| Flos lonicerae(the dried flower buds or initial flowers of Lonicera japonica Thunb.(Caprifoliaceae))and dendrobium candidum(stems of Dendrobium officinale Kimura et Migo)are Chinese medicinal materials with dual functions of medicine and food,which are in great demand in the market.However,there is a lack of comprehensive reports on pesticide residues in these two medicinal materials up to now.Consequently,for a comprehensive understanding of pesticide residues in these two medicinal materials from the production source,141 pesticides and metabolites were selected as detecting indexes after literature research and field survey.And a HPLC-MS/MS method was established for the analysis of 141 pesticides and metabolites in these two medicinal materials through different sample pretreatment methods.What's more,74 batches of flos lonicerae and 40 batches of fresh dendrobium candidum samples were collected and determined,according to the results of determination,risk assessment of residual pesticides on two medicinal materials was carried out.The main research results are as follows.1.A HPLC-MS/MS method for the analysis of 141 pesticides and relevant metabolites on flos lonicerae and fresh dendrobium candidum was established respectively.The average recoveries of most pesticides and metabolites method ranged from 60.3%to 109.8%in sample preparation method of flos lonicerae,with RSD?19.1%.The average recoveries of most pesticides and metabolites ranged from 60.4%to 112.4%in sample preparation method of dendrobium candidum,with RSD?18.4%,and the quantitative limits of most pesticides in the two methods did not exceed 10 ng/g.The two sample pretreatment methods are simple,rapid,economical and meet the requirements of multi-pesticide residue analysis.2.The planting situation of flos lonicerae and dendrobium candidum in China was investigated.Accordingly,74 batches of representative flos lonicerae samples and 40 batches of representative fresh dendrobium candidum samples collected from main producing areas were detected.The results showed that pesticides were detected in all 74 batches of flos lonicerae,and 69 pesticides and metabolites were detected,in which the highest detection rate was carbendazim(100%),followed by chlorpyrifos(82.4%),imidacloprid(71.6%),acetamiprid(60.8%)and so on.Among 40 batches of fresh dendrobium candidum,37 batches detected contained pesticide residues,and 43 pesticides and metabolites were detected,in which the highest detection rate was difenoconazole(70.0%),followed bypyraclostrobin(62.5%),tebuconazole(52.5%),azoxystrobin(50.0%),dimethomoph(45.0%)and so forth.3.The dietary risk assessment of residual pesticides in flos lonicerae and dendrobium candidum was carried out by means of point assessment.The cumulative risk of pesticide residues was calculated by hazard index(HI),and the risk ranking of residual pesticides was completed.The results showed that the chronic dietary hazard quotients(HQc),acute dietary hazard quotients(HQa)and hazard index(HI)of residual pesticides in flos lonicerae and dendrobium candidum were less than 100%,which indicated risks were within the acceptable range.The risk ranking of residual pesticides showed that 11 pesticides in flos lonicerae were high risk ones,.such as emamectin benzoate,omethoate,fipronil chlorpyrifos,carbofuran,phorate and so on while in dendrobium candidum the high risk ones were difenoconazole,carbofuran,fipronil,and emamectin benzoate.On the basis of investigation and risk assessment of residual pesticides in flos lonicerae and fresh dendrobium candidum.Pertinent suggestions for the rational use of pesticides in the planting process of two medicinal plants can be provided.Moreover,valuable and reliable references can be provided to relevant departments for the quality supervision and establishment of some pesticides' maximum residue limits in these two medicinal materials.To a certain extent,the research has significant practical value. |
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