| Plant growth hormone can affect plant growth and development,and has significance for agricultural production.With the development of modern agriculture,the accurate determination of plant growth hormone content is more and more important.Pesticides can kill pests,and has positive significance for agricultural production.But excessive pesticide residues have a huge impact on human health.This study was divided into three parts.1.A method for simultaneous determination of gibberellin A1,gibberellin A3,gibberellin A4and gibberellin A7 in vegetables by ultrahigh performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS)was established.The comparison experiment was carried out by the reference method.(1)The sample was extracted byacacetonitrile.The extract was dried by nitrogen.further extracted by HLB column.The eluting solution was dried by nitrogen and the residual was redissolved in methanol to a certain volume,then analyzed after membrane filtration.With formic acid/water and formic acacetonitrile as the two parts of mobile phase,their ratio and the flow rate were optimized,and the four kinds of gibberellin in plants were determined by ultra-high performance liquid chromatography-mass spectrometry(HPLC-MS/MS).The experimental results show that the method is linear with the correlation coefficient R~2?0.9995,and the standard deviation is 0.56~1.68.The recovery ratio was 70.1%-111.8%.The detection limit was 1.0-30.0?g/kg.Conclusion:this method is simple,effective,reliable,rapid and sensitive.The contents of gibberellin in carrot,radish and bean sprouts were determined by this method.(2)The pretreatment method from the reference is adopted.The experimental results were compared with that from the new method.The recovery ratio from the new one is slightly better.2.A method for simultaneous determination of 3-indoleformic acid,3-indoleacetic acid,3-indolebutyric acid and 2-cis-4-trans abscisic acid in vegetables by HPLC-MA/MS was established.The comparison experiment was carried out by using the method from the reference.(1)The sample was soaked in isopropanol-water-hydrochloric acid system,and then extracted by dichloromethane-water.The extract was dried by nitrogen.Sample analysis was carried out after the sample redissolution in methanol-water.The experimental results show that the method is linear with the correlation coefficient R~2?0.9993 and the standard deviation within 0.64-1.65.The recovery ratio was 70.3%-112.0%and the detection limit within0.1-12.0?g/kg.This method was applied to determine the hormones in carrot,radish and bean sprouts.(2)The literature method was used to finish the comparison experiments.The results showed that the recovery ratio of the new method was better.3.For the first time,a real-time direct analysis-tandem mass spectrometry(DART-MS/MS)method was established for the rapid screening of allyl morpholine,methylalaxole,oxalaxyl,Acetochlor,creatine and diphenyl ether triazole in vegetables.The comparison experiment was carried out by the reference method.(1)The samples were extracted by acetonitrile and dehydrated with anhydrous magnesium sulfate and anhydrous sodium acetate.The samples were centrifuged and concentrated before detected by DART-MS/MS.The results show that the detection limits of this method are between 0.025-0.1mg/kg and the repeatability is good.Compared with the existing national standards and industry standard methods,the pretreatment is simple and rapid,the determination speed is fast,and the results are consistent with the current national standards.This method was used to screen the vegetable samples from supermarkets.(2)The samples were treated by the reference method,and the detection limits of the different pretreatment methods were similar.But the new pre-processing method is simpler. |
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