Displaying publications 1 - 20 of 151 in total

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  1. Development and validation of a selective, sensitive and stability indicating UPLC-MS/MS method for rapid, simultaneous determination of six process related impurities in darunavir drug substance
    A VBR, Yusop Z, Jaafar J, Aris AB, Majid ZA, Umar K, et al.
    J Pharm Biomed Anal, 2016 Sep 05;128:141-148.
    PMID: 27262107 DOI: 10.1016/j.jpba.2016.05.026
    In this study a sensitive and selective gradient reverse phase UPLC-MS/MS method was developed for the simultaneous determination of six process related impurities viz., Imp-I, Imp-II, Imp-III, Imp-IV, Imp-V and Imp-VI in darunavir. The chromatographic separation was performed on Acquity UPLC BEH C18 (50 mm×2.1mm, 1.7μm) column using gradient elution of acetonitrile-methanol (80:20, v/v) and 5.0mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4mL/min. Both negative and positive electrospray ionization (ESI) modes were operated simultaneously using multiple reaction monitoring (MRM) for the quantification of all six impurities in darunavir. The developed method was fully validated following ICH guidelines with respect to specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, robustness and sample solution stability. The method was able to quantitate Imp-I, Imp-IV, Imp-V at 0.3ppm and Imp-II, Imp-III, and Imp-VI at 0.2ppm with respect to 5.0mg/mL of darunavir. The calibration curves showed good linearity over the concentration range of LOQ to 250% for all six impurities. The correlation coefficient obtained was >0.9989 in all the cases. The accuracy of the method lies between 89.90% and 104.60% for all six impurities. Finally, the method has been successfully applied for three formulation batches of darunavir to determine the above mentioned impurities, however no impurity was found beyond the LOQ. This method is a good quality control tool for the trace level quantification of six process related impurities in darunavir during its synthesis.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  2. Fulltext Mechanistic Studies of the Antiallergic Activity of Phyllanthus amarus Schum. & Thonn. and Its Compounds
    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
  3. Magnetic molecularly imprinted polymer nanoparticles for the extraction and clean-up of thiamethoxam and thiacloprid in light and dark honey
    Abdulhussein AQ, Jamil AKM, Bakar NKA
    Food Chem, 2021 Oct 15;359:129936.
    PMID: 33957328 DOI: 10.1016/j.foodchem.2021.129936
    In this work, new selective and sensitive dual-template molecularly imprinted polymer nanoparticles (MIPs) were synthesized and characterized. Sorbent MIPs were investigated for simultaneous extraction and clean-up of thiamethoxam and thiacloprid from light and dark honey samples. In this study, ultra-high-performance liquid chromatography-tandem mass spectrometry triple-quadrupole (UHPLC-MS/MS) (QQQ) was used to detect and quantify the pesticides. The kinetic model with adsorption kinetics of sorbent was investigated. The optimal adsorption conditions were 80 mg of polymer MIPs, a 30-min extraction time, and a pH of 7. The detection limit (LOD) and the quantification limit (LOQ) varied from 0.045 to 0.070 µg kg-1 and from 0.07 to 0.10 µg kg-1, respectively. The intra-day and inter-day precision (RSD, %) ranged from 1.3 to 2.0% and from 8.2 to 12.0%, respectively. The recovery of thiamethoxam and thiacloprid ranged from 96.8 to 106.5% and 95.3 to 104.4%, respectively, in light and dark honey samples.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  4. Fulltext Stability of glycated haemoglobin (HbA1c) measurements from whole blood samples kept at -196°C for seven to eight years in The Malaysian Cohort study
    Abdullah N, Goh YX, Othman R, Ismail N, Jalal N, Wan Sallam WAF, et al.
    J Clin Lab Anal, 2023 Apr;37(8):e24898.
    PMID: 37243371 DOI: 10.1002/jcla.24898
    OBJECTIVE: Glycated haemoglobin (HbA1c) is a standard indication for screening type 2 diabetes that also has been widely used in large-scale epidemiological studies. However, its long-term quality (in terms of reproducibility) stored in liquid nitrogen is still unknown. This study is aimed to evaluate the stability and reproducibility of HbA1c measurements from frozen whole blood samples kept at -196°C for more than 7 years.

    METHODS: A total of 401 whole blood samples with a fresh HbA1c measurement were randomly selected from The Malaysian Cohort's (TMC) biobank. The HbA1c measurements of fresh and frozen (stored for 7-8 years) samples were assayed using different high-performance liquid chromatography (HPLC) systems. The HbA1c values of the fresh samples were then calculated and corrected according to the later system. The reproducibility of HbA1c measurements between calculated-fresh and frozen samples was assessed using a Passing-Bablok linear regression model. The Bland-Altman plot was then used to evaluate the concordance of HbA1c values.

