Ismail Sahid

National University of Malaysia, Putrajaya, Putrajaya, Malaysia

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Publications (30)16.86 Total impact

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    Maznah Zainol · Halimah Muhamad · Ismail Sahid
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    ABSTRACT: Dithiocarbamate fungicides thiram (tetramethyl-thiuramdisulfide) is intensively used in oil palm nurseries for seeds protection and oil palm seedlings from a variety of fungal diseases. The dissipation and residual level of thiram were investigated under tropical condition at RISDA Estate, Sungkai, Perak. The experiment was conducted with three treatment conditions namely; manufacturer's recommended dosage (25.6 g a.i./plot), double the manufacturer's recommended dosage (51.2 g a.i./plot) and control (spraying with water). Soil, water and oil palm leaf were collected at the following intervals;-1 (before treatment), 0 (day of treatment), 1, 3, 5, 7, 14, 21, 30 and 60 days after treatment. The quantification of thiram residue was performed using high performance liquid chromatography with diode array detector (HPLC-DAD). Thiram residues were detected in the soil up to 30 cm depth in the range of 0.12 mg/kg to 27.04 mg/kg. Residue levels of thiram in water and oil palm leaf were found in the range of <0.1-2.52 µg/L to <0.1-1.28 mg/kg, respectively. Results showed that the dissipation of thiram was rapid under tropical climatic conditions. Therefore, thiram is safe for use in foliar treatment in oil palm nursery due to its short presence in soil and environment.
    Full-text · Conference Paper · Aug 2015
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    ABSTRACT: Eleusine indica (goosegrass) populations resistant to fluazifop, an acetyl-CoA carboxylase (ACCase: EC6.4.1.2)-inhibiting herbicide, were found in several states in Malaysia. Dose-response assay indicated a resistance factor of 87.5, 62.5 and 150 for biotypes P2, P3 and P4, respectively. DNA sequencing and allele-specific PCR revealed that both biotypes P2 and P3 exhibit a single non-synonymous point mutation from TGG to TGC that leads to a well known Trp-2027-Cys mutation. Interestingly, the highly resistant biotype, P4, did not contain any of the known mutation except the newly discovered target point Asn-2097-Asp, which resulted from a nucleotide change in the codon AAT to GAT. ACCase gene expression was found differentially regulated in the susceptible biotype (P1) and highly resistant biotype P4 from 24 to 72h after treatment (HAT) when being treated with the recommended field rate (198gha(-1)) of fluazifop. However, the small and erratic differences of ACCase gene expression between biotype P1 and P4 does not support the 150-fold resistance in biotype P4. Therefore, the involvement of the target point Asn-2097-Asp and other non-target-site-based resistance mechanisms in the biotype P4 could not be ruled out.
    Full-text · Article · May 2014 · Pesticide Biochemistry and Physiology
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    Full-text · Article · Jan 2014 · Pesticide Biochemistry and Physiology
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    ABSTRACT: The oil palm industry heavily relies on the world market. It is essential to ensure that the oil palm industry is ready to meet the demands and expectation of these overseas customers on the environmental performance of the oil palm industry. Malaysia produces 13.9 million tons of oil palm biomass including oil palm trunk (OPT), frond and empty fruits bunches (EFB) annually. OPT felled in some oil palm plantations during replanting is transported to various industries and one such industry is the plywood factories. In order to gauge the environmental performance of the use of OPT as plywood a Life Cycle Assessment (LCA) study was conducted for palm based plywood. LCA is an important tool to assess the environmental performance of a product or process. Life cycle inventory (LCI) is the heart of a LCA study. This LCI study has a gate-to-gate system boundary and the functional unit is 1 m(3) palm plywood produced and covers three types of plywood; Moisture Resistance Plywood (MR), Weather Boiling Proof Plywood Grade 1 (WBP Grade 1) at Factory D and Weather Boiling Proof Plywood Grade 2 (WBP Grade 2) at Factory E. Both factories use two different types of drying processes; conventional drying at Factory D and kiln drying at Factory E. This inventory data was collected from two factories (D and E) representing 40% of Malaysia palm plywood industry. The inputs are mainly the raw materials which are the oil palm trunks and tropical wood veneers and the energy from diesel and electricity from grid which is mainly used for the drying process. The other inputs include water, urea formaldehyde, phenol formaldehyde, flour and melamine powder. The outputs are the biomass waste which consists of oil palm trunk off-cut and emission from boiler. Generally, all types of plywood production use almost same materials and processing methods in different quantities. Due to the different process efficiency, Factory D uses less input of raw materials and energy compared to Factory E.
