短分离柱胶束液相色谱法同时测定酱油和食醋中的苯甲酸和山梨酸

建立了胶束液相色谱同时测定酱油和食醋中苯甲酸和山梨酸的检测方法。样品经过简单的稀释和过滤后直接注入高效液相色谱仪进行分析。分析柱使用两根串联的色谱保护柱(Zorbax Extend-C₁₈ 柱, 12.5 mm×4.6 mm, 5 μm),胶束流动相为含有2%(体积分数)异丙醇的0.01 mol/L十二烷基硫酸钠-0.01 mol/L醋酸钠(pH 4.9),检测器为二极管阵列检测器,检测波长为235 nm。苯甲酸和山梨酸在3.5 min内完全分离。检测的线性范围为10~100 μ g/mL,相关系数(r)为0.9999。检出限(S/N=3)和定量限(S/N=10)分别为0.04和0.14 μ g/mL。批间和批内精密度均不高于5.2%,高、中、低3个水平的加标回收率为90.5%~103.8%。该方法简单、快速,适用于食品质量监测的日常检测。

Simultaneous determination of benzoic acid and sorbic acid in soy sauce and vinegar by liquid chromatography using a short column and a micellar mobile phase

A rapid and reliable micellar liquid chromatographic method was developed to determinate benzoic acid and sorbic acid in soy sauce and vinegar samples. The samples were injected into a high performance liquid chromatograph (HPLC) directly after a simple dilution and filtration. Two guard columns were used in series as the analytical columns (Zorbax Extend-C₁₈ column, 12.5 mm×4.6 mm, 5 μm). The micellar mobile phase was 0.01 mol/L sodium dodecyl sulfate-0.01 mol/L sodium acetate containing 2% (v/v) isopropanol, adjusting the pH to 4.9 with acetic acid. The diode array detection wavelength was set at 235 nm. Under these conditions, analysis time was in 3.5 min for complete resolution of both analytes. Linearities were established in the range of 10-100 μ g/mL for both analytes. Both the correlation coefficients (r) were 0.9999. The limits of detection (S/N=3) and the limits of quantification (S/N=10) were 0.04 and 0.14 μ g/mL for the two analytes, respectively. The intra-day and inter-day precisions (RSDs) were not more than 5.2%. Spiked recoveries at three levels were from 90.5% to 103.8%. The simplicity of the method makes it a good candidate for use in routine analyses in food quality control.