Time filter

Source Type

San Diego, CA, United States

Pasin D.,University of Technology, Sydney | Bidny S.,Forensic Toxicology Laboratory | Fu S.,University of Technology, Sydney
Journal of Analytical Toxicology | Year: 2015

An analytical method was developed and validated for the purpose of detecting and quantifying 37 new designer drugs including cathinones, hallucinogenic phenethylamines and piperazines. Using only 100 μL whole blood, a salting-out-assisted liquid-liquid extraction with acetonitrile was performed to isolate target compounds followed by chromatographic separation using a Waters ACQUITY ultra performance liquid chromatograph coupled to a Waters XEVO quadrupole time-of-flight mass spectrometer. Mephedrone-d3 was used as an internal standard. A gradient elution was used in combination with a Waters ACQUITY HSS C18 column (2.1 × 150 mm, 1.8 μm). Samples were analyzed using the detector in positive electrospray ionization mode with MSE acquisition. All compounds of interest were resolved in a 15 min run time and positively identified based on accurate mass of the molecular ion, two product ions and retention time. All analyte calibration curves were linear over the range of 0.05-2 mg/L with most correlation coefficient (r2) values >0.98. The limits of detection were within the range of 0.007-0.07 mg/L and limits of quantification within 0.05-0.1 mg/L. All analytes were stable 48 h after extraction and most were stable in blood after 1 week stored in a refrigerator and 3 freeze-thaw cycles. No carryover was observed up to 10 mg/L and no interferences from common therapeutic drugs or endogenous compounds. Recoveries ranged from 71 to 100% and matrix effects were assessed for blank, post-mortem and decomposed blood. All bias and % coefficient of variation values were within the acceptable values of ±15 and ≤15%, respectively (±20 and ≤20% at lower limit of quantification). The method was applied to several forensic cases where the subject exhibited behavior characteristic of designer drug intoxication and where routine screening for a panel of drugs was negative. © The Author 2015. Published by Oxford University Press. All rights reserved.

McIntyre I.M.,Forensic Toxicology Laboratory
Forensic Science, Medicine, and Pathology | Year: 2014

The liver to peripheral blood (L/P) ratio, based upon review of previously published works, was evaluated as a marker of postmortem redistribution (PMR). Literature supported the proposed model that drugs exhibiting an L/P ratio of less than 5 are prone to little or no PMR, while those with an L/P ratio greater than 20-30 have propensity for significant redistribution. Many antidepressants, including both tricyclic antidepressants and selective serotonin re-uptake inhibitors, were markedly differentiated from drugs previously verified to be free from, or exhibit little, PMR. The magnitude of the liver to blood concentrations also appeared to provide an advantage over the conventional central to peripheral blood ratio model of PMR by demonstrating a wide range of values (1.6-97) for interpretation of drugs' potential for, and variations in, redistribution. © 2013 Springer Science+Business Media New York.

Sistani P.,University of Tabriz | Noori A.,Qazvin University of Medical Sciences | Motlagh M.F.,Payame Noor University | Tamijani A.H.,Forensic Toxicology Laboratory | And 7 more authors.
International Journal of Electrochemical Science | Year: 2014

To find hydrogen peroxide, different techniques applied, recently. In this practice we decided to produce a modified carbon paste electrode by catalase enzyme-Au nanoparticles for electrochemical sensing hydrogen peroxide and their electroactivity characteristics. Cyclic voltammetry were done electrochemical researches. A three-electrode method including a modified carbon paste electrode with catalase enzyme-Au nanoparticles as the operant electrode, a platinum string electrode as a counter electrode, and saturated calomel electrode as a reference electrode, was applied. Cyclic voltammetric assays were done with different scan speed area from of 50 mV s-1 to 500 mV s-1. Transmission electron microscopy was checked external morphological characteristics of Au nanoparticles. H2O2 in 100 μM to 450 μM area could find out by designed biosensor. By perform assays in two weeks regular interval, the resistance of modified carbon paste electrode with catalase enzyme-Au nanoparticles biosensor has been determine and it has been discovered that after 14 days, modified carbon paste electrode with catalase enzyme-Au nanoparticles keeps its 97% activity. © 2014 The Authors.

Rubio C.,Forensic Toxicology Laboratory | Strano-Rossi S.,University Cattolica Del ore | Tabernero M.J.,University of Santiago de Compostela | Anzillotti L.,University Cattolica Del ore | And 2 more authors.
Forensic Science International | Year: 2013

Cocaine abuse is widespread all over the world, and is performed generally by sniffing, injecting or smoking cocaine or crack. The distinction between the recreational use of cocaine from the practice of the so called "coqueo" is still an issue in those countries where this habit is diffused and where it is not considered an addiction, by this reason is necessary to develop a method for to distinguish the coca chewers and cocaine abusers. The use of an unique marker to distinguish between cocaine abuse and chewing of coca leaves is of fundamental importance in those countries where this habit is diffused. Certain alkaloids of the leaves of Erythroxylum coca are lost during the process of extraction/purification of cocaine and it is not possible to find them neither in seizures of chlorhidrate of cocaine nor urine samples of cocaine abusers. These markers are the hygrine and cuscohygrine that are present in the leaves of E. coca.A fast GC/MS method involving a liquid:liquid extraction procedure with tertbutylmethylether (TBME) is proposed for the determination of some alkaloids in cocaine leaves, cocaine seizures and biological samples. All specimens were alkalinized to pH 9 with a carbonate/bicarbonate buffer and then extracted with TBME. The analysis was carry out by GC/MS with electron impact at 70. eV and in full scan mode. The results demonstrate that hygrine and cuscohygrine are not found neither in the urine of cocaine abusers nor in cocaine seizures. For this reason this compounds could be considered as markers of coca chewing. This developed method permits to distinguish coca chewing from cocaine abuse in workplace drug testing through the analysis of urine samples. © 2012 Elsevier Ireland Ltd.

McIntyre I.M.,Forensic Toxicology Laboratory | Mallett P.,Forensic Toxicology Laboratory | Stolberg S.,County of San Diego Medical Examiners Office | Haas E.A.,Rady Childrens Hospital | Mena O.,County of San Diego Medical Examiners Office
Australian Journal of Forensic Sciences | Year: 2016

Toxicology testing revealed dramatic increases in whole-blood concentrations of verapamil and diphenhydramine in the short time between hospital admission and death (53 min) in a subject (with a history of overdosing) found unresponsive. While some degree of post-mortem redistribution (PMR) would be expected for the drugs found in this case, PMR cannot explain the considerable increases observed. It is recommended that in potential overdose cases without a clear manner of death but for which ante-mortem and post-mortem specimens (including gastric content) are available, all should be analysed and considered in order to make a more definitive conclusion regarding that death. © 2015 Australian Academy of Forensic Sciences.

Discover hidden collaborations