    Full-text · Conference Paper · Nov 2013
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    ABSTRACT: A field study on the leaching and persistence of herbicide diuron in an oil palm agro ecosystem was conducted in an oil palm plantation in Sepang, Selangor. Two treatments, namely the recommended and double the recommended dosage of diuron were applied in the field trial. Diuron was sprayed using a knapsack sprayer (18 litres) at the rate of 0.3 kg ha-1 (recommended dosage) and 0.6 kg ha-1 (double the recommended dosage). Soil samples were collected at different depths, viz. 0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm and 40-50 cm at the following intervals: -1 day (before treatment), 0 day (day of treatment, 6 hr later), 1 day, 3, 5, 7, 14, 21, 30, 60, 90 and 120 days after treatment. Diuron residue was detected in the soil sampled at all depths, for both the dosages applied from day 0 to 60 days after treatment (DAT), with the exception of day 90 where it was only detected at the 0-10 cm depth when the plot was sprayed at double the recommended dosage. The calculated half-life of diuron when applied at both dosages was also determined and results showed that the half-life of diuron in soil when applied at the recommended and double the recommended dosage was in the range of 22.35 - 49.5 days and 18.73 - 57.75 days, respectively.
    Full-text · Dataset · Apr 2013
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    ABSTRACT: The objective of this study was to develop a method for the determination of diuron (3-(3,4-dichlorophenyl)-1,1-dimethyl urea) residue in crude palm oil (CPO) and crude palm kernel oil (CPKO) matrices. The method involves the extraction of the herbicide from the oil matrix using low temperature precipitation and solid phase extraction techniques, detected by high performance liquid chromatography-ultra violet (HPLC-UV). The HPLC separation was carried out on an AscentisTM RP-Amide column and elution with acetonitrile (solvent A) and water-methanol (2:1, v/v) (solvent B) as a suitable solvent system, at ratio of 4:6 (v/v). The optimum volume of acetonitrile for the extraction of diuron was 30 mL and 4 mL was obtained as the optimum volume of the solvent for elution analyte through the SPE cartridge. A linear correlation was obtained for the concentration of diuron from 0.05–1.0 μg mL-1 with a correlation coefficient of 0.99. The recovery of diuron from CPO was 83.2–101.4% with a relative standard deviation of 1.4–9.9% and 79.4–87.9% with relative standard deviation of 0.9–5.6% for CPKO. The method detection limit and limit of quantification obtained were 0.018 μg g-1 and 0.058 μg g-1, respectively. The method was used to determine diuron residues in palm oil from different refineries situated at different locations throughout Malaysia
    No preview · Article · Nov 2012 · Sains Malaysiana
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    M. Zainol · I. Sahid · H. Muhamad
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    ABSTRACT: Thiram (tetramethylthiuram disulfide) is a fungicide used to control plant pathogenic fungi such as Rhizoctonia spp, Phythium spp. and Fusarium spp. which often infest oil palm seedlings from the prenursery until the main nursery stage. With increasing applications of thiram in oil palm nurseries, it is necessary to investigate the fate of thiram in the nursery environment. The trial was conducted from July till August 2008, i.e. during the wet season, at the Labu Estate Nursery (Sime Darby), Nilai, Negeri Sembilan. The subplots were treated with thiram at the manufacturer's recommended dose and at double recommended dose. Thiram residue was detected in the soil at all depths (from 0-50 cm) for both treatment doses on the day of spraying (0 DAT). The amount of residue was observed to decrease with soil depth. Analyses of water and oil palm leaflets within the trial showed that thiram was found at 0 and 3 days after treatment of the trial plots at the recommended and double the recommended doses. The results showed that adsorption and dissipation of thiram were slowly being influenced by the type of soil and the total amount of rain received during the experiment. Run-off and wash-off were the major causes of the loss of thiram residues from the water in the nursery environment and from the leaflets of the oil palm seedlings.
