Displaying publications 1 - 20 of 47 in total

  1. Lee TP, Saad B, Ng EP, Salleh B
    J Chromatogr A, 2012 May 11;1237:46-54.
    PMID: 22444432 DOI: 10.1016/j.chroma.2012.03.031
    Zeolite Linde Type L (LTL) crystals with different length, diameter and particle size (nanosized LTL, rod LTL, cylinder LTL and needle LTL) were synthesized, characterized and were used as sorbent in the micro-solid phase extraction of ochratoxin A (OTA) before the high performance liquid chromatography detection. Under the optimized conditions, the detection limits of OTA for coffee and cereal were 0.09 ng g(-1) and 0.03 ng g(-1), respectively, while the quantification limits were 0.28 ng g(-1) and 0.08 ng g(-1), respectively. The recoveries of OTA of coffee and cereal spiked at 0.5, 10 and 25 ng g(-1) ranged from 91.7 to 101.0%. The proposed method was applied to forty-five samples of coffee and cereal. The presence of OTA was found in twenty-five samples, ranging from 0.28 to 9.33 ng g(-1).
    Matched MeSH terms: Solid Phase Extraction/methods*
  2. Lai CS, Nair NK, Muniandy A, Mansor SM, Olliaro PL, Navaratnam V
    J Chromatogr B Analyt Technol Biomed Life Sci, 2009 Feb 15;877(5-6):558-62.
    PMID: 19147417 DOI: 10.1016/j.jchromb.2008.12.037
    With the expanded use of the combination of artesunate (AS) and amodiaquine (AQ) for the treatment of falciparum malaria and the abundance of products on the market, comes the need for rapid and reliable bioanalytical methods for the determination of the parent compounds and their metabolites. While the existing methods were developed for the determination of either AS or AQ in biological fluids, the current validated method allows simultaneous extraction and determination of AS and AQ in human plasma. Extraction is carried out on Supelclean LC-18 extraction cartridges where AS, its metabolite dihydroartemisinin (DHA) and the internal standard artemisinin (QHS) are separated from AQ, its metabolite desethylamodiaquine (DeAQ) and the internal standard, an isobutyl analogue of desethylamodiaquine (IB-DeAQ). AS, DHA and QHS are then analysed using Hypersil C4 column with acetonitrile-acetic acid (0.05M adjusted to pH 5.2 with 1.00M NaOH) (42:58, v/v) as mobile phase at flow rate 1.50ml/min. The analytes are detected with an electrochemical detector operating in the reductive mode. Chromatography of AQ, DeAQ and IB-DeAQ is carried out on an Inertsil C4 column with acetonitrile-KH(2)PO(4) (pH 4.0, 0.05M) (11:89, v/v) as mobile phase at flow rate 1.00ml/min. The analytes are detected by an electrochemical detector operating in the oxidative mode. The recoveries of AS, DHA, AQ and DeAQ vary between 79.1% and 104.0% over the concentration range of 50-1400ng/ml plasma. The accuracies of the determination of all the analytes are 96.8-103.9%, while the variation for within-day and day-to-day analysis are <15%. The lower limit of quantification for all the analytes is 20ng/ml and limit of detection is 8ng/ml. The method is sensitive, selective, accurate, reproducible and suited particularly for pharmacokinetic study of AS-AQ drug combination and can also be used to compare the bioavailability of different formulations, including a fixed-dose AS-AQ co-formulation.
    Matched MeSH terms: Solid Phase Extraction/methods*
  3. Amiri A, Ghaemi F
    J Chromatogr A, 2021 Jul 05;1648:462168.
    PMID: 33984648 DOI: 10.1016/j.chroma.2021.462168
    In this research, the Cu-based metal-organic framework (MOF-199) was fabricated and coated on the stainless steel mesh as substrates through sol-gel procedure. Then the coated substrates were placed in a small column known as solid-phase extraction cartridge. The SPE based coated stainless steel mesh coupled with high-performance liquid chromatography-UV detector (HPLC-UV) was used for the fast extraction, and quantification of non-steroidal anti-inflammatory drugs (NSAIDs) from human plasma and water samples. To find optimum extraction conditions, the impacts of effective parameters on analytical performance like sample pH, sample volume, type, and volume of desorption solvent were optimized. At the optimized conditions, calibration graphs of analytes were linear in the concentration range of 0.03-300 ng mL-1 for water samples, and 0.1-200 ng mL-1 for plasma samples. The correlation coefficients were in the range of 0.9938 to 0.9989. Also, the limits of detection (LODs) were from 0.01 to 0.02 ng mL-1 for water samples and 0.03 to 0.1 ng mL-1 for plasma samples. The cartridge repeatability was studied at different values, and the relative standard deviations (RSDs%) were achieved between 3.5 and 5.1%. Consequently, this procedure was successfully used in the extraction and detection of NSAIDs in real water and plasma samples with relative recoveries ranged from 93.6 to 99.6%.
