Displaying publications 1 - 20 of 32 in total

Abstract:
Sort:
  1. Sampling and Sample Preparation Techniques for the Analysis of Organophosphorus Pesticides in Soil Matrices
    Mohamed AH, Noorhisham NA, Yahaya N, Mohamad S, Kamaruzzaman S, Osman H, et al.
    Crit Rev Anal Chem, 2023;53(4):906-927.
    PMID: 34693833 DOI: 10.1080/10408347.2021.1992262
    Despite organophosphorus pesticides (OPPs) benefits in controlling vector-borne diseases and noxious insects, the bioaccumulation and persistence in the soil system may metamorphose into new substances which could pose a serious threat to the ecosystems and human health. The generally low levels of OPPs residues and often the complexity of the soil matrix are the issues that researcher must deal with. Thus, it is essential to isolate and preconcentrate the OPPs from the matrix to reduce interference effects to obtain a reliable detection. Researchers have reported sample preparation techniques as a promising approach to improve analytical measurement of merits including recovery, precision, linearity, limit of detection, and limit of quantification. Under the selected conditions, limits of detection range between 0.001 and 143 ng/mL, and extraction recovery range between 5 and 154% were obtained. This review evaluates the challenges and opportunities, emphasizes the prospects of sampling techniques and various (micro)extraction coupled with chromatographic methods in different soil samples. Based on the finding, the extraction efficiency depended largely on the interaction between OPPs and extraction media. The fate, migration, toxicity impact, sampling procedure, and storage which influenced the sample preparation were comprehensively discussed.
    Matched MeSH terms: Organophosphorus Compounds/analysis
  2. Biodegradation mechanism of chlorpyrifos by halophilic bacterium Hortaea sp. B15
    Hadibarata T, Kristanti RA, Bilal M, Yilmaz M, Sathishkumar P
    Chemosphere, 2023 Jan;312(Pt 1):137260.
    PMID: 36400190 DOI: 10.1016/j.chemosphere.2022.137260
    For decades, most of the developing nations have relied on chlorpyrifos for insecticidal activity in the agriculture sector. It is a common chlorinated organophosphorus pesticide that has been widely used to control insects to protect plants. This study aimed to investigate the effects of environmental characteristics such as salinity, pH, temperature, and surfactant on Hortaea sp. B15 mediated degradation of chlorpyrifos as well as enzyme activity and metabolic pathway. The highest bacterial growth (4.6 × 1016 CFU/mL) was achieved after 20 h of incubation in a 100 mg/L chlorpyrifos amended culture. The fit model and feasible way to express the chlorpyrifos biodegradation kinetics in normal condition and optimized was a first-order rate equation, with an R2 value of 0.95-0.98. The optimum pH for chlorpyrifos biodegradation was pH 9, which resulted in a high removal rate (91.1%) and a maximum total count of 3.8 × 1016 CFU/mL. Increasing the temperature over 40 °C may inhibit microbial development and biodegradation. There was no significant effect of culture salinity on degradation and bacterial growth. In the presence of non-ionic surfactant Tween 80, the maximum chlorpyrifos degradation (89.5%) and bacterial growth (3.8 × 1016 CFU/mL) was achieved. Metabolites such as 3,5,6-trichloropyridin-2-ol and 2-pyridinol were identified in the Hortaea sp. B15 mediated degradation of chlorpyrifos. According to the findings, Hortaea sp. B15 should be recommended for use in the investigation of in situ biodegradation of pesticides.
    Matched MeSH terms: Organophosphorus Compounds
  3. Fulltext Enhancement of Dose Response and Nuclear Magnetic Resonance Image of PAGAT Polymer Gel Dosimeter by Adding Silver Nanoparticles
    Sabbaghizadeh R, Shamsudin R, Deyhimihaghighi N, Sedghi A
    PLoS One, 2017;12(1):e0168737.
