RESUMEN
Objective To establish a quantitative method for the simultaneous measurement of the residual level of three pesticides in Nelumbinis semen by GC-MS/MS. Methods The samples were extracted by acetonitrile and purify by Cleanert TPH column. The samples were then tested by GC-MS/MS. Information on relative retention time and mass charge ratio was used for qualitative analysis. The peak area obtained by secondary ion MS of bifenthrin (181.1/166.1)was used as the reference peak to calculate the relative correction factor for the peak area of fenpropathrin (265.1/210.1) and deltamethrin (252.9/93.0), to establish a method using bifenthrin as the reference substance to determinate there sidual quantity of three pesticides in Nelumbinis semen by GC-MS/MS. Results When the injection quantity of the sample containing bifenthrin,fenpropathrin and deltamethrin in the range of 0.01-0.1 ng , there was a good linear relationship between the injection quantity and peak are a Limitation of quantification (LOQ) of bifenthrin , fenpropathrin and deltamethrin were 4.321×10-4 ng, 3.435×10-4 ng, 8.913×10-3 ng, respectively. The average recovery rates of bifenthrin, fenpropathrin and deltamethrin were 93.5％, 93.5％ and 93.8％, respectively. Conclusions The method of quantitative analysis of multi-components with a single-marker is simple, quick and accurate. It suitable for the detection of residual quantity of bifenthrin, fenpropathrin and deltamethrin in Nelumbinis semen.
RESUMEN
A method was developed for the determination of bifenthrin in tea by ultra performance convergence chromatography ( UPC2 ) . The samples were extracted with petroleum ether and cleaned up with Waters Sep-Pak:Carbon NH2 , and then detected by UPC2 . The mobile phase was the mixture of supercritical CO2 and acetonitrile at a flow rate of 1. 5 mL/min. The separation was conducted on a column of ACQUITY UPC2 TM BEH (100 mmí3. 0 mm,1. 7 μm). The UV detector was set at a wavelength of 220 nm. The detection limit was 20 μg/L. The linear range of bifenthrin was 0. 32-10. 30 mg/L. The recoveries ranged from 88. 7% to 98. 2%. The relative standard deviations (RSD) were from 1. 4% to 2. 8%. The result showed that the UPC2 was more efficient, rapid and low-cost than GC-MS. The method can meet the testing requirements of bifenthrin in tea. The efficacy of UPC2 on testing the concentration of bifenthrin in tea was compared with GC-MS based on National Proficiency Testing and the results were satisfactory.
RESUMEN
Field experiment carried out during kharif, 2012 to evaluate the dissipation pattern of most commonly used insecticide bifenthrin 10 EC @ 100 g a.i. ha-1 with two sprays of insecticide first given after fruit initiation and the second spray 10 days later and collecting the fruits at 0, 1, 3, 5, 7, 10, 15, 20 days after last spray, and analysed for residues using the validated QuEChERS method. The initial deposits of bifenthrin were 0.85 mg kg-1 which dissipated to 0.39, 0.15 mg kg-1 by 1st and 3rd day after last spray, respectively, and to BDL by 5th day. Bifenthrin initial deposits were dissipated to 82.35% by 3rd day after last spray, and pre-harvest interval of 3 days is suggested taking into consideration of MRLs of bifenthrin in tomato (0.3 mg kg-1) as per Codex Alimentarius Commission.