    Matched MeSH terms: Solid Phase Extraction/methods*
  4. Omar MM, Wan Ibrahim WA, Elbashir AA
    Food Chem, 2014 Sep 1;158:302-9.
    PMID: 24731346 DOI: 10.1016/j.foodchem.2014.02.045
    A sol-gel hybrid sorbent, methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was successfully used as new dispersive solid phase extraction (dSPE) sorbent material in the determination of acrylamide in several Sudanese foods and analysis using GC-MS. Several important dSPE parameters were optimised. Under the optimised conditions, excellent linearity (r(2)>0.9998) was achieved using matrix matched standard calibration in the concentration range 50-1000 μg kg(-1). The limits of detection (LOD) and limit of quantification ranged from 9.1 to 12.8 μg/kg and 27.8-38.9 μg/kg, respectively. The precision (RSD%) of the method was ⩽6.6% and recoveries of acrylamide obtained were in the range of 88-103%, (n=3). The LOD obtained is comparable with the LODs of primary secondary amine dSPE. The proposed MTMOS-TEOS dSPE method is direct and safe for acrylamide analysis, showed reliable method validation performances and good cleanup effects. It was successfully applied to the analysis of acrylamide in real food samples.
    Matched MeSH terms: Solid Phase Extraction/methods*
  5. Lawal A, Wong RCS, Tan GH, Abdulra'uf LB, Alsharif AMA
    J Chromatogr Sci, 2018 Aug 01;56(7):656-669.
    PMID: 29688338 DOI: 10.1093/chromsci/bmy032
    Fruits and vegetables constitute a major type of food consumed daily apart from whole grains. Unfortunately, the residual deposits of pesticides in these products are becoming a major health concern for human consumption. Consequently, the outcome of the long-term accumulation of pesticide residues has posed many health issues to both humans and animals in the environment. However, the residues have previously been determined using conventionally known techniques, which include liquid-liquid extraction, solid-phase extraction (SPE) and the recently used liquid-phase microextraction techniques. Despite the positive technological effects of these methods, their limitations include; time-consuming, operational difficulty, use of toxic organic solvents, low selective property and expensive extraction setups, with shorter lifespan of instrumental performances. Thus, the potential and maximum use of these methods for pesticides residue determination has resulted in the urgent need for better techniques that will overcome the highlighted drawbacks. Alternatively, attention has been drawn recently towards the use of quick, easy, cheap, effective, rugged and safe technique (QuEChERS) coupled with dispersive solid-phase extraction (dSPE) to overcome the setback challenges experienced by the previous technologies. Conclusively, the reviewed QuEChERS-dSPE techniques and the recent cleanup modifications justifiably prove to be reliable for routine determination and monitoring the concentration levels of pesticide residues using advanced instruments such as high-performance liquid chromatography, liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry.
    Matched MeSH terms: Solid Phase Extraction/methods*
  6. Diong SH, Mohd Yusoff NS, Sim MS, Raja Aziddin RE, Chik Z, Rajan P, et al.
    J Anal Toxicol, 2014 Nov-Dec;38(9):660-6.
    PMID: 25106416 DOI: 10.1093/jat/bku096
    Gas chromatography-mass spectrometry quantitative method was developed to monitor concentrations of methadone and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in plasma and urine of patients. The developed method was simple, accurate and reproducible to quantify methadone and EDDP in plasma and urine samples in the concentration range of 15-1,000 and 50-2,000 ng/mL, respectively. The proposed analytical method was applied to plasma and urine samples obtained from 96 patients undergoing methadone maintenance treatment (MMT) with daily methadone doses of 2-120 mg/day. Urinary methadone excretion was observed to be significantly affected by pH, in which the ratio of methadone to EDDP was two times higher in acidic urine (P = 0.029). The findings of this study further enhance the guidelines for monitoring of methadone treatment among outpatients. Methadone-to-EDDP ratio in urine was found to be consistent at 24 and 4 h, hence suggesting the possibility that outpatients may be monitored with single urine sample in order to check for compliance. This study which provides data on peak concentrations of methadone and EDDP as well as the ratio of both compounds has added to the body of knowledge regarding pharmacokinetic properties of methadone among heroin-dependent patients under MMT.