    PMID: 28060829 DOI: 10.1371/journal.pone.0168737
    In the present study, the normoxic polyacrylamide gelatin and tetrakis hydroxy methyl phosphoniun chloride (PAGAT) polymer gel dosimeters were synthesized with and without the presence of silver (Ag) nanoparticles. The amount of Ag nanoparticles varied from 1 to 3 ml with concentration 3.14 g/l, thus forming two types of PAGAT polymer gel dosimeters before irradiating them with 6 to 25 Gy produced by 1.25-MeV 60Co gamma rays. In this range, the predominant gamma ray interaction with matter is by Compton scattering effect, as the photoelectric absorption effect diminishes. MRI was employed when evaluating the polymerization of the dosimeters and the gray scale of the MRI film was determined via an optical densitometer. Subsequent analyses of optical densities revealed that the extent of polymerization increased with the increase in the absorbed dose, while the increase of penetration depth within the dosimeters has a reverse effect. Moreover, a significant increase in the optical density-dose response (11.82%) was noted for dosimeters containing 2 ml Ag nanoparticles.
    Matched MeSH terms: Organophosphorus Compounds*
  4. Solid phase microextraction using new sol-gel hybrid polydimethylsiloxane-2-hydroxymethyl-18-crown-6-coated fiber for determination of organophosphorous pesticides
    Wan Ibrahim WA, Farhani H, Sanagi MM, Aboul-Enein HY
    J Chromatogr A, 2010 Jul 23;1217(30):4890-7.
    PMID: 20561627 DOI: 10.1016/j.chroma.2010.05.050
    A new sol-gel hybrid coating, polydimethylsiloxane-2-hydroxymethyl-18-crown-6 (PDMS-2OHMe18C6) was prepared in-house for use in solid phase microextraction (SPME). The three compositions produced were assessed for its extraction efficiency towards three selected organophosphorus pesticides (OPPs) based on peak area extracted obtained from gas chromatography with electron capture detection. All three compositions showed superior extraction efficiencies compared to commercial 100 microm PDMS fiber. The composition showing best extraction performance was used to obtain optimized SPME conditions: 75 degrees C extraction temperature, 10 min extraction time, 120 rpm stirring rate, desorption time 5 min, desorption temperature 250 degrees C and 1.5% (w/v) of NaCl salt addition. The method detection limits (S/N=3) of the OPPs with the new sol-gel hybrid material ranged from 4.5 to 4.8 ng g(-1), which is well below the maximum residue limit set by Codex Alimentarius Commission and European Commission. Percentage recovery of OPPs from strawberry, green apple and grape samples with the new hybrid sol-gel SPME material ranged from 65 to 125% with good precision of the method (%RSD) ranging from 0.3 to 7.4%.
    Matched MeSH terms: Organophosphorus Compounds/analysis*
  5. Selective binding of imidazolium cations in building multi-component layers
    Ling I, Alias Y, Sobolev AN, Byrne LT, Raston CL
    Chemistry, 2010 Jun 18;16(23):6973-82.
    PMID: 20455217 DOI: 10.1002/chem.200903320
    Addition of 1-alkyl-3-methylimidazolium (C(n)-mim) cations 3-5 to a mixture of bis-phosphonium cation 2 and sodium p-sulfonatocalix[4]arene (1) in the presence of lanthanide ions results in the selective binding of an imidazolium cation into the cavity of the calixarene. The result is a multi-layered solid material with an inherently flexible interplay of the components. Incorporating ethyl-, n-butyl- or n-hexyl-mim cations into the multi-layers results in significant perturbation of the structure, the most striking effect is the tilting of the plane of the bowl-shaped calixarene relative to the plane of the multi-layer, with tilt angles of 7.2, 28.9 and 65.5 degrees , respectively. The lanthanide ions facilitate complexation, but are not incorporated into the structures and, in all cases, the calixarene takes on a 5- charge, with one of the lower-rim phenolic groups deprotonated. ROESY NMR experiments and other (1)H NMR spectroscopy studies establish the formation of 1:1 supermolecules of C(n)-mim and calixarene, regardless of the ratio of the two components, and indicate that the supermolecules undergo rapid exchange on the NMR spectroscopy timescale.
