Conversion of inhibition biosensing to substrate-like biosensing for quinalphos selective detection.
Since all of the organophosphorus pesticides (OPP) inhibit the cholinesterases with a common mechanism, it is still challenging to detect OPP selectively with inhibition-based biosensors. This study focuses on the conversion of a typical inhibition biosensing to a selective substrate-like biosensing. The interaction of quinalphos with plant-esterase involves not only a decrease in enzyme activity but also a heterolytic bond cleavage of quinalphos. The leaving group eliminated from quinalphos is an ideal biomarker due to its specificity in most OPP. Thus, using 2-hydroxyquinoxaline (HQO), the leaving group of quinalphos, as the biomarker and meso-tetra (4-sulfonatophenyl) porphine (TPPS4) as an optical probe, quinalphos can be selectively detected. The molecular recognition between TPPS4 and HQO leads to a considerable sensitivity of the detection. The spectral responses of TPPS4 show a linear dependence on quinalphos concentration in the presence of plant-esterase within the 0.01-1 mg kg(-1) range. The detection limit is 0.01 mg kg(-1), well below the maximum residue limits (MRLs) defined by European Union (0.05 mg kg(-1)) and China (0.2 mg kg(-1)).
State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, Shandong 266555, P. R. China.
Limin
L
Yang
State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, Shandong 266555, P. R. China.
Juan
J
Han
State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, Shandong 266555, P. R. China.
Wei
W
Liu
State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, Shandong 266555, P. R. China.
Jiqiang
J
Li
State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, Shandong 266555, P. R. China.
Lei
L
Jiang
D015374:Biosensing Techniques / Q000379:methods*; D004950:Esterases / Q000378:metabolism; D007306:Insecticides / Q000032:analysis* / Q000378:metabolism; D057230:Limit of Detection; D009946:Organothiophosphorus Compounds / Q000032:analysis* / Q000378:metabolism; D011166:Porphyrins / Q000032:analysis / Q000378:metabolism; D011810:Quinoxalines / Q000032:analysis / Q000378:metabolism; D014908:Triticum / Q000201:enzymology
D007306:Insecticides; D009946:Organothiophosphorus Compounds; D011166:Porphyrins; D011810:Quinoxalines; C098565:2-hydroxyquinoxaline; C009145:quinalphos; C016136:tetraphenylporphine sulfonate; D004950:Esterases