Browsing by Author "Abdulra’uf, L. B."

Now showing 1 - 16 of 16
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    Chemometric approach to the optimization of HS SPME/GC-MS for the determination of multiclass pesticide residues in fruits and vegetables
    (Elsevier, 2015) Abdulra’uf, L. B.; Tan G. H.
    An HS-SPME method was developed using multivariate experimental designs, which was conducted in two stages. The significance of each factor was estimated using the Plackett–Burman (P–B) design, for the identification of significant factors, followed by the optimization of the significant factors using central composite design (CCD). The multivariate experiment involved the use of MinitabÒ statistical software for the generation of a 27–4 P–B design and CCD matrices. The method performance evaluated with internal standard calibration method produced good analytical figures of merit with linearity ranging from 1 to 500 lg/kg with correlation coefficient greater than 0.99, LOD and LOQ were found between 0.35 and 8.33 lg/kg and 1.15 and 27.76 lg/kg respectively. The average recovery was between 73% and 118% with relative standard deviation (RSD = 1.5–14%) for all the investigated pesticides. The multivariate method helps to reduce optimization time and improve analytical throughput.
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    Chemometric study and optimization of HS-SPME parameters for the analysis of pesticide residues in processed cocoa powder
    (Chemical Society of Nigeria, 2013) Abdulra’uf, L. B.; Tan, G. H.
    Solid-phase microextraction (SPME) is a solvent-less sample preparation method which combines sample preparation, isolation, concentration and enrichment into one step
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    Composition of Coconut (Cocos nucifera L. Cv. Fiji Dwarf) Edible Endosperm and Physicochemical Properties of its Oil
    (Jewel Journal of Scientific Research, 2021-08-21) Abdulkareem, K. A.; Olayinka, B. U.; Lawal, A. R.; Adeniji, O. A.; Ibuowo, M. B.; Jacobs, O. E.; Abdulra’uf, L. B.; Kareem, I.; Aboyeji, O. O.; Mustapha, O. T.; Etejere, E. O.
    Coconut (Cocos nucifera L.) is one of the most important oil producing crops in the world. It has enormous industrial and health benefits. To affirm the foregoing, the proximate and physicochemical constituents of the oil extracted from the edible endosperm were determined. The results showed that percentage moisture, protein, ash, crude fat, crude fibre and carbohydrate had respective values of 42.39 %, 6.21 %, 1.04 %, 17.18 %, 8.95, and 23.69 %. The edible mesocarp has high amount of mineral elements such nitrogen, potassium, calcium and phosphorus. Whereas, elements such as sodium, manganese, magnesium, copper and chlorine occurred in low quantity. The physicochemical properties of the oil showed a refractive index of 1.46, specific gravity of 0.92 g/cm3, acid value of 2.15 %, free fatty acid of 1.08 %, saponification of 125.980 mgKOH/g and iodine value of 2.89 indicating that the oil is good for consumption. Given, the results of proximate and mineral compositions, the edible endosperm could therefore be considered as good source of energy and alternative source of dietary supplement for human nutrition.
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    Composition of Coconut (Cocos nucifera L. Cv. Fiji Dwarf) Edible Endosperm and Physicochemical Properties of its Oil
    (Federal University of Kashere-Nigeria, 2021) Abdulkareem, K. A.; Olayinka, B. U.; Lawal, A. R; Adeniji, O. A.; Ibuowo, M. B.; Jacobs, O. E.; Abdulra’uf, L. B.; Kareem, I.; Aboyeji, O. O.; Mustapha, O. T.; Etejere, E. O.
    Coconut (Cocos nucifera L.) is one of the most important oil producing crops in the world. It has enormous industrial and health benefits. To affirm the foregoing, the proximate and physicochemical constituents of the oil extracted from the edible endosperm were determined. The results showed that percentage moisture, protein, ash, crude fat, crude fibre and carbohydrate had respective values of 42.39 %, 6.21 %, 1.04 %, 17.18 %, 8.95, and 23.69 %. The edible mesocarp has high amount of mineral elements such nitrogen, potassium, calcium and phosphorus. Whereas, elements such as sodium, manganese, magnesium, copper and chlorine occurred in low quantity. The physicochemical properties of the oil showed a refractive index of 1.46, specific gravity of 0.92 g/cm3, acid value of 2.15 %, free fatty acid of 1.08 %, saponification of 125.980 mgKOH/g and iodine value of 2.89 indicating that the oil is good for consumption. Given, the results of proximate and mineral compositions, the edible endosperm could therefore be considered as good source of energy and alternative source of dietary supplement for human nutrition.
