Displaying publications 341 - 360 of 680 in total

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  1. 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: Chromatography, High Pressure Liquid/methods
  2. Hamid HA, Ramli ANM, Zamri N, Yusoff MM
    Food Chem, 2018 Nov 01;265:253-259.
    PMID: 29884381 DOI: 10.1016/j.foodchem.2018.05.033
    Eleven compounds were identified during profiling of polyphenols by UPLC-QTOF/MS. In abundance was quercetin-3-O-α-l-arabinofuranoside in M. malabathricum ethanolic leaves extract while 6-hydroxykaempferol-3-O-glucoside was present in the leaves extract of M. decenfidum (its rare variety). TPC and TFC were significantly higher in M. decemfidum extract than M. malabathricum extract. During DPPH, FRAF and β-carotene bleaching assays, M. decemfidum extract exhibited greater antioxidant activity compared to M. malabathricum extract. Effect of M. malabathricum and M. decemfidum extracts on viability of MDA-MB-231 cell at concentrations 6.25-100 μg/mL were evaluated for 24, 48 and 72 h. After 48 and 72 h treatment, M. malabathricum and M. decemfidum leaves extracts exhibited significant activity in inhibiting MDA-MB-231 cancer cell line with M. malabathricum extract being more cytotoxic. M. malabathricum and M. imbricatum serves as potential daily dietary source of natural phenolics and to improve chemotherapeutic effectiveness.
    Matched MeSH terms: Chromatography, High Pressure Liquid*
  3. 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: Chromatography, High Pressure Liquid/methods
  4. Liem LK, Choong LH, Woo KT
    Clin Biochem, 2002 May;35(3):181-7.
    PMID: 12074825
    OBJECTIVE: Dihydropyrimidine dehydrogenase (DPD) catalyzes the degradation of thymine, uracil, and the chemotherapeutic drug 5-Fluorouracil. In general reverse-phase high pressure liquid chromatography is the standard method for separating 5-[2-(14)C]Fluorouracil and 5-[2-(14)C]Fluoro-5,6-dihydrouracil. However, the use of 100% aqueous solution (as HPLC mobile phase) may collapse the C-18 bonded phase and result in a retention time shift. The aim of this study is to develop a rapid, reproducible, sensitive method for screening partial DPD deficiency in healthy volunteers.

    DESIGN AND METHODS: The activity of DPD was measured using 5-[2- (14)C]Fluorouracil (5-[2-(14)C]FUra) followed by separation of substrate and product 5-[2-(14)C]FUraH(2) with a 15 x 4.6 mm I.D., 5 microm particle size (d(p)) porous graphitic carbon (PGC) column (Hypercarb(R)) and HPLC with online detection of the radioactivity. This was standardized using the protein concentration of the cytosol (NanoOrange(R) Protein Quantitation).

    RESULTS: Complete baseline separation of 5-[2-(14)C]Fluorouracil (5-[2-(14)C]FUra) and 5-[2-(14)C]Fluoro-5,6-dihydrouracil (5-[2-(14)C]FUraH(2)) was achieved using a porous graphitic carbon (PGC) column. The detection limit for 5-[2-(14)C]FUraH(2) was 0.4 pmol.

    CONCLUSIONS: By using linear gradient separation (0.1% Trifluoroacetic acid [TFA] in water to 100% Methanol) protocols in concert with PGC columns (Hypercarb(R)), we have demonstrated that a PGC column has a distinct advantage over C-18 reverse phase columns in terms of column stability (pH 1-14). This method provides an improvement on the specific assay for DPD enzyme activity. It is rapid, reproducible and sensitive and can be used for routine screening for healthy and cancer patients for partial and profound DPD deficiency before treatment with 5- FUra.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  5. Abd Wahib SM, Wan Ibrahim WA, Sanagi MM, Kamboh MA, Abdul Keyon AS
    J Chromatogr A, 2018 Jan 12;1532:50-57.
