作业场所空气中邻氯甲苯的溶剂解吸气相色谱测定法

Gas chromatography in detecting o-chlorotoluene in the air of workplaces

目的 建立作业场所空气中邻氯甲苯的溶剂解吸气相色谱测定方法。方法 用活性炭管采集空气中的邻氯甲苯 ,样品经二硫化碳溶剂解吸 ,色谱仪检测。结果 当空气中邻氯甲苯的浓度范围在 2 5～ 10mg/m3 时 ,方法的精密度即合并变异为 1 3 1% ;回归方程式Y =13 6+2 7 0X ,相关系数r =0 9995。最低检测限 0 3× 10 -3 μg(进样 1 0 μl)。总平均解吸效率为 92 0 % ;当发生空气中邻氯甲苯的浓度范围在 70～ 90mg/m3 时 ,用该法采样 3～ 4h ,每 10 0mg活性炭对其最大吸附容量为 8 5mg(漏出率 <1 5 % ,尚未穿透 )。吸附于炭管中的邻氯甲笨 ,在常温下样品放置 10d后 ,回收率仍可达 91%。结论 该法的测定范围上限取决于活性炭的吸附量 。

Objective] To establish a method of gas chromatography in detecting o-chlorotoluene in the air of workplaces. [Methods] O-chlorotoluene in the air was collected with active carbon. The samples were dissolved in CS 2 solvent and detected with Gas chromatography. [Results] When the concentration of the o-chlorotoluene in air samples range from 2.5～10 mg/m 3 (refer to the US standard: 5.0 mg/m 3), the precision of this method was 1.31%; the equation of regression was Y=13.6+27.0 X; the coefficient of variability r=0.999 5; the minimum detection limit was 0.3×10-3 μg (injected 1.0 ul). The total average desorption rate was 92.0%. When the concentration ranged from 70～90 mg/m 3 and the samples had been collected for 3～4 hr, the maximum absorbency of o-chlorotoluene was 8.5 mg per 100 mg active carbon (leakage rate <1.5% without penetration). The recovery rate of the o-chlorotoluene absorbed in the carbon tube was 91% under the condition of 10 d in normal temperature. [Conclusion] The upper limit of detection with this method depends on the absorption amount of active carbon, which varies with the concentration of o-chlorotoluenein in the air and the coexistence of other substances.