Forensic Chemistry Laboratory

Seocho gu, South Korea

Forensic Chemistry Laboratory

Seocho gu, South Korea
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Jeong Y.-D.,Yonsei University | Suh S.,Forensic Chemistry Laboratory | In M.K.,Forensic Chemistry Laboratory | Paeng K.-J.,Yonsei University | Kim J.Y.,Forensic Research Institute office of Forensic Science Planning
Analytical Letters | Year: 2017

Toluene is the major volatile organic compound found in glue and is often used as a hallucinogenic for abusers. Use with alcohol increases the risk of adverse effects from toluene exposure. In this study, a headspace and cryotrapping gas chromatography–mass spectrometry method was developed and validated for the determination of toluene and ethanol in urine. Experimental and instrumental variables were investigated to optimize the method for sensitivity. Excess sodium sulfate was used as the salting-out reagent before the headspace protocol. Linear least squares regression with a 1/x weighting factor was used to construct calibration curves from 0.002 to 0.4 µg mL−1 for toluene and 10 to 2000 µg mL−1 for ethanol. The correlation coefficients exceeded 0.9993. The limits of detection were 0.0005 µg mL−1 for toluene and 0.21 µg mL−1 for ethanol. Intraday and interday precisions were within 5.4 and 11.5%, while intraday and interday accuracies were between −11.3 to −4.0% and −11.0 to 1.2%, respectively. The method validation results for selectivity and stability were satisfactory. The validation results were used to estimate the expanded uncertainty and the contribution of individual steps in the method for the quantification of toluene and ethanol. The relative expanded uncertainties were 14.1% for toluene and 4.6% for ethanol. © 2017 Taylor & Francis.

Abdel-Ghani N.T.,Cairo University | Rizk M.S.,Cairo University | Mostafa M.,Forensic Chemistry Laboratory
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

Simple, rapid, sensitive, precise and accurate spectrophotometeric methods for the determination of ephedrine hydrochloride (E-HCl) and bromhexine hydrochloride (Br-HCl) in bulk samples, dosage form and in spiked urine samples were investigated. The methods are based on the formation of a yellow colored ion-associates due to the interaction between the examined drugs with picric acid (PA), chlorophyllin coppered trisodium salt (CLPH), alizarin red (AR) and ammonium reineckate (Rk) reagents. A buffer solution had been used and the extraction was carried out using organic solvent, the ion associates exhibit absorption maxima at 410, 410, 430 and 530 nm of (Br-HCl)with PA, CLPH, AR and Rk respectively; 410, 410, 435 and 530 of (E-HCl) with PA, CLPH, AR and Rk respectively. (E-HCl) and (Br-HCl) could be determined up to 13, 121, 120 and 160; 25, 200, 92 and 206 μg mL-1, using PA, CLPH, AR and Rk respectively. The optimum reaction conditions for quantitative analysis were investigated. In addition, the molar absorptivity, Sandell sensitivity were determined for the investigated drug. The correlation coefficient was ≥0.995 (n = 6) with a relative standard deviation (RSD) ≤1.15 for five selected concentrations of the reagents. Therefore the concentration of Br-HCl and E-HCl drugs in their pharmaceutical formulations and spiked urine samples had been determined successfully. © 2013 Elsevier B.V. All rights reserved.

Kim J.Y.,Forensic Chemistry Laboratory | Kwon W.,Forensic Chemistry Laboratory | Kim H.S.,Forensic Chemistry Laboratory | Suh S.,Forensic Chemistry Laboratory | In M.K.,Forensic Chemistry Laboratory
Journal of Analytical Toxicology | Year: 2014

Recently, the estimation of the measurement uncertainty has become a significant issue in the quality control of forensic drug testing. In the present study, the uncertainty of the measurement was calculated for the quantification of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) and its glucuronide conjugate (THC-COOH-glu) in urine using liquid chromatography-tandem mass spectrometry. The procedure was based on liquid-liquid extraction of a volume of urine (800 μL) with ethyl acetate. The sources of uncertainty were identified and classified into four major categories as follows: standard preparation, calibration curve, method precision and bias. The overall contribution of combined standard uncertainty on THC-COOH increased in the order of standard preparation (0.9%), method precision (10.4%), calibration curve (30.3%) and bias (58.4%) and, while calibration curve (53.0%) and bias (40.4%) gave the bigger contributions to the combined standard uncertainty for THC-COOH-glu than method precision and standard preparation, which accounted for 6.3 and 0.3%, respectively. The reliability of a measurement was expressed by stating the expanded uncertainty of the measurement result at 95% confidence level. The concentrations of THC-COOH and THC-COOH-glu in the urine sample with their expanded uncertainties were 10.20 ± 1.14 ng/mL and 25.42 ± 5.01 ng/mL, respectively. © The Author [2014]. Published by Oxford University Press. All rights reserved.

