主次波长分光光度法测定环境水中溶解氧

Determination of DO in Environmental Water by Primary-Secondary Wavelengths Spectrophotometry

研究了主次波长光度法测定天然水和工业废水中溶解氧。采用加热碘化样品，使碘升华至吸收液中显色的预处理方法，能够有效地消除色度、浊度和部分物质的干扰，提高分析选择性。选择主波长λ＿ｐ＝４５０ｎｍ，次波长λ＿ｓ＝４８０ｎｍ能满足环境水ＤＯ测定要求。ＤＯ在０－１２ｍｇ／Ｌ浓度范围内，相对标准偏差ＲＳＤ５％，加标回收率９３．６％－１０７％。ＤＯ检出限０．０５ｍｇ／Ｌ。适合于天然水和任何性质工业废水分析。

Dissolved oxygen (DO)in water can react with manganese sulfate, potassium iodide andsulfate acid to form yellow iodine molecules.This paper studies the primary-secondarywavelengths spectrophotometric determination of trace amount of DO based on the above-mentioned reaction. It is higher in both precision and sensitivity than other methods,andthe calculated curve is very stable. Suitable pretreatment can effectively eliminate theinterference caused by color,turbidity and ions.Experimental results show that λ_p=450nm,λ_s=480nm,and within the range of 0-12mg/L of DO,the parameter log y is linear withlog x and RSD≤5%and the recovery is between 93.6%-107%,Minimum detection concen-tration of DO is 0.05mg/L. The method is suitable for natural and industrial wastes.