痕量草酸的催化荧光分析

Analysis of Trace Oxalic Acid by Catalytic Spectrophotofluorimetry

中文关键词:  草酸  罗丹明B  催化荧光法

英文关键词:oxalic acid  rhodamine B  catalytic spectrophotofluorimetry

中文摘要:

      在0.04mol/LH₂SO₄介质中及80℃条件下,草酸对K₂Cr₂₇氧化罗丹明B(λ_ex/λ_em=310nm/560nm)这一荧光猝灭反应具有较强的催化作用.以自来水冷却中止反应,采用荧光法研究了催化测定草酸的各种影响因素,建立了一个测定范围和检出限分别为0.03～3μg/mL和0.01μg/mL草酸的催化荧光分析法,用于尿样分析,结果满意.

英文摘要:

      Under the condition of 0.04 mol/LH₂SO₄ medium at 80℃ oxalic acid has catalytic effect on the fluorescense quenching reaction of rhodamine B oxidized by K₂Cr₂₇. Tap water cooling was selected for quenching the reaction. The effect of various factors on catalytic determination of oxalic acid has been studied spectrophotofluorimetrically. Among the media ofH₂SO₄, HCl and H₃PO₄, oxalic acid inH₂SO₄ has the most catalytic activity. The value of log(Fb/Fc) is increasing with the increase of the concentration of K₂Cr₂₇ in the range of 0～1.0×10^-3 mol/L. The value of log(Fb/Fc) increases slowly when the concentration of K₂Cr₂₇ is more than 1.0×10^-3 mol/L. A concentration of 1.25×10^-3 mol/L K₂Cr₂₇ was chosen for use. Rhodamine B is the most sensitivity indicator among rhodamine B, rhodamine S and butylrhodamine B. The value of log(Fb/Fc) is maximum when the concentration of rhodamine B is at 4.0×10^-6 mol/L. The optimum reaction temperature is at 80℃ and the reaction time is 8 minutes. 23 kinds of co existence substances which effect on the catalytic spectrophotofluorimetric determination of 1 μg/mL oxalic acid have been studied. The results show that most common substances do not interfere to the determination. A new catalytic spectrophotfluorimetric method has been descrided for the determination of 0.03～3μg/mL oxalic acid. The method has been applied to the analysis of oxalic acid in urine sample with satisfactory results.