    RESULTS: The different HPLC systems highly correlated (r = 0.99) and agreed (ICC = 0.96) with each other. Furthermore, the HbA1c measurements for frozen samples strongly correlate with the corrected HbA1c values of the fresh samples (r = 0.875) with a mean difference of -0.02 (SD: -0.38 to 0.38). Although the mean difference is small, discrepancies were observed within the diabetic and non-diabetic samples.

    CONCLUSION: These data demonstrate that the HbA1c measurements between fresh and frozen samples are highly correlated and reproducible.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  5. Vortex-assisted liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of furfurals and patulin in fruit juices
    Abu-Bakar NB, Makahleh A, Saad B
    Talanta, 2014 Mar;120:47-54.
    PMID: 24468341 DOI: 10.1016/j.talanta.2013.11.081
    A fast and simple solvent microextraction technique using salting out-vortex-assisted liquid-liquid microextraction (salting out-VALLME) was developed for the extraction of furfurals (2-furfural (2-F), 3-furfural (3-F), 5-methylfurfural (5-MF) and 5-hydroxymethylfurfural (5-HMF)) and patulin (PAT) in fruit juice samples. The optimum extraction conditions for 5 mL sample were: extraction solvent, 1-hexanol; volume of extractant, 200 µL; vortex time, 45 s; salt addition, 20%. The simultaneous determination of the furfurals and PAT were investigated using high performance liquid chromatography coupled with diode array detector (HPLC-DAD). The separation was performed using ODS Hypersil C18 column (4.6 mm i.d × 250 mm, 5 μm) under gradient elution. The detection wavelengths used for all compounds were 280 nm except for 3-F (210 nm). The furfurals and PAT were successfully separated in less than 9 min. Good linearities (r(2)>0.99) were obtained within the range 1-5000 μg L(-1) for all compounds except for 3-F (10-5000 µg L(-1)) and PAT (0.5-100 μg L(-1)). The limits of detection (0.28-3.2 µg L(-1)) were estimated at S/N ratio of 3. The validated salting out-VALLME-HPLC method was applied for the analysis of furfurals and PAT in fruit juice samples (apple, mango and grape).
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  6. Fulltext Assessing product adulteration of Eurycoma longifolia (Tongkat Ali) herbal medicinal product using DNA barcoding and HPLC analysis
    Abubakar BM, Salleh FM, Shamsir Omar MS, Wagiran A
    Pharm Biol, 2018 Dec;56(1):368-377.
    PMID: 30058427 DOI: 10.1080/13880209.2018.1479869
    CONTEXT: Eurycoma longifolia Jack (Simaroubaceae) commonly known as Tongkat Ali is one of the most important plants in Malaysia. The plant extracts (particularly roots) are widely used for the treatment of cough and fever besides having antimalarial, antidiabetic, anticancer and aphrodisiac activities.

    OBJECTIVES: This study assesses the extent of adulteration of E. longifolia herbal medicinal products (HMPs) using DNA barcoding validated by HPLC analysis.

    MATERIALS AND METHODS: Chloroplastic rbcL and nuclear ITS2 barcode regions were used in the present study. The sequences generated from E. longifolia HMPs were compared to sequences in the GenBank using MEGABLAST to verify their taxonomic identity. These results were verified by neighbor-joining tree analysis in which branches of unknown specimen are compared to the reference sequences established from this study and other retrieved from the GenBank. The HMPs were also analysed using HPLC analysis for the presence of eurycomanone bioactive marker.

    RESULTS: Identification using DNA barcoding revealed that 37% of the tested HMPs were authentic while 27% were adulterated with the ITS2 barcode region proven to be the ideal marker. The validation of the authenticity using HPLC analysis showed a situation in which a species which was identified as authentic was found not to contain the expected chemical compound.

