Displaying publications 41 - 53 of 53 in total

Abstract:
Sort:
  1. Capillary electrophoresis with capacitively coupled contactless conductivity detection for the determination of cis/trans isomers of octadec-9-enoic acid and other long chain fatty acids
    Wong YF, Saad B, Makahleh A
    J Chromatogr A, 2013 May 17;1290:82-90.
    PMID: 23578483 DOI: 10.1016/j.chroma.2013.03.014
    A capillary electrophoresis (CE)-capacitively coupled contactless conductivity detection (C(4)D) method for the simultaneous separation of eleven underivatized fatty acids (FAs), namely, lauric, myristic, tridecanoic (internal standard), pentadecanoic, palmitic, stearic, oleic, elaidic, linoleic, linolenic and arachidic acids is described. The separation was carried out in normal polarity mode at 20 °C, 30 kV and using hydrodynamic injection (50 mbar for 1 s). The separation was achieved in a bare fused-silica capillary (70 cm × 75 μm i.d.) using a background electrolyte of methyl-β-cyclodextrin (~6 mM) and heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (~8 mM) dissolved in a mixture of Na2HPO4/KH2PO4 (5 mM, pH 7.4):ACN:MeOH:n-octanol (3:4:2.5:0.5, v/v/v/v). C(4)D parameters were set at fixed amplitude of 100 V and frequency of 1000 kHz. The developed method was validated. Calibration curves of the ten FAs were well correlated (r(2)>0.99) within the range of 5-250 μg mL(-1) for lauric acid, and 3-250 μg mL(-1) for the other FAs. The method was simple and sensitive with detection limits (S/N=3) of 0.9-1.9 μg mL(-1) and good relative standard deviations of intra- and inter-day for migration times and peak areas (≤9.7%) were achieved. The method was applied to the determination of FAs in margarine samples. The proposed method offers distinct advantages over the GC and HPLC methods, especially in terms of simplicity (without derivatization) and sensitivity.
    Matched MeSH terms: Electrophoresis, Capillary/methods*
  2. Hollow fiber liquid-phase microextraction for the determination of trace amounts of rosiglitazone (anti-diabetic drug) in biological fluids using capillary electrophoresis and high performance liquid chromatographic methods
    Al Azzam KM, Makahleah A, Saad B, Mansor SM
    J Chromatogr A, 2010 Jun 4;1217(23):3654-9.
    PMID: 20409552 DOI: 10.1016/j.chroma.2010.03.055
    A three-phase hollow fiber liquid-phase microextraction (HF-LPME) coupled either with capillary electrophoresis (CE) or high performance liquid chromatography (HPLC) with UV detection methods was successfully developed for the determination of trace levels of the anti-diabetic drug, rosiglitazone (ROSI) in biological fluids. The analyte was extracted into dihexyl ether that was immobilized in the wall pores of a porous hollow fiber from 10 mL of aqueous sample, pH 9.5 (donor phase), and was back extracted into the acceptor phase that contained 0.1M HCl located in the lumen of the hollow fiber. Parameters affecting the extraction process such as type of extraction solvent, HCl concentration, donor phase pH, extraction time, stirring speed, and salt addition were studied and optimized. Under the optimized conditions (extraction solvent, dihexyl ether; donor phase pH, 9.5; acceptor phase, 0.1M HCl; stirring speed, 600 rpm; extraction time, 30 min; without addition of salt), enrichment factor of 280 was obtained. Good linearity and correlation coefficients of the analyte was obtained over the concentration ranges of 1.0-500 and 5.0-500 ng mL(-1) for the HPLC (r(2)=0.9988) and CE (r(2)=0.9967) methods, respectively. The limits of detection (LOD) and limits of quantitation (LOQ) for the HPLC and CE methods were (0.18, 2.83) and (0.56, 5.00) ng mL(-1), respectively. The percent relative standard deviation (n=6) for the extraction and determination of three concentration levels (10, 250, 500 ng mL(-1)) of ROSI using the HPLC and CE methods were less than 10.9% and 13.2%, respectively. The developed methods are simple, rapid, sensitive and are suitable for the determination of trace amounts of ROSI in biological fluids.
