Displaying publications 1 - 20 of 34 in total

  1. Abu-Bakar NB, Makahleh A, Saad B
    J Sep Sci, 2016 Mar;39(5):947-55.
    PMID: 26718308 DOI: 10.1002/jssc.201501109
    A novel microextraction method based on vortex- and CO2 -assisted liquid-liquid microextraction with salt addition for the isolation of furanic compounds (5-hydroxymethyl-2-furaldehyde, 5-methyl-2-furaldehyde, 2-furaldehyde, 3-furaldehyde, 2-furoic and 3-furoic acids) was developed. Purging the sample with CO2 was applied after vortexing to enhance the phase separation and mass transfer of the analytes. The optimum extraction conditions were: extraction solvent (volume), propyl acetate (125 μL); sample pH, 2.4; vortexing time, 45 s; salt concentration, 25% w/v and purging time, 5 min. The analytes were separated using an ODS Hypersil C18 column (250×4.6 mm i.d, 5 μm) under gradient flow. The proposed method showed good linearities (r(2) >0.999), low detection limits (0.08-1.9 μg/L) and good recoveries (80.7-122%). The validated method was successfully applied for the determination of the furanic compounds in concentrated juice (mango, date, orange, pomegranate, roselle, mangosteen and soursop) and dried fruit (prune, date and apricot paste) samples.
  2. Sanagi MM, Muhammad SS, Hussain I, Ibrahim WA, Ali I
    J Sep Sci, 2015 Feb;38(3):433-8.
    PMID: 25421899 DOI: 10.1002/jssc.201400912
    Novel, fast, selective, eco-friendly and reproducible solid-phase membrane tip extraction and gas chromatography with mass spectrometry methods were developed and validated for the analysis of triazine herbicides (atrazine and secbumeton) in stream and lake waters. The retention times of atrazine and secbumeton were 7.48 and 8.51 min. The solid-phase membrane tip extraction was carried out in semiautomated dynamic mode on multiwall carbon nanotubes enclosed in a cone-shaped polypropylene membrane cartridge. Acetone and methanol were found as the best preconditioning and desorption solvents, respectively. The extraction and desorption times for these herbicides were 15.0 and 10.0 min, respectively. The percentage recoveries of atrazine and secbumeton were 88.0 and 99.0%. The linearity range was 0.50-80.0 μg/L (r(2) > 0.994), with detection limits (<0.47 μg/L, S/N = 3) and good reproducibility (<8.0%). The ease of operation, eco-friendly nature, and low cost of solid-phase membrane tip extraction made these methods novel. The Solid-phase membrane tip extraction method was optimized by considering the effect of extraction time, desorbing solvents and time.
  3. Reddy AV, Jaafar J, Umar K, Majid ZA, Aris AB, Talib J, et al.
    J Sep Sci, 2015 Mar;38(5):764-79.
    PMID: 25556762 DOI: 10.1002/jssc.201401143
    Potential genotoxic impurities in pharmaceuticals at trace levels are of increasing concern to both pharmaceutical industries and regulatory agencies due to their possibility for human carcinogenesis. Molecular functional groups that render starting materials and synthetic intermediates as reactive building blocks for small molecules may also be responsible for their genotoxicity. Determination of these genotoxic impurities at trace levels requires highly sensitive and selective analytical methodologies, which poses tremendous challenges on analytical communities in pharmaceutical research and development. Experimental guidance for the analytical determination of some important classes of genotoxic impurities is still unavailable in the literature. Therefore, the present review explores the structural alerts of commonly encountered potential genotoxic impurities, draft guidance of various regulatory authorities in order to control the level of impurities in drug substances and to assess their toxicity. This review also describes the analytical considerations for the determination of potential genotoxic impurities at trace levels and finally few case studies are also discussed for the determination of some important classes of potential genotoxic impurities. It is the authors' intention to provide a complete strategy that helps analytical scientists for the analysis of such potential genotoxic impurities in pharmaceuticals.
  4. Waseem R, Low KH
    J Sep Sci, 2015 Feb;38(3):483-501.
