408 Improvement of determination method for ethylene glycol in the air of workplace by capillary gas chromatography


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Abstract

IntroductionEthylene glycol, which is colourless and odourless, is widely used in the field of manufacture of coolant, antifreeze, synthetic polyester and resin, etc. Although ethylene glycol is a compound with low toxicity, cases concerning the damage of glycol to central nervous system and respiratory system occur frequently because of its widely use. Long-term exposure under the workplace air with ethylene glycol can lead to coma, heart-failure and even death. The recommended method for the determination of ethylene glycol in the air of workplace ruled in current standard of government (GBZ/T 160.48–2007) has a detection limit of 14 mg/m3. Considering the occupational exposure limit (PC-TWA) of ethylene glycol given by China’s Ministry of Health is 20 mg/m3, there is a risk of ‘once detection, beyond limit already’. So an improved method with higher sensitivity and lower detection limit should be established to meet the need of practical application.MethodsEthylene glycol in the air of workplace was collected by solid sorbent tube containing silica gel and desorbed by solvent in the lab. The thus abtained sample was determined by capillary gas chromatography with FID detector. The performance of different kinds of desorption solvent and capillary column was investigated, and the condition of analysis was also optimised. Furthermore, the parameters of the improved method such as detection limit and precision were analysed.ResultsAs desorption solvent, methanol exhibited best performance with high desorption efficiency and equilibrium speed. And DB-WAXetr is the most suitable capillary column, as ethylene glycol showed stable retention time and sharp peak with good symmetry on it. The regression equation showed a good linear relationship in the range of 0.05–1.0 mg/mL. The detection limit of the method was 0.92 mg/m3 and the precision is 1.5%–4.2%.ConclusionAn improved method for the determination of ethylene glycol by capillary gas chromatography was developed. The method is simple, rapid and accurate with wide linear range. Compared with the traditional recommended method, the sensitivity of the novel method was greatly improved with a much lower detection limit of 0.92 mg/m3. The new method is more suitable and reliable for the determination of ethylene glycol in the air of workplace.

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