Nafion化学修饰钨丝圆盘预富集─石墨炉原子吸收法联用间接测定抗菌类药物头孢拉定的研究

Indirect Determination of Cephradine by GFAAS with Preconcentration on Nafion Chemically Modified Tungsten Coil

本文研究了Ｎａｆｉｏｎ化学修饰钨丝圆盘预富集－石墨炉原子吸收法间接测定头孢拉定的方法，并探讨了测定的机理。在ｐＨ为６．９的Ｃｕ２＋液中，加入的头孢拉定与Ｃｕ２＋进行配合反应，使原来溶液中的Ｃｕ２＋量减少，于是交换到Ｎａｆｉｏｎ膜上的Ｃｕ２＋的量也相应减少，从而测得Ｃｕ２＋的吸光度信号下降。头孢拉定浓度在１．５×１０－６－１．０×１０－５ｍｏｌ／Ｌ范围内，与吸光度下降值呈良好的线性关系，平行测定十次，相对标准偏差为２．０％，最低检出限为１．０×１０－６ｍｏｌ／Ｌ。同时测得Ｃｕ２＋与头孢拉定的配合比为１∶２，条件稳定常数为６．９×１０９。实测药物中头孢拉定的含量，结果令人满意。

A method and its mechaniem for the indirect determination of cephradine by GFAAS after preconentration on Nafion chemically modified tungsten coil are described. In the solution of PH 6.9, cephradine reacts with Cu2+ so that the concentration of Cu2+ in the solution decreases.The amount of Cu2+ exchanged on the Nafion membrane decreases, as a result, the absorption signal of Cu2+ decreases, A linear relation between the decrease of absorbance and concentration of cephradine added is obtained in the range of 1.5 × 10-6-1.0 × 10-5mol / L, The relative standard deviation for ten parallel determinations is 2.0 %. The detection limit by this method is 1.0 × 10-6mol/ L. The complex ratio of Cu2+ and cephradine is 1∶2. The complex stability constant is 6.9 × 109. The results of the content of cephradine in the medicines are satisfactory.