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.

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.

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.

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.

Aldicarb: uma possibilidade de análise com finalidade forense / Aldicarb: an analysis with forensic aim

The carbamate insecticide Aldicarb is a chemical prevalent in suicide, homicide and accidental intoxication. The LD50 in rats is 1 mgkg-1 bory wegth. The laboratorial diagnosis is carried out by toxicological analysis. It can show the presence of this toxic agent. the objective of this work is to show that the detection and differentiation of carbamate in forensic samples is possible by thin layer...

Validacao de metodos cromatograficos em analises toxicologicas / Validation of chromatographic methods in toxicological analyses

A identificacao e quantificacao de xenobioticos em amostras biologicas pressupoe a utilizacao de metodologia cuja validacao tenha sido devidamente estabelecida. Agencias internacionais, tais como, Environmental Protection Agency, Food and Drug Administration, American Industry Hygiene Association, etc., responsaveis por programas de seguranca da qualidade em analises toxicologicas exigem relatos dos processos de validacao. A maxima "faca o que esta escrito e escreva o que e feito" mostra a enfase dada a tal documentacao. A validacao de um metodo analitico inclui todos os procedimentos realizados para garantir a qualidade dos dados produzidos. Independentemente do processo analitico a ser utilizado, preconiza-se um protocolo composto, basicamente, de tres estagios. O primeiro relaciona-se a procedimentos de afericao de instrumentos e calibracao de equipamentos visando assegurar a confiabilidade das medidas. O segundo diz respeito ao estudo da estabilidade do xenobiotico na matriz, considerando as condicoes de armazenamento e ciclos de congelamento e descongelamento, recuperacao, precisao, exatidao, limites de deteccao e quantificacao, especificidade e intervalo dinamico. O terceiro estagio baseia-se nos procedimentos adotados pelo laboratorio para garantir que o procedimento, como um todo, esta sob controle. Neste trabalho descrevem-se principios praticos e recomendacoes gerais no sentido de indicar diretrizes para o estabelecimento de protocolos que atestem a validade do resultado analitico