    PMID: 29241956 DOI: 10.1016/j.chroma.2017.11.059
    A facile dispersive-micro-solid phase extraction (D-μ-SPE) method coupled with HPLC for the analysis of selected non-steroidal anti-inflammatory drugs (NSAIDs) in water samples was developed using a newly prepared magnetic sporopollenin-cyanopropyltriethoxysilane (MS-CNPrTEOS) sorbent. Sporopollenin homogenous microparticles of Lycopodium clavatum spores possessed accessible functional groups that facilitated surface modification. Simple modification was performed by functionalization with 3-cyanopropyltriethoxysilane (CNPrTEOS) and magnetite was introduced onto the biopolymer to simplify the extraction process. MS-CNPrTEOS was identified by infrared spectrometrywhile the morphology and the magnetic property were confirmed by scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM), respectively. To maximize the extraction performance of ketoprofen, ibuprofen, diclofenac and mefenamic acid using the proposed MS-CNPrTEOS, important D-μ-SPE parameters were comprehensively optimized. The optimum extraction conditions were sorbent amount, 40 mg; extraction time, 5 min; desorption time; 5 min; sample volume, 15 mL; sample pH 2.0; and salt addition, 2.5% (w/v). The feasibility of the developed method was evaluated using spiked tap water, lake water, river water and waste water samples. Results showed that ketoprofen and ibuprofen were linear in the range of 1.0-1000 μg L-1whilst diclofenac and mefenamic acid were linear in the range 0.8-500 μg L-1. The results also showed good detection limits for the studied NSAIDs in the range of 0.21-0.51 μg L-1and good recoveries for spiked water samples in the range of 85.1-106.4%. The MS-CNPrTEOS proved a promising dispersive sorbent and applicable to facile and rapid assay of NSAIDs in water samples.
    Matched MeSH terms: Chromatography, High Pressure Liquid*
  6. Alshishani A, Salhimi SM, Saad B
    PMID: 29241085 DOI: 10.1016/j.jchromb.2017.12.013
    A new salting-out assisted liquid-liquid extraction (SALLE) sample preparation method for the determination of the polar anti-diabetic biguanide drugs (metformin, buformin and phenformin) in blood plasma, urine and lake water samples were developed. The SALLE was performed by mixing samples (plasma (0.2mL), urine or lake water (1.0mL)) with acetonitrile (0.4mL for plasma, 0.5mL for urine or lake water), sodium hydroxide powder was then added for the phase separation. The effects of type of salting-out reagent, type of extraction solvent, volumes of acetonitrile and sample, amount of sodium hydroxide, vortexing and centrifugation times on the extraction efficiency were investigated. The upper layer, containing the biguanides, was directly injected into a HPLC unit using ZIC-HILIC column (150mm×2.1mm×3.5μm) and was detected at 236nm. The method was validated and calibration curves were linear with r2>0.99 over the range of 20-2000μgL-1for plasma and 5-2000μgL-1for urine and lake water samples. The limits of detection were in the range (3.8-5.6)μgL-1, (0.8-1.5)μgL-1and (0.3-0.8)μgL-1for plasma, urine and lake water, respectively. The accuracies in the three matrices were within 87.3-103%, 87.4-109%, 82.2-109% of the nominal concentration for metformin, buformin and phenformin, respectively. The relative standard deviation for inter- and intra -day precision were in the range of 1.0-17% for all analytes in the three matrices.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  7. Tan KL, Ankathil R, Gan SH
    J Chromatogr B Analyt Technol Biomed Life Sci, 2011 Nov 15;879(30):3583-91.
