TBA-Pb^(2+)-hemin模拟酶催化显色法测定水中痕量铅

A catalytic colorimetric method for the detection of Pb^(2+) by TBA-Pb^(2+) -hemin mimicking DNAzyme system

在pH 7.5的Tris-HCl缓冲液中,凝血酶适体(TBA)与Pb2+形成复合物,再与氯化血红素(hemin)配位结合,形成辣根过氧化物模拟酶,能催化H2O2氧化2,2'-连氮-双(3-乙基苯并噻唑-6-磺酸)(ABTS),生成蓝绿色自由基产物,导致体系在415 nm处吸光度值增加,且在1.07×10-10~6.01×10-7mol/L范围内△A值与Pb2+浓度有良好线性关系,其回归方程为△A=0.409 c(×10-9mol/L)+40.7,相关系数r=0.996 6,检出限为3.21×10-11mol/L,相对标准偏差在0.67%~3.45%。用于环境水样测定,回收率在98.2%~102.7%。该方法特异性好、灵敏度高。

In the Tris-HCl （pH 7.5） buffer,thrombin binding aptamer interacts with lead ion to form a complex,which could form a horseradish peroxidase mimicking DNAzyme with hemin.This DNAzyme can catalyze the oxidation of ABTS by H2O2,generating blue-green free radical.The enhancement of the absorbance intensity of the system was proportional to the concentration of lead ion at 415 nm in the range of 1.07 × 10-10 ～ 6.01 × 10-7 mol/L,the correlation coefficient r =0.996 6,the detection limit of 3.21 × 10-11 mol/L,the recovery was 98.2％ ～ 102.7％.The method is specific and sensitive.