Study On The Migration Of Chloramphenicol Antibiotics In Pakchoi-soil System

With the rapid development of science and technology,it has been found that chloramphenicol antibiotics are slowly metabolized in animals,and can cause irreversible bone marrow hematopoietic dysfunction in severe cases.It is a broad-spectrum antibiotic;The banned drugs were deleted from the 2000 edition of "Chinese Veterinary Pharmacopoeia";the Ministry of Agriculture 235 announcement strictly restricted the amount of thiamphenicol and florfenicol in animal-derived samples.At present,China still lacks relevant research materials,corresponding investigations and standards,concerning migration of chloramphenicol antibiotics remaining in the environment into plants.Therefore,the establishment of UPLC-MS/MS detection method for chloramphenicol antibiotics in plants and soil is of great significance.This article establishes the UPLC-MS/MS detection method of pakchoi and soil according to their material characteristics;under the conditions of three chloramphenicol antibiotics,observe the characterization of pakchoi,after eliminating other possible interference factors;After 33 days,the content of chloramphenicol antibiotics in the rhizome leaves and soil was determined.The experimental results of this paper are as follows:1.After optimizing pretreatment and instrument methods,establish UPLC-MS/MS detection methods for 3 chloramphenicol antibiotics in plant-derived food and soil The results are as follows:(1)The pakchoi sample was extracted with acetonitrile,purified with an Oasis HLB solid phase extraction column,and 20%acetonitrile-water constant volume;the mobile phase was methanol-water,the flow rate was 0.3 mL/min,and the ACQUITY HSS T3 column was separated.Spray mode ionization,multi-reaction monitoring mode sample injection analysis,the added drug levels are 1 μg/kg,2 μg/kg and 4 μg/kg,the pakchoi sample recovery rate is 96.6～101.5%,the relative standard deviation is 2.4～4.6%(n=7),the detection limit is 0.1 μg/kg and the limit of quantification is 0.5 μ/kg;(2)Soil samples are extracted with 1%ammoniated acetonitrile and purified with Oasis HLB solid phase extraction column,20%Acetonitrile-water constant volume;under the same instrument method as pakchoi,add drug levels of 1 μg/kg,2μg/kg and 4 μg/kg,the recovery rate is between 86.8～106%,and the relative standard deviation is 2.7～4.8%(n=7),the detection limit is 0.1μg/kg,and the limit of quantification is 0.5 μg/kg;the method is simple in pretreatment and the instrument sample injection completion time does not exceed 7 min.2.Under natural conditions,soil temperature and light intensity can meet the growth of pakchoi;the lead,cadmium,nickel and mercury in the soil are lower than the limit value in the national soil environmental quality standard,after detection by atomic absorption instrument and atomic absorption photometer;planting On 7 d,in the low-concentration treatment group(5 mg/kg),medium-concentration treatment group(10 mg/kg),high-concentration treatment group(25 mg/kg),yellow leaves appeared in the pakchoi,and the plants were dwarfed in the low-concentration treatment group There are many yellow leaves and light yellow leaves in the pakchoi,and there are deaths in the medium concentration treatment group;there are many deaths in the pakchoi,and the leaves are mostly white and light yellow,in the high concentration treatment group.After 33 days of planting,the survival rate of pakchoi was low.In the high concentration treatment group,three chloramphenicol antibiotics showed physiological toxicity to pakchoi.3.After 33 days of planting and collecting pakchoi and soil,UPLC-MS/MS detected three chloramphenicol antibiotics.Accumulation in pakchoi samples:florfenicol>chloramphenicol>thiamphenicol;the cumulative status of florfenicol and chloramphenicol in different parts of pakchoi:leaf>stem>root;Accumulation of thiamphenicol,the status is in different parts of pakchoi:root>stem>leave;According to the level of drug addition,the accumulation in the soil is a decreasing relationship;In pakchoi,the bioconcentration coefficients of the three chloramphenicol antibiotics are:Florfenicol>chloramphenicol>thiamphenicol;the enrichment ability of pakchoi leaves is greater than that of roots and stems;In pakchoi leaves,the bioconcentration coefficient of florfenicol reaches moderate enrichment;The degree of enrichment of three chloramphenicol antibiotics in other parts of pakchoi is very light,and can be regarded as no enrichment.