改进国标方法检测海岸带水体铁的研究

为了更加准确地检测海岸带水体中的铁含量,将邻菲啰啉分光光度法测定水质铁(国标法)的方法进行了改进.在邻菲啰啉分光光度法的基础上,在pH调节方式、比色皿皿差和显色剂三个方面进行改进.结果表明,改进后方法的线性、准确度和精密度都优于国标法.但改变pH调节方式和扣除比色皿皿差后检测低浓度铁的水样的精密度依然较差(RSD>5%),说明邻菲啰啉的灵敏度较低.以5-Br-PADAP为显色剂用分光光度法检测水样时,方法的准确度和精密度较好(RSD<5%,加标回收率在96.0%~106%之间),该方法可以用于海岸带水体中铁的检测.

Determination of Iron in Coastal Zone Water with Improved National Standard Method

The determination of iron with phenanthroline spectrophotometry( National Standard Method) was improved in order to detect coastal zone water more accurately. The improvement was carried out from three aspects:the adjustment of pH values, the difference between the cuvettes and chromogenic agent. The results demonstrated that the linearity, accuracy and precision of the improved methods were better than that of the National Standard Method. But the precision of the improvement of the adjust-ment method of pH and the difference between the cuvettes was still poor for detecting samples with low concentration. This indi-cated that the sensitivity for iron by using phenanthroline was low. However, the sensitivity, the accuracy and precision for iron by using 5-Br-PADAP was relatively more excellent when it was utilized for detecting coastal water( RSD<5%, recoveries were in the range of 96. 0% and 106%). It implied that the spectrophotometry based on 5-Br-PADAP could be used to determine the iron in coastal waters.