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    Detection of pendimethalin and cypermetrin residues in locally produced tomato using QuEChERS-HPLC analysis
    (Nigerian Journal of Basic and Applied Sciences, 2019) Abdulra’uf, L. B.; Adeyemo, F. A.; Atanda, F. B.; Lawal, A. R.
    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.
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    Determination of pesticide residues in beans using QuEChERS technique coupled to gas chromatography-mass spectrometry: Multivariate optimization of CEN and AOAC methods
    (Elsevier, 2025) Abdulra’uf, L. B.; Junaid, A. M.; Lawal, A. R.; Ibrahim, H. B.; Tan, G. H.
    The use of pesticides has led to environmental pollution and posed a global health risk, since they remain as residues on foods. Beans one of the most widely cultivated crop in Africa, and susceptible to attack by insects both on field and during storage, leading to the application of pesticides to control pests’ infestation. However, misuse of these chemicals by farmers on beans has resulted in the rejection of beans exported to European countries, due to the presence of pesticide residues at concentrations higher than the maximum residues levels (MRLs). In this study, the effectiveness of the Association Official Analytical Chemists (AOAC) Official Method and the European Committee of Standardization (CEN) Standard Method, were determined using multivariate approach for the analysis of organochlorine pesticide residues in 6 varieties of beans samples. The significance of factors (mass of sample, volume of acetonitrile, mass of magnesium sulphate, sample pH, centrifugation time and speed) affecting the efficiency of extraction was estimated using Plackett-Burman design, while central composite design was used to optimize the significant factors. The following optimum factors were subsequently used for method validation, recovery tests, and real sample analysis: 4 g of sample sludge (1:1 v/v), 10 mL of acetonitrile, 4.45 g of MgSO4, and 5 min of centrifugation at 5000 rpm. The figure of merit of analytical methodology estimated using matrix-matched internal standard calibration method gave linearity ranging from 0.25 to 500 μg/kg, with correlation coefficient (R2) greater than 0.99, the recovery ranged from 75.55 to 110.41 (RSD = 0.70–16.65), with LOD and LOQ of 0.23–1.77 μg/kg and 0.76–5.88 μg/kg, respectively.
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    Development of headspace solid-phase microextraction method for the analysis of pesticide residues in fruit and vegetable samples using OFAT design
    (Journal of Applied Sciences and Environmental Management, 2017) Abdulra’uf, L. B.; Lawal, A. R.; Tan, G. H.
    A headspace solid-phase microextraction (HS-SPME) method was developed as a preliminary investigation using univariate approach for the analysis of 14 multiclass pesticide residues in fruits and vegetable samples. The gas chromatography mass spectrometry parameters (desorption temperature and time, column flow rate, interface temperature) and solid phase microextraction parameters (fiber coating type, extraction temperature and time, pH, salt addition, stirring rate, dilution factor, organic solvent type and amount) were all investigated and optimized. The optimum values for the optimized parameters are as follows: Injection Temperature, 270 °C; Interface temperature, 300 °C; Column flow rate, 1.3 mL/min; Fiber coating, PDMS/DVB; Extraction time, 30 mins; Extraction temperature, 60 °C; Stirring rate, 300 rpm; Salt addition, 10% (v/w) NaCl; pH, 7; Desorption time, 7 min; Desorption temperature, 270°C; Organic solvent 3 % (methanol/acetone, 21:79%). The optimization of the mixture of organic solvents was optimized using design of experiment (DOE) with simplex lattice, designed using Minitab Statistical Software®. The developed method was then applied to the analysis of samples of apple, tomato, broccoli, lettuce, grape, cucumber, cabbage and pear. The investigated pesticides were found to be below the maximum residue levels, while some were not found. This shows that the fruit and vegetable samples are safe for consumption and do not pose any health risk for consumers
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    Effect of Copper-Based Fungicide on Chemical Composition of Cocoa Seeds
    (2025) Lawal, A. R.; Olayinka, B. U.; Olahan, G. S.; Omorinoye, O. A.; Abdulsalam, H. A.; Abdulra’uf, L. B.