    Matched MeSH terms: Organophosphorus Compounds/chemistry
  6. Blood cholinesterase levels among agricultural workers in four Asian countries
    Jeyaratnam J, Lun KC, Phoon WO
    Toxicol Lett, 1986 Oct;33(1-3):195-201.
    PMID: 3775817
    In this study whole blood cholinesterase activities were determined (tintometric method) of agricultural pesticide users exposed to organophosphorus compounds in Indonesia, Malaysia, Sri Lanka and Thailand. Analysis of the data demonstrated a universal relationship between cholinesterase levels and the time between the last exposure to organophosphorus compounds and the day of blood collection for cholinesterase determination. It is suggested that it takes approximately 5 days before whole blood cholinesterase levels revert to their normal values. No relationship between whole blood cholinesterase levels and the sex of pesticide users was demonstrated except in Sri Lanka where female sprayers had lower values. It is suggested that these lower values are associated with the anaemic status of female agricultural workers. No relationship between whole blood cholinesterase level and age was demonstrated. The measurement of pre-exposure cholinesterase values is essential for comparison of values after pesticide application.
    Matched MeSH terms: Organophosphorus Compounds*
  7. Toxicological studies of insecticides on Cullex quinquefasciatus Say and Aedes aegypti (L.)
    Chen YP, Sudderuddin KI
    Southeast Asian J. Trop. Med. Public Health, 1978 Sep;9(3):378-83.
    PMID: 749224
    Toxicity tests carried out on the larvae of A. aegypti and C. quinquefasciatus showed the former to be more tolerant of all insecticides tested, the order of toxicity being temephos greater than DDT greater than DDVP greater than malathion greater than lindane greater than carbaryl; also the second instar larvae of A. aegypti were more susceptible than fourth instar larvae. Enzyme kinetic studies on the total non-specific esterases and CarEs of adults and larvae of both species showed the Km values for total esterases of adult A. aegypti to be 0.333 mM vs 0.233 mM for C. quinquefasciatus; for adult CarEs it was 0.250 mM vs 0.220 mM. For total larval esterases of A. aegypti it was 0.112 mM vs 0.175 mM for C. quinquefasciatus: and for larval CarES it was 0.159 mM vs 0.213 mM respectively. Although some correlation between in vivo toxicity (LD50 values) and in vitro esterase inhibition (I50 values) between species could be discerned, overall correlation could not be established.
    Matched MeSH terms: Organophosphorus Compounds*
  8. A new solid phase extraction sorbent developed based on cyanopropyl functionalized silica nanoparticles for organophosphorus pesticides determination
    Korrani ZS, Khalili E, Kamyab H, Wan Ibrahim WA, Hashim H
    Environ Res, 2023 Dec 01;238(Pt 2):117167.
    PMID: 37722580 DOI: 10.1016/j.envres.2023.117167
    In this work, a simple sol-gel approach was used for the preparation of cyanopropyl (CNPr) functionalized silica nanoparticles (SiO2-CNPr) that tetraethoxysilane (TEOS) and cyanopropyltriethoxysilane (CNPrTEOS) used as precursors. This as-prepared SiO2-CNPr nanoparticle sorbent was first characterized using FESEM, EDX, FTIR, TGA, and BET techniques. Then, the SiO2-CNPr nanoparticle was applied as a new SPE sorbent for determining trace levels of OPPs in environmental water samples. To enhance the simultaneous extraction of non-polar or/and polar OPPs and to obtain the most efficient sorbent, several sol-gel synthesis parameters were studied. In addition, the effect of several effective parameters on SPE performance was investigated toward simultaneous extraction of non-polar or/and polar OPPs. Moreover, the figures of merit such as precision, linearity, LOQ, LOD, and recovery were evaluated for the sorbent. Finally, the designed SiO2-CNPr SPE was used to determine OPPs in real water samples, and its extraction performance was compared to commercial cartridges based on cyanopropyl.