    Full-text · Article · Aug 2012 · Journal of oil palm research
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    ABSTRACT: In oil palm plantations, the fungicide hexaconazole is used to control Ganoderma infection that threatens to destroy or compromisethe palm. The application of hexaconazole is usually through soil drenching, trunk injection, or a combination of these two methods. It is therefore important to have a method to determine the residual amount of hexaconazole in the field such as in samples of water, soil, and leaf to monitor the use and fate of the fungicide in oil palm plantations. This study on the behaviour of hexaconazole in oil palm agro-environment was carried out at the UKM-MPOB Research Station, Bangi Lama, Selangor. Three experimental plots in this estate with 7-year-old Dura x Pisifera (DxP) palms were selected for the field trial. One plot was sprayed with hexaconazole at the manufacturer's recommended dosage, one at double the recommended dosage, and the third plot was untreated control. Hexaconazole residues in the soil, leaf, and water were determined before and after fungicide treatment. Soil samples were randomly collected from three locations at different depths (0-50 cm) and soil collected fromthe same depth were bulked together. Soil, water, and palm leaf were collected at -1 (day before treatment), 0 (day of treatment), 1, 3, 7, 14, 21, 70, 90, and 120 days after treatment. Hexaconazole was detected in soil and oil palm leaf, but was not detected in water from the nearby stream.
    Full-text · Article · Aug 2012 · Drug Testing and Analysis
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    ABSTRACT: The palm oil industry has played an important role in the economic development of Malaysia and has enhanced the economic welfare of its people. To determine the environmental impact of the oil palm seedling at the nursery stage, information on inputs and outputs need to be assessed. The oil palm nursery is the first link in the palm oil supply chain. A gate-to-gate study was carried out whereby the system boundary was set to only include the process of the oil palm seedling. The starting point was a germinated seed in a small polyethylene bag (6 in × 9 in) in which it remained until the seedling was approximately 3 to 4 months old. The seedling was then transferred into a larger polyethylene bag (12 in × 15 in), where it remained until it was 10-12 months old, when it was planted in the field (plantation). The functional unit for this life cycle inventory (LCI) is based on the production of one seedling. Generally, within the system boundary, the production of an oil palm seedling has only two major environmental impact points, the polybags used to grow the seedling and the fungicide (dithiocarbamate) used to control pathogenic fungi, as both the polybags and the dithiocarbamate are derived from fossil fuel.
    No preview · Article · May 2012
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    ABSTRACT: Limnocaris flava (L.) Buchenau (yellow bur head) is an aggressive broadleaf weed in lowland rice ecosystem. Resistance of L. flava to herbicides like synthetic auxins and acetolactate-synthase inhibitor has been reported in Malaysia. The study was, therefore, conducted to reconfirm the resistance of L. flava to bensulfuron-methyl and 2,4-D, and subsequently to determine the efficacy of herbicide mixtures in controlling the resistant biotype of L. flava. For screening out the resistant biotype, different rates up to 16 times higher than recommended doses of bensulfuron methyl and 2,4-D were applied. To control resistant biotype, different rates of bensulfuron methyl and bentazon-sodium/MCPA dimethyl in single or in combinations were tried against five week-old resistant biotype of L. flava. Results showed that resistant L. flava biotype tolerated up to 4 times higher than recommended doses of bensulfuron methyl and 2,4-D. Bentazon-sodium/MCPA dimethyl alone effectively controlled resistant biotype of L. flava at the recommended rate (0.74 kg a.i/ha), while bensulfuron-methyl alone failed to control resistant biotype of L. flava even at double the recommended rate. Among the different tank-mix combinations of bensulfuron methyl and bentazon-sodium/MCPA dimethyl, three antagonistic and six additive joint actions were observed.
