Alice A. da Matta Chasin

Simple method for determination of cocaine and main metabolites in urine by CE coupled to MS

In this work, a simple method for the simultaneous determination of cocaine (COC) and five COC metabolites (benzoylecgonine, cocaethylene (CET), anhydroecgonine, anhydroecgonine methyl ester and ecgonine methyl ester) in human urine using CE coupled to MS via electrospray ionization (CE‐ESI‐MS) was developed and validated. Formic acid at 1 mol/L concentration was used as electrolyte whereas formic acid at 0.05 mol/L concentration in 1:1 methanol:water composed the coaxial sheath liquid at the ESI nozzle. The developed method presented good linearity in the dynamic range from 250 ng/mL to 5000 ng/mL (coefficient of determination greater than 0.98 for all compounds). LODs (signal‐to‐noise ratio of 3) were 100 ng/mL for COC and CET and 250 ng/mL for the other studied metabolites whereas LOQs (signal‐to‐noise ratio of 10) were 250 ng/mL for COC and CET and 500 ng/mL for all other compounds. Intra‐day precision and recovery tests estimated at three different concentration levels (500, 1500 and 5000 ng/mL) provided RSD lower than 10% (except anhydroecgonine, 18% RSD) and recoveries from 83–109% for all analytes. The method was successfully applied to real cases. For the positive urine samples, the presence of COC and its metabolites was further confirmed by MS/MS experiments.

Workplace drug testing, different matrices different objectives

Drug testing is used by employers to detect drug use by employees or job candidates. It can identify recent use of alcohol, prescription drugs, and illicit drugs as a screening tool for potential health and safety and performance issues. Urine is the most commonly used sample for illicit drugs. It detects the use of a drug within the last few days and as such is evidence of recent use; but a positive test does not necessarily mean that the individual was impaired at the time of the test. Abstention from use for three days will often produce a negative test result. Analysis of hair provides a much longer window of detection, typically 1 to 3 months. Hence the likelihood of a falsely negative test using hair is very much less than with a urine test. Conversely, a negative hair test is a substantially stronger indicator of a non-drug user than a negative urine test. Oral fluid (saliva) is also easy to collect. Drugs remain in oral fluid for a similar time as in blood. The method is a good way of detecting current use and is more likely to reflect current impairment. It offers promise as a test in post-accident, for cause, and on-duty situations. Studies have shown that within the same industrial settings, hair testing can detect twice as many drug users as urine testing.

Purity and adulterant analysis of crack seizures in Brazil

Cocaine represents a serious problem to society. Smoked cocaine is very addictive and it is frequently associated with violence and health issues. Knowledge of the purity and adulterants present in seized cocaine, as well as variations in drug characteristics are useful to identify drug source and estimate health impact. No data are available regarding smoked cocaine composition in most countries, and the smoked form is increasing in the Brazilian market. The purpose of the present study is to contribute to the current knowledge on the status of crack cocaine seized samples on the illicit market by the police of São Paulo. Thus, 404 samples obtained from street seizures conducted by the police were examined. The specimens were macroscopically characterized by color, form, odor, purity, and adulterant type, as well as smoke composition. Samples were screened for cocaine using modified Scott test and thin-layer chromatographic (TLC) technique. Analyses of purity and adulterants were performed with gas chromatography equipped with flame ionization detector (GC-FID). Additionally, smoke composition was analyzed by GC-mass spectrometry (MS), after samples burning. Samples showed different colors and forms, the majority of which is yellow (74.0%) or white (20.0%). Samples free of adulterants represented 76.3% of the total. Mean purity of the analyzed drug was 71.3%. Crack cocaine presented no correlations between macroscopic characteristics and purity. Smoke analysis showed compounds found also in the degradation of diesel and gasoline. Therefore, the drug marketed as crack cocaine in São Paulo has similar characteristics to coca paste. High purity can represent a greater risk of dependency and smoke compounds are possibly worsening drug health impact.

Development of a method for the analysis of drugs of abuse in vitreous humor by capillary electrophoresis with diode array detection (CE–DAD)

This work presents the development of an analytical method based on capillary electrophoresis with diode array detection for the analysis of drugs of abuse and biotransformation products in vitreous humor. Composition of the background electrolyte, implementation of an online pre-concentration strategy and sample preparation procedures were objects of study. The complete electrophoretic separation of 12 analytes (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), ketamine, cocaine, cocaethylene, lidocaine, morphine, 6-monoacetylmorphine and heroin) and the internal standard N-methyl-1-(3,4-methylenedioxyphenyl)-2-butamine (MBDB) was obtained within 13min of run. The method was validated presenting good linearity (r(2)>0.99), recovery ≥90%, precision better than 12% RSD and acceptable accuracy in the range of 86-118% at three concentration levels (50, 100 and 500ng/mL). LODs and LOQs in the order of 1-5ng/mL and 5-10ng/mL, respectively, were obtained. After validation, the method was applied to eighty-seven vitreous humor samples and the results were compared to those obtained by a liquid chromatography tandem mass spectrometry (LC-MS/MS) screening method, routinely used by the forensic toxicology laboratory of the Sao Paulo State Police, Brazil. Cocaine was detected in 7.1%, cocaethylene in 3.6%, lidocaine in 2.4% and ketamine in 1.2% of the total number of analyzed samples.

