D_(206)阴离子交换树脂微柱富集光度法测定湖水中痕量铬(Ⅵ)

Photometric Determination of Trace Amount of Chromium(Ⅵ) in Lake Water After Enrichment on D_(206) Anion Exchange Resin Micro-column

用D206阴离子交换树脂填充的微交换柱,从酸度为0.05 mol.L-1硫酸的试样溶液中分离并富集痕量铬(Ⅵ)。试液以2 mL.min-1流量通过交换柱,用0.05 mol.L-1硫酸溶液0.5 mL淋洗交换柱两次,然后用0.5 mol.L-1氢氧化钠溶液及2 mol.L-1氯化钠溶液的混合溶液3 mL分3次洗脱吸附于交换柱上的铬(Ⅵ),洗脱液接受于25 mL容量瓶中,在0.5 mol.L-1硫酸溶液中,加入1.5 mol.L-1磷酸溶液0.5 mL作掩蔽剂后,用二苯碳酰二肼试剂显色光度法测定铬(Ⅵ)含量。

A micro-column packed with D206 anion exchange resin was used for separation and enrichment of trace amount of Cr（Ⅵ） from sample solution with acidity of 0.05 mol·L-1 H2SO4,passing through the column at a flow-rate of 2 mL·min-1.After rinsing the column twice with 0.5 mL of 0.05 mol·L-1 H2SO4,Cr（Ⅵ） was eluted with totally 3 mL of mixed solution of 0.5 mol·L-1 NaOH solution and 2 mol·L-1 NaCl solution for 3 times.The eluates was collected in a 25 mL volumetric flask and its Cr（Ⅵ） content was determined by the diphenylcarbazide-photometric method in a solution of 0.5 mol·L-1 H2SO4,with addition of 0.5 mL of 1.5 mol·L-1 H3PO4 solution as masking agent.