    Matched MeSH terms: Electrophoresis, Capillary/methods*
  3. Structure-informed detection and quantification of peptides in food and biological fluids
    Agyei D, Pan S, Acquah C, Bekhit AEA, Danquah MK
    J Food Biochem, 2019 01;43(1):e12482.
    PMID: 31353495 DOI: 10.1111/jfbc.12482
    Peptides with biological properties, that is, bioactive peptides, are a class of biomolecules whose health-promoting properties are increasingly being exploited in food and health products. However, research on targeted techniques for the detection and quantification of these peptides is still in its infancy. Such information is needed in order to enhance the biological and chemometric characterization of peptides and their subsequent application in the functional food and pharmaceutical industries. In this review, the role of classic techniques such as electrophoretic, chromatographic, and peptide mass spectrometry in the structure-informed detection and quantitation of bioactive peptides are discussed. Prospects for the use of aptamers in the characterization of bioactive peptides are also discussed. PRACTICAL APPLICATIONS: Although bioactive peptides have huge potential applications in the functional foods and health area, there are limited techniques in enhancing throughput detection, quantification, and characterization of these peptides. This review discusses state-of-the-art techniques relevant in complementing bioactive detection and profiling irrespective of the small number of amino acid units. Insights into challenges, possible remedies and prevailing areas requiring thorough research in the extant literature for food chemists and biotechnologists are also presented.
    Matched MeSH terms: Electrophoresis, Capillary/methods
  4. Combination of Cyclodextrin and Ionic Liquid in Analytical Chemistry: Current and Future Perspectives
    Hui BY, Raoov M, Zain NNM, Mohamad S, Osman H
    Crit Rev Anal Chem, 2017 Sep 03;47(5):454-467.
    PMID: 28453309 DOI: 10.1080/10408347.2017.1320936
    The growth in driving force and popularity of cyclodextrin (CDs) and ionic liquids (ILs) as promising materials in the field of analytical chemistry has resulted in an exponentially increase of their exploitation and production in analytical chemistry field. CDs belong to the family of cyclic oligosaccharides composing of α-(1,4) linked glucopyranose subunits and possess a cage-like supramolecular structure. This structure enables chemical reactions to proceed between interacting ions, radical or molecules in the absence of covalent bonds. Conversely, ILs are an ionic fluids comprising of only cation and anion often with immeasurable vapor pressure making them as green or designer solvent. The cooperative effect between CD and IL due to their fascinating properties, have nowadays contributed their footprints for a better development in analytical chemistry nowadays. This comprehensive review serves to give an overview on some of the recent studies and provides an analytical trend for the application of CDs with the combination of ILs that possess beneficial and remarkable effects in analytical chemistry including their use in various sample preparation techniques such as solid phase extraction, magnetic solid phase extraction, cloud point extraction, microextraction, and separation techniques which includes gas chromatography, high-performance liquid chromatography, capillary electrophoresis as well as applications of electrochemical sensors as electrode modifiers with references to recent applications. This review will highlight the nature of interactions and synergic effects between CDs, ILs, and analytes. It is hoped that this review will stimulate further research in analytical chemistry.
    Matched MeSH terms: Electrophoresis, Capillary/methods
  5. Monitoring of tobramycin in human plasma via mixed matrix membrane extraction prior to capillary electrophoresis with contactless conductivity detection
    Mukhtar NH, Mamat NA, See HH
    J Pharm Biomed Anal, 2018 Sep 05;158:184-188.
    PMID: 29883881 DOI: 10.1016/j.jpba.2018.05.044
    A sample pre-treatment method based on a dynamic mixed matrix membrane tip extraction followed by capillary electrophoresis with contactless conductivity detection (CE-C4D) was evaluated for the determination of tobramycin in human plasma. The extraction tip device consisted of a cellulose triacetate membrane tip wall immobilised with 15% (w/w) of hydrophilic lipophilic balance (HLB) nanoparticles as adsorbent. The extraction was performed dynamically by withdrawing/dispensing the plasma sample through the tip device followed by desorption into 20 μL of acidified aqueous solution at pH 3 prior to the CE-C4D analysis. Under the optimum conditions, the detection limit of the method for tobramycin was 10 ng/mL, with intraday and interday repeatability RSDs of 3.5% and 4.5%, respectively. Relative recoveries in spiked human plasma were 99.6%-99.9%. The developed approach was successfully demonstrated for the quantification of tobramycin in human plasma samples.
