摘要目的 建立以磷酸二氢钾为缓冲体系测定尿液中微量草酸和柠檬酸的毛细管电泳分析法,考察了缓冲液体系选择、缓冲液pH值、缓冲液浓度、分离电压、进样时间对分离测定的影响.方法 在毛细管区带电泳模式下,采用非涂层石英毛细管、磷酸二氢钾缓冲液进行电泳,直接紫外检测.收集2013年2月至3月间复旦大学附属中山医院尿石症患者24 h尿标本5份,健康体检患者24 h尿液标本5份,对该方法进行系统的方法学评价.对优化分离条件下检测的出峰时间与峰面积进行重复性验证,标准样品的浓度线性验证和加样回收率验证.结果 当毛细管柱内径为50 μm,长度为50 cm(有效长度为40 cm)、分离电压为-30 kV、缓冲溶液采用50 mmol/L(pH 6.5)、检测波长为200 nm时,尿液中草酸和柠檬酸在5 min内得到基线分离,草酸和柠檬酸迁移时间和峰面积的批内标准偏差分别小于1.0％和3.0％,批间标准偏差小于2.0％和4.0％,检测限均为1 mg/L,尿液中草酸和柠檬酸浓度在0～500 mg/L范围内线性关系均良好(r=0.999 5、0.995 4,P ＜0.05),回收率分别为102.38％和92.74％.结论 该方法简单、准确、成本低,可为尿液样品中微量草酸和柠檬酸的分析测定提供参考.

abstractsObjective To establish a method for determining oxalate and citrate in urine simultaneously by capillary electrophoresis.The components,the concentration and pH of the buffer solution,the separation voltage and the injection time on theseparation were studied in detail.Methods The separations were carried out using potassium dihydrogen phosphatebuffer ina fused-silica capillary tubeby capillary zone electrophoresis (CZE) and the detection were monitored by UV.24 h-urine samples from patients (n =5) and health control (n =5) were collected from Zhongshan Hospital of Fudan University for systematically validating the method developed.Results The optimized separations were carried out using a 50 mmol/L potassium dihydrogen phosphatebuffer solution (pH 6.5) in a fused-silica capillary tube of 50 cm × 50 μm I.D.Injections were made by using the pressure mode for 10 s at 34 mbar.The detections were monitored by a UV at 200 nm after samples were separated at avohage of 30 kV.Under the seconditions,urinary oxalate and citrate were separated completely within 5 min.The relative standard deviations of migration time and peak area within-run foroxalate and citrate were less than 1％ and 3.0％ and the betweenrun relative standard deviations were less than 2.0％ and 4.0％,respectively.The detection limits were 1 mg/L for both oxalate and citrate.The linearity ranges of oxalate and citrate were both 0-500 mg/L with the correlation coefficient between 0.999 5 and 0.995 4 (P ＜ 0.05),respectively.The average recoveries were 102.38％ for oxalate and 92.74％ for citrate.Conclusion This method is proved to be simple,sensitive and accurate,and also applied to determine oxalate and citrate in urine samples with satisfactory results.