对超声提取法从尼龙等食品接触材料中分离出5种酸胺类物质（丙烯酰胺、甲基丙烯酰胺、己内酰胺、油酸酰胺和硬脂酰胺）的条件进行了优化。预先将所分析的材料洗净晾干，剪成0.5 cm×0.5 cm的小块，并混匀。取此样品1.00 g，用甲醇先后提取2次，每次加甲醇25 mL，于25℃超声提取30 min。将提取后过滤所得滤液合并，在45℃吹氮至近干。残渣用甲醇溶解并定容至50.0 mL。取此溶液1.0 mL，用0.22 μm滤膜过滤，取其滤液按仪器工作条件进行气相色谱-质谱分析。选用Agilent HP5-MS色谱柱及在60~270℃区间按程序升温模式进行色谱分离，并按5种酰胺化合物的保留时间进行质谱测定。上述5种酰胺的质量浓度均在5~100 mg·L^-1内与其对应的峰面积呈线性关系。测得其检出限（3S/N）为0.08~1.0 mg·L^-1。以空白样品为基体，加入5种酰胺的混合标准溶液进行回收试验，测得回收率为90.2%~104%，测定值的相对标准偏差（n=6）为0.78%~1.7%。按本方法分析了4件实样，结果仅在尼龙炊具中检测到已内酰胺，质量分数为10 mg·kg^-1，小于欧盟规定的迁移限量（15 mg·kg^-1）。

Conditions of ultrasonicated extraction for separation of 5 amides (i.e., acrylamide, methylacrylamide, caprolactam, oleamide and stearamide) from plastic food-contacting materials, e.g., nylon, were studied and optimized. The food-contacting material, as sample for analysis should be washed, air-dried and cut to small pieces of 0.5 cm×0.5 cm. A portion of the cut sample (1.00 g) was taken and extracted twice ultrasonically for 30 min at 25℃ using 25 mL of methanol in each extraction. The mixture was filtered, and the 2 filtrates were combined and evaporated to near-dryness by N₂-blowing at 45℃. The residue was dissolved and diluted to 50 mL with methanol. An aliquot of 1.0 mL was taken and filtered through 0.22 μm filtering membrane. The filtrate was used for GC-MS analysis under the working conditions of the instrument. Agilent HP5-MS chromatographic column and program of temperature elevation from 60℃ to 270℃ were adopted in GC-separation. MS determination was done at the respective retention times of the 5 amides. Linearity ranges of the standard curves of the 5 amides were found same between 5 to 100 mg·L^-1. Their detection limits (3S/N) were found in the range of 0.08 to 1.0 mg·L^-1. Using a blank sample as matrix, test for recovery was made by addition of mixed standard solution, giving results of recovery in the range of 90.2% to 104%. Values of RSDs (n=6) found were in the range of 0.78% to 1.7%. 4 substantial samples were analyzed by the present method, and only caprolactam was found in the nylon sample, giving a values of 10 mg·kg^-1, which was lower than the limit of migration (15 mg·kg^-1) as stipulated by the European Economic Community.