基于磁性功能复合材料的新型比色法检测Cu^(2+)

A Novel Colorimetric Method Based on Magnetic Functional Composites for Detection of Cu^(2+)

基于新型类过氧化物酶活性的磁性功能化磁珠/金/聚苯胺/MnO_(2)复合物复合材料(MB/Au/PANI/MnO_(2)),联合半胱氨酸的选择性反应机制,构建了一种快速且灵敏的Cu^(2+)比色检测法。采用原位还原法制备MB/Au/PANI/MnO_(2)复合材料,该材料可直接使4,3,3,5,5-四甲基联苯胺(TMB)氧化成阳离子自由基(oxTMB,蓝色);而半胱氨酸(L-Cys)与复合材料结合可以抑制其氧化显色反应。Cu^(2+)存在时,L-Cys优先与Cu^(2+)形成不溶性硫醇盐,从而恢复磁性复合材料氧化TMB显色的能力。在652 nm波长下,随着Cu^(2+)浓度增大,响应信号逐渐增大。最优条件下检测范围为1.0×10^(2)~1.0×10^(7) nmol/L,检测限为1.54 nmol/L。

A rapid and sensitive colorimetric method for Cu^(2+)detection was established based on a new kind of magnetic functional composite materials with activity of peroxidase(magnetic beads/gold/polyaniline/manganese dioxide compound,MB/Au/PANI/MnO_(2)),coupling with the selective mechanism of cysteine(L-Cys).The MB/Au/PANI/MnO_(2),which was prepared by in-situ reduction method,possessed peroxidase activity,and could oxidize TMB(colorless)to cation radicals(blue).Meanwhile,L-Cys could combine with the composite material to effectively inhibit the catalytic chromogenic reaction.In the presence of Cu^(2+),L-Cys preferred to form insoluble mercaptan with Cu^(2+),so as to release the free magnetic composite material and restore its catalytic TMB color development process.As he concentration of Cu^(2+)increased,the color rendering became more and more obvious,and the absorption increased gradually at 652 nm.Under the optimal conditions,the detection range was 1.0×10^(2) nmol/L-1.0×10^(7) nmol/L,and the detection limit was 1.54 nmol/L(3σ).The standard recovery rate of Cu^(2+)in actual water samples was 85.03%-106.90%,and the relative standard deviation was less than 5%,which can meet the detection requirements of Cu^(2+)in actual water samples.