), MDA (60.2) MDMA (90.2), MDA (99.0) MA, AMP MA, AMP 9 MA (245.8), AMP (30.2) MA (241.7), AMP (28.6) MA (98.3), AMP (94.7) MA (230.8), AMP (25.6) MA (93.8), AMP (84.7) MA, AMP MA, AMP 10 MA (297.6), AMP (58.0) MA (291.6), AMP (55.0) MA (97.9), AMP (94.8) MA (281.2), AMP (60.0) MA (94.4), AMP (103.4) MDMA, MDA MDMA, MDA 11 PTM (157.8) PTM (160.2) PTM (101.5) PTM (155.8) PTM (98.7) MDA MDA 12 MA (275.0), AMP (70.3) MA (278.3), AMP (67.4) MA (101.2), AMP (95.8) MA (270.2), AMP (60.0) MA (98.2), AMP (85.3) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 13 MA (680.9), AMP (86.2) MA (678.0), AMP (85.4) MA (99.5), AMP (99.0) MA (690.0), AMP (90.2) MA (101.3), AMP (104.6) MDMA, MDA MDMA, MDA 14 MA (450.0), AMP (40.6) MA (445.1), AMP (38.6) MA (98.9), AMP (95.1) MA (435.0), AMP (40.2) MA (96.7), AMP (99.0) MA, AMP MA, AMP 15 MA (370.7), AMP (45.0) MA (375.1), AMP (43.7) MA (101.1), AMP (97.1) MA (350.9), AMP (37.8) MA (94.6), AMP (84.0) MA, AMP MA, AMP 16 PEP (57.8) PEP (56.8) PEP (98.2) PEP (60.2) PEP (104.1) MA, AMP MA, AMP 17 MDMA (50.8), MDA (42.5) MDMA (51.6), MDA (44.6) MDMA (101.5), MDA (104.9) MDMA (48.7), MDA (41.5) MDMA (95.8), MDA (97.6) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 18 MDMA (60.0), MDA (45.0) MDMA (59.9), MDA (40.3) MDMA (99.8), MDA (89.5) MDMA (62.5), MDA (43.7) MDMA (104.1), MDA (97.1) PTM PTM 19 PEP (55.0) PEP (57.0) PEP (103.6) PEP (50.8) PEP (92.3) MA, AMP MA, AMP 20 MA (218.7), AMP (23.8) MA (222.4), AMP (25.4) MA (101.6), AMP (106.7) MA (212.9), AMP (21.5) MA (97.3), AMP (90.3) MDMA, MDA MDMA, MDA QC 1 MA (769.42), AMP (150.10) MA (750.20), AMP (135.50) MA (97.5), AMP (90.3) MA (753.3), AMP (138.6) MA (97.9), AMP (92.3) PEP, EP PEP, EP QC 2 MA (395.65), AMP (75.84), MDMA (1220.50), MDA (201.93) MA (360.10), AMP (78.3), MDMA (1300), MDA (185.80) MA (91.0), AMP (103.2), MDMA (106.5), MDA (92.0) MA (356.8), AMP (80.2), MDMA (1280), MDA (178.9) MA (90.1), AMP (105.7), MDMA (104.8), MDA (88.6) MDA MDA QC 3 MA (299.66), AMP (49.44) MA (275.80), AMP (51.70) MA (92.0), AMP (104.5) MA (268.4), AMP (52.31) MA (89.6), AMP (105.8) MDA MDA QC 4 PTM (248.50) PTM (240.25) PTM (96.6) PTM (235.9) PTM (94.9) MA MA QC 5 n.a n.a n.a n.a n.a MA, AMP MA, AMP QC 6 n.a n.a n.a n.a n.a MDMA MDMA Sample Whole blood sample Dried blood stain Urine* Intended response (ng/mL) Measured response (ng/mL) Accuracy (%) Measured response (ng/mL) Accuracy (%) Intended response (ng/mL) Measured response (ng/mL) 1 MDMA (600.0), MDA (50.0) MDMA (591.2), MDA (48.6) MDMA (98.5), MDA (97.2) MDMA (585.3), MDA (48.0) MDMA (97.5), MDA (96.0) PTM PTM 2 MDMA (200.0), MDA (35.4), MA (40.1) MDMA (190.4), MDA (31.2), MA (33.4) MDMA (95.2), MDA (88.1), MA (83.3) MDMA (192.6), MDA (30.1), MA (33.4) MDMA (96.3), MDA (85.0), MA (83.3) PTM, PEP PTM, PEP 3 MA (105.8), AMP (16.8) MA (100.5), AMP (14.2) MA (95.0), AMP (84.5) MA (98.8), AMP (13.6) MA (93.3), AMP (81.0) MDMA, MDA MDMA, MDA 4 PEP (350.6) PEP (352.3) PEP (100.4) PEP (348.6) PEP (99.4) MA, AMP, EP MA, AMP, EP 5 MDMA (635.2), MDA (56.3) MDMA (621.3), MDA (52.1) MDMA (97.8), MDA (92.5) MDMA (612.5), MDA (48.7) MDMA (96.4), MDA (86.5) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 6 PTM (485.6), PEP (205.8) PTM (451.0), PEP (215.2) PTM (92.8), PEP (104.5) PTM (447.9), PEP (216.0) PTM (92.2), PEP (104.9) PEP PEP 7 PTM (151.2) PTM (130.4) PTM (86.2) PTM (132.2) PTM (87.4) MDEA MDEA 8 MDMA (1130.2), MDA (60.8) MDMA (1100), MDA (65.8) MDMA (97.3), MDA (108.2) MDMA (1020), MDA (60.2) MDMA (90.2), MDA (99.0) MA, AMP MA, AMP 9 MA (245.8), AMP (30.2) MA (241.7), AMP (28.6) MA (98.3), AMP (94.7) MA (230.8), AMP (25.6) MA (93.8), AMP (84.7) MA, AMP MA, AMP 10 MA (297.6), AMP (58.0) MA (291.6), AMP (55.0) MA (97.9), AMP (94.8) MA (281.2), AMP (60.0) MA (94.4), AMP (103.4) MDMA, MDA MDMA, MDA 11 PTM (157.8) PTM (160.2) PTM (101.5) PTM (155.8) PTM (98.7) MDA MDA 12 MA (275.0), AMP (70.3) MA (278.3), AMP (67.4) MA (101.2), AMP (95.8) MA (270.2), AMP (60.0) MA (98.2), AMP (85.3) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 13 MA (680.9), AMP (86.2) MA (678.0), AMP (85.4) MA (99.5), AMP (99.0) MA (690.0), AMP (90.2) MA (101.3), AMP (104.6) MDMA, MDA MDMA, MDA 14 MA (450.0), AMP (40.6) MA (445.1), AMP (38.6) MA (98.9), AMP (95.1) MA (435.0), AMP (40.2) MA (96.7), AMP (99.0) MA, AMP MA, AMP 15 MA (370.7), AMP (45.0) MA (375.1), AMP (43.7) MA (101.1), AMP (97.1) MA (350.9), AMP (37.8) MA (94.6), AMP (84.0) MA, AMP MA, AMP 16 PEP (57.8) PEP (56.8) PEP (98.2) PEP (60.2) PEP (104.1) MA, AMP MA, AMP 17 MDMA (50.8), MDA (42.5) MDMA (51.6), MDA (44.6) MDMA (101.5), MDA (104.9) MDMA (48.7), MDA (41.5) MDMA (95.8), MDA (97.6) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 18 MDMA (60.0), MDA (45.0) MDMA (59.9), MDA (40.3) MDMA (99.8), MDA (89.5) MDMA (62.5), MDA (43.7) MDMA (104.1), MDA (97.1) PTM PTM 19 PEP (55.0) PEP (57.0) PEP (103.6) PEP (50.8) PEP (92.3) MA, AMP MA, AMP 20 MA (218.7), AMP (23.8) MA (222.4), AMP (25.4) MA (101.6), AMP (106.7) MA (212.9), AMP (21.5) MA (97.3), AMP (90.3) MDMA, MDA MDMA, MDA QC 1 MA (769.42), AMP (150.10) MA (750.20), AMP (135.50) MA (97.5), AMP (90.3) MA (753.3), AMP (138.6) MA (97.9), AMP (92.3) PEP, EP PEP, EP QC 2 MA (395.65), AMP (75.84), MDMA (1220.50), MDA (201.93) MA (360.10), AMP (78.3), MDMA (1300), MDA (185.80) MA (91.0), AMP (103.2), MDMA (106.5), MDA (92.0) MA (356.8), AMP (80.2), MDMA (1280), MDA (178.9) MA (90.1), AMP (105.7), MDMA (104.8), MDA (88.6) MDA MDA QC 3 MA (299.66), AMP (49.44) MA (275.80), AMP (51.70) MA (92.0), AMP (104.5) MA (268.4), AMP (52.31) MA (89.6), AMP (105.8) MDA MDA QC 4 PTM (248.50) PTM (240.25) PTM (96.6) PTM (235.9) PTM (94.9) MA MA QC 5 n.a n.a n.a n.a n.a MA, AMP MA, AMP QC 6 n.a n.a