    Matched MeSH terms: Organophosphorus Compounds
  9. Fulltext Determination of carbamate and organophosphorus pesticides in vegetable samples and the efficiency of gamma-radiation in their removal
    Chowdhury MA, Jahan I, Karim N, Alam MK, Abdur Rahman M, Moniruzzaman M, et al.
    Biomed Res Int, 2014;2014:145159.
    PMID: 24711991 DOI: 10.1155/2014/145159
    In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena) (n = 16), purchased from four different markets in Dhaka, Bangladesh. The carbamate and organophosphorus pesticide residual levels were determined by high performance liquid chromatography (HPLC), and the efficiency of gamma radiation on pesticide removal in three different types of vegetables was also studied. Many (50%) of the samples contained pesticides, and three samples had residual levels above the maximum residue levels determined by the World Health Organisation. Three carbamates (carbaryl, carbofuran, and pirimicarb) and six organophosphates (phenthoate, diazinon, parathion, dimethoate, phosphamidon, and pirimiphos-methyl) were detected in eggplant samples; the highest carbofuran level detected was 1.86 mg/kg, while phenthoate was detected at 0.311 mg/kg. Gamma radiation decreased pesticide levels proportionately with increasing radiation doses. Diazinon, chlorpyrifos, and phosphamidon were reduced by 40-48%, 35-43%, and 30-45%, respectively, when a radiation strength of 0.5 kGy was utilized. However, when the radiation dose was increased to 1.0 kGy, the levels of the pesticides were reduced to 85-90%, 80-91%, and 90-95%, respectively. In summary, our study revealed that pesticide residues are present at high amounts in vegetable samples and that gamma radiation at 1.0 kGy can remove 80-95% of some pesticides.
    Matched MeSH terms: Organophosphorus Compounds/radiation effects*; Organophosphorus Compounds/chemistry*
  10. Application of continual injection liquid-phase microextraction method coupled with liquid chromatography to the analysis of organophosphorus pesticides
    Raharjo Y, Sanagi MM, Ibrahim WA, Naim AA, Aboul-Enein HY
    J Sep Sci, 2009 Feb;32(4):623-9.
    PMID: 19165835 DOI: 10.1002/jssc.200800566
    A liquid-phase microextraction coupled with LC method has been developed for the determination of organophosphorus pesticides (methidation, quinalphos and profenofos) in drinking water samples. In this method, a small amount (3 microL) of isooctane as the acceptor phase was introduced continually to fill-up the channel of a 1.5 cm polypropylene hollow fiber using a microsyringe while the hollow fiber was immersed in an aqueous donor solution. A portion of the acceptor phase (ca. 0.4 microL) was first introduced into the hollow fiber and additional amounts (ca. 0.2 microL) of the acceptor phase were introduced to replenish at intervals of 3 min until set end of extraction (40 min). After extraction, the acceptor phase was withdrawn and transferred into a 2 mL vial for a drying step prior to injection into a LC system. Parameters that affect the extraction efficiency were studied including the organic solvent, length of fiber, volume of acceptor and donor phase, stirring rate, extraction time, and effect of salting out. The proposed method provided good enrichment factors of up to 189.50, with RSD ranging from 0.10 to 0.29%, analyte recoveries of over 79.80% and good linearity ranging from 10.0 to 1.25 mg/L. The LOD ranged from 2.86 to 82.66 microg/L. This method was applied successfully to the determination of organophosphorus pesticides in selected drinking water samples.
    Matched MeSH terms: Organophosphorus Compounds/analysis*; Organophosphorus Compounds/chemistry*
  11. Novel sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane as solid phase extraction sorbent for organophosphorus pesticides
    Wan Ibrahim WA, Veloo KV, Sanagi MM
    J Chromatogr A, 2012 Mar 16;1229:55-62.
