Application Of Catalytic Spectrophotometry With Enzyme To Environment And Food Assay

With the enhancement of automation of analytical instruments, the detection sensitivity,detection limit and accuracy have been improved greatly.However,these instruments are almost expensive,and need many professional technical personnels to use,so these disadvantages limit their application. In addition,it is difficult to directly measure complicated analytes with mordern analytical instruments, thus various pretreatment methods are demanded. Such techniques as liquid liquid extraction, the microwave assisted extraction, the distillation, the centrifugalization, and the precipitation are tedious,laborious and solvent-consuming.furthermore,in the process of pretreatment,the lose of sample and errors are easily brought about.In this study, the direct detection method of samples of environment and food by the combination of the enzymatic analysis and ultraviolet-visible spectrophotometry has been developed. It is applied to analyze the substances in rain water, wine and saliva. The proposed method is simple,sensitive and no pretreatment process.The enzymatic analysis is directly applied to detect ethanol in saliva without other instruments.Whether Ethanol is in saliva can be qualitatively detected by the obvious change of the reaction solution color, which provides theoretical basis for the measurement of driving after drinking and makes out the basic research for the preparation of merchandise reagent box. The method has strong actual significance and potential social value. This work includes three parts:1. Determination oi: hydrogen peroxide in rain water with catalase.The various analytical conditions are studied.It is based on the strong absorption of the product in 505nm,determine the amount of hydrogen peroxide according to product's absorption in 505nm.Under the optimized conditions,The linear range is 0.0030~ 0.3000 mmol/L ,the recovery is 95.7%~ 106.0% and the RSD is ranged from 1.99% to 3.58%.The proposed method is simple, accurate and has wide linear range .2. Determination of ethanol in saliva by using enzymatic reaction of alcohol oxidase and indicative reaction of catalase. The catalytic spectrophotometry with enzyme for determination of ethanol in saliva of drinker is firstly reported, under the optimized conditions, the amount of ethanol is measured indirectly by the determination of the final product at A505nm,which is formed in indicative reaction, the linearity is ranged from0.06860 mmol/L to 5.115 mmol/L , the recovery is 92.1% ~ 103.4% and the RSD is 2.60% to 3.06%. The optimized method can be applied to determine ethanol in real samples.3. Determination of formalde in wine with formalde hydrogenase. It is based on the strong absorption of NADH in 340nm that is produced by the reaction of formalde and NAD+, the amount of formalde can be detected according to NADH's absorptivity in 340nm.The conditions of experiment are investigated. The linear range is 0.01452~ 0.2904 mmol/L, the recovery is 96.0% ~103.80%,and the RSD is ranged from 1.50% to 2.32%. The simple method is applied to determine formalde in wine,and it can obtain good results with good precision and high recovery.