抄録
Trace amount of CrO42- in water sample was collected and concentrated on a cartridge type mini-column (4 cm in length and 2 mm i.d.) packed with anion-exchange resin, Toyopearl QAE-550C. The collection and concentration were carried out automatically using a sequential injection procedure. The handling sequence was the steps of cleaning, washing and conditioning of the resin, collection of CrO42- on the resin, and elution of CrO42- from the resin to a detection system. The CrO42- eluate was introduced into the photometric flow injection analysis system using 1,5-diphenylcarbazide as a derivatizing reagent. When an aliquot of 5.0 mL or 20 mL sample solution was treated, the sensitivity increased by 6.4 and 23 times, respectively. By combing the automated on-line pretreatment system with the photometric flow injection system, CrO42- at 10-9 mol L-1 level was determined without expensive detectors such as ICP-AES. On the basis of the interference study, the proposed system was applied to the analysis of a river water sample. Concentration of CrO42- at 2.5x10-9 mol L-1 was determined, and satisfactory results were also obtained with recovery tests.
