取样品0.100 0 g用5.0 mL水超声溶解，并引入顶空进样仪中，在80 ℃下加热30 min达到平衡。对溶液中甲醇经顶空提取后，以HP-INNOWAX毛细管色谱柱为固定相进行气相色谱分离。质谱分析中采用选择离子监测模式，外标法定量。甲醇的质量浓度在0.50~100 mg·L^-1内与其峰面积呈线性关系，检出限（3S/N）为0.002 5%。按标准加入法进行回收试验，测得回收率在90.0%~100%之间，测定值的相对标准偏差（n=6）均小于2.2%。

The sample (0.100 0 g) was dissolved ultrasonically with 5.0 mL of water, and the solution was introduced into the headspace sampling apparatus, and equilibrated at 80 ℃ for 30 min. After the headspace extraction gaseous of methanol from the solution, HP-INNOWAX capillary column was used as stationary phase for gas chromatography separation. The mode of SIM was adopted in MS, and external standard method was adopted for quantification. Linear relationship between values of peak area and mass concentration of methanol was found in the range of 0.50-100 mg·L^-1, with detection limits (3S/N) of 0.002 5%. Test for recovery was made by standard addition method, giving results in the range of 90.0%-100%, with RSDs (n=6) less than 2.2%.