Detection Technology Of Organophosphorus Pesticide Residue In Gannan Navel Orange And Fresh Fruit Monitoring

As a well-known navel orange brand,Gannan Navel Orange is widely welcomed due to its attractive shape,favorable flavor,and rich nutrients.With the increase of planting area and output year by year,Gannan navel orange industry has rapidly developed into a local pillar industry.In order to maintain the high-quality image of “Gannan Navel Orange”,regular monitoring of both pesticide residues in fresh fruits and risk analysis of fruit and processed products are crucial measures.Therefore,the following researches are carried out and the results are presented in this paper:Using gas chromatography,the widely used standard method issued by Ministry of Agriculture "NY / T 761-2008 Part 1: The determination of organophosphorus multi-residues in vegetables and fruits” was optimized by matrix interference elimination and sample pretreatment improvement.Periodic monitoring of organophosphorus residues in navel oranges,collected from seven demonstration orchards in southern Jiangxi,were conducted to explore the absorption,degradation and distribution rules of organophosphorus pesticides during different growth stages.The results showed that the contents of chlorpyrifos,promethoxine and triazophos pesticides decreased with the growth of the fruit.Organophosphorus pesticides absorbed mostly in peel,specifically in the oily layer of the outermost layer instead of the surface layer.No pesticide residue enrichment was observed in the fruit’s navel section,in which the same amount of residue as that in the rest part of the fruit was determined.Navel orange products from 32 navel orange orchards in 18 counties and districts in southern Jiangxi were collected and analyzed to monitor organophosphorus pesticide residues by GC method.At the same time,a comprehensive survey of pesticide residues including Organophosphates,pyrethroids,imidazoles and carbamates was conducted by GC-MS.The monitoring results show that no organophosphorus residues were detected in the pulp of the navel orange,which proves safety in fruit consumption.When the whole fruit including pulp and peel was tested,three organophosphorus pesticides of chlorpyrifos,probromophos,and triazophos,were detected with detection rate of 81%,indicating that these three organophosphorus pesticides were commonly used in Gannan navel orange orchards.20 pesticides residue contents were in accordance with national limitation standards in spite of a relatively high detection rate.Considering pesticide residues were generally absorbed in peel,consumption risk should be taken into account when peel is used as raw materials in food processing.