【摘要】 基于在磷酸介质中,痕量甲醛对溴酸钾氧化伊文思蓝褪色反应有催化作用,且催化褪色程度与溶液中甲醛的量在一定范围内成正比,建立了测定痕量甲醛的动力学光度法。讨论了反应介质、试剂用量、反应温度、反应时间及共存离子的影响,确立了最佳反应条件。在选定的条件下,方法的线性范围为0.015~0.30μg/mL,检出限为8.6×10-8g/mL。利用此法测定了废水和空气中的痕量甲醛,相对标准偏差(RSD)小于2.50%(n=6),回收率在99%~102%之间,测定结果与酚试剂法的结果相一致。更多还原

【Abstract】 A new kinetic spectrophotometric method for the determination of trace formaldehyde has been developed,based on the catalytic effect of trace amount of formaldehyde on the discoloring oxidation reaction between potassium bromate and evans blue in dilute H3PO4 medium.The decrease in the absorbance has a quantitative relationship with the concentration of formaldehyde.The influence of reaction medium,concentration of reagent,reaction temperature and time,and coexisting ions on the reaction were discussed.Under the selected conditions,the linear range of determination is 0.015-0.30 μg/mL and the detection limit is 8.6×10-8g/mL.The method has been applied to the determination of trace formaldehyde in waste water and air samples with the recovery of 99%-102% and the RSD of less than 2.50%(n=6).The results are in good agreement with those obtained by MBTH method.更多还原