三甲基氯硅烷涂层毛细管胶束电动色谱法测定苯甲酸和邻苯二甲酸

目的]建立测定苯甲酸和邻苯二甲酸含量的毛细管胶束电动色谱涂层新方法。方法]采用三甲基氯硅烷涂层的毛细管胶束t动色谱一紫外二极管阵列检测的新方法来分离测定饮料中的苯甲酸和实验室废水中的苯甲酸和邻笨二甲酸，考察了波长、pH值、缓≯介质和电压等因素对苯甲酸和邻苯二甲酸分离测定的影响。结果]以20mmol／LSDS＋35retool／L硼砂（pH值9．5）为运行缓冲液，_检测波长为210nm，分离电压为14kV条件下，苯甲酸和邻苯二甲酸在3min内实现分离，在2～800μg/L范围内两者峰高与浓度有J好的线性关系，其相关系数分别为0．9993和0．9999，迁移时间的RSD分别为2．65％和3．69％，峰高的RSD分别是3．12％和4．52％，j出限分别为0．1067和0．1213μg／ml。结论]该测定方法具有试样用量少、操作简捷、灵敏度和准确性好的特点，为防腐剂的分析提4了有效的检测方法。

Determination on Benzoic Acid and Phthalic Acid by Micellar Electrokinetic Chromatography with Trimethylchlorosilane-coated Capillaries

Objective] The study aimed to establish the new method for determining the contents of the benzoic acid and phthalic acid by the micellar electrokinetic chromatography with the coated capillaries.Method] The new method of micellar electrokinetic chromatography by using the trimethylchlorosilane coated capillaries with UV diode array detection was used for the separation and determination of benzoic acid in the drink and benzoic acid and phthalic acid in the laboratory waste water.The effects of the wavelength,pH value,buffer solution,voltage and other factors on the separation and determination of the benzoic acid and phthalic acid were investigated.Result] Under the optimized operation conditions of 20 mmol/L SDS + 35 mmol/L borate(pH of 9.5)as the running buffer solution,the detection wavelength of 210 nm,and the separation voltage of 14 kV,the benzoic acid and phthalic acid could be separated in 3 min,their good linear relationships between the peak heights and concn.were obtained in the range of 2-800 μg/L,with their correlation coefficients being 0.999 3 and 0.999 9 resp,the RSD of migration time being 2.65% and 3.69% resp.,the RSD of peak height being 3.12% and 4.52%,resp.,and the detection limits being 0.1067 and 0.121 3 μg/ml resp.Conclusion] This new measuring method had the characters of less sample dosage,easy operation and good sensitivity and accuracy,which provided an effective method for the analysis of the preservatives.