    PMID: 22326188 DOI: 10.1016/j.chroma.2012.01.022
    A novel sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was produced and applied as sorbent for solid phase extraction (SPE). Five selected organophosphorus pesticides (OPPs) were employed as model compounds to evaluate the extraction performance of the synthesized sol-gel organic-inorganic hybrid MTMOS-TEOS. Analysis was performed using gas chromatography-mass spectrometry. Several important SPE parameters were optimized. Under the optimum extraction conditions, the method using the sol-gel organic-inorganic hybrid MTMOS-TEOS as SPE sorbent showed good linearity in the range of 0.001-1 μg L(-1), good repeatability (RSD 2.1-3.1%, n=5), low limits of detection at S/N=3 (0.5-0.9 pg mL(-1)) and limit of quantification (1-3 pg mL(-1), S/N=10). The performance of the MTMOS-TEOS SPE was compared to commercial C18 Supelclean SPE since C18 SPE is widely used for OPPs. The MTMOS-TEOS SPE method LOD was 500-600 × lower than the LOD of commercial C18 SPE. The LOD achieved with the sol-gel organic-inorganic hybrid MTMOS-TEOS SPE sorbent allowed the detection of these OPPs in drinking water well below the level set by European Union (EU) at 0.1 μg L(-1) of each pesticides. The developed MTMOS-TEOS SPE method was successfully applied to real sample analysis of the selected OPPs from several water samples and its application extended to the analysis of several fruits samples. Excellent recoveries and RSDs of the OPPs were obtained from the various water samples (recoveries: 97-111%, RSDs 0.4-2.8%, n=3) and fruit samples (recoveries: 96-111%), RSDs 1-4%, n=5) using the sol-gel organic-inorganic hybrid MTMOS-TEOS SPE sorbent. Recoveries and RSDs of OPPs from river water samples and fruit samples using C18 Supelclean SPE sorbent were 91-97%, RSD 0.9-2.6, n=3 and 86-96%, RSD 3-8%, n=5, respectively). The novel sol-gel hybrid MTMOS-TEOS SPE sorbent demonstrate the potential as an alternative inexpensive extraction sorbent for OPPs with higher sensitivity for the OPPs.
    Matched MeSH terms: Organophosphorus Compounds/analysis*; Organophosphorus Compounds/isolation & purification
  12. Predictors of Detected Organophosphorus Pesticides Among Orang Asli Children Living in Malaysia
    Mat Sutris J, Md Isa Z, Sumeri SA, Ghazi HF
    Ann Glob Health, 2017 3 12;82(5):770-778.
    PMID: 28283128 DOI: 10.1016/j.aogh.2016.10.008
    BACKGROUND: Increasing use of pesticides in agriculture to control pest may result in permanent damage to the environment and consequently cause harmful health problems especially among infant and children. Due to pesticide's natural toxicity and its widespread use, it causes a serious threat to public health especially to this vulnerable group.

    OBJECTIVE: The purpose of this study was to determine the organophosphorus pesticide urinary metabolite levels and its predictors among Orang Asli children of the Mah Meri tribe living in an agricultural island in Kuala Langat, Selangor.

    METHODS: Data collection was carried out at an island in Kuala Langat, Selangor, where a total of 180 Orang Asli children of the Mah Meri tribe voluntarily participated in the study. Data were collected via a validated, modified questionnaire. Urinary organophosphate metabolites, namely dimethylphosphate, diethylphosphate, dimethylthiophosphate, dimethyldithiophosphate, diethylthiophosphate, and diethyldithiophosphate were measured to assess organophosphate pesticide exposure in children.

    FINDINGS: Eighty-four (46.7%) of the respondents were positive for urine dialkyl phosphate metabolites. In multivariable analysis, children who frequently consumed apples had 4 times higher risk of pesticide detection than those who consumed apple less frequently. In addition, those who frequently ate cucumbers had 4 times higher risk for pesticide detection than those who ate cucumbers less frequently. Children with a father whose occupation involved high exposure to pesticides (agriculture) had 3 times higher risk of pesticide detection than those with a father in a low-risk occupation (nonagriculture).