    Study site: University Malaya Medical Centre (UMMC), HKL, University Malaya Centre for Addiction Sciences (UMCAS) and Rehabilitation Centre of Al-Rahman Mosque, Kuala Lumpur, Malaysia
    Matched MeSH terms: Solid Phase Extraction/methods
  7. Azlan NSM, Wee SY, Ismail NAH, Nasir HM, Aris AZ
    Environ Toxicol Chem, 2020 10;39(10):1908-1917.
    PMID: 32621623 DOI: 10.1002/etc.4813
    The organophosphorus pesticides (OPPs) commonly used in agricultural practices can pose a risk of potential exposure to humans via food consumption. We describe an analytical method for solid-phase extraction coupled with high-performance liquid chromatography-diode array detector (SPE-HPLC-DAD) for the detection of OPPs (quinalphos, diazinon, and chlorpyrifos) in rice grains. The isolation of targeted residues was initiated with double extraction before SPE-HPLC-DAD, crucially reducing matrix interferences and detecting a wide range of multiple residues in rice grains. Coefficients of 0.9968 to 0.9991 showed a strong linearity, with limits of detection and quantification ranging from 0.36 to 0.68 µg/kg and from 1.20 to 2.28 µg/kg, respectively. High recoveries (80.4-110.3%) were observed at 3 spiking levels (50, 100, and 200 µg/kg), indicating good accuracy. The relative standard deviations of all residues (0.19-8.66%) validated the method precision. Sample analysis of 10 rice grain types (n = 30) available in the Asian market revealed that quinalphos, diazinon, and chlorpyrifos at concentrations of 1.08, 1.11, and 1.79 µg/kg, respectively, remained far below the maximum residue limits (0.01-0.5 mg/kg). However, regular monitoring is necessary to confirm that multiresidue occurrence remains below permissible limits while controlling pests. Environ Toxicol Chem 2020;39:1908-1917. © 2020 SETAC.
    Matched MeSH terms: Solid Phase Extraction/methods
  8. Chai M, Tan G, Lal A
    Anal Sci, 2008 Feb;24(2):273-6.
    PMID: 18270422
    A headspace solid-phase microextraction method has been developed for the determination of 8 pesticides in vegetables and fruits by using gas chromatography with an electron capture detector. Two types of fibers (polyacrylate, 85 microm and polydimethylsiloxane, 100 microm) have been assayed and compared. The main factors: extraction and desorption parameters, ionic strength, and the effects of dilution and organic solvents, were studied and optimized. The optimized procedures resulted in more than 80% recovery for all the investigated vegetable and fruit samples with RSD values below 10%.
    Matched MeSH terms: Solid Phase Extraction/methods*
  9. Venkatesh G, Majid MI, Ramanathan S, Mansor SM, Nair NK, Croft SL, et al.
    Biomed Chromatogr, 2008 May;22(5):535-41.
    PMID: 18205140 DOI: 10.1002/bmc.965
    A simple, sensitive and specific reversed-phase high-performance liquid chromatographic method with UV detection at 251 nm was developed for quantitation of buparvaquone (BPQ) in human and rabbit plasma. The method utilizes 250 microL of plasma and sample preparation involves protein precipitation followed by solid-phase extraction. The method was validated on a C18 column with mobile phase consisting of ammonium acetate buffer (0.02 m, pH 3.0) and acetonitrile in the ratio of 18:82 (v/v) at a flow rate of 1.1 mL/min. The calibration curves were linear (correlation coefficient>or=0.998) in the selected range. The method is specific and sensitive with limit of quantitation of 50 ng/mL for BPQ. The validated method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions and BPQ was found to be stable. Partial validation studies were carried out using rabbit plasma and intra- and inter-day precision and accuracy were within 7%. This method is simple, reliable and can be routinely used for preclinical pharmacokinetic studies for BPQ.