    PMID: 25403494 DOI: 10.1002/jssc.201400724
    In recent years, essential oils have received a growing interest because of the positive health effects of their novel characteristics such as antibacterial, antifungal, and antioxidant activities. For the extraction of plant-derived essential oils, there is the need of advanced analytical techniques and innovative methodologies. An exhaustive study of hydrodistillation, supercritical fluid extraction, ultrasound- and microwave-assisted extraction, solid-phase microextraction, pressurized liquid extraction, pressurized hot water extraction, liquid-liquid extraction, liquid-phase microextraction, matrix solid-phase dispersion, and gas chromatography (one- and two-dimensional) hyphenated with mass spectrometry for the extraction through various plant species and analysis of essential oils has been provided in this review. Essential oils are composed of mainly terpenes and terpenoids with low-molecular-weight aromatic and aliphatic constituents that are particularly important for public health.
  5. Ongkudon CM, Kansil T, Wong C
    J Sep Sci, 2014 Mar;37(5):455-64.
    PMID: 24376196 DOI: 10.1002/jssc.201300995
    To date, the number of published reports on the large-volume preparation of polymer-based monolithic chromatography adsorbents is still lacking and is of great importance. Many critical factors need to be considered when manufacturing a large-volume polymer-based monolith for chromatographic applications. Structural integrity, validity, and repeatability are thought to be the key factors determining the usability of a large-volume monolith in a separation process. In this review, we focus on problems and solutions pertaining to heat dissipation, pore size distribution, "wall channel" effect, and mechanical strength in monolith preparation. A template-based method comprising sacrificial and nonsacrificial techniques is possibly the method of choice due to its precise control over the porous structure. However, additional expensive steps are usually required for the template removal. Other strategies in monolith preparation are also discussed.
  6. Sanagi MM, Miskam M, Wan Ibrahim WA, Hermawan D, Aboul-Enein HY
    J Sep Sci, 2010 Jul;33(14):2131-9.
    PMID: 20549667 DOI: 10.1002/jssc.201000172
    A three-phase hollow fiber liquid-phase microextraction method coupled with CE was developed and used for the determination of partition coefficients and analysis of selected nitrophenols in water samples. The selected nitrophenols were extracted from 14 mL of aqueous solution (donor solution) with the pH adjusted to pH 3 into an organic phase (1-octanol) immobilized in the pores of the hollow fiber and finally backextracted into 40.0 microL of the acceptor phase (NaOH) at pH 12.0 located inside the lumen of the hollow fiber. The extractions were carried out under the following optimum conditions: donor solution, 0.05 M H(3)PO(4), pH 3.0; organic solvent, 1-octanol; acceptor solution, 40 microL of 0.1 M NaOH, pH 12.0; agitation rate, 1050 rpm; extraction time, 15 min. Under optimized conditions, the calibration curves for the analytes were linear in the range of 0.05-0.30 mg/L with r(2)>0.9900 and LODs were in the range of 0.01-0.04 mg/L with RSDs of 1.25-2.32%. Excellent enrichment factors of up to 398-folds were obtained. It was found that the partition coefficient (K(a/d)) values were high for 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol and 2,6-dinitrophenol and that the individual partition coefficients (K(org/d) and K(a/org)) promoted efficient simultaneous extraction from the donor through the organic phase and further into the acceptor phase. The developed method was successfully applied for the analysis of water samples.
  7. Surugau N, Urban PL
    J Sep Sci, 2009 Jun;32(11):1889-906.
    PMID: 19479769 DOI: 10.1002/jssc.200900071
    This article reviews progress in the application of electrophoretic techniques for the separation of nanoparticles. Numerous types of nanoparticles have recently been synthesised and integrated into different products and procedures. Consequently, analytical methods for the efficient characterisation of nanoparticles are now required. Several studies have revealed that gel electrophoresis can readily be used for separating nanoparticles according to their size or shape. However, many other studies focused on separation of nanoparticles by CE. In some cases nanoparticles could be separated by CZE, simply using pure buffer as the BGE. In other studies, buffer additives (most often SDS) were used, enabling fast separations of metallic nanoparticles by size. Other CE methods also allowed for separation of nanoparticle conjugates with biomolecules. Dielectrophoresis is yet another electrophoretic technique useful in separation and characterisation of nanoparticles; particularly nanotubes. Detection methods often used after electrophoretic separation include UV/Vis absorption and fluorescence spectroscopy. Examples of recent and relevant older reports are presented here. The authors conclude that electrophoretic methods for nanoanalysis can provide inexpensive and efficient tools for quality assurance and safety control; and as a consequence, they can augment transfer of nanotechnologies from research to industry.
