建立了气相色谱-质谱法（GC-MS）测定电子电气产品中4种甲基环硅氧烷含量的方法。称取粉碎后的样品1 g，加入10 mL四氢呋喃，于30℃超声提取30 min，提取液经0.22 μm有机系滤膜过滤，采用GC-MS测定其中4种甲基环硅氧烷的含量。结果显示，4种甲基环硅氧烷的质量浓度在0.1~10.0 mg·L^-1内与其对应的峰面积呈线性关系，检出限（3S/N）为1.86×10^-3~7.02×10^-2mg·kg^-1；对阴性样品进行3个浓度水平的加标回收试验，4种甲基环硅氧烷的回收率为85.7%~106%，测定值的相对标准偏差（RSD，n=7）均小于5.0%。

A method for determination of the 4 methyl cyclosiloxanes in electronic and electrical products by gas chromatography-mass spectrometry was established. The crushed sample powder of 1 g was extracted by ultrasonic at 30℃ for 30 min with 10 mL of tetrahydrofuran. The extracting solution was filtered by 0.22 μm organic filter membrane, the 4 methyl cyclosiloxanes of which were determined by GC-MS. As shown by the results, linear relationships between mass concentration of 4 methyl cyclosiloxanes and their peak area were kept in the range of 0.1-10.0 mg·L^-1, with detection limits (3S/N) in the range of 1.86×10^-3-7.02×10^-2mg·kg^-1. Recovery test was made on negative samples at 3 concentration levels by standard addition method, giving results in the range of 85.7%-106%, and RSDs (n=7) of the determined values were less than 5.0%.