    PMID: 22000961 DOI: 10.1016/j.jchromb.2011.09.048
    We developed a simple and sensitive method for the simultaneous detection of imatinib mesylate (IM) and its active metabolite, N-desmethyl imatinib (M1), in human serum samples. Separation was successfully achieved using an Agilent(®) ZORBAX Eclipse plus C(18) reversed phase column (50 mm × 2.1 mm, i.d.; 1.8 μm) under isocratic mobile phase conditions consisting of acetonitrile: 0.02 M potassium dihydrogen phosphate with 0.2% triethylamine at pH 3 (25:75, v/v) and ultra-violet detection was achieved at 235 nm. Extraction of the target compounds was completed using 100% cold acetonitrile. Good linearities (r(2)>0.99) for both IM and M1 were achieved for the concentration ranges of 50-1800 ng/mL and 50-360 ng/mL, respectively. The detection limits were 20 ng/mL and 10 ng/mL for M1 and IM, respectively. The intra- and inter-day precisions were less than 1% with percent recoveries of more than 90%. The method was successfully applied to calculate the pharmacokinetic parameters of chronic myeloid leukemia patients receiving imatinib. The method is suitable to be routinely applied for determination of IM and M1 in serum.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  8. Agatonovic-Kustrin S, Morton DW
    J Chromatogr A, 2017 Dec 29;1530:197-203.
    PMID: 29157606 DOI: 10.1016/j.chroma.2017.11.024
    High-Performance Thin-layer chromatography (HPTLC) combined with DPPH free radical method and α-amylase bioassay was used to compare antioxidant and antidiabetic activities in ethanol and ethyl acetate extracts from 10 marine macroalgae species (3 Chlorophyta, 4 Phaeophyta and 3 Rhodophyta) from Blue Lagoon beach (Malaysia). Samples were also evaluated for their phenolic and stigmasterol content. On average, higher antioxidant activity was observed in the ethyl acetate extracts (55.1mg/100g gallic acid equivalents (GAE) compared to 35.0mg/100g GAE) while, as expected, phenolic content was higher in ethanol extracts (330.5mg/100g GAE compared to 289.5mg/100g GAE). Amounts of fucoxanthin, stigmasterol and α-amylase inhibitory activities were higher in ethyl acetate extracts. Higher enzyme inhibition is therefore related to higher concentrations of triterpenes and phytosterols (Note: these compounds are more soluble in ethyl acetate). Ethyl acetate extracts from Caulerpa racemosa and Padina minor, had the highest α-amylase inhibitory activity, and also showed moderately high antioxidant activities, stigmasterol content and polyphenolic content. Caulerpa racemose, being green algae, does not contain fucoxanthin, while Padina minor, being brown algae, contains high amounts of fucoxanthin. Therefore, it is very unlikely that fucoxanthin contributes to α-amylase inhibitory activity as previously reported.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  9. Abd Rani NZ, Lam KW, Jalil J, Mohamad HF, Mat Ali MS, Husain K
    Molecules, 2021 Jan 28;26(3).
    PMID: 33525733 DOI: 10.3390/molecules26030695
    Phyllanthus amarus Schum. & Thonn. (Phyllanthaceae) is a medicinal plant that is commonly used to treat diseases such as asthma, diabetes, and anemia. This study aimed to examine the antiallergic activity of P. amarus extract and its compounds. The antiallergic activity was determined by measuring the concentration of allergy markers release from rat basophilic leukemia (RBL-2H3) cells with ketotifen fumarate as the positive control. As a result, P. amarus did not stabilize mast cell degranulation but exhibited antihistamine activity. The antihistamine activity was evaluated by conducting a competition radioligand binding assay on the histamine 1 receptor (H1R). Four compounds were identified from the high performance liquid chromatography (HPLC) analysis which were phyllanthin (1), hypophyllanthin (2), niranthin (3), and corilagin (4). To gain insights into the binding interactions of the most active compound hypophyllanthin (2), molecular docking was conducted and found that hypophyllanthin (2) exhibited favorable binding in the H1R binding site. In conclusion, P. amarus and hypophyllanthin (2) could potentially exhibit antiallergic activity by preventing the activation of the H1 receptor.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  10. Yahya NA, Ismail Z, Embong KH, Mohamad SA
    PMID: 8629091
    High performance liquid chromatography (HPLC) with phenylisothiocyanate (PITC) is recently used for confirming the diagnosis of inborn errors of metabolism (IEM) especially amino acid disorders in Malaysian children. The method of HPLC used is a precolumn derivatization of amino acids with phenylisothiocyanate and is separated by reversed phase chromatography using 3.9 x 300 mm free amino acid columns and is detected by a UV/Vis detector. The samples are obtained from cases suspected of inborn errors of metabolism, especially of amino acid disorders, which are detected clinically by pediatricians. Initially, samples from patients suspected of inborn errors of metabolism, either urine or serum, are run on one-dimensional thin layer chromatography and supplementary chemical tests to detect the abnormal bands and associated abnormalities respectively. Positive samples are further run on HPLC to determine the specific amino acids abnormality. An examples of a case of maple syrup urine disease is discussed, based on the thin layer chromatography findings and HPLC findings.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  11. Alauddin H, Mohamad Nasir S, Ahadon M, Raja Sabudin RZ, Ithnin A, Hussin NH, et al.
