正己烷萃取-顶空气相色谱法测定乳胶漆中苯系物含量

Head-Space Gas Chromatographic Determination of Contents of Benzene Homologues in Dispersion Paints after Extraction with n-Hexane

应用顶空气相色谱法测定了乳胶漆中7种苯系物,即苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯及苯乙烯。作为对常规的顶空法的改进,乳胶漆中的上述7种化合物预先在顶空瓶中用n-己烷萃取,以提高方法的回收率。取1 mL气体供气相色谱分析,用HP-INNOWAX极性柱作为分离柱,并采用氢火焰离子化检测器。按保留时间值作定性分析,定量分析则采用外标法。文中给出7种化合物的线性回归方程,其相关系数在0.998 9-0.999 9之间,求得7种化合物的检出限（S/N=3）为0.05 ng或0.1μg·kg^-1（对0.5g试样）。用此方法分析了两件乳胶漆样品,根据测得结果,算得其相对标准（n=5）值均小于5%;进行了回收试验,回收率结果苯为90%-105%,甲苯为88%-102%,乙苯为85%-102%,二甲苯为80%-98%及苯乙烯为85%-102%。

Seven benzene homologues, namely benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene and styrene, were determined by head-spacegas chromatography. As a modification of the conventional head-space method, the dispersion paint sample was pretreated by extraction with n-hexane. One mL of the gas sample was used for GC analysis. The polar column （HP-INNOWAX） was used in the separation and FID detector was used in the measurement. Qualitative analysis was done by retention time, and the external standard method was used for quantitative analysis. Linear regression equations for the 7 compounds were given with correlation coefficients in the range from 0. 998 9-0. 999 9. Detection limit （S/N=3） of these homologues was found to be 0. 05 ng or 0. 1 μg · kg^-1 on the base of 0. 5 g of the paint sample. In the analysis of 2 samples of dispersion paints, values of RSD＇s （n=5） found for the 7 compounds were less that 5%. Test for recovery was made and results obtained were in the ranges of 90%-105% （for benzene）, 88%-102% （for toluene）, 85%-102%（for ethyl benzene）, 80%-98% （for xylenes） and 85%-102% （for styrene）.