Ovandir Alves Silva

Solid-phase micro-extraction-gas chromatography-mass spectrometry and headspace-gas chromatography of tetrahydrocannabinol, amphetamine, methamphetamine, cocaine and ethanol in saliva samples

In the present work, a method was developed aiming at the serial detection of tetrahydrocannabinol (THC), amphetamine, methamphetamine, cocaine and ethanol in saliva. Saliva samples were submitted to an initial headspace procedure for ethanol determination by gas chromatography/flame ionization detector (GC-FID). After this step, two consecutive solid-phase micro-extractions (SPME) were carried out: THC was extracted by submersing a polydimethylsiloxane fiber (100 micro m) in the vial for 20 min; amphetamine, methamphetamine and cocaine were subsequently extracted after alkalinization. Derivatization of the amphetamines was carried out directly in the solution by adding 2 micro l of butylchloroformate. Gas chromatography-mass spectrometry (GC-MS) was used to identify the analytes in selected ion monitoring (SIM) mode. Confidence parameters of validation of the method were: recovery, linearity, intra- and inter-assay precision as well as limits of detection and quantification of the analytes. The limits of quantification (LOQ) obtained were: ethanol (0.010 g/l); amphetamine (5.0 ng/ml); methamphetamine (0.5 ng/ml); cocaine (5 ng/ml) and THC (5 ng/ml). The method proved to be highly precise (coefficient of variation<8%) for all detected substances.

Blood alcohol content prevalence among trauma patients seen at a level 1 trauma center

OBJECTIVE To investigate the prevalence of blood alcohol content (BAC) among patients seen at a level 1 trauma center. METHODS A cross-sectional study was carried out and patients were randomly selected at the emergency room of a level I trauma center in the city of São Paulo, Brazil, throughout a year (August 1998 to August 1999). Blood samples were drawn and data was collected using an adapted version of a questionnaire developed by the Medical Research Institute of San Francisco - Alcohol Research Group. RESULTS A population sample of 464 patients was analyzed. Most of them were males (73.7%) and the median age was 29 years old. Positive BAC was found in 28.9% of the cases (CI95% 24.8 - 33.2) and in 84.3% BAC was =0.10%. Type of injury, gender, age group, marital status and outcome showed statistically significant associations with BAC with the highest BAC prevalence observed among assault victims (46.2%), males (33.9%), 25 to 44 years old (37.6%), singles (33.0%), and patients admitted in the hospital (41.4%). CONCLUSIONS The results reinforce the relationship of alcohol and trauma. Preventive actions at different levels focusing on higher risk groups for alcohol-related injuries should be considered as part of prevention programs to both reduce injuries and curb recurrent events.

Drug Use by Truck Drivers in Brazil

In Brazil, those who are suspected of driving under the influence of drugs are tested only for ethanol. Professional drivers, especially truck drivers, use stimulant drugs to prevent sleeping during long-distance driving. Surveys on the patterns of use of illicit drugs in the workplace have rarely been conducted in Brazil, in spite of the high costs and the potential risk to public health. Since 1996, the authors have been compiling the results of tests, performed in their laboratories, for drugs in urine samples from truck drivers. The drugs analyzed were: amphetamine, methamphetamine, cannabinoids and cocaine. Urine samples (728) were collected in three out of the five geographical regions of Brazil: southeast (517 samples), northeast (161 samples) and south (50 samples). Fluorescence polarization immunoassay and capillary gas chromatography/mass spectrometry were utilized for the urinalyses. The results obtained were as follows: 41 samples (5.63% of the total) tested positive for the drugs being studied. The frequency of positivity of samples was quite similar for the three regions: 6% in the south, 6% in the southeast and 4.35% in the northeast. However, distribution of the drugs in the samples showed regional variations. Results such as those that we have obtained can provide an estimation of the extent of drug use by truck drivers in Brazil.

Confirmation of cocaine exposure by gas chromatography–mass spectrometry of urine extracts after methylation of benzoylecgonine

Volatility and thermal stability are necessary physical-chemical properties for analysing a substance by gas chromatography. A derivatization step is required before gas chromatography of benzoylecgonine (the main metabolite of cocaine). In the literature, reactions such as silylation, perfluoroalkylation or alkylation are the most frequently used to derivatize benzoylecgonine. However, they allow the formation of products sensitive to moisture or require a purification step. So, a procedure to derivatize benzoylecgonine with diazomethane before gas chromatographic analysis was evaluated. A study was performed to evaluate the efficiency of conversion of benzoylecgonine in cocaine, the necessary time for reaction and the stability of ethereal solution of diazomethane. The reaction was shown to be very fast in mild conditions and there was no need for a further purification step. When benzoylecgonine was extracted from urine by solid-phase extraction and derivatized with diazomethane, concentrations as low as 25 ng/ml could be detected using GC-MS in the full scan mode.

