工作场所空气中丙二醇单甲醚同分异构体的溶剂解吸-气相色谱测定法

Propylene glycol monomethyl ether isomers in workplace air determined by solvent desorption-gas chromatography

[背景]丙二醇单甲醚(PGME)是一种被广泛使用的有机溶剂,在工作场所中以两种异构体的形式存在,会引起职业人员眼部和上呼吸道刺激等不良影响。但是,我国尚缺乏同时检测PGME两种异构体的标准检测方法。[目的]建立工作场所空气中PGME的两种同分异构体[1-甲氧基-2-丙醇(α-PGME)、2-甲氧基-1-丙醇(β-PGME)]的溶剂解吸-气相色谱法。用溶剂解吸型活性炭管采集工作场所空气中α-PGME、β-PGME,使用二氯甲烷/甲醇(85:15)的解吸液解吸后,经具有游离脂肪酸固定相(FFAP)的熔融二氧化硅毛细管色谱柱分离,带氢焰离子化检测器(FID)检测,以峰面积定量,建立工作场所空气中α-PGME、β-PGME的溶剂解吸-气相色谱法,得到标准曲线、检出限、定量下限等指标,以相对标准偏差(RSD)考察精密度,采用测定样品溶液加标回收率来评估本标准方法的准确度。进行解吸效率、采样效率、吸附容量试验,使用加标活性炭管保存试验评价样品稳定性,并进行干扰实验。将所建立的方法应用到现场空气样品检测中。[结果]本法使用二氯甲烷/甲醇(85:15)作为样品解吸溶液,α-PGME和β-PGME的定量检测范围分别为0.95~923.0μg·mL^(-1)和0.97~912.0μg·mL^(-1),相关系数均为0.9999,方法检出限分别为0.28μg·mL^(-1)和0.29μg·mL^(-1),方法定量下限分别为0.95μg·mL^(-1)和0.97μg·mL^(-1)。在采样体积为1.5 L,解吸液体积为1.0 mL的条件下,最低检出质量浓度(简称浓度)均为0.19 mg·m^(-3),最低定量浓度分别为0.63 mg·m^(-3)和0.65 mg·m^(-3)。本法α-PGME和β-PGME的批内精密度分别为2.8%~4.9%和2.8%~5.1%,批间精密度分别为4.2%~5.7%和4.5%~5.9%,加标回收率分别为98.8%~100.3%和96.4%~102.9%,解吸效率分别为92.7%~97.3%和92.2%~98.1%,本法平均采样效率均为100%,样品在室温(25~30℃)下至少可保存7 d,在4℃下至少可保存15 d。活性炭采样管对α-PGME和β-PGME的吸附容量分别大于13.9 mg和2.7 mg(100 mg活性炭吸附剂)。工作场所可能共存成分不干扰α-PGME和β-PGME的测定。使用本法测定某汽车制造公司喷涂空间空气,α-PGME和β-PGME的短时间接触浓度为18.69 mg·m^(-3)和2.19 mg·m-2,时间加权平均浓度为6.03 mg·m^(-3)和1.08 mg·m^(-3)。[结论]本方法准确度高,精密度好,适用于工作场所空气中PGME的两种同分异构体的现场监测。

[Background]Propylene glycol monomethyl ether(PGME)is a widely used organic solvent.It exists in the form of two isomers in the workplace,which will cause adverse effects such as eye and upper respiratory tract irritation in workers.However,there is still a lack of standard detection methods for simultaneous detection of two isomers of PGME in China.[Objective]To establish a solvent desorption-gas chromatographic method for two isomers of PGME[1-methoxy-2-propanol(α-PGME),2-methoxy-1-propanol(β-PGME)]in workplace air.[Methods]A method of solvent desorption-gas chromatography forα-PGME andβ-PGME in workplace air were proposed.Air samples were collected with solvent desorption activated carbon tubes,desorbed using a desorption solution of dichloromethane/methanol(85:15),and then separated on a free fatty acid phase(FFAP)fused silica capillary chromatography column,detected with a flame ionization detector(FID),and quantified by peak area.Standard evaluation protocol was followed to obtain key indicators:standard curve,limit of detection,lower limit of quantification,relative standard deviation(RSD)that measures precision,and spiked recovery of sample solutions that measures accuracy.Desorption efficiency,sampling efficiency,and adsorption capacity tests were conducted,sample stability was evaluated using spiked activated carbon tube preservation test,and interference test was also assessed.The developed method was then applied to field air sample testing.[Results]In this method,using dichloromethane/methanol(85:15)as the sample desorption solution,the quantitative detection ranges ofα-PGME andβ-PGME were 0.95-923.0μg·mL^(-1) and 0.97-912.0μg·mL^(-1) with both correlation coefficients of 0.9999,the method limits of detection were 0.28μg·mL^(-1) and 0.29μg·mL^(-1),and the lower limits of quantification were 0.95μg·mL^(-1) and 0.97μg·mL1,respectively.The lowest concentrations detected were both 0.19 mg·m^(-3),and the lowest concentrations quantified were 0.63 mg·m^(-3) and 0.65 mg·m^(-3),respectively,under the conditions of sampling volume of 1.5 L and the volume of desorption solution of 1.0 mL.The intra-batch precisions forα-PGME andβ-PGME were 2.8%-4.9%and 2.8%-5.1%,the inter-batch precisions were 4.2%-5.7%and 4.5%-5.9%,the spiked recoveries were 98.8%-100.3%and 96.4%-102.9%,and the desorption efficiencies were 92.7%-97.3%and 92.2%-98.1%,respectively.The average sampling efficiency was 100%,and the samples could be stored at room temperature(25-30℃)for at least 7 d and at 4℃for at least 15 d.The adsorption capacities of the activated carbon sampling tube forα-PGME andβ-PGME were greater than 13.9 mg and 2.7 mg(100 mg of activated carbon adsorbent),respectively.Possible co-existing components in workplace did not interfere with the determination ofα-PGME andβ-PGME.The short-time exposure concentrations ofα-PGME andβ-PGME in the spray painting unit of an automobile manu-facturing company were determined to be 18.69 mg·m^(-3) and 2.19 mg·m^(-3),and the time-weighted average concentrations were 6.03 mg·m^(-3) and 1.08 mg·m^(-3) respectively.[Conclusion]This method is accurate,precise and suitable for on-site monitoring of the two isomers of PGME in workplace air.