n.a n.a n.a MDMA MDMA aQualitative analysis based on the routine laboratory practice. QC: College of American Pathologists (CAP) and Quality Assurance Div., Dept. of Chemistry, Malaysia Open in new tab Table V. Measured response and accuracy for ATS-related drugs in whole blood sample, dried blood stain and urine samples Sample Whole blood sample Dried blood stain Urine* Intended response (ng/mL) Measured response (ng/mL) Accuracy (%) Measured response (ng/mL) Accuracy (%) Intended response (ng/mL) Measured response (ng/mL) 1 MDMA (600.0), MDA (50.0) MDMA (591.2), MDA (48.6) MDMA (98.5), MDA (97.2) MDMA (585.3), MDA (48.0) MDMA (97.5), MDA (96.0) PTM PTM 2 MDMA (200.0), MDA (35.4), MA (40.1) MDMA (190.4), MDA (31.2), MA (33.4) MDMA (95.2), MDA (88.1), MA (83.3) MDMA (192.6), MDA (30.1), MA (33.4) MDMA (96.3), MDA (85.0), MA (83.3) PTM, PEP PTM, PEP 3 MA (105.8), AMP (16.8) MA (100.5), AMP (14.2) MA (95.0), AMP (84.5) MA (98.8), AMP (13.6) MA (93.3), AMP (81.0) MDMA, MDA MDMA, MDA 4 PEP (350.6) PEP (352.3) PEP (100.4) PEP (348.6) PEP (99.4) MA, AMP, EP MA, AMP, EP 5 MDMA (635.2), MDA (56.3) MDMA (621.3), MDA (52.1) MDMA (97.8), MDA (92.5) MDMA (612.5), MDA (48.7) MDMA (96.4), MDA (86.5) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 6 PTM (485.6), PEP (205.8) PTM (451.0), PEP (215.2) PTM (92.8), PEP (104.5) PTM (447.9), PEP (216.0) PTM (92.2), PEP (104.9) PEP PEP 7 PTM (151.2) PTM (130.4) PTM (86.2) PTM (132.2) PTM (87.4) MDEA MDEA 8 MDMA (1130.2), MDA (60.8) MDMA (1100), MDA (65.8) MDMA (97.3), MDA (108.2) MDMA (1020), MDA (60.2) MDMA (90.2), MDA (99.0) MA, AMP MA, AMP 9 MA (245.8), AMP (30.2) MA (241.7), AMP (28.6) MA (98.3), AMP (94.7) MA (230.8), AMP (25.6) MA (93.8), AMP (84.7) MA, AMP MA, AMP 10 MA (297.6), AMP (58.0) MA (291.6), AMP (55.0) MA (97.9), AMP (94.8) MA (281.2), AMP (60.0) MA (94.4), AMP (103.4) MDMA, MDA MDMA, MDA 11 PTM (157.8) PTM (160.2) PTM (101.5) PTM (155.8) PTM (98.7) MDA MDA 12 MA (275.0), AMP (70.3) MA (278.3), AMP (67.4) MA (101.2), AMP (95.8) MA (270.2), AMP (60.0) MA (98.2), AMP (85.3) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 13 MA (680.9), AMP (86.2) MA (678.0), AMP (85.4) MA (99.5), AMP (99.0) MA (690.0), AMP (90.2) MA (101.3), AMP (104.6) MDMA, MDA MDMA, MDA 14 MA (450.0), AMP (40.6) MA (445.1), AMP (38.6) MA (98.9), AMP (95.1) MA (435.0), AMP (40.2) MA (96.7), AMP (99.0) MA, AMP MA, AMP 15 MA (370.7), AMP (45.0) MA (375.1), AMP (43.7) MA (101.1), AMP (97.1) MA (350.9), AMP (37.8) MA (94.6), AMP (84.0) MA, AMP MA, AMP 16 PEP (57.8) PEP (56.8) PEP (98.2) PEP (60.2) PEP (104.1) MA, AMP MA, AMP 17 MDMA (50.8), MDA (42.5) MDMA (51.6), MDA (44.6) MDMA (101.5), MDA (104.9) MDMA (48.7), MDA (41.5) MDMA (95.8), MDA (97.6) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 18 MDMA (60.0), MDA (45.0) MDMA (59.9), MDA (40.3) MDMA (99.8), MDA (89.5) MDMA (62.5), MDA (43.7) MDMA (104.1), MDA (97.1) PTM PTM 19 PEP (55.0) PEP (57.0) PEP (103.6) PEP (50.8) PEP (92.3) MA, AMP MA, AMP 20 MA (218.7), AMP (23.8) MA (222.4), AMP (25.4) MA (101.6), AMP (106.7) MA (212.9), AMP (21.5) MA (97.3), AMP (90.3) MDMA, MDA MDMA, MDA QC 1 MA (769.42), AMP (150.10) MA (750.20), AMP (135.50) MA (97.5), AMP (90.3) MA (753.3), AMP (138.6) MA (97.9), AMP (92.3) PEP, EP PEP, EP QC 2 MA (395.65), AMP (75.84), MDMA (1220.50), MDA (201.93) MA (360.10), AMP (78.3), MDMA (1300), MDA (185.80) MA (91.0), AMP (103.2), MDMA (106.5), MDA (92.0) MA (356.8), AMP (80.2), MDMA (1280), MDA (178.9) MA (90.1), AMP (105.7), MDMA (104.8), MDA (88.6) MDA MDA QC 3 MA (299.66), AMP (49.44) MA (275.80), AMP (51.70) MA (92.0), AMP (104.5) MA (268.4), AMP (52.31) MA (89.6), AMP (105.8) MDA MDA QC 4 PTM (248.50) PTM (240.25) PTM (96.6) PTM (235.9) PTM (94.9) MA MA QC 5 n.a n.a n.a n.a n.a MA, AMP MA, AMP QC 6 n.a n.a n.a n.a n.a MDMA MDMA Sample Whole blood sample Dried blood stain Urine* Intended response (ng/mL) Measured response (ng/mL) Accuracy (%) Measured response (ng/mL) Accuracy (%) Intended response (ng/mL) Measured response (ng/mL) 1 MDMA (600.0), MDA (50.0) MDMA (591.2), MDA (48.6) MDMA (98.5), MDA (97.2) MDMA (585.3), MDA (48.0) MDMA (97.5), MDA (96.0) PTM PTM 2 MDMA (200.0), MDA (35.4), MA (40.1) MDMA (190.4), MDA (31.2), MA (33.4) MDMA (95.2), MDA (88.1), MA (83.3) MDMA (192.6), MDA (30.1), MA (33.4) MDMA (96.3), MDA (85.0), MA (83.3) PTM, PEP PTM, PEP 3 MA (105.8), AMP (16.8) MA (100.5), AMP (14.2) MA (95.0), AMP (84.5) MA (98.8), AMP (13.6) MA (93.3), AMP (81.0) MDMA, MDA MDMA, MDA 4 PEP (350.6) PEP (352.3) PEP (100.4) PEP (348.6) PEP (99.4) MA, AMP, EP MA, AMP, EP 5 MDMA (635.2), MDA (56.3) MDMA (621.3), MDA (52.1) MDMA (97.8), MDA (92.5) MDMA (612.5), MDA (48.7) MDMA (96.4), MDA (86.5) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 6 PTM (485.6), PEP (205.8) PTM (451.0), PEP (215.2) PTM (92.8), PEP (104.5) PTM (447.9), PEP (216.0) PTM (92.2), PEP (104.9) PEP PEP 7 PTM (151.2) PTM (130.4) PTM (86.2) PTM (132.2) PTM (87.4) MDEA MDEA 8 MDMA (1130.2), MDA (60.8) MDMA (1100), MDA (65.8) MDMA (97.3), MDA (108.2) MDMA (1020), MDA (60.2) MDMA (90.2), MDA (99.0) MA, AMP MA, AMP 9 MA (245.8), AMP (30.2) MA (241.7), AMP (28.6) MA (98.3), AMP (94.7) MA (230.8), AMP (25.6) MA (93.8), AMP (84.7) MA, AMP MA, AMP 10 MA (297.6), AMP (58.0) MA (291.6), AMP (55.0) MA (97.9), AMP (94.8) MA (281.2), AMP (60.0) MA (94.4), AMP (103.4) MDMA, MDA MDMA, MDA 11 PTM (157.8) PTM (160.2) PTM (101.5) PTM (155.8) PTM (98.7) MDA MDA 12 MA (275.0), AMP (70.3) MA (278.3), AMP (67.4) MA (101.2), AMP (95.8) MA (270.2), AMP (60.0) MA (98.2), AMP (85.3) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 13 MA (680.9), AMP (86.2) MA (678.0), AMP (85.4) MA (99.5), AMP (99.0) MA (690.0), AMP (90.2) MA (101.3), AMP (104.6) MDMA, MDA MDMA, MDA 14 MA (450.0), AMP (40.6) MA (445.1), AMP (38.6) MA (98.9), AMP (95.1) MA (435.0), AMP (40.2) MA (96.7), AMP (99.0) MA, AMP MA, AMP 15 MA (370.7), AMP (45.0) MA (375.1), AMP (43.7) MA (101.1), AMP (97.1) MA (350.9), AMP (37.8) MA (94.6), AMP (84.0) MA, AMP MA, AMP 16 PEP (57.8) PEP (56.8) PEP (98.2) PEP (60.2) PEP (104.1) MA, AMP MA, AMP 17 MDMA (50.8), MDA (42.5) MDMA (51.6), MDA (44.6) MDMA (101.5), MDA (104.9) MDMA (48.7), MDA (41.5) MDMA (95.8), MDA (97.6) MA, AMP, MDMA, MDA MA, AMP, MDMA, MDA 18 MDMA (60.0), MDA (45.0) MDMA (59.9), MDA (40.3) MDMA (99.8), MDA (89.5) MDMA (62.5), MDA (43.7) MDMA (104.1), MDA (97.1) PTM PTM 19 PEP (55.0) PEP (57.0) PEP (103.6) PEP (50.8) PEP (92.3) MA, AMP MA, AMP 20 MA (218.7), AMP (23.8) MA (222.4), AMP (25.4) MA (101.6), AMP (106.7) MA (212.9), AMP (21.5) MA (97.3), AMP (90.3) MDMA, MDA MDMA, MDA QC 1 MA (769.42), AMP (150.10) MA (750.20), AMP (135.50) MA (97.5), AMP (90.3) MA (753.3), AMP (138.6) MA (97.9), AMP (92.3) PEP, EP PEP, EP QC 2 MA (395.65), AMP (75.84), MDMA (1220.50), MDA (201.93) MA (360.10), AMP (78.3), MDMA (1300), MDA (185.80) MA (91.0), AMP (103.2), MDMA (106.5), MDA (92.0) MA (356.8), AMP (80.2), MDMA (1280), MDA (178.9) MA (90.1), AMP (105.7), MDMA (104.8), MDA (88.6) MDA MDA QC 3 MA (299.66), AMP (49.44) MA (275.80), AMP (51.70) MA (92.0), AMP (104.5) MA (268.4), AMP (52.31) MA (89.6), AMP (105.8) MDA MDA QC 4 PTM (248.50) PTM (240.25) PTM (96.6) PTM (235.9) PTM (94.9) MA MA QC 5 n.a n.a n.a n.a n.a MA, AMP MA, AMP QC 6 n.a n.a n.a n.a n.a MDMA MDMA aQualitative analysis based on the routine laboratory practice. QC: College of American Pathologists (CAP) and Quality Assurance Div., Dept. of Chemistry, Malaysia Open in new tab Conclusion The high prevalence of ATS drugs abuse together with the complicated background of toxicology cases, has urged for a rapid and simple confirmatory approach. In this study, a sensitive and selective MRM-EPI-MRM3 experimental methodology using LC-MS/MS was developed and validated for higher confidence level with unique identification of ATS-related drugs in whole blood, urine and dried blood stain matrices. Funding This work is partially supported by the Forensic Division, Department of Chemistry, Malaysia (MOSTI). References 1 Middleberg , R.A. , Homan , J. Quantitation of amphetamine-type stimulants by LC-MS/MS. In: Langman , L. , Snozek , C. (eds). LC-MS in Drug Analysis. Methods in Molecular Biology (Methods and Protocols) , Vol. 902 . Humana Press : Totowa, NJ , 2012 , pp. 105–114. Google Preview WorldCat COPAC 2 World Health Organization (WHO) . Management of Substance Abuse ( 2016 ) 3 Rang , H.P. , Dale , M.M. , Ritter , J.M. , Moore , P.K. Pharmacology. , 6th ed. Elsevier : London , 2007 . Google Preview WorldCat COPAC 4 Deventer , K. , Roels , K. , Delbeke , F.T. , Van Eenoo , P. ( 2011 ) Prevalence of legal and illegal stimulating agents in sports . Analytical and Bioanalytical Chemistry , 401 , 421 – 432 . Google Scholar Crossref Search ADS PubMed WorldCat 5 Karila , L. , Petit , A. , Cottencin , O. , Reynaud , M. ( 2010 ) Methamphetamine dependence: Consequences and complications . Presse Medicale , 39 , 1246 – 1253 . Google Scholar Crossref Search ADS WorldCat 6 Baselt , R.C. Disposition of Toxic Drugs and Chemicals in Man , 5th Edition. Biomedical Publications: Seal Beach, CA , 2000 . Google Preview WorldCat COPAC 7 MyHEALTH Official Guidelines. Ministry of Health, Malaysia. 8 UNODC . Terminology and Information on Drugs , 3rd Edition. United Nations Publication: New York , 2016 . Google Preview WorldCat COPAC 9 United Nations . World Drug Report 2016. New York ( 2016 ). 10 Dasgupta , A. Defending positive amphetamine results. In: Dasgupta A (eds). Beating Drug Tests and Defending Positive Results ,1st Edition, Chapter 9. Humana Press: Mumbai, India, 2010; pp. 115–129. Google Preview WorldCat COPAC 11 Scientific Working Group for Forensic Toxicology . ( 2013 ) Scientific Working Group for Forensic Toxicology (SWGTOX) standard practices for method validation in forensic toxicology . Journal of Analytical Toxicology , 37 , 452 – 474 . Crossref Search ADS PubMed WorldCat 12 UNODC . Guidance for the validation of analytical methodology and calibration of equipment used for testing of illicit drugs in seized materials and biological samples. Laboratory and Scientific Section (LSS) of the United Nations Office on Drugs and Crime (UNODC) ( 2009 ). 13 Matuszewski , B.K. ( 2006 ) Standard line slopes as a measure of a relative matrix effect in quantitative HPLC-MS bioanalysis. Journal of Chromatography B , 830 , 293 – 300 . Crossref Search ADS 14 Remane , D. , Meyer , M.R. , Peters , F.T. , WIssenbach , D.K. , Maurer , H.H. ( 2010 ) Fast and simple procedure for liquid-liquid extraction of 136 analytes from different drug classes for development of a liquid chromatographic-tandem mass spectrometric quantification method in human plasma . Analytical and Bioanalytical Chemistry , 397 , 2303 – 2314 . Google Scholar Crossref Search ADS PubMed WorldCat © The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
TI - A Novel Liquid Chromatography Tandem Mass Spectrometry Technique using Multi-Period-Multi-Experiment of MRM-EPI-MRM3 with Library Matching for Simultaneous Determination of Amphetamine Type Stimulants Related Drugs in Whole Blood, Urine and Dried Blood Stain (DBS)—Application to Forensic Toxicology Cases in Malaysia
JF - Journal of Analytical Toxicology
DO - 10.1093/jat/bkz017
DA - 2019-08-23
UR - https://www.deepdyve.com/lp/oxford-university-press/a-novel-liquid-chromatography-tandem-mass-spectrometry-technique-using-kNPmvdWmoW
SP - 528
VL - 43
IS - 7
DP - DeepDyve
ER -