Trace analysis of xylene in occupational exposures monitoring

Determination of organic pollutants usually requires extraction of the pollutants from samples, using hazardous solvent. Solid phase micro-extraction [SPME] is a solvent-free equilibrium extraction method, in which, proper calibration can allow quantitative measurements of organic pollutants at a very good sensitivity without the use of any organic solvent. Because individual VOCs are generally present in urine only at trace levels, a sensitive and accurate determination technique is essential. This study describes the optimization of headspace solid phase micro-extraction [HS-SPME] followed by gas chromatography equipped with flame ionization detector [GC-FID] for xylene in spiked urine. Through this investigation, the parameters affecting the extraction and GC determination of xylene, including extraction time, temperature, desorption temperature, desorption time, salt addition, sample pH, sample volume and sample agitation were studied. An optimized headspace extraction was carried out at 30°C for 6 min in presence of 0.2 gml-1 of NaCl in the sample solution. Desorption of the xylene was carried out for 60 sec. at 250°C. The optimized procedure was also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. In this study, the accuracy, linearity, and detection limits were also determined. The HS-SPME-GC-FID technique provided a relatively simple, convenient, practical procedure, which can be successfully applied for determination of xylene in spiked urine when an occupational exposure monitoring is required

[Study of the effective parameters on the making use of protective devices in Qom province workers community in 2006]

Noise threats health of many groups of industrial workers and causes hearing loss. Use of personal protective device is the best control method to protect against hazardous conditions. Hence, this investigation was carried out to determine situation of using of protective devices and effective parameters on it, in Qom province workers community in 2006. This research is descriptive-sectional study. Sample volume was designed 378 persons working in factories in Qom. First of all, list of Qom factories with noise pollution problems, were collected and 30 important factories among them were selected randomly. In the second stage, 378 persons were selected randomly from workers. The interest information was obtained by questionnaire and collected data were analyzed by SPSS software. The obtained results showed that, 83.6% of workers have been using ear protective devices. 296 of them, which were using ear protective devices, had an occupational hygienist in their workplaces. This research also showed that, 109 workers that used ear protective devices, had moderate knowledge level. Moreover, 82.5% of trained workers have used ear protective devices. The statistical analysis of the results showed that there were no significant relationship between use of ear protective devices and existence of occupational hygienist in workplace, knowledge and age of workers, worker's antecedent, physical health of workers and kind of ear protective devices [p > 0.05]. These results showed that among all considered parameters; only four parameters were effective in using ear protective devices; education of workers before employment, head workman and employer's knowledge level, factories facilitation and kind of ear protective devices

Solid phase microextraction for trace analysis of urinary benzene in environmental monitoring

Conventional analytical method for organic pollutants in water requires extraction of the pollutants, using hazardous solvent. Solid phase microextraction is a solvent free equilibrium extraction method, in which, proper calibration can allow quantitative determinations of organic pollutants at a very good sensitivity without the use of any organic solvent. Because individual volatile organic carbons are generally exposed environmentally and present in urine only at trace levels, a sensitive and accurate determination technique is essential. So, this study describes the optimization of headspace solid phase microextraction [HS-SPME] followed by GC-FID for benzene in spiked urine. Through this investigations, the parameters affecting the extraction and gas chromatographic determination of analytes, including extraction time, temperature, desorption temperature, desorption time, salt addition, sample pH, sample volume and sample agitation were studied. An optimized headspace extraction was carried out at 30°C for 6 min in the presence of 0.2 g/mL of NaCl in the sample solution. Desorption of the analytes was carried out for 60 sec. at 250°C. The optimized procedure was also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. The accuracy, linearity, detection limits were also determined. The headspace solid phase microextraction, GC-FID technique provides a relatively simple, convenient, practical procedure, which was here successfully applied to determine benzene in spiked urine