    No preview · Article · Jan 2012 · Journal of Food Agriculture and Environment
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    ABSTRACT: A cross-section analytical study was conducted to evaluate the risk of pesticide exposure to those applying the Class II pesticides 2,4-D and paraquat in the paddy-growing areas of Kerian, Perak, Malaysia. It investigated the influence of weather on exposure as well as documented health problems commonly related to pesticide exposure. Potential inhalation and dermal exposure for 140 paddy farmers (handlers of pesticides) were assessed. Results showed that while temperature and humidity affected exposure, windspeed had the strongest impact on pesticide exposure via inhalation. However, the degree of exposure to both herbicides via inhalation was below the permissible exposure limits set by United States National Institute of Occupational Safety and Health (NIOSH). Dermal Exposure Assessment Method (DREAM) readings showed that dermal exposure with manual spraying ranged from moderate to high. With motorized sprayers, however, the level of dermal exposure ranged from low to moderate. Dermal exposure was significantly negatively correlated with the usage of protective clothing. Various types of deleterious health effects were detected among users of manual knapsack sprayers. Long-term spraying activities were positively correlated with increasing levels of the gamma-glutamyl transpeptidase (GGT) liver enzyme. The type of spraying equipment, usage of proper protective clothing and adherence to correct spraying practices were found to be the most important factors influencing the degree of pesticide exposure among those applying pesticides.
    Full-text · Article · Oct 2011 · Journal of Environmental Science and Health Part B Pesticides Food Contaminants and Agricultural Wastes
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    ISMAIL B. SAHID · JULIANA KARSO · TSE-SENG CHUAH
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    ABSTRACT: The resistance mechanism of Leptochloa chinensis Nees to propanil was investigated, based on propanil metabolism, aryl acylamidase activity, and chlorophyll fluorescence at the 8 week growth stage of L. chinensis. The concentration of propanil in the leaf and culm extracts of the resistant (R) and susceptible (S) biotypes, as measured by gas chromatography (GC), was found to increase after propanil treatment. The concentration of propanil in the leaf and culm extracts of the S biotype at 72 h was 1.55 and 0.49 µg mL−1, respectively. However, a lower concentration of propanil was observed in the R biotype, as compared to that in the S biotype. The residue of 3,4-dichloroaniline, as measured by GC, was detected only in the leaf extracts of the R biotype. In contrast, no residue of 3,4-dichloroaniline was observed in the S biotype. The level of aryl acylamidase in the leaf tissue extracts of the R biotype was ∼140% higher than that in the S biotype. The fluorescence studies showed that propanil inhibited the quantum efficiency of the photosystem II in both the R and S biotypes after 2 h of incubation time. However, when the leaf disks were transferred and incubated in deionized water for 48 h, the quantum efficiency increased in the R biotype but decreased in the S biotype. These results suggest that propanil metabolism, enhanced by aryl acylamidase activity, is the most likely factor contributing towards the mechanism of propanil resistance in L. chinensis plants at the 8 week growth stage.
    Full-text · Article · Jun 2011 · Weed Biology and Management
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    CHUAH TSE SENG · LOW VAN LUN · CHA THYE SAN · ISMAIL BIN SAHID
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    ABSTRACT: Field and glasshouse studies have confirmed the presence of a glufosinate- and paraquat-resistant goosegrass biotype that has infested a bitter gourd field in Air Kuning, Perak, Malaysia. Glufosinate and paraquat had been applied at least six times per year to the affected fields (originally a rubber plantation) for more than four consecutive years. Paraquat had been used since 1970 for weed control in the rubber plantation. An on-site field trial revealed that the control of the goosegrass plants, measuring 20–35 cm in height, ranged from 20 to 35% 3 weeks after being treated with each herbicide at twice the recommended rate. Dose–response tests were conducted in the glasshouse, using seedlings at the three-to-four-leaf stage that had been obtained from the plants that had received repeated exposure to these herbicides and a biotype with no history of any herbicide resistance. The comparison of the GR50 (the herbicide rate that is required to reduce the shoot fresh weight by 50%) of the seedlings indicated that the resistant biotype of goosegrass is 3.4-fold and 3.6-fold more resistant than the susceptible biotype following treatment with glufosinate and paraquat, respectively. This study has demonstrated the world's first field-evolved instance of multiple resistance in goosegrass to two non-selective herbicides, glufosinate and paraquat.
