建立了在酸性条件下基于羟自由基(·OH)反应的流动注射-化学发光检测水中焦性没食子酸的新方法。羟自由基由Fe^3+和过氧化氢在线混合产生。它能氧化罗丹明6G产生微弱的光,而焦性没食子酸能显著的增强这一反应。方法的检出限为2.7×10^-7g/L;线性范围为8.0×10^-7~1.0×10^-4g/L;线性方程为ΔI=25.436C+21.822(C:μg/L,r=0.9996)。对2.0×10^-6g/L的焦性没食子酸平行测定11次,其相对标准偏差为4.80%。该方法成功的应用于环境水中焦性没食子酸的检测,其回收率在91.1%-108.8%。并探讨了该反应可能的机理。
A new flow injection chemiluminescence (CL) method was described. It was based on the chemiluminescence of excited Rhodamine 6G (Rh6G) which was oxidized by peroxyl radial ( · OH) in acid medium. The peroxyl radical was generated by admixing ferric and hydrogen peroxide for several seconds. It is observed that pyrogallol can greatly enhance this weak CL reaction. Under the optimum experimental conditions of 0.01 mol/L Fe^3+ 1.0 mol/L H2O2 and 3.0 × 10^ -4 mol/L Rh6G, the detection limit is 2.7 × 10^ -7g/L with a linear range from 8.0 × 10^- 7g/L to 1.0 × 10^-4 g/L. The linear equation is ΔI =25. 436C +21. 822 (C:μg/L,r = 0. 9996). The relative standard deviation of 2.0 × 10^-6 g/L pyrogallol is 4.8% (n = 11 ). It was successfully applied to the determination of pyrogallol in water. The recovery was 91.09% -108.75%. A possible mechanism was discussed.