    Malays J Pathol, 2015 Dec;37(3):287-92.
    PMID: 26712677
    Haemoglobin (Hb) Lepore is a variant Hb consisting of two α-globin and two δβ-globin chains. In a heterozygote, it is associated with clinical findings of thalassaemia minor, but interactions with other haemoglobinopathies can lead to various clinical phenotypes and pose diagnostic challenges. We reported a pair of siblings from a Malay family, who presented with pallor and hepatosplenomegaly at the ages of 21 months and 14 months old. The red cell indices and peripheral blood smears of both patients showed features of thalassaemia intermedia. Other laboratory investigations of the patients showed conflicting results. However, laboratory investigation results of the parents had led to a presumptive diagnosis of compound heterozygote Hb Lepore/β-thalassaemia and co-inheritance α+-thalassaemia (-α3.7). Hb Lepore has rarely been detected in Southeast Asian countries, particularly in Malaysia. These two cases highlight the importance of family studies for accurate diagnosis, hence appropriate clinical management and genetic counseling.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  12. Ali N, Hashim NH, Shuib NS
    PMID: 25658149 DOI: 10.1080/19440049.2015.1011712
    The analysis of aflatoxins (B1, B2, G1 and G2) and ochratoxin A (OTA) was performed in processed spices marketed in Penang, Malaysia, using immunoaffinity columns and HPLC equipped with fluorescence detector (HPLC-FD). The processed powdered spices analysed include dried chilli, fennel, cumin, turmeric, black and white pepper, poppy seed, coriander, 'garam masala', and mixed spices for fish, meat and chicken curry. Two different studies were carried out. The limit of detection (LOD) was 0.01 ng g(-1) for each aflatoxin (AF) and 0.10 ng g(-1) for OTA (signal-to-noise ratio = 3:1). In the first study, 34 commercial processed spices analysed with a mean level, range and incidence of positive samples for total AF were 1.61 ng g(-1), 0.01-9.34 ng g(-1) and 85%, respectively, and for AFB1 were 1.38 ng g(-1), 0.01-7.68 ng g(-1) and 85%, respectively. The mean level, range and incidence of positive samples for OTA were 2.21 ng g(-1), 0.14-20.40 ng g(-1) and 79%, respectively. Natural co-occurrence of AF and OTA was found in 25 (74%) samples. In the second study of 24 commercial processed spices, the mean level, range and incidence of positive samples for total AF were 8.38 ng g(-1), 0.32-31.17 ng g(-1) and 88%, respectively, and for AFB1 were 7.31 ng g(-1), 0.32-28.43 ng g(-1) and 83%, respectively. Fifteen positive samples for total AF and two positive samples for OTA exceeded the permissible Malaysian limit of 5 ng g(-1). Contamination of both mycotoxins in spices may represent another route of exposure to consumers due to their frequent and prolonged consumption, as spices are common ingredients in popular dishes among Asian countries.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  13. Ahmed IA, Mikail MA, Bin Ibrahim M, Bin Hazali N, Rasad MS, Ghani RA, et al.
    Food Chem, 2015 Apr 1;172:778-87.
