Reseach Of Techniques For Removal Of Pesticide Residues On The "Jujuba" Dongzao And Its Influence On Qualities And Physiological Characteristic Of Fruit

In this paper,different treatments to elute three residues of organophosphorus pestcides (dichlorvos,phoxim and parathion) on'Dongzao'jujube fruit were studied, detected by SPME-GC, then select the better eluting liquid and setup orthogonal design to select the best way, and mensurate the infection of the best way on the quality(Vc, firmness, soluble sugar, decay rate, and titrated acid) and physiology(rate of water loss, PPO activity, POD activity, soluble pectin, insoluble pectin, respiratory intensity and releasing of C2H2) of'Dongzao'jujube fruit during shelf-life. Some conclusions were drawn as follows:The effect of different pre-treatment methods of sample show that: dispersal-speed of disperser, stiring-speed of stirrer, concentration of ion joined else, extraction-time and parse-temperature of SPME, parse-time of SPME have important influence on detecting the pesticide residues. Appropriate dispersal-speed is 14000 r.min^-1, feasible stiring-speed is 450 r.min^-1～500 r.min^-1, extraction-time is 30min～40min. Enough high temperature and enough time is necessary to parse completely and that centration of ion joined else is nil is best for extraction.The pesticide residues on fruit surface could be able to reduce massively by many different ways of cleaning. pH value had significant influence in eluting pesticide residues, when pH value was 10, the effect was best. Citric acid of 0.50 mg.ml^-1 had the function to elute three kinde of pesticide residues very well, the function of NaHCO3 depends on the type of pesticides, phoxim was the best, sodium chloride of different concentrations had positive effect on eluting these three kinds of pesticides, Xidiling of 2.00 mg.ml^-1 had slight function to promoting the elution of phoxim and the parathion, however, it almost had no function on eluting dichlorvos.Elution rate of pesticide residues is affected, in some extent, by eluting-time, temperature and concentration of elution. In some range of temperature, high temperature can promote elution rate of pesticide residues, but it's not all. Long-playing eluting is unnecessary, and some perfect elution effect is presented in short eluting-time. On the criterion of elution rate, some good eluting ways were selected, which based on the orthogonal design: Citric acid (0.5...