    Production of cocoa seeds, one of Nigeria’s major non-oil foreign exchange earners as well as a major raw material for the beverage industry, is greatly hindered by diseases caused by various species of the genus Phytophthora. To avert this, copper-based fungicides are sprayed on the leaves of cocoa trees to control or prevent the survival of this organism by the farmers without paying attention to the effects of this chemical on the proximate composition of cocoa seeds. This study therefore investigated the effects of a copper-based fungicide (Ridomil Gold Copper) on the quality of the cocoa seeds by spraying cocoa trees, including the pods, with 50.00 g/L of copper-based fungicide. The results obtained showed that cocoa seeds from the control trees showed significantly higher contents of fiber (4.51%), protein (15.1%), and fat (36.1%) when compared to the respective values of 3.45, 3.95, and 7.59% obtained for the cocoa seeds harvested from the fungicide-treated cocoa trees. All other proximate compositions did not show any statistical difference, except for carbohydrate and calorific values, which were significantly higher in cocoa seeds from fungicide treated cocoa trees. Seeds from fungicide-treated trees showed significantly higher potassium, phosphorus, and magnesium contents but lower zinc and copper contents. However, phytochemicals such as phenols, alkaloids, flavonoids, and tannins were significantly lower in content in the seeds of fungicide-treated cocoa trees. The contents of glycosides and antioxidants in the cocoa seeds were statistically similar for both the control and treatment, except for ascorbic acid, which showed a significantly lower value (4.8 mg/100 ml) in cocoa seeds from fungicide-treated cocoa trees, compared with the value recorded for the control in this study (13.33%). The foregoing results showed that the use of copper-based fungicides for the control of black pod disease in cocoa adversely affected the quality of cocoa seeds from the treated trees.
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    Effect of phosphorus fertilizer and shoot pruning on growth, yield and fruit quality of tomato (Solanum lycopersicum)
    (Indian Journal of Agricultural Sciences,Indian Council of Agricultural Research, 2023-12-29) Olayinka, B. U.; Abdulbaki, A. S.; Oyewole, M.; Jacob, O. E.; Abdulkareem, K. A.; Lawal, A. R.; Abdulra’uf, L. B.; Isiaka, K.; Muhammed, G. Y.; Ezekekwu, C. P.; Mustapha, O. T.
    This study aimed to investigate the tolerance level and the use of primers (H2O, KNO3, ascorbic acid and salicylic acid), in mitigating stress in maize in the newly released cultivars (SWAN-LSR-Y, BR9928-OMR-SR-Y and OMR-LSR-SY). Activities of SOD, APX, CAT and GSH and lipid peroxidation were investigated, to measure the biochemical response of the primed maize seeds. Maize seeds primed with KNO3 and ascorbic acid improved germination and anti-oxidative potential against ROS in ameliorating the salinity stress, while salicylic acid slowed germination. The same trend was followed in the seed vigour index and radicle length of seeds primed with ascorbic acid, which recorded the highest values. The control was observed to have the highest seed vigour index, while seeds primed with salicylic acid showed the least vigour index in the maize seeds. Increased salinity stress showed adverse effects on all growth parameters. Of the maize cultivars tested, SWAN-LSR-Y showed the most tolerance to salinity stress, in terms of germination. Significant high enzymatic activities and lipid peroxidation were recorded in seeds primed with ascorbic acid and KNO3 show their importance in plant metabolic activities.
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    EFFECTS OF EXPIRED, NON-EXPIRED PENDIMETHALIN AND HAND WEEDING ON THE BIO- PRODUCTIVITY AND SEED QUALITY OF GROUNDNUT (ARACHIS HYPOGAEA L.)
    (2023-03) Lawal, A. R.; Olayinka, B.U.; Ayinla, A,; Sidiq, A.; Bulala, A. F.; MUKTAR, S. M.; Abdulra’uf, L. B.
