Montaño A, Sánchez A H, Rejano L
Departamento de Biotecnología de Alimentos, Instituto de la Grasa (CSIC), Seville, Spain.
Analyst. 1995 Oct;120(10):2483-7. doi: 10.1039/an9952002483.
Three analytical methods for determining sorbic and benzoic acids in various packaged vegetable products were evaluated, with special attention being paid to green olives. Two of these methods used a simple, isocratic, reversed-phase HPLC technique for separating and detecting the preservatives, but differed in the preparation of the sample (extraction with 60% methanol or steam distillation). The third method was based on separation by steam distillation and determination of the acids in the distillate by spectrophotometry. For the olives, while this method proved to be excellent (total error < 25%) for high concentrations (> 100 ppm), the HPLC methods were more efficient for the whole range of concentrations studied (5-500 ppm). Both HPLC methods had detection limits of approximately 1 ppm for the two preservatives. With other sample matrices (tomatoes, cucumbers, caperberries, silver-skinned onions and hot peppers), the three methods proved to be excellent for high concentrations of preservatives (500 ppm), but at low levels (20 ppm), the spectrophotometric method and the HPLC method with extraction by 60% methanol proved to be unacceptable (total error > 50%) in some cases.
对三种测定各类包装蔬菜产品中山梨酸和苯甲酸的分析方法进行了评估，其中特别关注了绿橄榄。其中两种方法采用简单的等度反相高效液相色谱技术分离和检测防腐剂，但样品制备方法不同（用60%甲醇萃取或水蒸气蒸馏）。第三种方法基于水蒸气蒸馏分离，并用分光光度法测定馏出物中的酸。对于橄榄，虽然该方法在高浓度（>100 ppm）时表现出色（总误差<25%），但高效液相色谱法在整个研究浓度范围（5 - 500 ppm）内更有效。两种高效液相色谱法对两种防腐剂的检测限均约为1 ppm。对于其他样品基质（番茄、黄瓜、刺山柑、白皮洋葱和辣椒），这三种方法在高浓度防腐剂（500 ppm）时表现出色，但在低浓度（20 ppm）时，分光光度法和用60%甲醇萃取的高效液相色谱法在某些情况下被证明是不可接受的（总误差>50%）。
