| Objective:In recent years,ginseng flower as a functional food with a variety of pharmacological value has been more and more popular in the international community.With people’s increasing concern about health and food safety,countries are becoming more and more stringent on pesticide residue limits in ginseng flowers.However,at present,there are no quality control standards for ginseng flowers and ginseng flower teas at home and abroad,and relatively few studies have been made on pesticide residue detection techniques in ginseng flowers.Therefore,it is urgent to establish a high-throughput ginseng multi-pesticide residue rapid detection technology for ginseng flower multi-pesticide residue detection to provide technical support,for the formulation of national standards and industry standards to provide a theoretical basis.Methods:1.This study optimized the extraction and purification conditions of QuEChERS method,making it more suitable for extracting pesticide residues in ginseng flowers,and the main optimization process included the selection of extractors and extraction methods,and the volume of water use and purification agent dosage.By comparing the recovery efficiency,the optimal extraction and purification conditions were determined,so as to extract the residual pesticides from ginseng flowers to the maximum extent,and establish an accurate quantitative method of ginseng pesticide residues.2.In this study,14 pesticide standards were used to collect the mass spectrometry information of each pesticide in TOF scanning mode,and a precise quality database and spectral library of 14 pesticides were established in combination with the Peak View software.The precise mass quality database included the English name of the compound,the molecular formula and relative molecular mass.The pesticide residues in ginseng flowers were initially screened by comparing with the information such as precise mass deviation,isotope distribution and isotope ratio of molecular ions in the database.The spectral library included all the debris ion information of the compound,which can be qualitatively verified by comparing the spectral information of the actual sample with the fragment ion information in the spectral library.3.By optimizing the high-efficiency liquid chromatography conditions and flight time mass spectrometry conditions,the rapid screening and confirmation analysis methods of 14 pesticide residues were established by HPLC-TOF/MS.The established methods were evaluated by linear range,detection limit,precision and recovery rate.Using the established method,14 pesticides in 20 ginseng flower samples on the market were tested to examine the practicality of the method.Results:1.The experiment finally decided to add 3 m L water to the sample,extracted it twice with 10 m L acetonitrile contained 1%acetic acid,then added sodium chloride and waterless magnesium sulfate to the salt analysis effect and centrifugation,selected primary secondary amine(PSA),octane silane bonded silicone(C18)and graphite carbon black(GCB)as purification agent,for the pre-treatment of ginseng flower samples.2.Screening of the target pesticides through the XIC Manager screening list,it was found that 14 pesticides all formed[M+H]~+quasi-molecular ion peak in positive ion mode,and each pesticide contained 2 characteristic secondary fragment ions.The error value of the exact mass deviation of 14 pesticide compounds was within±2 ppm,and the screening score exceeded 60 points,proving that the experiment has successfully established a database for accurate screening and verification of 14 targets,which can be further applied to the screening process of actual samples.3.We optimized chromatography and mass spectrometry conditions to determine the appropriate chromatographic column and gradient elution conditions.A set of TOF MS-IDA-MS/MS workflows has been established that uses the information dependency model(information acquisition,IDA)to collect first-level high-resolution mass spectrometry and full-scan high-resolution fragment ion mass spectrometry data within the full mass-to-load ratio range(100-1000).Finally,based on HPLC-TOF/MS,a screening confirmation method for multi-residual ginseng pesticide was established.Methodologically,the results showed that the linear correlation coefficient R~2≥0.999.The detection limit(LOD)of this method is 0.05～2.0 ng/g,and the quantitative limit(LOQ)is 0.15～6.0 ng/g.The recoveries rate of real samples was between 74.5～103.5%,the relative standard deviation was between 3.9～14.9%(n=6),which met the requirements of multi-pesticide residues detection.This study can achieve rapid and high-volume detection of multi-pesticide residues in ginseng flowers.4.This study tested pesticide residues through 20 ginseng flower samples samples sampled in the main ginseng flower producing area and Jilin Province market to understand the pesticide residue of ginseng flowers in Jilin Province’s ginseng flower planting base and market sampling.The results showed that ginseng flowers contain a variety of pesticide residues to varying degrees in ginseng flower planting bases and market sampling.Among them,pyrimethanil,azoxystrobin and difenoconazole were all detected in 20 samples,carbendazim and tebuconazole were detected 16 times,flusilazole 15 times,propiconazole 12 times,dimethomorph 8 times,fluopyram 1 time,indicating that there was pesticide residue in ginseng flowers in China.Conclusions:In this paper,QuEChERS method was used to pre-treat ginseng flower samples,and a rapid screening and confirmation method of 14 pesticide residues in ginseng flowers was established in combination with HPLC-TOF/MS.The method was simple,efficient,highly sensitive and repetitive,can accurately and quickly confirm and quantitatively confirm 14 kinds of pesticides in ginseng flower samples,had a lower detection limit and a relatively wide linear range,and can be further applied to more pesticide detection by expanding the quality database and optimizing the experimental parameters. |
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