    PMID: 25442620 DOI: 10.1016/j.foodchem.2014.09.122
    Baccaurea angulata is an underutilised tropical fruit of Borneo Island of Malaysia. The effect of solvents was examined on yield, total phenolic (TPC), total flavonoids (TFC), total carotene content (TCC), free radical scavenging activities and lipid peroxidation inhibition activities. The results indicated that the pulp (edible portion) had the highest yield, while methanol extracts were significantly (p < 0.01) found to contain higher TPC, TFC and TCC than phosphate buffered saline (PBS) extracts for all the fruits parts. The methanol extracts also showed remarkable antiradical activity and significant lipid peroxidation inhibition activities, with their IC50 results highly comparable to that of commercial blueberry. The variations in the results among the extracts suggest different interactions, such as negative or antagonistic (interference), additive and synergistic effect interactions. The study indicated that B. angulata like other underutilised tropical fruits contained remarkable primary antioxidants. Thus, the fruit has the potential to be sources of antioxidant components.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  14. Saad LB, Hwi KK, Quah T
    PMID: 25371587
    BACKGROUND: There are severe adverse effects of analgesic drugs on human body. Extraction of analgesic drugs from natural products has therefore become the prime objective of the study. In this study, we aimed to evaluate the antinociceptive activity of the pomegranate fruit.

    MATERIALS AND METHODS: Antinociceptive activity of ethanol pomegranate extract was examined using three models of pain: the writhing test, the hot tail flick test and the plantar test. The ethanolic extract of pomegranate was administered by oral gavages in doses of (100,150 and 200mg/kg, p.o (orally)), for all the tests and compared with aspirin (100mg/kg, p.o.) which was considered as the standard drug. Phytochemical screening and HPLC analysis of the plant species was carried out.

    RESULTS: In the writhing test, the index of pain inhibition (IPI) was 37% for ethanolic extract of pomegranate (200mg/kg, p.o.), and 59% for aspirin. In the hot tail flick test, the ethanolic extract of pomegranate (200mg/kg, p.o.), has shown significant analgesia reaching its peak at 60 min maximum possible analgesia (MPA), was 24.1% as compared with aspirin 37.5%. Hyperalgesia was successfully induced by the plantar test and the ethanol extract of pomegranate (100,150,200mg/kg, p.o.), reduced the hyperalgesia in a dose dependent manner comparable to aspirin at (100mg/kg, p.o.). HPLC analysis revealed the presence of gallic acid, ellagic acid and Punicalagins A&B.

    CONCLUSION: The results demonstrated that ethanol pomegranate extract has an antinociceptive effect that may be related to the presence of identified phytochemicals.

    Matched MeSH terms: Chromatography, High Pressure Liquid
  15. Abdul Keyon AS, Guijt RM, Bolch CJ, Breadmore MC
    J Chromatogr A, 2014 Oct 17;1364:295-302.
    PMID: 25223612 DOI: 10.1016/j.chroma.2014.08.074
    The accumulation of paralytic shellfish toxins (PSTs) in contaminated shellfish is a serious health risk making early detection important to improve shellfish safety and biotoxin management. Capillary electrophoresis (CE) has been proven as a high resolution separation technique compatible with miniaturization, making it an attractive choice in the development of portable instrumentation for early, on-site detection of PSTs. In this work, capillary zone electrophoresis (CZE) with capacitively coupled contactless conductivity detector (C(4)D) and UV detection were examined with counter-flow transient isotachophoresis (tITP) to improve the sensitivity and deal with the high conductivity sample matrix. The high sodium concentration in the sample was used as the leading ion while l-alanine was used as the terminating electrolyte (TE) and background electrolyte (BGE) in which the toxins were separated. Careful optimization of the injected sample volume and duration of the counter-flow resulted in limit of detections (LODs) ranging from 74.2 to 1020 ng/mL for tITP-CZE-C(4)D and 141 to 461 ng/mL for tITP-CZE-UV, an 8-97 fold reduction compared to conventional CZE. The LODs were adequate for the analysis of PSTs in shellfish samples close to the regulatory limit. Intra-day and inter-day repeatability values (percentage relative standard deviation, n=3) of tITP-CZE-C(4)D and tITP-CZE-UV methods for both migration time and peak height were in the range of 0.82-11% and 0.76-10%, respectively. The developed method was applied to the analysis of a contaminated mussel sample and validated against an Association of Official Analytical Chemists (AOAC)-approved method for PSTs analysis by high performance liquid chromatography (HPLC) with fluorescence detection (FLD) after pre-column oxidation of the sample. The method presented has potential for incorporation in to field-deployable devices for the early detection of PSTs on-site.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  16. Moniruzzaman M, Yung An C, Rao PV, Hawlader MN, Azlan SA, Sulaiman SA, et al.