Drug abuse among workers in Brazilian regions

OBJECTIVE Many business organizations in Brazil have adopted drug testing programs in the workplace since 1992. Rehabilitation, rather than layoff and disciplinary measures, has been offered as part of the Brazilian employee assistance programs. The purpose study is to profile drug abuse among company workers of different Brazilian geographical regions. METHODS Urine samples of 12,700 workers from five geographical regions were tested for the most common illicit drugs of abuse in the country: marijuana, cocaine, and amphetamine. Enzyme multiplied immunoassay technique (EMIT) and gas chromatography coupled with mass spectrometry (GC/MS) were the techniques utilized for urine testing. The distribution of collected urine samples according to geographical regions was: 72.0% southeast, 13.8% northeast, 7.9% south, 5.7% central west and 0.6% north. RESULTS Of all samples analyzed, 1.8% was found to be positive for drugs: 0.5% from the south region, 1.1% from northeast, 1.2% from central west, 1.3% from north, and 2.2% from southeast. Of these, 59.9% was marijuana, 17.7% cocaine, 14.6% amphetamine, and 7.7% associated drugs. CONCLUSIONS The distribution of drugs found in the samples shows a regional variation. Marijuana, however, was found in all regions. Cocaine was seen only in central west and southeast regions. Amphetamine was found in northeast, central west, and southeast regions.

One-step liquid–liquid extraction of cocaine from urine samples for gas chromatographic analysis

An improved technique for cocaine extraction from urine samples for gas chromatographic (GC) analysis is described. Employing a simple liquid-liquid extraction (LLE) of cocaine with a mixture of ethyl ether:isopropanol (9:1) the method presents a mean recovery of 74.49%. Limit of detection (LOD) and limit of quantification (LOQ) were 5 and 20 ng/ml, respectively. The method is highly precise (coefficient of variation (CV) <8%) and linear from 20 to 2000 ng/ml. It can he applied to detect the presence of cocaine in urine as a marker of its recent use in drug abuse treatment protocols.

The Possibilities of Hair Analysis in the Determination of Involuntary Doping in Sports

AbstractAlthough not yet fully recognised by international sporting committees, hair analysis in doping control may be a useful adjunct to drug testing of urine. It may permit access to retrospective information and the identification of banned substances, especially when exogenous abuse has to be distinguished from other forms of involuntary exposure to identical substances. Negative hair results coupled with positive urine samples may be used to draw conclusions of involuntary doping in sports whenever athletes claim not to have ingested any drug, identical substances are present in their environment or are normal constituents of food and beverages served to them immediately before the competition. Two cases are well described in the literature in which hair analyses were fundamental in documenting positive doping after urinalysis. In Brazil, 2 cases of athletes testing positive for banned substances caught our attention because of the possibility of involuntary doping; hair analysis, if performed, may have helped to clarify the results of the urinalysis.Despite the fact that it cannot be used for routine control and overrule positive urinalysis, hair analysis can detect long term exposure as well as those substances which are not excreted in urine. In the current International Olympic Committee (IOC) code, hair analysis is not yet considered useful even in special cases of doping control.

Identificação de anfetamina em amostras de cabelo por imunofluorescência polarizada

O uso indevido de anfetaminas tem preocupado as autoridades sanitarias em todo o mundo. No Brasil, destacam-se os anorexigenos anfetaminicos como o femproporex, que, no organismo, se biotransforma em anfetamina. Apesar de ser controlado por legislacao especifica, este farmaco tem sido amplamente utilizado em nosso pais. Nas analises toxicologicas para verificacao do uso de farmacos e drogas de abuso, tem-se empregado diferentes amostras biologicas. Mais recentemente a utilizacao do cabelo tem sido preconizada principalmente por informar sobre um uso a longo prazo da substância. A tecnica para identificacao de anfetaminas em cabelo e a cromatografia em fase gasosa acoplada a espectrometria de massas (CG-EM). A partir de um metodo descrito na literatura foram desenvolvidos estudos para avaliacao da imunofluorescencia polarizada como tecnica de triagem na identificacao de anfetamina em cabelo de usuarios de anfetaminicos. Os resultados obtidos indicam que o metodo otimizado pode ser utilizado como triagem na identificacao de anfetamina em cabelo.

Identification of Amphetamine, Mefenorex and Fencanfamin in Three Cases of Doping

The identification of drugs present in urine samples submitted to the analytical procedure for doping control is a need. However, it is not always easy to achieve that since most drugs cannot be detected in their original structure. Few hours after being administered, they will appear in urine together with the parent drug and the lack of standards of these products of biotransformation make the proper identification rather impossible. So, urine samples from volunteers who have taken the drugs must be used as controls. Extraction and identification of drugs present in urine samples from volunteers and athletes are described and the obtained results are presented. Comments on the interpretation of the results found in three cases of positive reactions for amphetamine, mefenorex and fencanfamin are made. Urine (10 to 15 ml) is made acidic (pH — 5,0) by adding 1% HCl solution and extracted with 2 x 30 ml CHC13 : diethyl-ether (2:1). The organic layer is transferred by filtration through anhydrous Na2SO4. The extract is then concentrated to about 10 ml in a 70oC water bath under a N2 stream. The residue (I) is used for TLC and GLC screening. The remaining urine is made alkaline (pH 8,0) by adding 2% NaOH solution and extracted once with the solvent mixture. The pH is adjusted to 10–11 and another extraction is made. The combined organic extracts (II) are concentrated as above, taking care to add some drops of 1% HCl prior to concentration. The solution is then analysed by TLC and GLC. The Kovats retention indices in two columns of different polarities is determined.