    The use of expired herbicides to suppress weeds growth is becoming prevalent among farmers. Hence the need to investigate and compare the effect of expired and non-expired pendimethalin and hand weeding on weed suppression, growth, yield and composition of groundnut. The experiment was carried to investigate seven weed treatments during the rainy season in 2020. These were sole pendimethalin non-expired at 0.75 kg ai/ha (T1), pendimethalin non-expired at 0.75 kg ai/ha + one hand weeding at 6 weeks after sowing (T2), pendimethalin expired at 0.75 kg ai/ha (T3), pendimethalin expired at 0.75 kg ai/ha + one hand weeding at 6 WAS (T4), two hand weeding at 3 and 6 WAS (T5), weed free check (T6) and weedy check (T7). Desmodium trifolium, Amaranthus spinosus and Commelina benghalensis were the most preponderant weed species. Both expired or non-expired pendimethalin and their integration with one hand weeding reduced weed population than other treatments. Pendimethalin nonexpired + one hand weeding at 6WAS and two hand weeding at 3 and 6 WAS significantly increased the growth parameters and yield when compared with other treatments. There was marked increase in protein, fat and ash contents of the seeds in all the weed control treatments than the weedy check. Also, the mineral elements (Fe, Ca, K and N) with the exception of zinc (Zn) were significantly higher in weed control treatments compared with the weedy check. The study established in spite of positive influence of all weed control treatments on seed quality, two hand weeding at 3 and 6 WAS and non-expired pendimethalin + one hand weeding 6 WAS, should be reinforced for weed control and the use of expired pendimethalin should be discouraged.
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    Headspace solid phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC/MS) for the analysis of multi-class pesticides
    (Ilorin Journal of Science, 2014) Abdulra’uf, L. B.; Ibrahim, H. B.; Tan G. H.
    The development of a method based on headspace solid phase microextraction (HS-SPME) technique, for the simultaneous determination of 7 multiclass and multiresidue pesticides (fenobucarb, diazinon, chlorothalonil, thiobencarb,chlorpyrifos,endosulfan I and endosulfan II) in two species of apple, using gas chromatographymass spectrometry is discussed. The different parameters affecting the SPME technique were evaluated. The extraction capacity of three fiber coatings; polydimethylsiloxane (100µm PDMS), polyacrylate (65µm PA), and polydimethylsiloxane-divinylbenzene (85µm PDMS-DVB), were studied and compared. Validation of the method using two apple species spiked with standard solution yield better linear range, accuracy, precision, detection and quantification limits. The linearity was between 5 to 500 µg.kg–1 with good correlation coefficients (R) greater than 0.989. The average recoveries for all pesticides investigated were between 89– 100% in green apple and 94–103% in red apple with RSD ranging from 0.67–3.32% and 1.00 - 2.69 % respectively. The LOQs were between 6.71 and 14.56 µg.kg–1 and LODs ranged from 2.23 to 11.11 µg.kg-1.
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    Influence of pendimethalin and hand weeding on mineral composition of maize, cowpea and their intercop
    (Journal of Biological Research & Biotechnology, 2020) Lawal, A. R.; Olayinka, B. U.; Abdulra’uf, L. B.; Etejere, E. O.
    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.
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    Influence of pendimethalin and hand weeding on mineral composition of maize, cowpea and their intercrop
    (Faculty of Biological Sciences, University of Nigeria, Nsukka, Nigeria, 2020) Lawal, A. R.; Olayinka, B. U.; Abdulra’uf, L. B.; Etejere, E. O
    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.
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    Pesticide use: properties and environmental fate
    (Al-Hikmah Journal of Pure and Applied Sciences, 2016) Abdulra’uf, L. B.; Ibrahim, H. B.; Lawal, A. R.; Tan, G. H.
    This paper reviews the benefits and risks of pesticides use with brief discussion on their properties and movement in the environment. The growing demand for food by the ever increasing world population has led to tremendous increase in the use of pesticide. However, recent developments in pesticide production has helped to reduce the volume of pesticide use due to the synthesis of more potent active ingredients and the introduction of good agricultural practices. The transportation, accumulation and degradation of pesticide residues in the environment depend on their properties. The analysis of pesticide residues on food especially fruits and vegetables which are consumed raw have been a matter of public concern, due to the health risks. Therefore, there is need to balance the expected benefits of pesticide use and their risks to human health.
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    Strategies to reducing postharvest losses of perishable crops: A way of ensuring food security in Nigeria.
    (Al-Hikmah Journal of Education, 2017) Lawal, A. R.; Olayinka, B. U.; Abdulra’uf, L. B.; Etejere, E. O.
    Nigeria is a country reach in a great supply of agricultural produce
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    The roles of vegetable fibres in green chemistry. In: Vegetable fiber composites and their technological applications
    (Springer, 2021) Ajiboye, A. T.; Otun, K. O.; Babamale, H. F.; Abdulra’uf, L. B.
    Green chemistry holds a prominent position in the fabrication of chemical products and processes that lessen or wipe out the utilization and production of harmful substances