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    顶空-气相色谱法测定油基金属加工液中10种挥发性有机物

    Determination of 10 Volatile Organic Compounds in Oil-Based Metal Working Fluid by Headspace-Gas Chromatography

    • 摘要: 称取油基金属加工液样品(5.00±0.01)g置于仪器的顶空瓶中,盖紧后,按所选择的顶空条件(平衡温度145℃,平衡时间30 min,定量环体积及温度分别为1 mL和155℃,进样时间0.5 min)进行操作。用HP-5毛细管色谱柱(30 m×320 μm,0.5 μm)在程序升温(温度区间在35~160℃)的条件下进行色谱分离,以氮气为载气,用火焰离子化检测器检测10种被测挥发性有机物的峰面积。选用v-slov基础油作为基体,加入不同量的10种挥发性有机物的标准溶液系列,按方法的条件制作标准曲线,用外标法定量。所测定的10种挥发性有机物依次为二氯甲烷、正己烷、苯、甲苯、正辛烷、乙苯、对二甲苯、邻二甲苯、正壬烷和正十一烷。测得以上10种挥发性有机物分别在一定浓度范围内与其相应峰面积之间呈线性关系,所得线性相关系数均大于0.999。10种挥发性有机物的测定下限(10S/N)在0.40~10 mg·kg-1之间。在已知样品的基础上用标准加入法进行回收试验,测得回收率在88.0%~115%之间,测定结果的相对标准偏差(n=6)在1.0%~5.6%之间。

       

      Abstract: (5.00±0.01) g of the oil-based metal-working fluid sample were taken and placed into the headspace flask. After capping of the headspace flask, the headspace processing was carried out according to the optimized conditions of equilibrium temperature (145℃) and equilibrium time (30 min), with volume and temperature of the quantitative circle of 1 mL and 155℃, and time of sample introduction of 0.5 min. Gas chromatography separation was performed on HP-5 capillary chromatographic column (30 m×320 μm, 0.5 μm) and under temperature elevation program in the temperature interval between 35℃ to 160℃. Nitrogen was used as carrying gas. FID was used for measuring the peak areas of the 10 analytes of VOCs in the sample, namely dichloromethane, n-hexane, benzene, toluene, n-octane, ethylbenzene, p-dimethylbenzene, o-dimethylbenzene, nonane and undecane. The v-slov base oil was selected as matrix in headspace operation and in preparation of standard curves by addition of mixed standard solution of the 10 VOCs. Linear relationships between values of peak areas and the mass fraction of the respective analytes were found in definite ranges, having linear correlation coefficients greater than 0.999. Values of lower limits (10S/N) of determination of the 10 VOCs were found in the range of 0.40-10 mg·kg-1. Test for recovery was made by standard addition using a known sample as matrix. Results of recovery were found ranged from 88.0% to 115%. Values of RSDs (n=6) were found in the range of 1.0%-5.6%.

       

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