停流－配体交换动力学法测定痕量银的研究

THE INVESTIGATION ON DETERMINATION OF TRACE SILVER WITH A STOPPED FLOW-LIGAND SUBSTITUTION KINETIC METHOD

本文依据银对亚铁氰化钾与Ａ，Ａ＇－联吡啶配体交换反应的催化作用，以生成的红色配合物为指示剂，建立了测定痕量银的停流流动注射催化光度法。线性范围为０－７５ＮＧ／ＭＬ，方法检测限为０．５ＮＧ／ＭＬ。除ＨＧ２＋严重影响测定，ＦＥ２＋、ＣＯ２＋和ＺＮ２＋对测定有轻度干扰外，其余离子不影响测定。用本法测定了自来水及模拟样品中的银含量，回收率为９７．８％－１０３．４％，变异系数ＲＳＤ＝０．９５％－１．７４％。

A STOPPED FLOW-CATALYTIC SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF TRACE SILVER HAS BEEN ESTABLISHED, BASED ON ITS CATALYTIC EFFECT ON THE LIGAND SUBSTITUTION REACTION BETWEEN FERROCYANIDE AND A, A'-BIPYRIDYL BY USING THE RED COMPLEX FORMED AS INDICATOR. THE CALIBRATION GRAPH IS LINEAR IN THE RANGE OF 0 TO 75 NG/ML, AND THE DETECTION LIMIT IS 0. 5 NG/ML. MOST FOREIGN IONS DON'T INTERFERE WITH THE DETERMINATION, EXCEPT FOR THE SERIOUS INTERFERENCE OF HG2+ AND SLIGHT INTERFERENCE OF FE3+, CO2+ AND ZN2+. THE SILVER CONTENT IN TAP WATER, WASTE WATER AND A SYNTHETIC SAMPLE WAS DETERMINED WITH THE METHOD, AND THE RECOVERIES WERE 97. 8% TO 103. 4% AND THE RSD WAS 0. 95% TO 1. 74%.