Carlson M, Habeger L E
J Pharm Sci. 1980 Jul;69(7):826-8. doi: 10.1002/jps.2600690721.
The quantitative analysis of edetate disodium in nonprescription eyewash and ophthalmic solutions is described. The method involves differential pulse polarography using a dropping mercury electrode. A known concentration of cadmium or zinc is added to a buffer in a polarographic cell. The sample solution is incremented into the cell with a micropipet. The peak current decreases because the resulting chelate is not reducible at the potentials used. The quantity of edetate disodium in the sample then is determined graphically. Some contact lens cleaning and wetting solutions containing polymeric compounds are amenable to assay to edetate disodium if extraction, precipitation, centrifugation, or dilution steps minimize the maximum suppressor effect of the additives. These steps are very effective with cellulose ether compounds but are ineffective with polyvinyl alcohol.
本文描述了非处方洗眼液和眼科溶液中依地酸二钠的定量分析方法。该方法采用滴汞电极进行差分脉冲极谱法。将已知浓度的镉或锌添加到极谱池中含有缓冲剂的溶液中。用微量移液器将样品溶液逐步加入池中。由于生成的螯合物在所使用的电位下不可还原，峰值电流会降低。然后通过图形法测定样品中依地酸二钠的含量。如果通过萃取、沉淀、离心或稀释步骤将添加剂的最大抑制作用降至最低，一些含有聚合物化合物的隐形眼镜清洁和润眼液也适用于依地酸二钠的测定。这些步骤对纤维素醚化合物非常有效，但对聚乙烯醇无效。