    Matched MeSH terms: Solid Phase Extraction/methods*
  10. Wan Ibrahim WA, Hermawan D, Sanagi MM
    J Chromatogr A, 2007 Nov 2;1170(1-2):107-13.
    PMID: 17915239
    A method for the chiral separation of propiconazole using cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) with hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) as chiral selector is reported. The use of a mixture of 30 mM HP-gamma-CD, 50mM SDS, methanol-acetonitrile 10%:5% (v/v) in 25 mM phosphate buffer solution was able to separate two enantiomeric pairs of propiconazole. Stacking- and sweeping-CD-MEKC under neutral pH (pH 7) and under acidic condition (pH 3.0) were used as two on-line preconcentration methods to increase detection sensitivity of propiconazole. Good repeatabilities in the migration time, peak area and peak height were obtained in terms of relative standard deviation (RSD). A sensitivity enhancement factor of 100-fold was achieved using sweeping-CD-MEKC at acidic pH. This is the first report on the separation of two pairs of propiconazole enantiomers and all the enantiomers of fenbuconazole and tebuconazole using sweeping-CD-MEKC. The limit of detection (S/N=3) for the three triazole fungicides ranged from 0.09 to 0.1 microg/mL, which is well below the maximum residue limits (MRL) set by Codex Alimentarius Commission (CAC). Combination of solid-phase extraction (SPE) pretreatment and sweeping-CD-MEKC procedure was applied to the determination of selected triazole fungicides in grapes samples spiked at concentration 10-40 times lower than the MRL established by the CAC. The average recoveries of the selected fungicides in spiked grapes samples were good, ranging from 73% to 109% with RSD of 9-12% (n=3).
    Matched MeSH terms: Solid Phase Extraction/methods
  11. Zainuddin AH, Wee SY, Aris AZ
    Environ Geochem Health, 2020 Nov;42(11):3703-3715.
    PMID: 32488800 DOI: 10.1007/s10653-020-00604-4
    The application of organophosphorus pesticides (OPPs) increased gradually because of the rise in global food demand that triggered the agriculture sector to increase the production, leading to OPP residues in the surface water. This study elucidated the presence of OPPs and estimated its ecological risk in the riverine ecosystem of the urbanised Linggi River, Negeri Sembilan, Malaysia. The OPP concentration in surface water was determined using solid-phase extraction method and high-performance liquid chromatography coupled with diode array detection. Further, the ecological risk was estimated by using the risk quotient (RQ) method. The three OPPs, i.e. chlorpyrifos, diazinon, and quinalphos were detected with mean concentrations of 0.0275 µg/L, 0.0328 µg/L, and 0.0362 µg/L, respectively. The OPPs were at high risk (in general and worst cases) under acute exposure. The estimated risk of diazinon was observed as medium for general (RQm = 0.5857) and high for worst cases (RQex = 4.4678). Notably, the estimated risk for chlorpyrifos was high for both general and worst cases (RQm = 1.9643 and RQex = 11.5643) towards the aquatic ecosystem of the Linggi River. Chronic risk of quinalphos remains unknown because of the absence of toxicity endpoints. This study presented clear knowledge regarding OPP contamination and possible risk for aquatic ecosystems. Hence, OPPs should be listed as one of the main priority contaminants in pesticide mitigation management in the future.
    Matched MeSH terms: Solid Phase Extraction/methods
  12. 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: Solid Phase Extraction/methods*
  13. Rozi SKM, Nodeh HR, Kamboh MA, Manan NSA, Mohamad S
    J Oleo Sci, 2017 Jul 01;66(7):771-784.
