Inhalant abuse detection and evaluation in young Tunisians

Chakroun R., Faidi F., Hedhili A, Charbaji K., Nouaigui H., Ben Laiba M.

Occupational exposure biological monitoring techniques were applied for the diagnosis of inhalation abuse and the evaluation of levels of exposure to benzene, toluene, ethylbenzene, xylenes and n-hexane, in 44 Tunisian adolescents and children suspected for volatile substance addiction. Urinary trans,trans-muconic acid (t,t-MA), hippuric acid (HA), mandelic acid (MA), methylhippuric acids (MHAs) determinations were performed by high performance liquid chromatography with a photodiode array detector (HPLC/PAD) and, urinary o-Cresol (o-Cr) and 2,5-hexanedione (HD) were extracted simultaneously and measured using gas chromatography with a flame ionization detector (GC/FID).

Given the high linearity ranges, HD and o-Cr occupational exposure monitoring techniques could be applied without modification. However, urinary sample dilution was necessary before HA analysis.

Concentrations were compared to the maxima of normal values (MNVs) in the general population and to the biological exposure indices (BEIs) used in occupational toxicology. Values as high as 6610 fold the MNV and 68 times the BEI were registered. The subjects showed high exposure to toluene and hexane. Measured metabolites HA and/or o-Cr and HD enabled the easy detection and evaluation of exposure levels.
The problem of inhalant abuse should be given more attention and treated through an effective prevention strategy.

Journal of Forensic Sciences 2008; 53:1:232-237.

Simultaneous HPLC Determination of Urinary Metabolites of Toluene, Xylenes, and Ethylbenzene; and Its Application to Biological Monitoring of Tunisian Workers Exposure

Chakroun R., Hedhili A, Faidi F., Nouaigui H., Ben Laiba M.

A simple, sensitive, and reproducible high performance liquid chromatographic procedure is described for the simultaneous determination of urinary metabolites of several aromatic hydrocarbons: mandelic and phenylglyoxylic acids from ethylbenzene; hippuric acid from toluene, and methylhippuric acids from xylenes. The employed mobile phase and the chromatographic conditions allowed relatively low detection limits (0.1 to 0.2 mg/L). The method was tested on 33 workers in the paint industry and on 33 nonoccupationally exposed Tunisian subjects. A significant difference of metabolite concentrations was found between the two groups. In the exposed group, most of the measured levels were lower than the biological exposure indices.

Analytical Letters. 2006; 39:1:83-97.

Benzene Exposure Monitoring of Tunisian Workers

Chakroun R., Kaabachi N., Hedhili A, Feki M., Nouaigui H., Ben Laiba M., Mebazaa A.

To monitor benzene exposure and to check reliability of urinary trans,trans-Muconic Acid (t,t-MA) as a bio-marker of benzene exposure in local conditions, a study was conducted on 30 Tunisian exposed workers (20 tanker fillers and 10 filling station attendants). The analyses were carried out on environmental air and urinary t,t-MA before (t,t-MAA) and at the end of work shift (t,t-MAB). 20 nonoccupationally exposed subjects were also investigated.

The average value of environmental benzene concentration was 0.17 ppm. The differences between t,t-MAA and t,t-MAB concentrations and between t,t-MAB and t,t-MA measured in controls (t,t-MAC) were both significant (p < 0.001). Benzene air concentrations were well correlated with t,t-MAB: R = 0.76. In the nonexposed group, average t,t-MA concentrations is significantly higher among smokers than nonsmokers (P < 0.02). Analysis of urinary t,t-MA offers a relatively simple and suitable method for benzene exposure monitoring.

Journal of Occupational and Environmental Medicine. 2002 ; 44:12:1173-1178.