    Full-text · Article · Dec 2010 · Weed Biology and Management
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    Halimah Muhamad · Tan Yew Ai · Ismail Sahid · Nashriyah Mat
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    ABSTRACT: A study on the leaching of chlorpyrifos in an oil palm agro ecosystem was conducted in an oil palm plantation in Sepang, Selangor. The insecticide chlorpyrifos was sprayed using a knapsack sprayer at the recommended and double the recommended dosage. Soil samples were collected at different depths, viz. 0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm and 40-50 cm at the following intervals: -1 day (before treatment), 0 day (day of treatment, 6 hr later), 1 day, 3, 7, 14, 30 and 60 days after treatment. Recovery of chlorpyrifos from the soil spiked with chlorpyrifos at 4-50 μg kg-1 ranged from 88%-99% with the coefficients of variation ranging from 2.0% to 7.5%. Chlorpyrifos residue was detected at 0-10 cm and 10-20 cm depths when applied at the recommended and double the recommended dosages, respectively. The residue was only detected in the soil for up to five and seven days after treatment, respectively, when applied at the recommended and double the recommended dosages.
    Full-text · Article · Apr 2010 · Journal of oil palm research
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    Halimah Muhamad · Tan Yew Ai · Ismail Sahid · Nashriyah Mat
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    ABSTRACT: A study on the leaching of chlorpyrifos in an oil palm agro ecosystem was conducted in an oil palm plantation in Sepang, Selangor. The insecticide chlorpyrifos was sprayed using a knapsack sprayer at the recommended and double the recommended dosage. Soil samples were collected at different depths, viz. 0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm and 40-50 cm at the following intervals: -1 day (before treatment), 0 day (day of treatment, 6 hr later), 1 day, 3, 7, 14, 30 and 60 days after treatment. Recovery of chlorpyrifos from the soil spiked with chlorpyrifos at 4-50 μg kg-1 ranged from 88%-99% with the coefficients of variation ranging from 2.0% to 7.5%. Chlorpyrifos residue was detected at 0-10 cm and 10-20 cm depths when applied at the recommended and double the recommended dosages, respectively. The residue was only detected in the soil for up to five and seven days after treatment, respectively, when applied at the recommended and double the recommended dosages.
    Full-text · Article · Apr 2010 · Journal of oil palm research
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    M. Motior Rahman · Ismail Bin Sahid · Abdul Shukor Juraimi
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    ABSTRACT: Present study was carried out to identify resistant biotypes of Echinochloa crus-galli and to determine their control measures by application of herbicides. Propanil, quinclorac and cyhalofop-butyl was tested against 10 populations of Echinochloa crus-galli which was collected from rice fields of Kedah, Malaysia. Weed populations such as KPT, SB1, SB2, KPE, SY, TD, DB, KB1 and KB2 was identified as resistant biotypes and only KP population recorded as susceptible biotype to propanil. Out of 10 populations, only KB1 was found resistant biotypes and all others identified as susceptible to quinclorac. Weed populations of KP, KPT, SB1, KPE, SY and KB2 was found susceptible while SB2, TD and KB1 identified as resistant biotypes to Cyhalofop-butyl. Among 10 tested populations, only KB1 was found resistant biotype to propanil, quinclorac and cyhalofop-butyl. The ED 50 values from the dose-response experiments indicated that the resistant biotype was >four times resistant to propanil, >10 times resistant to quinclorac and >17 times resistant to cyhalofop-butyl, respectively than susceptible biotype. Resistant biotype KB1 was controlled by combined application of quinclorac and propanil at rates of 0.30 and 5.50 and kg a.i. ha -1 or quinclorac and cyhalofop-butyl at rates of 0.30 and 0.80 kg a.i. ha -1 respectively.
    Full-text · Article · Mar 2010 · Australian Journal of Crop Science
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    ABSTRACT: Leaching of fluroxypyr-MHE in an oil palm agroecosystem was conducted for two seasons; the dry and wet season. The oil palm estate is situated in central Selangor, Peninsular Malaysia at an altitude of 70 m to 100 m above sea level. The study plot covered six ha, and consisted of nine subplots of 0.66 ha each. The nine subplots received three treatments namely; the manufacturer's recommended dosage (T1), double the manufacturer's recommended dosage (T2), and the control (T3) with no herbicide treatment. Each treatment was done in triplicate each subplot was separated by a two meter buffer zone. The herbicide fluroxypyr-MHE (Starane  200 EC; Dow Elanco Ltd.) was applied as an aqueous spray using a knapsack sprayer at a spraying volume of 250 L/ha. Soil samples collected at different depths (viz. 0-10, 10-20, 20-30, 30-40 and 40-50 cm) and at the following intervals -1 (before treatment), 1, 3, 7, 14, 30 and 60 days after treatment. Fluroxypyr-MHE was observed at all depths (0-50 cm) for the wet season when applied at the recommended and doubles the recommended dosages. Meanwhile for the dry season, fluroxypyr-MHE was detected in the soil up to 1 and 5 days after treatment when applied at the recommended and double the recommended dosages, respectively.
