Optimisation of a solid-phase microextraction method for the analysis of nicotine in hair.

A headspace solid-phase microextraction method (HS-SPME) followed by gas chromatography with mass spectrometric detection (GC/MS) has been developed for the determination of low concentrations of nicotine in hair. Parameters affecting the SPME procedure including type of fiber coating, extraction mode, extraction temperature and time, desorption time, stirring, and salt addition have been evaluated and optimised. The method provided good linearity (r(2)≥0.9980) over the concentration range tested (0.2-20 ng/mg) and low detection limit (0.02 ng/mg). Precision expressed as relative standard deviation was <10%. The average accuracy was 95%. The proposed method was used to determine hair nicotine levels in 100 children in order to assess exposure to environmental tobacco smoke (ETS). The described HS-SPME procedure is fast, simple, sensitive, and solvent-free and is therefore suitable for studies involving ETS exposure assessment.

Comparison between dynamic headspace and headspace solid-phase microextraction for gas chromatography of BTEX in urine.

The aim of this study was to compare two extraction procedures: dynamic headspace-purge and trap (PT) and headspace solid-phase microextraction (HS-SPME) for gas chromatographic determination of benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) in urine with photoionization (PID) and mass spectrometric (MS) detection, respectively. Both methods showed linearity in the range of interest [(50-2000) ng L-1], good accuracy (80% to 100%), and repeatability (RSD< or =11%). Detection limits were in the low ng L-1 level for both methods, although slightly greater sensitivity was found for the PT method. In comparison with PT, HS-SPME was simpler and required less time for analysis. Although the analytical features of both examined methods are appropriate for biomonitoring of environmental exposure to BTEX, only the HS-SPME-GC-MS method is recommended for routine analysis of BTEX in urine. The method was applied for the quantitative analysis of BTEX in urine samples collected from non-smokers (n=10) and smokers (n=10).

Urine analysis for the evaluation of environmental exposures to aromatic hydrocarbons.

The authors have developed a dynamic headspace (purge-and-trap) gas chromatographic method, with photoionization detection, for the determination of benzene (C6H6), toluene (C7H8), ethylbenzene (C8H10), and isomeric (o-, m-, p-) xylenes (C8H10) (BTEX) in urine. Detection limits ranged between 15 and 35 ng/l, relative standard deviations between 0.2 and 10%, and accuracy between 80 and 100%. The primary objective of this study was to use this new method to establish baseline concentration data for BTEX in the urine of the general population of Zagreb, Croatia. A second objective was to evaluate the effect of cigarette smoking on those baseline values. BTEX were analyzed in the urine of 72 subjects (36 nonsmokers and 36 smokers) without occupational exposure to BTEX. The nonsmokers had measurable BTEX in their urine, except for ethylbenzene in 13 and o-xylene in 15 of the samples. Values for BTEX were markedly higher among smokers than nonsmokers. Because the sources of BTEX exposure are commonly derived (i.e., vehicle exhausts and smoking), their values in subjects' urine were significantly intercorrelated. Levels of toluene and o-xylene were correlated significantly with the number of cigarettes smoked per day. The use of purge-and-trap gas chromatography with photoionization detection to determine BTEX in urine offers a convenient approach for biological monitoring of the general population. Study data provide referent values for BTEX in urine, which can be used as biomarkers for environmental exposures. Smoking contributes significantly to the urinary concentration of BTEX.

Hair testing for drugs of abuse.

Hair testing for drugs of abuse is a developing technology, which offers the possibility of longer detection times than is commonly obtained with urine analysis. It is the main method for evaluation of an individual's drugs of abuse history. In many countries hair analysis is routinely used to detect drug abuse in forensic cases, occupational and traffic medicine and clinical toxicology. Hair analysis in pregnant women, neonates and infants is a useful tool for the detection of drug exposure in utero. In Croatia hair testing for drugs of abuse is performed at the Institute for Medical Research and Occupational Health. Three-year experience in drugs of abuse analysis in hair is described. In 331 hair samples (270 from adolescents and 61 from adults) opiates and metabolites, cocaine, methadone, and amphetamines were analyzed by gas chromatography/mass spectrometry. Most prevalent drugs of abuse in adolescents were amphetamines, and in adults heroin. From the examples cited and samples analyzed it is evident that hair testing is emerging as a reliable biological marker for cumulative account of individual exposure to drugs of abuse.

Determination of benzene in urine by static headspace gas chromatography.

This paper describes the application of static headspace gas chromatography in determining benzene in urine. The method was analytically validated for sensitivity (DL = 42 ng/l), repeatability (RSD = 3% and 4%), and accuracy (71%), and was applied in measuring urine benzene in nonsmokers (N = 14) and smokers (N = 18). All urine samples had measurable benzene concentrations. The method proved sensitive enough to establish a significant statistical difference (P < 0.000614) in urine benzene concentrations between smokers (mean = 760; range = 181-1869 ng/l) and nonsmokers (mean = 214; range = 61-515 ng/l).

Hair testing for drugs of abuse: a two-year experience.

This article gives a brief account of a two-year experience with gas chromatography/mass spectrometry methods developed for the analysis of opiates (morphine, codeine, heroin and 6-acetylmorphine), cocaine, methadone, and amphetamines (amphetamine; methamphetamine; 3,4-methylenedioxyamphetamine--MDA, and 3,4-methylenedioxymethamphetamine--MDMA, Ecstasy) in hair. The methods developed were reproducible (RSD = 5.0-16.1%), accurate (85.1-100.6%) and sensitive (LD = 0.05-0.30 ng/mg). They were applied in the analysis of 221 hair samples obtained from young subjects aged 15-25 years, who were suspected of drug abuse. Seventy-seven hair samples were found positive for drugs of abuse. Forty-two subjects were found to have consumed amphetamine, of whom 40 were found MDMA (Ecstasy). Heroin consumption, based on positive 6-acetylmorphine, was found in 26 subjects. Cocaine alone was present in three subjects, two were found cocaine and heroin, two cocaine and methadone, and one cocaine and MDMA. These results could indicate the trend in drug abuse among young people in Croatia.