The Development Of The Biosensor Method For Rapidly Detecting Hydrogen Peroxide Residue In Food

Hydrogen peroxide (H2O2) is still illegally used in food processing for sterilizing microorganisms and keeping good appearance. A survey of food quality revealed that excessive H2O2 had been detected in bean production,floury production and salted meat. H2O2 can induce cardiovascular disease, carcinoma and accelerate ageing. The Food Sanitation law of China orders that H2O2 is not permitted to be detectable in food.The standard method for detecting hydrogen peroxide is chemical titration by potassium permanganate or iodide, which takes longer time, has more complex sample pre-treating process. The detecting reproducibility and precision is poor because of reducibility or oxidisability of substance in samples. In this study, two biosensors for determining H2O2 were devoleped, and the procedures are shown as follows:1. The devolepment of photoelectrical biosensor for detecting H2O2. Maked trial strips by the enzyme immobilization technology, after the coloring reaction, the green reflected light strucked the trial strips with homogeneous light was collected and transformed to a electrical signal, then a photoelectrical biosensor was manufactured successfully for rapidly detecting H2O2.The optimal conditions of the reaction and capability of the method were evaluated. The results showed that after 75 seconds, a good liner correlation was shown between the reflecting rate of color-changed trial strip and the contents of H2O2, and the regression equation was Y=-0.52913X+2.14664,r=0.99465(p<0.0001). The detecting limit reached 0.5mg/L,and the RSD,the accuracy and recovery were 2.3%, 99.5%, 95.7% , respectively. The detecting time for one sample was less than 2minutes. Using the method, H2O2 can be more rapidly detected on-site without any chemical agent.2. The devolepment of amperometric biosensor for detecting H₂O₂.Manufactured sensitive and cheap amperometric screen-printed electrode to substitute traditional GC electrode, the electro-chemical action of H2O2 was got on the screen-printed electrode, then the level of H₂O₂ was detected by the way of constant potential impulse.The results showed that enzyme electrode exhibited a well stablity, and a good linear correlation between current and concentration of H₂O₂ with the concentration of H2O2 over 5-120mg/L and 3mg/mL of enzyme. The equation of linear regression was Y=0.05745X+ 0.36125 (X, the concentration of H₂O₂, r=0.99744, p<0.0001). The detecting limit and RSD were 0.5mg/mL and less than 6%, respectively. And the detecting time was less than 6 seconds. The new and sensitive method with good reproducibility and simple pre-treatment of sample has a distinguished anti-inference ability against Glucose, Vitamin C, Fe3+and so on. The biosensor, cheaper, smaller and convenient, would be suitable for family use or food safety detection institutes.