    PMID: 28626137 DOI: 10.5650/jos.ess17016
    A novel adsorbent, palm fatty acid coated magnetic Fe3O4 nanoparticles (MNP-FA) was successfully synthesized with immobilization of the palm fatty acid onto the surface of MNPs. The successful synthesis of MNP-FA was further confirmed by X-Ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and Energy dispersive X-Ray spectroscopy (EDX) analyses and water contact angle (WCA) measurement. This newly synthesized MNP-FA was applied as magnetic solid phase extraction (MSPE) adsorbent for the enrichment of polycyclic aromatic hydrocarbons (PAHs), namely fluoranthene (FLT), pyrene (Pyr), chrysene (Cry) and benzo(a)pyrene (BaP) from environmental samples prior to High Performance Liquid Chromatography- Diode Array Detector (HPLC-DAD) analysis. The MSPE method was optimized by several parameters such as amount of sorbent, desorption solvent, volume of desorption solvent, extraction time, desorption time, pH and sample volume. Under the optimized conditions, MSPE method provided a low detection limit (LOD) for FLT, Pyr, Cry and BaP in the range of 0.01-0.05 ng mL(-1). The PAHs recoveries of the spiked leachate samples ranged from 98.5% to 113.8% with the RSDs (n = 5) ranging from 3.5% to 12.2%, while for the spiked sludge samples, the recoveries ranged from 81.1% to 119.3% with the RSDs (n = 5) ranging from 3.1% to 13.6%. The recyclability study revealed that MNP-FA has excellent reusability up to five times. Chromatrographic analysis demonstrated the suitability of MNP-FA as MSPE adsorbent for the efficient extraction of PAHs from environmental samples.
    Matched MeSH terms: Solid Phase Extraction/methods*
  14. Marsin FM, Wan Ibrahim WA, Nodeh HR, Sanagi MM
    J Chromatogr A, 2020 Feb 08;1612:460638.
    PMID: 31676087 DOI: 10.1016/j.chroma.2019.460638
    Magnetic solid phase extraction (MSPE) employing oil-palm fiber activated carbon (OPAC) modified with magnetite (Fe3O4) and polypyrrole (OPAC-Fe3O4-PPy) was successfully used for the determination of two organochlorine pesticides (OCPs), namely endosulfan and dieldrin in environmental water samples. Analysis was performed using gas chromatography with micro-electron capture detection (GC-μECD). The effects of three preparation variables, namely Fe3O4:OPAC ratio, amount of pyrrole monomer, and amount of FeCl3 oxidant were optimized using Box-Behnken design (BBD) (R2 < 0.99, p-value < 0.001%). The optimum conditions were as follows: Fe3O4:OPAC ratio of 2:1 w/w, 1 g of FeCl3 and 100 μL of pyrrole monomer. The experimental results obtained agreed satisfactorily with the model prediction (> 90% agreement). Optimized OPAC-Fe3O4-PPy composite was characterized using field emission scanning electron microscope, vibrating sample magnetometer and Fourier transform infrared spectroscopy. Four numerical parameters of MSPE procedure was optimized using BBD. The significance of the MSPE parameters were salt addition > sample solution pH > extraction time and desorption time. Under the optimized conditions (extraction time: 90 s, desorption time: 10 min, salt: 0%, and pH: 5.8), the method demonstrated good linearity (25-1000 ng L-1) with coefficients of determination, R2 > 0.991, and low detection limits for both endosulfan (7.3 ng L-1) and dieldrin (8.6 ng L-1). The method showed high analyte recoveries in the range of 98.6-103.5% for environmental water samples. The proposed OPAC-Fe3O4-PPy MSPE method offered good features such as sustainability, simplicity, and rapid extraction.
    Matched MeSH terms: Solid Phase Extraction/methods*
  15. Rashidi Nodeh H, Wan Ibrahim WA, Kamboh MA, Sanagi MM
    Chemosphere, 2017 Jan;166:21-30.
    PMID: 27681257 DOI: 10.1016/j.chemosphere.2016.09.054
    A new graphene-based tetraethoxysilane-methyltrimethoxysilane sol-gel hybrid magnetic nanocomposite (Fe3O4@G-TEOS-MTMOS) was synthesised, characterized and successfully applied in magnetic solid-phase extraction (MSPE) for simultaneous analysis of polar and non-polar organophosphorus pesticides from several water samples. The Fe3O4@G-TEOS-MTMOS nanocomposite was characterized using Fourier transform-infrared spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy and X-ray diffraction. Separation, determination and quantification were achieved using gas chromatography coupled with micro electron capture detector. Adsorption capacity of the sorbent was calculated using Langmuir equation. MSPE was linear in the range 100-1000 pg mL(-1) for phosphamidon and dimethoate, and 10-100 pg mL(-1) for chlorpyrifos and diazinon, with limit of detection (S/N = 3) of 19.8, 23.7, 1.4 and 2.9 pg mL(-1) for phosphamidon, dimethoate, diazinon and chlorpyrifos, respectively. The LODs obtained is well below the maximum residual level (100 pg mL(-1)) as set by European Union for pesticides in drinking water. Acceptable precision (%RSD) was achieved for intra-day (1.3-8.7%, n = 3) and inter-day (7.6-17.8%, n = 15) analyses. Fe3O4@G-TEOS-MTMOS showed high adsorption capacity (54.4-76.3 mg g(-1)) for the selected OPPs. No pesticide residues were detected in the water samples analysed. Excellent extraction recoveries (83-105%) were obtained for the spiked OPPs from tap, river, lake and sea water samples. The newly synthesised Fe3O4@G-TEOS-MTMOS showed high potential as adsorbent for OPPs analysis.
