Photometric Determination of Trace Amount of Chromium(Ⅵ) in Lake Water After Enrichment on D206 Anion Exchange Resin Micro-column

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.