    CONCLUSIONS: Almost half of the children (46.7%) in the study area tested positive for urinary dialkyl phosphate metabolite levels. Most of the metabolite levels were equal to or higher than that reported in other previous studies. Major factors associated with pesticide detection in children in this study were frequent intake of apple and cucumber and fathers who are working in an agricultural area.

    Matched MeSH terms: Organophosphorus Compounds/adverse effects; Organophosphorus Compounds/urine*
  13. Luminescent Cu4I4-Cu3(Pyrazolate)3Coordination Frameworks: Postsynthetic Ligand Substitution Leads to Network Displacement and Entanglement
    Zhan SZ, Li M, Zheng J, Wang QJ, Ng SW, Li D
    Inorg Chem, 2017 Nov 06;56(21):13446-13455.
    PMID: 29023107 DOI: 10.1021/acs.inorgchem.7b02144
    Six daughter complexes based on two-dimensional (2-D) luminescent Cu4I4-Cu3Pz3(Pz = pyrazolate) coordination networks, which exhibit an uncommon Cu4I4L3L' (L = pyridine; L' = acetonitrile, pyridine, pyrazine, 1,4-diazabicyclo[2.2.2]octane, triphenylphosphine, none) local configuration, were prepared through a postsynthetic modification method starting from a parent complex (L' = NH3). This work has successfully implemented the single-site substitution of Cu4I4-based coordination frameworks, which have rarely been reported for isolated Cu4I4-type compounds, by taking advantage of the solvent-assisted ligand substitution strategy recently developed in metal-organic framework (MOF) chemistry. Such a procedure not only resulted in the variation of local geometry in the Cu4I4units but also led to interlayer network displacement and entanglement. Particularly, an interesting topological transformation (from 2-D to 2-D → 3-D interpenetration) occurred when linear bidentate linkers (e.g., pyrazine and 1,4-diazabicyclo[2.2.2]octane) are inserted between the 2-D layers. Moreover, the variation in the L' sites can effectively tune the emission colors, ranging from green to orange (λemmax540-605 nm at room temperature). The photoluminescence origins are tentatively assigned to be a mixture of3MLCT and3XLCT, different from that of the well-studied isolated Cu4I4-type complexes.
    Matched MeSH terms: Organophosphorus Compounds
  14. Relationship Between Alcohol Co-Ingestion and Clinical Outcome in Pesticide Self-Poisoning: A Systematic Review and Meta-Analysis
    Dhanarisi J, Perera S, Wijerathna T, Gawarammana I, Shihana F, Pathiraja V, et al.
    Alcohol Alcohol, 2023 Jan 09;58(1):4-12.
    PMID: 36172715 DOI: 10.1093/alcalc/agac045
    AIM: Alcohol is a commonly co-ingested compound during self-poisoning with pesticides. Clinical experiences suggest alcohol co-ingestion (or withdrawal) makes patient management more difficult after self-poisoning and may contribute to poor clinical outcomes. We aimed to systematically review the world literature to explore the relationship between alcohol co-ingestion and outcome in pesticide self-poisoning.

    METHODS: We searched 13 electronic databases and Google scholar, conducted citation searching and a review of reference lists to find studies which investigated the relationship of alcohol with clinical outcome of pesticide self-poisoning in different countries. Thirteen studies, including 11 case series/reports and two cohort studies were considered for inclusion.

    RESULTS: Meta-analysis showed that alcohol co-ingestion in pesticide self-poisoning was associated with increased risk of death [odds ratio (OR) 4.9, 95% confidence interval (CI) 2.9-8.2 P<0.0001] and that alcohol co-ingested group required intubation eight times more often than non-co-ingested group in organophosphorus insecticide self-poisoning (OR 8.0, 95% CI 4.9-13.0 P<0.0001). Cases who co-ingested alcohol were older than non-alcohol group in two studies. One cohort study demonstrated that alcohol co-ingestion was associated with larger pesticide ingestions but did not itself affect the outcome.

