Md. Sultan Ahmed
Division of Entomology, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur-1701, Bangladesh
Afroza Begum
Division of Entomology, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur-1701, Bangladesh
Mohammad Dalower Hossain Prodhan
Division of Entomology, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur-1701, Bangladesh
Marina Afroze
Division of Entomology, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur-1701, Bangladesh
Debasish Sarker
Division of Entomology, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur-1701, Bangladesh
Organophosphorus, pesticide; Residue; MRL; Eggplant; Tomato
Four different regions namely Jeshore, Cumilla, Narsingdi, and Bogura in Bangladesh.
Pest Management
The standard for chlorpyrifos, quinalphos, acephate, dimethoate, diazinon, malathion, and fenitrothion was obtained from Sigma-Aldrich Laborchemikalien, Seelze, Germany via Bangladesh Scientific Pvt. ltd. Dhaka, Bangladesh. Standards of all the pesticides contained >99.6% purity. Available vegetable samples of eggplant and tomato were collected from the local markets of four different regions namely Jeshore, Cumilla, Narsingdi, and Bogura. The collected vegetable samples (≥250 g) were grounded thoroughly with the meat grinder (Handmixer M-122, Bamix, Switzerland) that was randomly taken from 1Kg of the stored samples. A sub-sample of 20 g was taken into a wide mouth jar then 100 ml of hexane was added to it. Anhydrous sodium sulphate (Na2SO4) was also added with the sample until the water was removed from the sample. The mixture was then macerated with a high-speed homogenizer (Ultraturax, IKA T18 basic, Germany) for 2 minutes. The homogenized material was then poured into a 250 ml conical flask and placed into a shaker (Orbital Shaking Incubator, Rexmed, Sweden) for 12hrs continuous shaking. After shaking, the slurry was filtered through a Buchner funnel with suction. The flask and filter cakes were rinsed with 25 ml of hexane each. The filtrate was then transferred into a 250 ml round bottom flask and was dried to 3-5 ml by evaporation using a rotary vacuum evaporator (Laborota-4001, Heidolph, Germany). The concentrated filtrate was then transferred into a volumetric flask making 10 ml in volume. For colour removal, 20 ml methanol was added with 10 ml filtrate and shaked vigorously for 3-5 minutes. After shaking, the separatory funnel was set on a stand and kept undisturbed for 3-5 minutes. Then the clear part of the solution from the bottom of the separatory funnel was collected in a vial which was then centrifuged at 1200 rpm for 5minutes (Laboratory Centrifuges, Sigma-3K30, Germany). After centrifuge, the supernatant was collected for injection. Prior to the injection, this volume was again cleaned up by HPLC filter (0.2PTFE) which was ready for injection in Gas Chromatography. The concentrated extracts were analyzed by GC-2010 (Shimadzu) with Flame Thermionic Detector (FTD) for detection of seven organophosphorus pesticides (acephate, diazinon, fenitrothion, malathion, quinalphos, dimethoate, and chlorpyrifos). The capillary column used was AT-1, length 30m, ID 0.25mm, and film thickness 0.25µm in the case of both detectors. Helium was used as a carrier and makeup gas in FTD. The instrument parameters for GC-FTD were as follows: Injection port temperature was 2500C, Column oven initial temperature was 1500C which went up to 2200C following 10 min incremental time. Detector temperature was 2800C, Stop time: 10 min, Current: 1.0 pA, Makeup flow: 30 ml/min, H2 Flow: 1.5 mL/min and Airflow: 145 ml/min. Prior to the injection of the sample extract, standard solutions of different concentrations of each pesticide were prepared and injected with selected instrument parameters. The samples were calibrated (retention time, peak area, etc.) against a four-pointed calibration curve of the standard solution of the concerned pesticide. Each peak was characterized by its retention time. Sample results were expressed in mg/Kg automatically by the GC software which represented the concentration of the final volume injected.
Asian Australas. J. Food Saf. Secur. 2021, 5 (1), 27-31
Journal