Study On Portable Double-channel Prussian Blue Electrochemical Sensor And Its Application

Electrochemical biosensor is a kind of biosensor device containing electrochemical sensor and biological molecular specificity recognition,which has the advantages of high sensitivity,short test time and convenient testing procession.Nowadays,electrochemical biosensor is developing rapidly,and has been widely applied on various fields.Among them,on-site,rapid and simultaneous detection become the research hotspot and developing direction.This work realize the detection of pesticide residues and diabetes by designing double-channel Prussian blue（PB）modified enzyme electrodes combined with the portable smartphone-controlled potentiostat.Firstly,the fixed acetylthiocholine（ATCh）with Nafion solution was modified on the dual-channel PB screen-printing electrode.And then,the modified electrode was used for the detection of organophosphorus pesticide.The structure and morphology were characterized by scanning electron microscopy.The inhibition ratio of AChE was detected by comparing the electrical current of ATCh that was catalyzed by the enzyme electrodes with and without organophosphorus pesticide.The results show that,under the best conditions（pH6.9,working voltage 0.2 V,enzyme modification measures 2.5μL,inhibit time 15 min）,enzyme inhibition rate are linearly related with the negative logarithm of organophosphorus pesticide concentration in the range of10^-7 to 5×10^-6 g/mL with the detection limit of 10^-7 g/mL.At the same time,three kinds of simulated samples were tested to verify the feasibility of the method.Sencondly,the PB-DSPE was used to detect fructose valine,and indirectly detect glycosylated hemoglobin and glycosylated serum protein concentration.The optimum experimental condition were the pH of 7.5,rate of 100 mV/s,4μL enzyme content and action time of 5 min.It shows a good linear relationship of fructose valine concentration and the current signal of H₂O₂ concentrationwith the detection limit of0.1 mmol/L.At the same time,the simulated and real samples of glycosylated hemoglobin and glycosylated serum protein were determined to verify the feasibility of the method.Finally,tris（hydroxymethyl）aminomethane（THAM）was chosen to improve the stability of the PB film in the neutral and alkaline conditions.The surface morphology of THAM-PB film was characterized by scanning electron microscopy and its molecular stucture was further characterized by infrared spectroscopy.The improved electrochemical biosensor was used for detecting the concentration of fructose valine at optimum condition.