Pyrazosulfuron And Penoxsulam Study On Storage Stability In Rice Samples

Pyrazosulfuron was a new kind Sulfonylurea herbicide found by Nippon Chemical Industry Co. Ltd in 1985. It was widely and safety used to prevent broadleaf weeds. Penoxsulam was postemergence herbicide found by Dow Agrosciences Company, by inhibition of Acetolactate Synthase activity caused by it. At present, the determination of pyrazosulfuron and penoxsulam simultaneous analysis has not yet been reported. Therefore, establish the study of residues detection method on pyrazosulfuron and penoxsulam have important practical significance to safe use and residues detection. The data shows, pesticide residue samples storage stability study is less, pyrazosulfuron and penoxsulam in the rice residue storage stability research has not reported. We were using HPLC analysis method to research the residual pyrazosulfuron and penoxsulam in rice. The method is rapid, accuracy and precision can meet the requirement of quantitative analysis. This method can also be set up to relevant departments for the similar research to provide reference for sample storage。The aim was to establish a residue analysis method of pyrazosulfuron and penoxsulam in rice, and the storage stability of pyrazosulfuron and penoxsulam in rice residue sample was proved. Different samples with different extraction agents, in the extraction of water samples, direct use of ethyl acetate for reverse phase extraction, and simplify the operation method. In the extraction of soil, plant, rice husk and brown rice samples, using acetonitrile as the extraction agent and can achieve good effect. The mixture of acetonitrile, water, acetic acid 55∶45∶0.1(v/v) was the mobile phase, In order to eliminate interference of impurities in the sample rice husk, determination of the rice husk mobile phase is set to 52∶48∶0.1(v/v). The flow rate was 0.8mL.min-1, using external standard method to pyrazosulfuron and penoxsulam quantitative analysis at 250 nm wavelength. Based on this method, studing pyrazosulfuron and penoxsulam stability of storage stability study at the two temperatures for five kinds of rice matrix. Pyrazosulfuron and penoxsulam average recovery was 73.04%-107.01% and 72.35%-90.24%, the standard deviation were 0.42%-4.10% and 0.53%-5.70%, and the linear correlation coefficients were 0.9999 and 0.9997 respectively. The method simple, quick, high precision and accuracy, can be used for the simultaneous analysis of pyrazosulfuron and penoxsulam in rice matrix.At-18℃,stored for 5 months(150 d), the initial concentration of pyrazosulfuron and penoxsulam in rice plant samples respectively 1.52 mg﹒kg-1and 1.20 mg﹒kg-1, after storage concentration respectively 1.50 mg﹒kg-1 and 1.18 mg﹒kg-1; stored initial concentration of rice soil respectively 0.27 mg﹒kg-1and 0.50 mg﹒kg-1, after storage concentration respectively 0.26 mg﹒kg-1 and 0.48 mg﹒kg-1;stored initial concentration of brown rice respectively 0.67 mg﹒kg-1 and 0.68 mg﹒kg-1, after storage concentration respectively 0.65 mg﹒kg-1 and 0.65 mg﹒kg-1; stored initial concentration of rice husk respectively 0.57 mg﹒kg-1 and 0.72 mg﹒kg-1, after storage concentration respectively 0.55 mg ﹒ kg-1 and 0.69 mg ﹒ kg-1; stored initial concentration of rice water respectively 0.60 mg﹒kg-1 and 0.70 mg﹒kg-1, after storage concentration respectively 0.58 mg﹒kg-1 and 0.68 mg﹒kg-1.The good stability of pyrazosulfuron and penoxsulam was achieved, pyrazosulfuron and penoxsulam decomposition rate was less than 5%,when stored at the temperature of-18℃、-20 ℃for 150 days in different samples matrix, compliance with Joint FAO / WHO Standards equivalent identification requirements. Pyrazosulfuron and Penoxsulam has good storage stability...