硫酸亚汞电极的研制与电位滴定法分析测定青霉素类抗生素  

Preparation of mercurous sulfate reference electrode and its analytical application on penicillins

作　　者：刘炜[1] 杜增辉[1] 张筱红[2] 张菁[1] 常俊山[1] 

机构地区：[1]河北省药品检验所,河北石家庄050011 [2]国家药典委员会,北京100061

出　　处：《中国药学杂志》2002年第4期294-298,共5页Chinese Pharmaceutical Journal

基　　金：河北省卫生厅科研资助课题 ( 95 0 45 )

摘　　要：目的　设计制备实用硫酸亚汞参比电极 ,测定其性能参数以及稳定性 ,探讨在分析测定青霉素类抗生素方面的应用。方法　制备硫酸亚汞、纯化汞 ,用聚丙烯塑料管作为电极体制备硫酸亚汞电极 ,测定在实验条件下电极电位对Hg2 + 的响应及相关参数 ,验证其用于分析测定青霉素类抗生素青霉素钠 (钾 )、氨苄西林钠、青霉素V钾、阿莫西林、苯唑西林钠、普鲁卡因青霉素以及氯唑西林钠等的可行性 ,探讨用电位滴定法测定哌拉西林钠和美洛西林钠的方法。结果　在汞离子浓度为 2 .0～5 3.0 μmol·L-1的范围内 ,实验电极的电极电位与汞离子浓度的对数值呈线性相关 (r =0 .9998,P <0 .0 0 1) ,平均响应斜率为37.0 0 ,与Nernst方程有良好的符合性 ,适用pH范围为 2 .8～ 9.0 ,检出限为 8.97× 10 -7mol·L-1,响应时间小于 18s ,温度系数为 - 1.39,电极电位的负性绝对值与温度呈正比 ,测定的标准电极电位与文献值基本一致 ,有效使用时间大于 5年 ;青霉素钠 (钾 )、氨苄西林 (钠 )、阿莫西林、苯唑西林钠、普鲁卡因青霉素、氯唑西林钠、青霉素V钾及美洛西林钠的电位滴定法测定结果与原方法一致 ,但哌拉西林钠的测定结果比HPLC的测定结果偏高。结论　制备的硫酸亚汞电极对汞离子有良好的线性响应 ,符合Nernst方程 。OBJECTIVE To design and make the mercurous sulfate electrode and measure the related parameters of the electrode,and to study its application on analysis of the penicillins.METHOD With the reagent of mercurous sulfate and the pure mercury,the electrode was made by using polypropylene plastic as the electrode body.The feasibility of the electrode on analysis of the penicillins was validated through determining Piperacillin and Mezlocillin by the mercury nitrate titration.RESULTS It was found that the electrode potential of the electrode had Nernst response with Hg 2+,and Nernst equation was obeyed over the range 2.0×10 -6～5.3×10 -5mol·L -1 of Hg 2+.The detection limit was 8.97×10 -7 mol·L -1.The average response slope was 37.0,and the applicable pH range was 2.8～9.0. The temperature coefficient measured was -1.39,and the absolute value of the electrode potential presented a direct ratio with temperature.The response time was less than 18 sec. 0.05 ml of 0.02 mol· L -1 of mercury nitrate could caused the potential change over 55 mV.The end point of petentiometry related to Hg 2+ was easy judged.The standard electrode potential of the electrode measured was consisted with reported.It was also observed that the term of validity was over 5 years.The samples of Benzylpenicillin , Phenoxymethylpenicillin, Oxacillin, Amoxicillin, Ampicillin, Procaine Benzylpenicillin, Piperacillin, Cloxacillin and Mezlocillin were determined by the potentiometric titration. It was found that the results of the determinations by the titration had no significant difference (P>0.05) with the original methods,but the result of the determination for Piperacillin was higher than that of the HPLC.CONCLUSION The mercurous sulfate electrode showed a perfect response with Hg 2+ and obey Nernst equation can over a wide range of pH.It can be used as the reference electrode on analysis of the penicillins by the mercury nitrate titration potentiometrically.

关 键 词：硫酸亚汞电极 塑料电极体 性能参数 电位滴定 青霉素 

分 类 号：R978.11[医药卫生—药品] R927.1[医药卫生—药学]