    Matched MeSH terms: Electrophoresis, Capillary/methods
  6. Fulltext Co-inheritance of compound heterozygous Hb Constant Spring and a single -alpha(3.7) gene deletion with heterozygous deltabeta thalassaemia: a diagnostic challenge
    Azma RZ, Othman A, Azman N, Alauddin H, Ithnin A, Yusof N, et al.
    Malays J Pathol, 2012 Jun;34(1):57-62.
    PMID: 22870600
    Haemoglobin Constant Spring (Hb CS) mutation and single gene deletions are common underlying genetic abnormalities for alpha thalassaemias. Co-inheritance of deletional and non-deletional alpha (alpha) thalassaemias may result in various thalassaemia syndromes. Concomitant co-inheritance with beta (beta) and delta (delta) gene abnormalities would result in improved clinical phenotype. We report here a 33-year-old male patient who was admitted with dengue haemorrhagic fever, with a background history of Grave's disease, incidentally noted to have mild hypochromic microcytic red cell indices. Physical examination revealed no thalassaemic features or hepatosplenomegaly. His full blood picture showed hypochromic microcytic red cells with normal haemoglobin (Hb) level. Quantitation of Hb using high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) revealed raised Hb F, normal Hb A2 and Hb A levels. There was also small peak of Hb CS noted in CE. H inclusions was negative. Kleihauer test was positive with heterocellular distribution of Hb F among the red cells. DNA analysis for alpha globin gene mutations showed a single -alpha(-3.7) deletion and Hb CS mutation. These findings were suggestive of compound heterozygosity of Hb CS and a single -alpha(-3.7) deletion with a concomitant heterozygous deltabeta thalassaemia. Co-inheritance of Hb CS and a single -alpha(-3.7) deletion is expected to result at the very least in a clinical phenotype similar to that of two alpha genes deletion. However we demonstrate here a phenotypic modification of alpha thalassemia presumptively as a result of co-inheritance with deltabeta chain abnormality as suggested by the high Hb F level.
    Matched MeSH terms: Electrophoresis, Capillary/methods
  7. In-vial liquid-liquid microextraction-capillary electrophoresis method for the determination of phenolic acids in vegetable oils
    Abu Bakar NB, Makahleh A, Saad B
    Anal Chim Acta, 2012 Sep 12;742:59-66.
    PMID: 22884208 DOI: 10.1016/j.aca.2012.02.045
    An in-vial liquid-liquid microextraction method was developed for the selective extraction of the phenolic acids (caffeic, gallic, cinnamic, ferulic, chlorogenic, syringic, vanillic, benzoic, p-hydroxybenzoic, 2,4-dihydroxybenzoic, o-coumaric, m-coumaric and p-coumaric) in vegetable oil samples. The optimised extraction conditions for 20 g sample were: volume of diluent (n-hexane), 2 mL; extractant, methanol: 5 mM sodium hydroxide (60:40; v/v); volume of extractant, 300 μL (twice); vortex, 1 min; centrifugation, 5 min. Recoveries for the studied phenolic acids were 80.1-119.5%. The simultaneous determination of the phenolic acid extracts was investigated by capillary electrophoresis (CE). Separations were carried out on a bare fused-silica capillary (50 μm i.d.× 40 cm length) involving 25 mM sodium tetraborate (pH 9.15) and 5% methanol as CE background electrolyte in the normal polarity mode, voltage of 30 kV, temperature of 25°C, injection time of 4s (50 mbar) and electropherograms were recorded at 200 nm. The phenolic acids were successfully separated in less than 10 min. The validated in-vial LLME-CE method was applied to the determination of phenolic acids in vegetable oil samples (extra virgin olive oil, virgin olive oil, pure olive oil, walnut oil and grapeseed oil). The developed method shows significant advantages over the current methods as lengthy evaporation step is not required.
    Matched MeSH terms: Electrophoresis, Capillary
  8. Enantioselective analysis of primaquine and its impurity quinocide by capillary electrophoresis
    Elbashir AA, Saad B, Ali AS, Saleh MI, Aboul-Enein HY
    Biomed Chromatogr, 2009 Mar;23(3):295-301.