  8. 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.
  9. Wan Ibrahim WA, Hermawan D, Sanagi MM, Aboul-Enein HY
    J Sep Sci, 2009 Feb;32(3):466-71.
    PMID: 19142910 DOI: 10.1002/jssc.200800512
    A CD-modified micellar EKC (CD-MEKC) method with 2-hydroxypropyl-gamma-CD (HP-gamma-CD) as chiral selector for the enantioseparation of three chiral triazole fungicides, namely hexaconazole, penconazole, and myclobutanil, is reported for the first time. Simultaneous enantioseparation of the three triazole fungicides was successfully achieved using a CD-MEKC system containing 40 mM HP-gamma-CD and 50 mM SDS in 25 mM phosphate buffer (pH 3.0) solution with resolutions (R(s)) greater than 1.60, peak efficiencies (N) greater than 200,000 for all enantiomers and an analysis time within 15 min compared to 36 min as previously reported using sulfated-beta-CD.
  10. Ong AL, Kamaruddin AH, Bhatia S, Aboul-Enein HY
    J Sep Sci, 2008 Jul;31(13):2476-85.
    PMID: 18646277 DOI: 10.1002/jssc.200800086
    An enzymatic membrane reactor (EMR) for enantioseparation of (R,S)-ketoprofen via Candida antarctica lipase B (CALB) as biocatalyst was investigated. A comparative study of free and immobilized CALB was further conducted. The catalytic behaviour of CALB in an EMR was affected by the process parameters of enzyme load, substrate concentration, substrate molar ratio, lipase solution pH, reaction temperature, and substrate flow rate. Immobilization of CALB in the EMR was able to reduce the amount of enzyme required for the enantioseparation of (R,S)-ketoprofen. Immobilized CALB in the EMR assured higher reaction capacity, better thermal stability, and reusability. It was also found to be more cost effective and practical than free CALB in a batch reactor.
  11. Jaafar J, Irwan Z, Ahamad R, Terabe S, Ikegami T, Tanaka N
    J Sep Sci, 2007 Feb;30(3):391-8.
    PMID: 17396598
    An online preconcentration technique by dynamic pH junction was studied to improve the detection limit for anionic arsenic compounds by CE. The main target compound is roxarsone, or 3-nitro-4-hydroxyphenylarsonic acid, which is being used as an animal feed additive. The other inorganic and organoarsenic compounds studied are the possible biotransformation products of roxarsone. The arsenic species were separated by a dynamic pH junction in a fused-silica capillary using 15 mM phosphate buffer (pH 10.6) as the BGE and 15 mM acetic acid as the sample matrix. CE with UV detection was monitored at a wavelength of 192 nm. The influence of buffer pH and concentration on dynamic pH junction were investigated. The arsenic species focusing resulted in LOD improvement by a factor of 100-800. The combined use of C18 and anion exchange SPE and dynamic pH junction to CE analysis of chicken litter and soils helps to increase the detection sensitivity. Recoveries of spiked samples ranged between 70 and 72%.
  12. Abdulra'uf LB, Sirhan AY, Huat Tan G
    J Sep Sci, 2012 Dec;35(24):3540-53.
    PMID: 23225719 DOI: 10.1002/jssc.201200427
    The sample preparation step has been identified as the bottleneck of analytical methodology in chemical analysis. Therefore, there is need for the development of cost-effective, easy to operate, and environmentally friendly miniaturized sample preparation technique. The microextraction techniques combine extraction, isolation, concentration, and introduction of analytes into analytical instrument, to a single and uninterrupted step, and improve sample throughput. The use of liquid-phase microextraction techniques for the analysis of pesticide residues in fruits and vegetables are discussed with the focus on the methodologies employed by different researchers and their analytical performances. Analytes are extracted using water-immiscible solvents and are desorbed into gas chromatography, liquid chromatography, or capillary electrophoresis for identification and quantitation.
  13. Leong YK, Lan JC, Loh HS, Ling TC, Ooi CW, Show PL
    J Sep Sci, 2016 Feb;39(4):640-7.
