Study On The Determination Of 18 Triazole Fungicide Residues In Vegetables And Fruit By GC-MS/MS

Nowadays, more and more pesticides were restricted or forbidden in vegetables and fruits, the maximum residue limit (MRL) of pesticide getting lower and lower is an inevitable development trend. The biggest part of fungicides which are useing is Triazole pesticides, thus it is necessary to establish a determination method of Triazole fungicides which is more sensitive and more accurate for qualitative and quantitative. The method of GC-MS/MS which has a higher sensitivity can not only avoid qualitative mistakes made by gas chromatography with mass spectrometry but also effectively eliminate complex matrix interferences, so that the test result is more accurate and reliable. A determination method of 18 Pesticides was studied in vegetables and fruits samples by GC-MS/MS, the main content and results were showed as follow:In this paper, Sample Preparation Techniques was studied for the selection of extraction reagent, extraction manner and purification. Acetonitrile, high-speed homogenization and solid-phase extraction was selected at last. Comparing the recovery result of Triazole Pesticides by different sorbents of florisil and Carbon/NH2, all of these pesticide recoveries reached more than 80%, at the same time we studied the purification effect of Cucumber, potatoes and cabbage between florisil and Carbon/NH2, the result showed that Carbon/NH2 has a better purification effect. Therefore we selected Carbon/NH2, acetonitrile-toluene (3:1, v/v) and 20 mL of eluent as experimental conditions.18 triazole pesticides had a good separation on the DB-5MS column by the optimize of Capillary column and Temperature-programmed. Mass spectrometry have three scan modes, respectively, full scan, selected ion monitoring and selected reaction monitoring mode. SRM was selected because that SRM not only has an advantage over the others on selectivity and sensitivity but also effectively rule out complex matrix interferences. An analytical method was developed for determination of 18 Triazole pesticides by selected reaction monitoring mode after the Optimization of Parent ion, product ion and their collision-induced dissociation voltage (CID).Matrix effects widely exit in analysis of chemistry; it has a greater impact on quantification especially in minor or trace analysis. Matrix effect of 18 triazole pesticides on different matrix of samples such as Beans, celery, potatoes and cabbage was evaluated. According to the result we found that different types of samples have different matrix effects. The matrix effect of beans was stronger than others, all pesticides showed varying degrees of matrix-induced response enhancement in the matrix of blank sample. Matrix matching the standard calibration method is the most effective way to solve the matrix effects by external standard for quantitation, matrix matching the standard calibration method can provide matrix effect compensation and improve the accuracy and reliability of quantitative results.This paper selected nine kinds of vegetables and fruits such as apple, cucumber, celery Etc.which were deal with the optimization of experiments conditions. The results indicated that recoveries of pesticide residues were 78.8%-113.3%, the relative standard deviation values were 0.8%-16.8%, low limits of detection were obtained which were 0.06μg/kg-62μg/kg, below the maximum residue limits (MRL). It was demonstrated that this method can meet the requirements of the pesticide residues analysis.