    PMID: 18816453 DOI: 10.1002/bmc.1113
    A capillary electrophoretic (CE) method for the baseline separation of the enantiomers of primaquine diphosphate (PQ) and quinocide (QC) (a major contaminant) in pharmaceutical formulations is proposed. Both components were separated under the following conditions: 50 mm tris phosphate buffer (pH 3.0) containing 15 mm hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) as background electrolyte; applied voltage, 16 kV; capillary temperature, 25 degrees C; detection wavelength, 254 nm; hydrostatic injection, 10 s. The separations were conducted using a 35 cm length and 50 microm i.d. uncoated fused silica capillary column. Under the optimized conditions, the components were successfully separated in about 5 min. Intraday precision of migration time and corrected peak areas when expressed as relative standard deviation ranged from 0.17 to 0.45 and 2.60 to 3.94%, respectively, while the interday precision ranged from 2.59 to 4.20 and 3.15 to 4.21%, respectively. After the validation exercise, the proposed method was applied for the determination of QC impurity in PQ formulations.
    Matched MeSH terms: Electrophoresis, Capillary
  9. HbA2 levels in normal, beta-thalassaemia and haemoglobin E carriers by capillary electrophoresis
    Hafiza A, Malisa MY, Khirotdin RD, Azlin I, Azma Z, Thong MC, et al.
    Malays J Pathol, 2012 Dec;34(2):161-4.
    PMID: 23424780
    The capillary electrophoresis (CE) is a new system that utilizes the principle of electrokinetic separation of molecules in eight electrolyte buffer-filled silica capillaries. In this study, we established the normal ranges of haemoglobin A2 (HbA2) and haemoglobin F (HbF) levels for normal individuals using this system and also the HbA2 level in beta thalassaemia and haemoglobin E (HbE) individuals.
    Matched MeSH terms: Electrophoresis, Capillary
  10. Electrokinetic supercharging in nonaqueous capillary electrophoresis for online preconcentration and determination of tamoxifen and its metabolites in human plasma
    Thang LY, Breadmore MC, See HH
    J Chromatogr A, 2016 Jul 27.
    PMID: 27485148 DOI: 10.1016/j.chroma.2016.07.067
    An online preconcentration method, namely electrokinetic supercharging (EKS), was evaluated for the determination of tamoxifen and its metabolites in human plasma in nonaqueous capillary electrophoresis with ultraviolet detection (NACE-UV). This method was comprehensively optimized in terms of the leading electrolyte (LE) and terminating electrolyte (TE) injection lengths, as well as electrokinetic sample injection time. The optimized EKS conditions employed were as follows: hydrodynamic injection (HI) of 10mM potassium chloride as LE at 150mbar for 36s (4% of total capillary volume). The sample was injected at 10kV for 300s, followed by HI of 10mM pimozide as TE at 150mbar for 36s (4% of total capillary volume). Separation was performed in 7.5mM deoxycholic acid sodium salt, 15mM acetic acid and 1mM 18-crown-6 in 100% methanol at +25kV with UV detection at 205nm. Under optimized conditions, the sensitivity was enhanced between 160- and 600-fold when compared with our previously developed method based on HI at 150mbar for 12s. The detection limit of the method for tamoxifen and its metabolites were 0.05-0.25ng/mL, with RSDs between 2.1% and 3.5%. Recoveries in spiked human plasma were 95.6%-99.7%. A comparison was also made between the proposed EKS approach and the standard field-amplified sample injection (FASI) technique. EKS proved to be 3-5 times more sensitive than the FASI. The new EKS method was applied to the analysis of tamoxifen and its metabolites in plasma samples from breast cancer patients after liquid-liquid extraction.
    Matched MeSH terms: Electrophoresis, Capillary
  11. Simultaneous electromembrane extraction of cationic and anionic herbicides across hollow polymer inclusion membranes with a bubbleless electrode
    Mamat NA, See HH
    J Chromatogr A, 2017 Jun 30;1504:9-16.