    PMID: 26447739 DOI: 10.1002/jssc.201500667
    Having the benefits of being environmentally friendly, providing a mild environment for bioseparation, and scalability, aqueous two-phase systems (ATPSs) have increasingly caught the attention of industry and researchers for their application in the isolation and recovery of bioproducts. The limitations of conventional ATPSs give rise to the development of temperature-induced ATPSs that have distinctive thermoseparating properties and easy recyclability. This review starts with a brief introduction to thermoseparating ATPSs, including its history, unique characteristics and advantages, and lastly, key factors that influence partitioning. The underlying mechanism of temperature-induced ATPSs is covered together with a summary of recent applications. Thermoseparating ATPSs have been proven as a solution to the demand for economically favorable and environmentally friendly industrial-scale bioextraction and purification techniques.
  14. 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.
  15. Sanagi MM, Loh SH, Wan Ibrahim WN, Pourmand N, Salisu A, Wan Ibrahim WA, et al.
    J Sep Sci, 2016 Mar;39(6):1152-9.
    PMID: 27027592 DOI: 10.1002/jssc.201501207
    Recently, there has been considerable interest in the use of miniaturized sample preparation techniques before the chromatographic monitoring of the analytes in unknown complex compositions. The use of biopolymer-based sorbents in solid-phase microextraction techniques has achieved a good reputation. A great variety of polysaccharides can be extracted from marine plants or microorganisms. Seaweeds are the major sources of polysaccharides such as alginate, agar, agarose, as well as carrageenans. Agarose and alginate (green biopolymers) have been manipulated for different microextraction approaches. The present review is focused on the classification of biopolymer and their applications in multidisciplinary research. Besides, efforts have been made to discuss the state-of-the-art of the new microextraction techniques that utilize commercial biopolymer interfaces such as agarose in liquid-phase microextraction and solid-phase microextraction.
  16. Soutoudehnia Korrani Z, Wan Ibrahim WA, Rashidi Nodeh H, Aboul-Enein HY, Sanagi MM
    J Sep Sci, 2016 Mar;39(6):1144-51.
    PMID: 26768840 DOI: 10.1002/jssc.201500896
    A new mesoporous silica based on the sol-gel material cyanopropyltriethoxysilane (CNPrTEOS) was successfully synthesized by the hydrolysis and condensation of CNPrTEOS in the presence of ammonium solution as catalyst and methanol as solvent. It was used as a solid-phase extraction sorbent for the simultaneous extraction of three organophosphorus pesticides, namely, polar dicrotophos and non-polar diazinon and chlorpyrifos. Analysis was performed using high-performance liquid chromatography with UV detection. CNPrTEOS was characterized by FTIR spectroscopy, field-emission scanning electron microscopy and nitrogen gas adsorption. The surface area and average pore diameter of the optimum sol-gel CNPrTEOS are 379 m(2) /g and 4.7 nm (mesoporous), respectively. The proposed solid-phase extraction based on CNPrTEOS exhibited good linearity in the range of 0.8-100 μg/L, satisfactory precision (1.15-3.82%), high enrichment factor (800) and low limit of detection (0.072-0.091 μg/L). The limits of detection obtained using the proposed solid-phase extraction method are well below the maximum residue limit set by European Union and are also lower (13.6-48.5×) than that obtained by using a commercial CN-SPE cartridge (0.98-4.41 μg/L). The new mesoporous sol-gel CNPrTEOS showed promising alternative as SPE sorbent material for the simultaneous extraction of polar and non-polar organophosphorus pesticides.
  17. Reddy AV, Jaafar J, Aris AB, Majid ZA, Umar K, Talib J, et al.
    J Sep Sci, 2015 Aug;38(15):2580-7.
    PMID: 25989063 DOI: 10.1002/jssc.201500250
    A sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the simultaneous determination of darunavir, ritonavir and tenofovir in human plasma. Sample preparation involved a simple liquid-liquid extraction using 200 μL of human plasma extracted with methyl tert-butyl ether for three analytes and internal standard. The separation was accomplished on an Acquity UPLC BEH C18 (50 mm x 2.1 mm, 1.7 μm) analytical column using gradient elution of acetonitrile/methanol (80:20, v/v) and 5.0 mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4 mL/min. The linearity of the method ranged between 20.0 and 12 000 ng/mL for darunavir, 2.0 and 2280 ng/mL for ritonavir, and 14.0 and 1600 ng/mL for tenofovir using 200 μL of plasma. The method was completely validated for its selectivity, sensitivity, linearity, precision and accuracy, recovery, matrix effect, stability, and dilution integrity. The extraction recoveries were consistent and ranged between 79.91 and 90.04% for all three analytes and internal standard. The method exhibited good intra-day and inter-day precision between 1.78 and 6.27%. Finally the method was successfully applied for human pharmacokinetic study in eight healthy male volunteers after the oral administration of 600 mg darunavir along with 100 mg ritonavir and 100 mg tenofovir as boosters.