    Matched MeSH terms: Solid Phase Extraction/methods*
  16. Raoov M, Mohamad S, bin Abas MR, Surikumaran H
    Talanta, 2014 Dec;130:155-63.
    PMID: 25159393 DOI: 10.1016/j.talanta.2014.06.067
    Cyclodextrin-ionic liquid polymer (βCD-BIMOTs-TDI) is a new class of macroporous material and has great potential to be used as an SPE adsorbent material for extraction of phenols in river water samples. Six phenols, as model analytes, were extracted on a βCD-BIMOTs-TDI SPE cartridge, and then, eluted with 2 mL of methanol containing 1% acetic acid. The optimum experimental condition was 15 mL of sample volume (sample at pH 6) and 2 mL of methanol containing 1% acetic acid as an eluent solvent. The eluent concentration was determined by using Gas Chromatography-Flame Ionization Detector (GC-FID). Under optimized condition, high sensitivity (detection limits 0.23-0.35 µg/L) and good recoveries (87-116%) were achieved with satisfactory relative standard deviation (RSD) (0.1-1.7%). The developed βCD-BIMOTs-TDI-SPE was then compared with other adsorbents, and the obtained results showed that the βCD-BIMOTs-TDI exhibited higher extraction recovery due to the unique structure and properties. Finally, the βCD-BIMOTs-TDI was applied as a solid phase extraction sorbent for phenols determination under optimized condition, in river and tap waters, prior to the GC-FID separation.
    Matched MeSH terms: Solid Phase Extraction/methods*
  17. Lal A, Tan G, Chai M
    Anal Sci, 2008 Feb;24(2):231-6.
    PMID: 18270414
    A new extraction and cleanup procedure with gas chromatography was developed for the sensitive determination of acephate, dimethoate, malathion, diazinon, quinalphos, chlorpyrifos, profenofos, alpha-endosulfan, beta-endosulfan, chlorothalonil and carbaryl using 1-chloro-4-fluorobenzene as an internal standard in fruits and vegetables. Several extracting and eluting solvents for solid-phase extraction were investigated. The overall extracting solvent with a mixture of acetone:ethyl acetate:hexane (10:80:10, v/v/v) and a eluting solvent of 5% acetone in hexane used with the RPC18 cartridge gave the best recovery for all of the investigated pesticides, and minimized the interference from co-extractants. Under the optimal extraction and clean-up conditions, recoveries of 85 - 99% with RSD < 5.0% (n = 3) for most of the pesticides at the 0.02 - 0.5 mg/kg level were obtained. The limit of detection was between 0.005 - 0.01 mg/kg and the limit of quantification was 0.01 mg/kg. This analytical procedure was characterized with high accuracy and acceptable sensitivity to meet requirements for monitoring pesticides in crops.
    Matched MeSH terms: Solid Phase Extraction/methods*
  18. Al-Qaim FF, Abdullah MP, Othman MR, Latip J, Zakaria Z
    J Chromatogr A, 2014 Jun 6;1345:139-53.
