Pesticide residue of some selected pesticides in guava fruit (Psidium guajava, cabi) sold at Giwa Market, Giwa Local Government Area, Kaduna State, Nigeria
The laboratory study was conducted to check for pesticide residues in guava fruits sold at Giwa markets in Giwa Local Government Area of Kaduna State. Three hundred grams (300g) of guava fruit samples was collected randomly each from ten different sellers during three consecutive market days to make up 3 kg. One kilogram (1k g) guava samples was randomly selected from the previously collected samples and blended into paste. One hundred grams (100 g) of the sample chopped from the blended samples was macerated in a blender and dipped in 150 mL acetone and kept overnight. The extracted sample was filtered through anhydrous sodium sulfate. The resulting extract was evaporated to near dryness using a rotary evaporator at a temperature of 28oC at Multi-user Laboratory. The residue was re-dissolved in 2 mL acetone and kept in the refrigerator for further determination by Gas Chromatography Mass Spectrometry (GC-MS) Analysis. Finally, 1 ul of the sample was injected into the GC machine (Shimadzu GCMS (QP 2010 plus)) column RTX, 30 m x 0.25 mm/d, with 0.25 um film thickness (5% diphenyl, 95% dimethyl polysitoxane). Twelve molecules of pesticide residues in the guava sample that corresponds to the pesticides standards were detected. The quantity of pesticide found were below the European Union maximum residues limits (MRLs) standards. This signifies that farmers in this study area minimize the application of pesticide for protection of their guava fruits, thus making the fruits save for consumption.