Shahat A.,Suez Canal University | Ali Mohammad E.A.,Forensic Chemistry Laboratory | El Shahat M.F.,Ain Shams University
Sensors and Actuators, B: Chemical | Year: 2015

Abstract Simple, rapid, sensitive, precise and accurate spectrophotometeric methods for detection and removal of ultra-traces of some toxic metal ions such as Cu(II), Pb(II), Hg(II) and Cd(II) in water and in biological samples have been developed. The procedure depends on a single-step detection and removal for metal ions based on dithizone (Dz) anchored on mesoporous TiO2 with rapid colorimetric response and high selectivity for the first time. The developed sensor was utilized for the detection of ultra-traces of some toxic metal ions with the naked eye. The new sensor displays high sensitivity and selectivity of a wide range of detectable metals analytes up to 10-9 mol dm-3 in solution. The proposed method was applied to the determination of the examined metal ions in post-mortem biological samples. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision. © 2015 Elsevier B.V.

Vanini G.,Federal University of Espirito Santo | Destefani C.A.,Federal University of Espirito Santo | Destefani C.A.,Forensic Chemistry Laboratory | Merlo B.B.,Forensic Chemistry Laboratory | And 4 more authors.
Microchemical Journal | Year: 2015

A new analytical method is proposed for the Pb, Ba and Sb quantifications on gunshot residues (GSR) from firearms using inductively coupled plasma optical emission spectrometry (ICP OES). Lead (Pb), barium (Ba) and antimony (Sb) concentrations in GSR from .38 revolver and .380 and .40 caliber pistols were determined as function of number of shots (from 1 to 5 for the .38 revolver and from 1 to 10 for the pistols) and multiple linear regression model was constructed to determine the number of shots. Also, the sensitivity of ICP OES was compared to conventional colorimetric test in function of distance of shooting (from 0 to 200cm). Analyzing the effect of distance of shooting over the GSR concentration, the colorimetric test evidenced the presence of a red-pink color only at short distances (from 0 to 10cm), thus indicating the presence of Pb. For ICP OES analyses, the two analytical methodologies employed presented higher sensitivity than the colorimetric assay, where Pb, Ba and Sb are found from 0cm ([Pb]=3158.63μgL-1; [Ba]=85.33μgL-1; and [Sb]=104.90μgL-1) to 200cm ([Pb]=81.52μgL-1; [Ba]=20.20μgL-1; and [Sb]=8.32μgL-1) for the extraction using digestion by microwave. For analyses of GSR using different firearms, good linear correlation coefficients (R2>0.97) were observed between the GSR concentration and the number of shots. Therefore, it was possible to predict the number of shots with good accuracy from Pb, Ba and Sb concentrations using .38 revolver and .40 and .380 caliber pistols. Furthermore, the GSR concentration from different firearms, increased in the following order: .40 pistol>.380 pistol>38 revolver. © 2014 Elsevier B.V.

Kwon W.,Forensic Chemistry Laboratory | Kim J.Y.,Forensic Chemistry Laboratory | Suh S.,Forensic Chemistry Laboratory | In M.K.,Forensic Chemistry Laboratory
Analytical Methods | Year: 2013

A liquid chromatography-electrospray ionization-tandem mass spectrometric method (LC-ESI-MS/MS) was developed and validated for the direct determination of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) and its glucuronide (THCCOOH-glu) in urine. The deuterium-labeled compounds were used as internal standards to quantify the analytes. After a simple liquid-liquid extraction with ethyl acetate at pH 4, the dried extracts were reconstituted in the mobile phase followed by injection onto the LC-ESI-MS/MS system. The mobile phase was composed of 0.2% formic acid and 2 mM ammonium formate in water and acetonitrile. A reversed phase column (C8, 150 mm × 2.1 mm i.d., 3.5 μm) was used as the analytical column. The limit of detection and lower limit of quantification values were 0.08 and 0.3 ng mL-1 for THCCOOH and 0.4 and 1.5 ng mL-1 for THCCOOH-glu, respectively. The calibration curve was linear over the concentration range of 0.3-100 ng mL-1 for THCCOOH and 1.5-100 ng mL-1 for THCCOOH-glu with the coefficients of determination (r2) above 0.9955. The intra- and inter-day precisions (% CV) were within 16.6% and 18.3%, respectively. The intra-day accuracies (% bias) ranged from -18.4 to 1.5% while inter-day accuracies were -5.9 to 1.8%. The validated method was successfully applied for the determination of THCCOOH and THCCOOH-glu in urine samples from marijuana users. This journal is © The Royal Society of Chemistry.