    PMID: 24768127 DOI: 10.1016/j.chroma.2014.04.025
    An analytical method that facilitated the analysis of 11 pharmaceuticals residue (caffeine, prazosin, enalapril, carbamazepine, nifedipine, levonorgestrel, simvastatin, hydrochlorothiazide, gliclazide, diclofenac-Na, and mefenamic acid) with a single pre-treatment protocol was developed. The proposed method included an isolation and concentration procedure using solid phase extraction (Oasis HLB), a separation step using high-performance liquid chromatography, and a detection procedure that applies time-of-flight mass spectrometry. The method was validated for drinking water (DW), surface water (SW), sewage treatment plant (STP) influent and effluent, and hospital (HSP) influent and effluent. The limits of quantification were as low as 0.4, 1.6, 5, 3, 2.2 and 11 ng/L in DW, SW, HSP influent and effluent, STP effluent, and STP influent, respectively. On average, good recoveries higher than 75% were obtained for most of the target analytes in all matrices. Matrix effect was evaluated for all samples matrices. The proposed method successfully determined and quantified the target compounds in raw and treated wastewater of four STPs and three hospitals in Malaysia, as well as in two SW sites. The results showed that a number of the studied compounds pose moderate to high persistency in sewage treatment effluents as well as in the recipient rivers, namely; caffeine, simvastatin, and hydrochlorothiazide. Ten out of 11 compounds were detected and quantified in 13 sampling points. Caffeine was detected with the highest level, with concentrations reaching up to 9099 ng/L in STP influent.
    Matched MeSH terms: Solid Phase Extraction/methods
  19. Al-Odaini NA, Zakaria MP, Yaziz MI, Surif S
    J Chromatogr A, 2010 Oct 29;1217(44):6791-806.
    PMID: 20851398 DOI: 10.1016/j.chroma.2010.08.033
    Pollutants such as human pharmaceuticals and synthetic hormones that are not covered by environmental legislation have increasingly become important emerging aquatic contaminants. This paper reports the development of a sensitive and selective multi-residue method for simultaneous determination and quantification of 23 pharmaceuticals and synthetic hormones from different therapeutic classes in water samples. Target pharmaceuticals include anti-diabetic, antihypertensive, hypolipidemic agents, β2-adrenergic receptor agonist, antihistamine, analgesic and sex hormones. The developed method is based on solid phase extraction (SPE) followed by instrumental analysis using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) with 30 min total run time. River water samples (150 mL) and (sewage treatment plant) STP effluents (100 mL) adjusted to pH 2, were loaded into MCX (3 cm(3), 60 mg) cartridge and eluted with four different reagents for maximum recovery. Quantification was achieved by using eight isotopically labeled internal standards (I.S.) that effectively correct for losses during sample preparation and matrix effects during LC-ESI-MS/MS analysis. Good recoveries higher than 70% were obtained for most of target analytes in all matrices. Method detection limit (MDL) ranged from 0.2 to 281 ng/L. The developed method was applied to determine the levels of target analytes in various samples, including river water and STP effluents. Among the tested emerging pollutants, chlorothiazide was found at the highest level, with concentrations reaching up to 865 ng/L in STP effluent, and 182 ng/L in river water.
    Matched MeSH terms: Solid Phase Extraction/methods*
  20. Markus A, Gbadamosi AO, Yusuff AS, Agi A, Oseh J
    Environ Sci Pollut Res Int, 2018 Dec;25(35):35130-35142.
    PMID: 30328041 DOI: 10.1007/s11356-018-3402-3
    In this study, a new magnetic adsorbent based on magnetite-sporopollenin/graphene oxide (Fe3O4-SP/GO) was successfully developed. The adsorbent was applied for magnetic solid phase extraction (MSPE) of three selected polar organophosphorus pesticides (OPPs), namely, dimethoate, phenthoate, and phosphamidon, prior to gas chromatography analysis with electron capture detection (GC-μECD). The Fe3O4-SP/GO adsorbent combines the advantages of superior adsorption capability of the modified sporopollenin (SP) with graphene oxide (GO) and magnetite (Fe3O4) for easy isolation from sample solution. Several MSPE parameters were optimized. Under optimized conditions, excellent linearity (R2 ≥ 0.9994) was achieved using matrix match calibration in the range of 0.1 to 500 ng mL-1. The limit of detection (LOD) method (S/N = 3) was from 0.02 to 0.05 ng mL-1. The developed Fe3O4-SP/GO MSPE method was successfully applied for the determination of these three polar OPPs in cucumber, long beans, bell pepper, and tomato samples. Good recoveries (81.0-120.0%) and good relative standard deviation (RSD) (1.4-7.8%, n = 3) were obtained for the spiked OPPs (1 ng mL-1) from real samples. This study is beneficial for adsorptive removal of toxic pesticide compounds from vegetable samples.
    Matched MeSH terms: Solid Phase Extraction/methods
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