    CONCLUSIONS: This systematic review indicates that alcohol co-ingestion may worsen clinical outcome in pesticide self-poisoning.

    Matched MeSH terms: Organophosphorus Compounds
  15. Assessment of cytotoxicity and toxicity for phosphonium-based deep eutectic solvents
    Hayyan M, Hashim MA, Al-Saadi MA, Hayyan A, AlNashef IM, Mirghani ME
    Chemosphere, 2013 Sep;93(2):455-9.
    PMID: 23820537 DOI: 10.1016/j.chemosphere.2013.05.013
    In this work, the cytotoxicity and toxicity of phosphonium-based deep eutectic solvents (DESs) with three hydrogen bond donors, namely glycerine, ethylene glycol, and triethylene glycol were investigated. The cytotoxicity effect was tested using brine shrimp (Artemia salina). The toxicity was investigated using the two Gram positive bacteria Bacillus subtilis and Staphylococcus aureus, and two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. The cytotoxicity of tested DESs was much higher than that of their individual components, indicating their toxicological behavior was different. It was also found that there was toxic effect on the studied bacteria, indicating their potential application as anti-bacterial agents. To the best of our knowledge, this is the first time the cytotoxicity and toxicity of phosphonium-based DESs were studied.
    Matched MeSH terms: Organophosphorus Compounds/chemistry*
  16. Comparison of HS-SDME with SPME and SPE for the determination of eight organochlorine and organophosphorus pesticide residues in food matrices
    Kin CM, Huat TG
    J Chromatogr Sci, 2009 Sep;47(8):694-9.
    PMID: 19772747
    A headspace single-drop microextraction (HS-SDME) procedure is optimized for the analysis of organochlorine and organophosphorous pesticide residues in food matrices, namely cucumbers and strawberries by gas chromatography with an electron capture detector. The parameters affecting the HS-SDME performance, such as selection of the extraction solvent, solvent drop volume, extraction time, temperature, stirring rate, and ionic strength, were studied and optimized. Extraction was achieved by exposing 1.5 microL toluene drop to the headspace of a 5 mL aqueous solution in a 15-mL vial and stirred at 800 rpm. The analytical parameters, such as linearity, correlation coefficients, precision, limits of detection (LOD), limits of quantification (LOQ), and recovery, were compared with those obtained from headspace solid-phase microextraction (HS-SPME) and solid-phase extraction. The mean recoveries for all three methods were all above 70% and below 104%. HS-SPME was the best method with the lowest LOD and LOQ values. Overall, the proposed HS-SDME method is acceptable in the analysis of pesticide residues in food matrices.
    Matched MeSH terms: Organophosphorus Compounds/analysis*
  17. Simultaneous determination of three organophosphorus pesticides in different food commodities by gas chromatography with mass spectrometry
    Vijaya Bhaskar Reddy A, Yusop Z, Jaafar J, Bin Aris A, Abdul Majid Z, Umar K, et al.
    J Sep Sci, 2016 Jun;39(12):2276-83.
    PMID: 27095506 DOI: 10.1002/jssc.201600155
    A sensitive and selective gas chromatography with mass spectrometry method was developed for the simultaneous determination of three organophosphorus pesticides, namely, chlorpyrifos, malathion, and diazinon in three different food commodities (milk, apples, and drinking water) employing solid-phase extraction for sample pretreatment. Pesticide extraction from different sample matrices was carried out on Chromabond C18 cartridges using 3.0 mL of methanol and 3.0 mL of a mixture of dichloromethane/acetonitrile (1:1 v/v) as the eluting solvent. Analysis was carried out by gas chromatography coupled with mass spectrometry using selected-ion monitoring mode. Good linear relationships were obtained in the range of 0.1-50 μg/L for chlorpyrifos, and 0.05-50 μg/L for both malathion and diazinon pesticides. Good repeatability and recoveries were obtained in the range of 78.54-86.73% for three pesticides under the optimized experimental conditions. The limit of detection ranged from 0.02 to 0.03 μg/L, and the limit of quantification ranged from 0.05 to 0.1 μg/L for all three pesticides. Finally, the developed method was successfully applied for the determination of three targeted pesticides in milk, apples, and drinking water samples each in triplicate. No pesticide was found in apple and milk samples, but chlorpyrifos was found in one drinking water sample below the quantification level.
