取固体样品（如糕点、肉肠等） 2.000 g，或液态样品（如饮料等） 10.00 mL，加少量水稀释后，加入220 g·L^-1乙酸锌和106 g·L^-1亚铁氰化钾溶液各2 mL沉淀蛋白质并离心除去；取半固体样品（如果冻等） 2.000 g，加水稀释后用氨水（1+1）溶液调节其酸度至pH 7~8，上述3种样品溶液均分别用水定容至25.0 mL。所得溶液进行高效液相色谱分离，以TSK Eclipse XDB-C₁₈色谱柱为固定相，和pH 5.0的甲醇-三乙胺缓冲溶液（1+9）为流动相。苯甲酸和山梨酸的质量浓度均在0.1~10.0 mg·L^-1内与峰面积呈线性关系，检出限（3S/N）分别为1.8，1.2 mg·kg^-1。按标准加入法在3个浓度水平上进行回收试验，回收率在90%~97%之间，测定值的相对标准偏差（n=6）均小于10%。

The solid sample, e.g. cake, sausage and etc., (2.000 g) or liquid sample, e.g., drinks etc. (10.00 mL) was taken and diluted with some water. 2 mL of 220 g·L^-1 zinc acetate solution and 2 mL of 106 g·L^-1 potassium ferrocyanide solution were added to precipitate protein and to remove it by centrifuge. In case of semi-solid sample, e.g., jelly, 2.000 g were taken and diluted with water. The acidity was adjusted to pH 7 to 8 with ammonia (1+1) solution. The sample solution described above was made up to 25.0 mL with water, and separated by HPLC using TSK Eclipse XDB-C₁₈ column as stationary phase and mixed solution of methanol and triethylamin (1+9) (pH 5.0) as mobile phase. Linear relationships between values of peak area and mass concentration of benzoic acid and sorbic acid were found in the same range of 0.1-10.0 mg·L^-1, with detection limits (3S/N) of 1.8, 1.2 mg·kg^-1, respectively. Test for recovery was made by standard addition method at 3 concentration levels, giving results in the range of 90%-97%, with RSDs (n=6) less than 10%.