Determination of Herbicides Paraquat, Glyphosate, and Aminomethylphosphonic Acid in Marijuana Samples by Capillary Electrophoresis

In this work, two methods were developed to determine herbicides paraquat, glyphosate, and aminomethylphosphonic acid (AMPA) in marijuana samples by capillary electrophoresis. For paraquat analysis, sample was extracted with aqueous acetic acid solution and analyzed by capillary zone electrophoresis with direct UV detection. The running electrolyte was 50 mmol/L phosphate buffer (pH 2.50). For glyphosate and AMPA, indirect UV/VIS detection was used, as these substances do not present chromophoric groups. Samples were extracted with 5 mmol/L hydrochloric acid. The running electrolyte was 10 mmol/L gallic acid, 6 mmol/L TRIS, and 0.1 mmol/L CTAB (pH = 4.7). The methods presented good linearity, precision, accuracy, and recovery. Paraquat was detected in 12 samples (n = 130), ranging from 0.01 to 25.1 mg/g. Three samples were positive for glyphosate (0.15–0.75 mg/g), and one sample presented AMPA as well. Experimental studies are suggested to evaluate the risks of these concentrations to marijuana user.

Cocaine postmortem distribution in three brain structures: A comparison with whole blood and vitreous humour

The presence of cocaine (COC) in fluids or tissues does not prove that death was due to drug consumption and the interpretation of postmortem concentrations is more complex than attempts at making such correlations in the living. The purpose of this study was to investigate the distribution of cocaine and its metabolite benzoylecgonine in brain and compare with whole blood and vitreous humour. The distribution in three brain structures (prefrontal cortex, basal ganglia and cerebellum) was homogeneous. There is a strong correlation for cocaine concentrations between vitreous humour and brain, vitreous humour and whole blood, and whole blood and brain in overdose cases. In addition, the comparison of COC/benzoylecgonine (BE) ratios in different experimental specimens proved to be more appropriate for evaluating cocaine-related death than individual drug values. These findings suggest that the comparison of cocaine levels in different compartments is essential to assess the cause of death.

A study on the stability of anhydroecgonine methyl ester (crack biomarker), benzoylecgonine, and cocaine in human urine

CONTEXTO: Cocaina (COC) e/ou metabolitos tem sido analisados em urina e outros fluidos biologicos para se determinar o uso de COC. A COC esta sujeita a numerosas reacoes de biotransformacao e degradacao. Individuos que fumam crack estao expostos ao ester metilanidroecgonina (AME), que pode ser empregado como marcador de uso desta droga. Nao ha referencias na literatura a respeito da estabilidade deste analito em urina humana. No organismo a COC e rapidamente biotransformada em outros metabolitos por meio de processos quimicos e enzimaticos e o principal metabolito urinario e a benzoilecgonina (BE). OBJETIVOS: O objetivo deste estudo foi determinar o efeito do tempo e da temperatura na estabilidade da COC, BE e do AME em urina humana. METODOS: A estabilidade do AME, BE e COC em urina foi investigada por intermedio do armazenamento da urina em freezer e em geladeira. Os analitos foram extraidos pela tecnica de extracao em fase solida e analisados por cromatografia gasosa acoplada ao detector por ionizacao em chama. RESULTADOS: As concentracoes de COC decresceram enquanto as BE aumentaram. As concentracoes de AME se mantiveram estaveis. CONCLUSOES: A temperatura e o tempo de armazenamento sao decisivos na hidrolise da COC. Este estudo sugere que as concentracoes de AME nao estao correlacionadas com o tempo ou a temperatura de armazenamento e o AME e mais estavel que a COC.

Aplicação de imunoensaios para análise de fármacos e drogas de abuso em sangue total, com finalidade forense

A tecnica de imunoensaio enzimatico e amplamente utilizada nos dias de hoje em diversas areas de diagnose e uma de suas aplicacoes e na deteccao de farmacos e drogas de abuso como cocaina, maconha, benzodiazepinicos, barbituricos, anfetaminicos, opioides, dentre outros. Uma das principais limitacoes desta tecnica e a sua aplicacao estar restrita a matrizes biologicas menos complexas como plasma, soro ou urina. Uma vez que em analises toxicologicas com finalidade forense o material mais adequado, dentre os disponiveis e o sangue total, o objetivo deste trabalho foi padronizar uma metodologia de extracao liquido – liquido para farmacos e drogas de abuso nessa matriz e torna-la aplicavel a identificacao de farmacos pelo EMIT