    Full-text · Article · Jan 2010
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    Halimah Muhamad · Nashriyah Mat · Ismail Sahid · Tan Yew Ai
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    ABSTRACT: Leaching of fluroxypyr-MHE in an oil palm agroecosystem was conducted for two seasons; the dry and wet season. The oil palm estate is situated in central Selangor, Peninsular Malaysia at an altitude of 70 m to 100 m above sea level. The study plot covered six ha, and consisted of nine subplots of 0.66 ha each. The nine subplots received three treatments namely; the manufacturer's recommended dosage (T1), double the manufacturer's recommended dosage (T2), and the control (T3) with no herbicide treatment. Each treatment was done in triplicate each subplot was separated by a two meter buffer zone. The herbicide fluroxypyr-MHE (Starane  200 EC; Dow Elanco Ltd.) was applied as an aqueous spray using a knapsack sprayer at a spraying volume of 250 L/ha. Soil samples collected at different depths (viz. 0-10, 10-20, 20-30, 30-40 and 40-50 cm) and at the following intervals -1 (before treatment), 1, 3, 7, 14, 30 and 60 days after treatment. Fluroxypyr-MHE was observed at all depths (0-50 cm) for the wet season when applied at the recommended and doubles the recommended dosages. Meanwhile for the dry season, fluroxypyr-MHE was detected in the soil up to 1 and 5 days after treatment when applied at the recommended and double the recommended dosages, respectively.
    Full-text · Article · Jan 2009
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    ABSTRACT: The downward movement of carbofuran in two Malaysian soil types was studied using soil columns. The columns were filled with disturbed and undisturbed soils of either the Bagan Datoh soil (clay) or the Labu soil (sandy clay). The average total percentage of carbofuran in the leachate of the undisturbed Labu soil after 14 days of watering (80.8%) was approximately similar to that of the total amount from the disturbed soil (81.4%). However, carbofuran leaching was observed in the disturbed soil after the fourth day of watering whereas for the undisturbed soil, leaching occurred after the first watering. A similar trend was observed in the Bagan Datoh soil where the residue of carbofuran was detected after the first day of watering in the undisturbed soil column but only at the eighth day of watering in the disturbed soil column. The total percentage carbofuran in the leachate of disturbed and undisturbed soil columns from Bagan Datoh after 14 days of watering was 3.6% and 41.7%, respectively. The study showed that less leaching occurred in soil columns with high organic content such as the Bagan Datoh soil and especially so in disturbed soils where the organic matter was homogeneously mixed in all layers.
    No preview · Article · Jul 2008 · Bulletin of Environmental Contamination and Toxicology
  • Halimah B Muhamad · Tan Yew Ai · Ismail B Sahid
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    ABSTRACT: The purpose of this study was to develop a method for the determination of fluroxypyr (4-amino-3,5-dichloro-6-fluro2-pyridyloxyacetic acid) residue in palm oil namely crude palm oil (CPO) and crude palm kernel oil (CPKO). The method involves the extraction of the herbicide from the oil matrix followed by low temperature precipitation and finally quantification of the residues using the high performance liquid chromatography (HPLC). The extraction efficiency of the method was evaluated by conducting recovery studies. The recovery of fluroxypyr from the fortified CPO samples ranged from 78%-111% with the relative values for the coefficient of variation ranging from 1.4 to 8.6%. Furthermore, the recovery of fluroxypyr from the spiked CPKO samples ranged from 91-107% with the relative values for the coefficient of variation ranging from 0.6 to 4.5%. The minimum detection limit of fluroxypyr in CPO and CPKO was 0.05 microg/g. The method was used to determine fluroxypyr residues from the field-treated samples of CPO and CPKO. When fluroxypyr was used for weed control in oil palm plantations no residue was detected in CPO and CPKO irrespective of the sampling interval and the dosage applied at the recommended or double the manufacturer's recommended dosage.
    No preview · Article · Mar 2008 · Journal of Environmental Science and Health Part B