Plant Growth Regulator Mena And Mh On The Storage Quality Of Potato Mining And Safety Evaluation

This paper mainly discussed the effect of plant growth regulators on the storage quality of potatoes, established GC or HPLC methods to determine MENA and MH contents in potatoes, studied the dynamics of the residues for MENA and MH, and conducted the hazard assessment for MENA and MH in potatoes.MENA and MH are two kinds of plant growth regulators most commonly used in the preservation of potatoes. During the storage period, the changes for moisure, Vc, soluble solids, polyphenol oxidase, starch and amylase in potatoes were analyzed, the preservation effect of the two kinds of plant growth regulators were compared, the rules of change of quality parameters were unraveled.A method for the determination of MENA in potatoes using gas chromatography was developed. The GC analysis was carried out by using DB-624 capillary column (30m×0.53mm×3.0um) and hydrogen ions flame detector. The potato samples were extracted by acidific methanol firstly and then pre-seperated by centrifugal precipitation. The linear range was 1.0～100.0mg/L and the detection limit was 5.0mg/kg. Recoveries were between77.5%～82.4%, RSDs were between 1.2 %～2.9%.A method for the determination of MH in potatoes by high performance liquid chromatography was established. Potato samples were separated with ZORBAX SB C₁₈ column (250mm×4.6mm×5um) using methanol-water( 10:90, pH2.7) as mobile phase, after extracted by acidific methanol firstly and pre-seperated by centrifugal precipitation. MH was quantified by external standards method and determined at UV205nm. Results showed that the linear range for MH extraction was 0.2～16.0 mg/L and the detection limit was 1.0mg/kg. Recoveries were between 81.7%～93.0% with RSDs were less than 2%.The hazard assessments were conducted for the two kinds of plant growth regulators. The residues on the potatoes, the acute exposure level and the chronic exposure level on the population were assessed. Through the determination of the residues in the potatoes, a predictive model was established, the 95 % reliable upper limit residue level was then estimated using this model. Through the investigation for probable intakes of potatoes on the population samples, the probable acute exposure level was estimated; the chronic exposure level was also assessed based the data. The results of hazard assessment confirmed the safety of the regular application of MENA and MH for preservation of the potatoes.