Study On Analytical Method For Trichlorfon And Sivelestat Sodium Hydrate

Residue of pesticides found in agriculture products, drinking water and environmental exposure has raised much concern from the general public in recent years. In order to protect persons' healthy, many countries have restricted the usage of pesticides and have established legal directives to control their levels in food, through the Maximum Residue Levels (MRLs). So the paper is mainly study the rapid detection of pesticide with electrochemical and solid phase extraction techniques, and the determination of a medicament has been obtained. The thesis includes three parts:In chapter I , Based on trichlorfon-catalyzed reaction of benzidine-sodium perborate by single sweep oscillopolarography, a new method is proposed for determination of trichlorfon. The peak potential is -0.7V(vs.SCE). There is a good linear relationship between peak current and concentration of trichlorfon in the range of 8.0 X 10~-7 to 1.0 X l0~-4 mol/L(r=0.9991). The detection limit is 8.0 X 10~-8mol/L. The relative standard deviation of 8.0 X 10~-5mol/L trichlorfon for 10 parallel determinations is 3.41%. The mechanism of electrode reduction has been discussed. The method has been applied to the determination of residues of trichlorfon in plant with satisfactory result.In chapter II, Under the conditions of methanol-water(3:1 ,V:V) at 100 ℃, trichlorfon had strong catalytic effect on the decolour reaction between sodium perborate oxidation benzidine. The UV-detector for HPLC was chosen to minitor the changes in concentration of bisazobiphenyle of the oxidizing product in the action system. A novel catalytic reaction-HPLC method for the determination of 6.00 X 10~-2~1.00X 10~2mg/kg trichlorfon described by the fixed-reaction time procedure. The detection is 6.00 X 10~-3mg/kg. The ODS column was used as separation column and eluted with methanol-water(3:l,V/V) at flow rate of 0.8mL/min, the detection wavelength was 365nm without the interfere of other insecticides. As solid-phase extraction solution, sodium dedecyl sulfate( SDS) has greately improve the security. The method has been applied to determination of residues of trichlorfon in plant with satisfactory result.In chapter III, The electrochemical behavior of sivelestat sodium hydrate was studied by using cyclic voltammetry, linear scanning voltammetry and bulkelectrolysis with coulometry. In a base solution of 0.2 mol/L HAc-NaAc at pH5.6, sivelestat sodium hydrate produced a sensitive reduction peak. The peak potential was -1.28V(vs.SCE).The linear relation holds between the peak current and the sivelestat sodium hydrate concentration in the range from 1.0x10~-5 to 2x10~-4mol/L(r=0.9976) with the detection limit of 2.0x10~-6mol/L. The relative standard deviation of 5.0x10~-5mol/L sivelestat sodium hydrate for 12 parallel determination was 0.56%.The peak also showed adsorptive characteristics. In addition to the number of electrons transferred in the reaction was calculated. Furthermore a possible mechanism of electrode reduction was discussed.