将美缝剂样品养护、冷冻过夜后,研磨成粒径不大于1 mm的颗粒,分取2.0 g样品,加入50 mL正己烷,在400 W超声功率下,于40 ℃水浴提取1 h。提取液用无水硫酸钠干燥,于35 ℃旋转蒸发至1 mL,全部过HLB固相萃取柱。分别用丙酮5 mL、体积比1∶1的丙酮-正己烷的混合溶液5 mL和正己烷5 mL洗脱,收集全部洗脱液,氮吹至近干,用正己烷稀释至1 mL,用气相色谱-质谱仪检测。以HP-5MS色谱柱作固定相进行分离,用电子轰击离子源电离,外标法定量。结果显示:12种壬基酚同分异构体保留时间为7.8~8.6 min,壬基酚的质量浓度在0.3~5.0 mg·L^-1内与定量离子[质荷比(m/z) 107,121,135,149,163]峰面积加和呈线性关系,检出限(3S/N)为0.05 mg·kg^-1;按照标准加入法进行回收试验,回收率为88.4%~98.6%,测定值的相对标准偏差(n=6)为2.7%~11%。方法用于8份市售美缝剂样品的分析,仅在1份样品检测出了壬基酚,检出量为0.21 mg·kg^-1。

The tile grout sample was incubated, frozen overnight, and ground into particles with particle size of not more than 1 mm. An aliquot (2.0 g) of the sample was taken, and 50 mL of n-hexane was added. The mixture was extracted under 400 W ultrasound power in 40 ℃ water bath for 1 h. The extract was dried by anhydrous sodium sulfate, and evaporated to 1 mL by rotating at 35 ℃, all of which passed through the HLB solid phase extraction column. Elution was carried out by 5 mL of acetone, 5 mL of mixed solution composed of acetone and n-hexane at volume ratio of 1∶1 and 5 mL of n-hexane, and all the eluate was collected, blown to near dryness by nitrogen, and diluted to 1 mL by n-hexane. The resulting solution was analyzed by gas chromatograph-mass spectrometer. Nonylphenol was separated on the HP-5MS chromatographic column as the stationary phase, ionized by electron impact ion source, and quantified by external standard method. As found by the results, the retention time of 12 nonylphenol isomers was found in the range of 7.8-8.6 min, and linear relationship between values of the mass concentration of nonylphenol and the sum of peak areas of quantitative ions (m/z 107, 121, 135, 149, 163) was kept in the range of 0.3-5.0 mg·L^-1, with detection limit (3S/N) of 0.05 mg·kg^-1. Test for recovery was made by standard addition method, giving recoveries in the range of 88.4%-98.6%, and RSDs (n=6) of the determined values ranged from 2.7% to 11%. The proposed method was applied to the analysis of 8 tile grout samples from the market, nonylphenol was detected in 1 sample, with detection amount of 0.21 mg·kg^-1.