  18. Abdul Keyon AS, Miskam M, Ishak NS, Mahat NA, Mohamed Huri MA, Abdul Wahab R, et al.
    J Sep Sci, 2019 Feb;42(4):906-924.
    PMID: 30605233 DOI: 10.1002/jssc.201800859
    Depression is a common mental disorder that may lead to major mental health problems, and antidepressant drugs have been used as a treatment of choice to mitigate symptoms of major depressive disorders by ameliorating the chemical imbalances of neurotransmitters in brain. Since abusing antidepressant drugs such as selective serotonin reuptake inhibitors and tricyclic antidepressant drugs can cause severe adverse effects, continuous toxicological monitoring of the parent compounds as well as their metabolites using numerous analytical methods appears pertinent. Among them, capillary electrophoresis has been popularly utilized since the method has a lot of advantages viz. using small amounts of sample and solvents, ease of operation, and rapid analysis. This review paper brings a survey of more than 30 papers on capillary electrophoresis of antidepressant drugs published approximately from 1999 until 2018. It focuses on the reported capillary electrophoresis techniques and their applications and challenges for determining antidepressant drugs and their metabolites. It is organized according to the commonly used capillary zone electrophoresis method, followed by non-aqueous capillary electrophoresis and micellar electrokinetic chromatography, with details on breakthrough findings. Where available, information is given about the background electrolyte used, detector utilized, and sensitivity obtained.
  19. Ng MH, Din AK
    J Sep Sci, 2020 Jan;43(1):285-291.
    PMID: 31294513 DOI: 10.1002/jssc.201900342
    Tocochromanols consisting of tocopherols and tocotrienols, is collectively known as vitamin E. Similarity in their structures, physical and chemical properties rendered the tocochromanols to be subject of chromatography interest. Supercritical fluid chromatography is a highly efficient tool for the separation and analysis of tocochromanols. Separation and analysis of tocochromanols using supercritical fluid chromatography had been carried out in the past using capillary or packed columns. Each of these techniques offer their own advantages and drawbacks. Besides being used for analysis, packed column supercritical fluid chromatography found applications as a purification and content enrichment tool. Emergence of new equipment and stationary phase technologies in recent years also helped in making supercritical fluid chromatography a highly efficient tool for the separation and analysis of tocochromanols. This paper gives an insight into the use of capillary and packed columns in supercritical fluid chromatography for the separation and/or analysis of tocochromanols. The types of stationary phase used, as well as chromatographic conditions are also discussed.
  20. Ahmad Hazmi AS, Abd Maurad Z, Mohd Noor MA, Nek Mat Din NSM, Idris Z
    J Sep Sci, 2021 Apr;44(7):1471-1481.
    PMID: 33522105 DOI: 10.1002/jssc.202000929
    Ethylene glycol is a super commodity chemical and it has vital roles in various applications. Its co-production with other chemicals, such as ethylene carbonate and glycerol carbonate, has promised cheaper production cost. Its quantification presents a challenge as its contaminants, such as ethylene carbonate, produce a signal-reducing effect in flame ionized detector. The aim of this study is to evaluate external standard to quantify the composition of glycol mixture. Measurement system analysis was employed on the external standard method. Reliability of the external standard is statistically significant with low p-values, excellent capability indices, and high F-values. The external standard is found to have remarkable precision and trueness as both capability indices are mirroring each other. Furthermore, the capability analysis has a strong correlation with quality measurement. Based on capability indices, the limit of detection is recommended at S/N = 25 and the limit of quantification is recommended at S/N = 100 for a reliable measurement. A high degree of reliability is achieved coherently as almost all uncertainties of coefficients of variations are less than 5%. The established method was validated and successfully applied to glycol mixture at azeotropic distillation pilot plant.
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