    Biomed Res Int, 2014;2014:737490.
    PMID: 25045696 DOI: 10.1155/2014/737490
    The aim of the present study was to characterize the phenolic acids, flavonoids, and antioxidant properties of monofloral honey collected from five different districts in Bangladesh. A new high performance liquid chromatography (HPLC) equipped with a UV detector method was developed for the identification of the phenolic acids and flavonoids. A total of five different phenolic acids were identified, with the most abundant being caffeic acid, benzoic acid, gallic acid, followed by chlorogenic acid and trans-cinnamic acid. The flavonoids, kaempferol, and catechin were most abundant, followed by myricetin and naringenin. The mean moisture content, total sugar content, and color characteristics of the honey samples were 18.36 ± 0.95%, 67.40 ± 5.63 g/100 g, and 129.27 ± 34.66 mm Pfund, respectively. The mean total phenolic acids, total flavonoid content, and proline content were 199.20 ± 135.23, 46.73 ± 34.16, and 556.40 ± 376.86 mg/kg, respectively, while the mean FRAP values and DPPH radical scavenging activity were 327.30 ± 231.87 μM Fe (II)/100 g and 36.95 ± 20.53%, respectively. Among the different types of honey, kalijira exhibited the highest phenolics and antioxidant properties. Overall, our study confirms that all the investigated honey samples are good sources of phenolic acids and flavonoids with good antioxidant properties.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  17. Ben-Hander GM, Makahleh A, Saad B, Saleh MI, Cheng KW
    Talanta, 2015 Jan;131:590-6.
    PMID: 25281145 DOI: 10.1016/j.talanta.2014.08.037
    A new analytical method for the simultaneous determination of the antidiabetic drugs rosiglitazone (ROS) and metformin hydrochloride (MH) with marked differences in their affinity towards organic solvents (log P of 2.4 and -1.43, respectively) was developed. Prior to the HPLC separation, the drugs were subjected to a sequential hollow fiber liquid phase microextraction (HF-LPME) procedure. Two sequential HF-LPME approaches were considered, the preferred one involves the use of two vials containing solution mixtures for the extraction of ROS (vial 1) and MH (vial 2), respectively, but using the same fiber and acceptor phase. Important parameters that affect the extraction efficiency such as extracting solvent, donor phase conditions, HCl concentration, agitation, extraction time, addition of salt, etc. were studied. Under the optimum conditions, good enrichment factors (EF, 471 and 86.6 for ROS and MH, respectively) were achieved. Calibration curves were linear over the range 1-500 (r(2)=0.998) and 5-2500 ng mL(-1) (r(2)=0.999) for ROS and MH, respectively. The relative standard deviation values (RSD%) for six replicates were below 8.4%. Detection and quantitation limits based on S/N ratio of 3 and 10 were 0.12, 1.0 and 0.36, 3.0 ng mL(-1) for ROS and MH, respectively. The proposed method is simple, sensitive and opens up new opportunities for the microextraction of analytes with contrasting properties.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  18. Shukor H, Al-Shorgani NK, Abdeshahian P, Hamid AA, Anuar N, Rahman NA, et al.
    Bioresour Technol, 2014 Oct;170:565-73.
