Allium sativum and Zingiber officinale are spices with great potentials as food additives and medicinal values. In this study, the phytochemical and proximate composition of the two spices were evaluated and compared. The results of phytochemical screening revealed the presence of saponins, tannins, terpenoids, flavonoids, glycosides and phenols in both the bulb of Allium sativum and rhizome of Zingiber officinale. The bulb of Allium sativum contained significantly higher amount of saponins, tannins and phenols when compared to the rhizome of Zingiber officinale. Zingiber officinale is rich in glycosides and flavonoids as compared to Allium sativum bulb. Terpenoids was the highest phytochemical detected in both spices while phenol recorded the least amount. The proximate composition of both spices showed moisture, protein, ash, fat fibre, and carbohydrate contents with values that ranged between 60.

This study investigated the levels of pendimethalin and cypermetrin residues in tomato sold in Malete market, Moro Local Government Area of Kwara State. Tomatoes were randomly collected from five different vendors in Malete market and analysis was performed using the QuEChERS (Quick, Easy Cheap, Effective, Rugged and Safe) method followed by chromatographic analysis using high performance liquid chromatography (HPLC) coupled to ultra-violet (UV) detector. Method validation of the study showed a linearity of the analytes which ranges from 5 – 500 μg/kg, with correlation coefficients greater than 0.999. The average recovery ranges from 75.6 to 111 % with relative standard deviation (RSD) from 2.74 to 9.03 %. The results indicated the presence of cypermethrin in analyzed samples at concentrations lower than the permissible maximum residue levels Keywords: Sample preparation, Pesticide residues, HPLC-UV, QuEChERS.

Design of experiment (DOE) was employed to develop a headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS) method for multiresidue analysis. The significance of SPME parameters was determined using Placket-Burman (P-B) design. The main effect and the interaction effect of the significant factors were also determined followed by the optimization of the significant factors using central composite design (CCD). A Minitab® statistical software was used to generate both the 27-4 Placket-Burman and the central composite design matrix. The same statistical software was also employed in the determination of the optimum level of the significant parameters using surface response optimizer and desirability surface plot. The most significant factors are: extraction temperature (90%), extraction time (80%), the pH and stirring rate (50% and 60% respectively). The optimum parameters are: Temperature, 62 °C; time, 34 min; NaCl, 10%; stirring, 350rpm; pH, 6. The figures of merit of analytical methodologies was determined using an internal standard calibration method. The linearity of the developed method ranges from 1- 500 µg/kg and correlation coefficient (R2) greater than 0.99. The average recovery was found between 74 – 115% and relative standard deviation ranges from 1.1 – 14%. The developed method was used to analyze 14 multiclass pesticide residues in two fruit (pear and grape) and two vegetable (lettuce and broccoli) samples, and the method was found to be satisfactory with LOD between 0.17 – 7.34 µg/kg and LOQ ranges from 0.55 – 24.50 µg/kg. Keyword: Design of experiment (DOE), solid phase microextraction, response surface optimizer, pesticide residues, Central composite Design

Weed competition has been a major challenge limiting crop yield especially in intercropping systems. Information on the use of chemicals for weed control in intercropping systems appears scanty. The aim of this study was to investigate the efficacy of pendimethalin (P) at 1 kg active ingredient/ha, and hand weeding (HW) on mineral contents of the harvested grains and effects of various weed control treatments in maize, cowpea, and their intercrop. Field experiments were carried out during the 2017 and 2018 rainy seasons. The field layout followed complete randomized block design with three replicates. There were eight treatments: Sole Maize/Cowpea + P, Sole Maize/Cowpea + P + 1HW at 3 weeks after sowing (WAS), Sole Maize/Cowpea + P+ 2HW at 3 and 6 weeks after sowing (WAS), Sole Maize/Cowpea weedy check, Intercrop + P, Intercrop + P + 1HW at 3WAS, Intercrop + P + 2HW at 3 and 6 WAS and Intercrop weedy check. It was observed that, P+1HW and P+2HW in both cropping systems have significant effects (p<0.05) and effectively control weed and increase the mineral contents in maize, cowpea, and their respective intercrop. The study revealed that, the mineral composition of maize and cowpea grains were improved by using pendimethalin with supplementary hand weeding. The study recommends that farmers should adopt intercropping maize with cowpea using pendimethalin plus one supplementary hand weeding at 3 WAS.