Kim Y.-J.,Korea Advanced Institute of Science and Technology | Jung H.-S.,U.S. National Institutes of Health | Lim J.,Seoul National University | Ryu S.-J.,Forensic Chemistry Laboratory | Lee J.-K.,Seoul National University
Langmuir | Year: 2016

Fluorescent silica nanoparticles (FSNPs) are synthesized through the Stöber method by incorporating silane-modified organic dye molecules. The modified fluorescent organic dye molecule is able to be prepared by allylation and hydrosilylation reactions. The optical properties of as-prepared FSNPs are shown the similar optical properties of PR254A (allylated Pigment Red 254) and have outstanding photostability. The polyvinylpyrrolidone (PVP) is introduced onto the surface of FSNP to enhance the binding affinity of PVP-coated FSNP for latent fingerprints (LFPs) detection. The simple preparation and easy control of surface properties of FSNPs show potential as a fluorescent labeling material for enhanced latent fingerprint detection on hydrophilic and hydrophobic substrates in forensic science for individual identification. © 2016 American Chemical Society.

Kim H.S.,Forensic Chemistry Laboratory | Cheong J.C.,Forensic Chemistry Laboratory | Lee J.I.,Forensic Chemistry Laboratory | In M.K.,Forensic Chemistry Laboratory
Journal of Pharmaceutical and Biomedical Analysis | Year: 2013

A fast, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the detection and quantitation of propofol glucuronide in human hair has been developed and validated. Propofol glucuronide was extracted from 10mg of hair using a simple methanol extraction method, with recovery greater than 91% at 3 quality control samples (15, 100, 4000pg/mg). A reversed phase column (C8) was used to analyze and the mobile phase was composed of ammonium formate and acetonitrile gradient at a flow rate of 0.2mL/min. The lower limit of quantitation (LLOQ) was 5pg/mg and the assay was linear to 5000pg/mg. The intra- and inter-day precision (% CV, coefficient of variation) ranged from 1.26 to 4.50% while the accuracy (% RE, relative error) were -4.24 to 4.4%. The matrix effects were monitored at 3 different concentrations and the %CV of the results for these concentrations was less than 10.6%. Propofol glucuronide was stable during processing and analysis in human hair. The procedure was validated and applied to the analysis of hair samples in human subjects previously administered in propofol. © 2013 Elsevier B.V.

PubMed | Forensic Chemistry Laboratory, Catholic University of Korea and St. Mary's College
Type: | Journal: Archives of pharmacal research | Year: 2016

Liquid chromatography-tandem mass spectrometric method for analysis of 113 abuse drugs and their metabolites in human urine was developed and validated. A simple sample clean-up procedure using the dilute and shoot approach, followed by reversed phase separation, provided a fast and reliable method for routine analysis. Drugs were separated in a Capcell Pak MG-III C

PubMed | Forensic Chemistry Laboratory and Catholic University of Korea
Type: | Journal: Journal of pharmaceutical and biomedical analysis | Year: 2015

In vitro metabolism of a new synthetic cannabinoid, EAM-2201, has been investigated with human liver microsomes and major cDNA-expressed cytochrome P450 (CYP) isozymes using liquid chromatography-high resolution mass spectrometry (LC-HRMS). Incubation of EAM-2201 with human liver microsomes in the presence of NADPH resulted in the formation of 37 metabolites, including nine hydroxy-EAM-2201 (M1-M9), five dihydroxy-EAM-2201 (M10-M14), dihydrodiol-EAM-2201 (M15), oxidative defluorinated EAM-2201 (M16), two hydroxy-M16 (M17 and M18), three dihydroxy-M16 (M19-M21), N-dealkyl-EAM-2201 (M22), two hydroxy-M22 (M23 and M24), dihydroxy-M22 (M25), EAM-2201 N-pentanoic acid (M26), hydroxy-M26 (M27), dehydro-EAM-2201 (M28), hydroxy-M28 (M29), seven dihydroxy-M28 (M30-M36), and oxidative defluorinated hydroxy-M28 (M37). Multiple CYPs, including CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 2J2, 3A4, and 3A5, were involved in the metabolism of EAM-2201. In conclusion, EAM-2201 is extensively metabolized by CYPs and its metabolites can be used as an indicator of EAM-2201 abuse.

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