Acetylcholinesterase-Free Colorimetric Detection of Chlorpyrifos in Fruit Juice Based on the Oxidation Reaction of H2O2 with Chlorpyrifos and ABTS(2-) Catalyzed by Hemin/G-Quadruplex DNAzyme

作者：Liu, Tao; Zhang, Xiao; Hao, Jianpeng; Zhu, Wenxin; Liu, Wei; Zhang, Daohong^*; Wang, Jianlong

来源：Food Analytical Methods, 2015, 8(6): 1556-1564.

DOI：10.1007/s12161-014-0042-1

• Chlorpyrifos
• H2O2
• DNAzyme
• Colorimetric detection

Herein, we for the first time report an acetylcholinesterase (AChE)-free colorimetric method for the detection of chlorpyrifos (CP), which is based on the oxidation reaction of H2O2 with CP and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS(2-)) catalyzed by hemin/G-quadruplex DNAzyme. In the absence of CP, ABTS(2-) is directly oxidized by H2O2 with hemin/G-quadruplex DNAzyme as a biocatalyst to produce the blue-green-colored free radical anion (ABTS(center dot-)), accompanied with an obvious UV-visible absorbance at 418 nm. However, the amount of H2O2 used in H2O2-DNAzyme-ABTS(2-) system will be decreased if CP is first reacted with H2O2, leading to the decrease of the amount of ABTS(center dot-) and a change in the UV-visible absorbance of ABTS(center dot-) at 418 nm. Thus, an indirect dependence relation between CP concentration and the absorbance of ABTS(center dot-) at 418 nm could be constructed and used for CP detection. Under optimal conditions, the detection range of the method is 0.04-1 mu g/mL, with a detection limit of 0.01 mu g/mL. Application of the method in real juice samples shows good analytical features in terms of recoveries (95-107.5 %), the relative standard deviation (RSD) (0.6-4.7 %), rendering it as an attractive candidate to current methodologies for the determination of CP.

• 出版日期2015-7
• 单位西北农林科技大学