    PMID: 28499598 DOI: 10.1016/j.chroma.2017.05.005
    A new electric-field driven extraction approach based on the integration of a bubbleless electrode into the electromembrane extraction (EME) across hollow polymer inclusion membranes (HPIMs) was demonstrated for the first time. The bubbleless electrode was prepared based on an in-situ synthesised polyacrylamide within a fused silica capillary. The electrode functions as a salt bridge, which conducts the electrical current between the acceptor phase in the lumen of the HPIM and the acceptor solution in the reservoir connected to a high voltage supply through a platinum electrode. Two types of HPIMs were employed, which consisted of desired proportions of cellulose acetate as base polymer, tris(2-ethylhexyl)phosphate as plasticizer, and di-(2-ethylhexyl)phosphoric acid as anionic carrier or Aliquat 336 as cationic carrier, respectively. The EME strategy was evaluated for the simultaneous determination of cationic quaternary ammonium and anionic chlorophenoxy acetic acid herbicides present in the river water, respectively. The analysis was carried out using capillary electrophoresis coupled with UV and contactless conductivity detection. Under the optimised conditions, enrichment factors in the range of 152-185-fold were obtained from 4mL of river water sample with a 20min extraction time and an applied voltage of 3000V. The proposed method provided good linearity with correlation coefficients ranging from 0.9982 to 0.9997 over a concentration range of 1-1000μg/L. The detection limits of the method for the herbicides were in the range of 0.3-0.4μg/L, with relative standard deviations of between 4.8% and 8.5%. The relative recoveries obtained when analysing the spiked river water ranged from 99.1% to 100%. A comparison was also made between the newly developed approach with the conventional EME setup by placing the platinum electrode directly in the lumen of the HPIMs.
    Matched MeSH terms: Electrophoresis, Capillary
  12. Fulltext Potential use of cord blood for Hb E hemoglobinopathy screening programme using capillary electrophoresis
    Wan Mohd Saman WA, Hassan R, Mohd Yusoff S, Che Yaakob CA, Abdullah NA, Ghazali S, et al.
    Malays J Pathol, 2016 Dec;38(3):235-239.
    PMID: 28028293 MyJurnal
    BACKGROUND: Thalassemia and hemoglobinopathies are inherited red blood cell disorders found worldwide. Hemoglobin (Hb) E disorder is one of the hemoglobinopathies known to have the high prevalence in South East Asia. Most of transfusion-dependent thalassemias were genotypically compound heterozygous Hb E/ β-thalassemia. In Malaysia, the national screening program for thalassemia was implemented for early pregnancy or secondary school girls; however many participants do not turn-up and missed the screening test. Screening for thalassemia using samples from cord blood is an alternative choice as it is a readily available source of blood and hence early detection of the disease. The purpose of this study was to determine the potential use of cord blood for the screening of HbE hemoglobinopathy by using capillary electrophoresis (CE).

    METHODS: Cord blood samples were collected from 300 newborns of healthy mothers. Hematological parameters were determined and hemoglobin quantitation for all cord blood samples were performed using capillary electrophoresis system (CES) and high performance liquid chromatography (HPLC).

    RESULTS: Majority of cord blood samples (63%) revealed Hb AF followed by Hb AFA2 (20%). Hb AFE was detected in 10.7% with the mean value of Hb E ranging from 2.3%-11.1%.

    CONCLUSION: Hemoglobin E was detected in cord blood using capillary electrophoresis system. It can be recommended in areas where Hb E/β is prevalent. Implementation of a screening strategy using CE on cord blood sampling will identify the disease early. With regular follow-up on these patients, the status of their disease can be determined earlier and appropriate management implemented.

    Matched MeSH terms: Electrophoresis, Capillary
  13. Hb Penang [β78(EF2)Leu→Pro, HBB: c.236T>C]: a Novel β-Globin Variant
    Hsu CH, Langdown J, Lynn R, Fisher C, Rose A, Proven M, et al.
    Hemoglobin, 2018 May;42(3):199-202.
    PMID: 30328734 DOI: 10.1080/03630269.2018.1513849
    We report a novel hemoglobin (Hb) variant with a β chain amino acid substitution at codon 78 (CTG>CCG) (HBB: c.236T>C), detected through prenatal screening via capillary electrophoresis (CE) in an otherwise healthy and asymptomatic 38-year-old female of Southeast Asian ancestry. The variant, named Hb Penang after the proband's Malaysian city of origin, underwent further characterization through high performance liquid chromatography (HPLC), reversed phase HPLC, Sanger sequencing, isopropanol stability testing and isoelectric focusing (IEF).
    Matched MeSH terms: Electrophoresis, Capillary
Related Terms
Filters
Contact Us

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

External Links