毛细管区带电泳-间接紫外检测法快速测定食品中乳糖、蔗糖、葡萄糖和果糖

建立了毛细管区带电泳-间接紫外检测快速测定食品中乳糖、蔗糖、葡萄糖和果糖的方法。以水或5 mmol/L醋酸为样品提取液,未涂层熔融石英毛细管(30.2 cm(有效长度20 cm)×50 μm)为分离柱,4 mmol/L山梨酸钾+10 mmol/L磷酸钠+30 mmol/L NaOH(pH 12.56)+0.5 mmol/L十六烷基三甲基溴化铵(CTAB)为分离缓冲液,在-8 kV下分离,于254 nm波长下检测,10 min内实现了食品中上述4种糖的同时分离与测定。乳糖、蔗糖、葡萄糖和果糖的检出限(S/N=3)分别为50、75、25和25 mg/L,定量限(S/N=10)分别为150、225、75和75 mg/L,回收率在87.0%~107.0%之间,相对标准偏差在1.2%~4.7%之间。整个实验过程未使用有机溶剂。用该法测定了9种食品样品及1个质控样品,结果表明该法简单、快速、准确,适用于食品中乳糖、蔗糖、葡萄糖和果糖的日常测定。

Rapid determination of lactose,sucrose,glucose and fructose in foods by capillary zone electrophoresis with indirect ultraviolet detection

A new and rapid method for the simultaneous determination of lactose, sucrose, glucose and fructose by capillary zone electrophoresis (CZE) with indirect ultraviolet detection was developed. The separation was completed with an uncoated fused-silica capillary with 30.2 cm of total length (effective length of 20 cm)×50 μm. The separation buffer consisted of 4 mmol/L potassium sorbate, 10 mmol/L sodium phosphate, 30 mmol/L NaOH (pH 12.56) and 0.5 mmol/L hexadecytrimethylammonium bromide (CTAB). The separation was performed at a voltage of -8 kV with the ultraviolet detection at 254 nm. The analysis of the four carbohydrates was completed within 10 min. The limits of detection (S/N=3) for lactose, sucrose, glucose and fructose were 50, 75, 25 and 25 mg/L, and the limits of quantification (S/N=10) were 150, 225, 75 and 75 mg/L, respectively. The average recoveries for the four carbohydrates were in the range of 87.0%-107.0% with the relative standard deviations of 1.2%-4.7%. No organic solvent was consumed throughout the whole process of the analysis. The method was used for the analysis of nine food samples and a quality control sample. The results demonstrated that the method is simple, rapid, accurate, and suitable for the routine analysis of the four carbohydrates in food samples.