ABSTRACT
This paper reports the residual status of forbidden and restricted pesticides of organophosphorus in Loincerae Japonicae Flos to provide reference for the risk control and the formulation of maximum residue limits of the flower. A method for the determination of residues of 23 forbidden and restricted pesticides of organophosphorus was established, and 64 collected samples were tested. Then a risk assessment based on the maximum residue limit was carried out. Results showed that the detection rate of samples was 58%. 6 of 23 pesticides were detected and the ratio was chlorpyrifos 41%, omethoate 23%, triazophos 11%, isofenphos-methyl 6.3%, methamidophos 1.6%, isocarbophos 1.6%, respectively. And the median of pesticide residues in the positive samples was chlorpyrifos 0.037 mg·kg⁻¹, omethoate 0.043 mg·kg⁻¹, triazophos 0.030 mg·kg⁻¹, isofenphos-methyl 0.18 mg·kg⁻¹, methamidophos 0.041 mg·kg⁻¹, isocarbophos 0.041 mg·kg⁻¹, respectively. In the samples with pesticide residues, the residue amount of methamidophos and isocarbophos was lower than the theoretical maximum residue limit, and the residue amount of chlorpyrifos, isofenphos-methyl, triazophos were higher than it individually, while, all the residue amount of omethoate was higher than it. According to the assessment result of theoretical maximum residue limit, it is suggested that relevant departments should accelerate the formulation of the maximum residue limit standard, and strengthen the supervision of the use of forbidden and restricted pesticides of organophosphorus in Loincerae Japonicae Flos.
ABSTRACT
OBJECTIVE: To establish a method for simultaneous determination of 187 kinds of pesticides in flowers and fruits of traditional Chinese medicine (TCM) by using gas and liquid chromatography tandem mass spectrometry, taking medlar and honeysuckle as examples. METHODS: The forbidden, restrictted and commonly used pesticides were picked out as detecting indexes according to the principals of risk management. The factors affecting the extraction, purification, and detection were optimized, and the final condition was established as follows: the samples were extracted with acetonitrile, and cleaned-up by carb solid phase extraction column. The separation of target compounds were performed by capillary or liquid column, and quantitative analysis was carrid out by GC-MS/MS or LC-MS/MS with MRM model. Internal standard was used to improve the accuracy of this method. RESULTS: Honeysuckle flower and Wolfberry were used to evaluate the accuracy of this method. The calibration curves were linear in the range of 1-100 ng · mL-1 with correction coefficients of greater than 0.99. The recoveries of more than 88% pesticides were ranged from 70% to 120% at three spiked levels (5, 20 and 100 μg · kg-1). CONCLUSION: The detecting indexes in this method cover most forbidden and restricted pesticides, which is meaningful for the safety supervision of TCM. With the advantage of rapidness and accuracy, this method can be used for routine determination of multi-pesticides in flowers and fruits of TCM.