    Matched MeSH terms: Organophosphorus Compounds/analysis*
  18. Fulltext Accidental organophosphate poisoning: two case reports
    Palam VSP, Abidin Z, Ong G, Loh TJ, Delilkan AE
    Med J Malaysia, 1984 Mar;39(1):85-7.
    PMID: 6513847
    Accidental organophosphate poisoning may occur in persons coming in close contact with animals being treated toitb organophosphate pesticides. The poisoning may manifest itself as a severe systemic disorder, but can be diagnosed by an alert physician and confirmed by specific tests of reduced cholinesterase activity in the blood, plasma and red blood cells. Treatment is with intravenous atropine. Supportive measures may be necessary.
    Matched MeSH terms: Organophosphorus Compounds*
  19. Pralidoxime as an insignificant reactivator in severe anticholinesterase (organophosphate insecticide) poisoning
    Ganendran A, Balabaskaran S
    Southeast Asian J. Trop. Med. Public Health, 1976 Dec;7(4):543-50.
    PMID: 1030852
    In acute severe anticholinesterase poisoning by organophosphate compounds, pralidoxime (P-2-AM, pyridine-2-aldoxime methiodide) used in the recommended doses, intravenously, has not been shown to reactivate the inhibited cholinesterase, as evidenced both clinically and biochemically. In vitro studies using pralidoxime iodide up to ten times the recommended concentrations, produced insignificant reactivation of cholinesterases inhibited by the organophosphate insecticide Bidrin (di-methyl-3-hydroxyl-N, N-dimethyl-crotonamide phosphate). This was even so despite prolonged exposure of the inhibited cholinesterases to the oxime. The value of pralidoxime as a reactivator of phosphorylated cholinesterases is therefore in doubt, and should not be used in preference to large doses of atropine and other supportive treatment in poisoning by organophosphate insecticides.
    Matched MeSH terms: Organophosphorus Compounds*
  20. Fulltext Identification and characterization of jasmonic acid- and linolenic acid-mediated transcriptional regulation of secondary laticifer differentiation in Hevea brasiliensis
    Loh SC, Othman AS, Veera Singham G
    Sci Rep, 2019 10 04;9(1):14296.
    PMID: 31586098 DOI: 10.1038/s41598-019-50800-1
    Hevea brasiliensis remains the primary crop commercially exploited to obtain latex, which is produced from the articulated secondary laticifer. Here, we described the transcriptional events related to jasmonic acid (JA)- and linolenic acid (LA)-induced secondary laticifer differentiation (SLD) in H. brasiliensis clone RRIM 600 based on RNA-seq approach. Histochemical approach proved that JA- and LA-treated samples resulted in SLD in H. brasiliensis when compared to ethephon and untreated control. RNA-seq data resulted in 86,614 unigenes, of which 2,664 genes were differentially expressed in JA and LA-induced secondary laticifer harvested from H. brasiliensis bark samples. Among these, 450 genes were unique to JA and LA as they were not differentially expressed in ethephon-treated samples compared with the untreated samples. Most transcription factors from the JA- and LA-specific dataset were classified under MYB, APETALA2/ethylene response factor (AP2/ERF), and basic-helix-loop-helix (bHLH) gene families that were involved in tissue developmental pathways, and we proposed that Bel5-GA2 oxidase 1-KNOTTED-like homeobox complex are likely involved in JA- and LA-induced SLD in H. brasiliensis. We also discovered alternative spliced transcripts, putative novel transcripts, and cis-natural antisense transcript pairs related to SLD event. This study has advanced understanding on the transcriptional regulatory network of SLD in H. brasiliensis.
    Matched MeSH terms: Organophosphorus Compounds/chemistry
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links