样品0.500 0 g置于10 mL烧杯中，用0.1 mol·L^-1氢氧化钾-甲醇溶液调节pH至8~9，于100℃将水分挥干。残渣用硫酸-甲醇（5+95）溶液10 mL溶解，并于70℃酯化反应30 min。取甲酯化后的溶液200 μL采用自主设计的微型液液萃取装置，以二氯甲烷1 mL为萃取剂进行萃取，再加入水1 mL进行振荡萃取。所得萃取液采用气相色谱-质谱法（GC-MS）测定其中丁酸和乳酸的含量。结果表明：丁酸和乳酸的质量浓度在0.10~50.00 mg·L^-1内与其峰面积呈线性关系，检出限（3S/N）分别为0.1，0.4 mg·kg^-1。按标准加入法进行回收试验，回收率为97.7%~108%，相对标准偏差（n=5）为0.60%~12%。

The sample of 0.500 0 g was placed into a baker of 10 mL, and adjusted to pH 8-9 with 0.1 mol·L^-1 KOH-methanol solution. Water in the sample was concentrated to dryness at 100℃.The residue was dissolved in 10 mL of sulfuric acid-methanol (5+95) solution and esterification reaction was taken for 30 min at 70℃. Then the reacted solution of 200 μL was extracted with dichloromethane of 1 mL as the extraction solvent in a self-designed micro liquid-liquid extraction device, and water of 1 mL was added to oscillate. n-Butyric acid and lactic acid were determined by gas chromatography-mass spectrometry (GC-MS). As shown by the results, Linear relationships between values of peak area and mass concentration of n-butanoic acid and lactic acid were found in the range of 0.10-50.00 mg·L^-1, with detection limits (3S/N) of 0.1 mg·kg^-1 for n-butanoic acid and 0.4 mg·kg^-1 for lactic acid. Test for recovery was made by standard addition method, giving results in the range of 97.7%-108%, with RSDs (n=5) ranged from 0.60% to 12%.