    PMID: 25171212 DOI: 10.1016/j.biortech.2014.07.055
    Palm kernel cake (PKC) was used for biobutanol production by Clostridium saccharoperbutylacetonicum N1-4 in acetone-butanol-ethanol (ABE) fermentation. PKC was subjected to acid hydrolysis pretreatment and hydrolysates released were detoxified by XAD-4 resin. The effect of pH, temperature and inoculum size on butanol production was evaluated using an empirical model. Twenty ABE fermentations were run according to an experimental design. Experimental results revealed that XAD-4 resin removed 50% furfural and 77.42% hydroxymethyl furfural. The analysis of the empirical model showed that linear effect of inoculums size with quadratic effect of pH and inoculum size influenced butanol production at 99% probability level (P<0.01). The optimum conditions for butanol production were pH 6.28, temperature of 28°C and inoculum size of 15.9%. ABE fermentation was carried out under optimum conditions which 0.1g/L butanol was obtained. Butanol production was enhanced by diluting PKC hydrolysate up to 70% in which 3.59g/L butanol was produced.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  19. Maail CM, Ariffin H, Hassan MA, Shah UK, Shirai Y
    Biomed Res Int, 2014;2014:465270.
    PMID: 25057489 DOI: 10.1155/2014/465270
    Oil palm frond (OPF) juice is a potential industrial fermentation substrate as it has high sugars content and the OPF are readily available daily. However, maximum sugars yield and storage stability of the OPF juice are yet to be determined. This study was conducted to determine the effect of physical pretreatment and storage duration of OPF petiole on sugars yield. Storage stability of OPF juice at different storing conditions was also investigated. It was found that OPF petiole squeezed by hydraulic pressing machine gave the highest sugars recovery at almost 40 g/kg, accounting for a recovery yield of 88%. Storage of OPF petiole up to 72 hrs prior to squeezing reduced the free sugars by 11 g/kg. Concentrated OPF juice with 95% water removal had the best storage stability at both 4 and 30°C, when it was stored for 10 days. Moreover, concentrated OPF syrup prepared by thermal processing did not give any Maillard effect on microbial growth. Based on our results, OPF juice meets all the criteria as a good fermentation substrate as it is renewable, consistently available, and easy to be obtained, it does not inhibit microbial growth and product formation, and it contains no impurities.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  20. Keyon AS, Guijt RM, Gaspar A, Kazarian AA, Nesterenko PN, Bolch CJ, et al.
    Electrophoresis, 2014 May;35(10):1496-503.
    PMID: 24591173 DOI: 10.1002/elps.201300353
    Paralytic shellfish toxins (PSTs) are produced by marine and freshwater microalgae and accumulate in shellfish including mussels, oysters, and scallops, causing possible fatalities when inadvertently consumed. Monitoring of PST content of shellfish is therefore important for food safety, with currently approved methods based on HPLC, using pre- or postcolumn oxidation for fluorescence detection (HPLC-FLD). CE is an attractive alternative for screening and detection of PSTs as it is compatible with miniaturization and could be implemented in portable instrumentation for on-site monitoring. In this study, CE methods were developed for C(4) D, FLD, UV absorption detection, and MS-making this first report of C(4) D and FLD for PSTs detection. Because most oxidized toxins are neutral, MEKC was used in combination with FLD. The developed CZE-UV and CZE-C(4) D methods provide better resolution, selectivity, and separation efficiency compared to CZE-MS and MEKC-FLD. The sensitivity of the CZE-C(4) D and MEKC-FLD methods was superior to UV and MS, with LOD values ranging from 140 to 715 ng/mL for CZE-C(4) D and 60.9 to 104 ng/mL for MEKC-FLD. With the regulatory limit for shellfish samples of 800 ng/mL, the CZE-C(4) D and MEKC-FLD methods were evaluated for the screening and detection of PSTs in shellfish samples. While the CZE-C(4) D method suffered from significant interferences from the shellfish matrix, MEKC-FLD was successfully used for PST screening of a periodate-oxidized mussel sample, with results confirmed by HPLC-FLD. This confirms the potential of MEKC-FLD for screening of PSTs in shellfish samples.
    Matched MeSH terms: Chromatography, High Pressure Liquid
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