    DISCUSSION AND CONCLUSIONS: DNA barcoding should be used as the first screening step for testing of HMPs raw materials. However, integration of DNA barcoding with HPLC analysis will help to provide detailed knowledge about the safety and efficacy of the HMPs.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  7. High-performance thin-layer chromatography HPTLC-direct bioautography as a method of choice for alpha-amylase and antioxidant activity evaluation in marine algae
    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*
  8. Quantification of PAH4 in roasted cocoa beans using QuEChERS and dispersive liquid-liquid micro-extraction (DLLME) coupled with HPLC-FLD
    Agus BAP, Hussain N, Selamat J
    Food Chem, 2020 Jan 15;303:125398.
    PMID: 31470272 DOI: 10.1016/j.foodchem.2019.125398
    Roasting is an important process in cocoa production which may lead to formation of non-desirable compounds such as polycyclic aromatic hydrocarbons (PAHs). Therefore, PAH4 (sum of four different polycyclic aromatic hydrocarbons; benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) in roasted cocoa beans was determined using a modified method (combination of QuEChERS and DLLME), and quantified by HPLC-FLD. The modified method was validated and met the performance criteria required by the EU Regulation (No. 836/2011). Results show a significant (p 
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  9. Chromatographic comparison of atenolol separation in reaction media on cellulose tris-(3,5-dimethylphenylcarbamate) chiral stationary phase using ultra fast liquid chromatography
    Agustian J, Kamaruddin AH, Aboul-Enein HY
    Chirality, 2012 May;24(5):356-67.
    PMID: 22517322 DOI: 10.1002/chir.22019
    Because chiral liquid chromatography (LC) could become a powerful tool to estimate racemic atenolol quantity, excellent enantiomeric separation should be produced during data acquisition for satisfactory observation of atenolol concentrations throughout the racemic resolution processes. Selection of chiral LC column and analytical protocol that fulfill demands of the ultra fast LC analysis is essential. This article describes the characteristics of atenolol chromatographic separation that resulted from different resolution media and analytical protocols with the use of a Chiralcel® OD column. The chromatograms showed quite different characteristics of the separation process. The single enantiomer and racemic atenolol could be recognized by the Chiralcel® OD column in less than 20 min. Symmetrical peaks were obtained; however, several protocols produced peaks with wide bases and slanted baselines. Observations showed that efficient enantioresolution of racemic atenolol was obtained at slow mobile phase flow rate, decreased concentration of amine-type modifier but increased alcohol content in mobile phase and highest ultraviolet detection wavelength were required. The optimal ultra fast LC protocol enables to reduce and eliminate the peaks of either the atenolol solvent or the buffers and provided the highest peak intensities of both atenolol enantiomers.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  10. 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: Chromatography, High Pressure Liquid/methods*
  11. Multi-residue analytical methodology-based liquid chromatography-time-of-flight-mass spectrometry for the analysis of pharmaceutical residues in surface water and effluents from sewage treatment plants and hospitals
    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: Chromatography, High Pressure Liquid/methods*
  12. Evaluation and application of a simple and rapid method for the analysis of aflatoxins in commercial foods from Malaysia and the Philippines
    Ali N, Hashim NH, Yoshizawa T
    Food Addit Contam, 1999 Jul;16(7):273-80.
    PMID: 10656052
    For application to the analysis of aflatoxins (AF) in commercial peanut and corn products, the ISOLUTE multimode column (IMC, solid phase multifunctional column) method was validated by comparing with the modified Florisil column (MFC) method. Twenty-two peanut and eight corn products from Malaysia and the Philippines were analysed for AFB1, AFB2, AFG1 and AFG2 firstly by the MFC method and then by the IMC method. For peanut products, 14 out of 22 samples were positive by the two methods in the range of 1-378 micrograms/kg of AF, and correlation coefficients (r) for AFB1 and AFB2 were 0.987 and 0.997, respectively. For corn and corn products, all the samples were positive in the range of 1-130 micrograms/kg, and r values were 0.992 and 0.805 for AFB1 and AFB2 respectively. Thus, the results were significantly (p < 0.01) in close agreement, particularly for lower range of 1-50 micrograms/kg of AF concentrations in all the samples. For the occurrence of AF, 11 (65%) of peanut products from Malaysia were contaminated with AF at a mean level of 50 micrograms/kg (maximum 180 micrograms/kg) and two (40% products from the Philippines were contaminated with as high as 375 micrograms/kg and 177 micrograms/kg of AF, respectively. All the corn products from the Philippines were contaminated with AF at a mean level of 44 micrograms/kg (maximum 130 micrograms/kg). Contamination of commercial foods with high levels of AF is a very important issue to both the countries since these foods are very popular among children.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  13. Evaluation of a method to determine the natural occurrence of aflatoxins in commercial traditional herbal medicines from Malaysia and Indonesia
    Ali N, Hashim NH, Saad B, Safan K, Nakajima M, Yoshizawa T
    Food Chem Toxicol, 2005 Dec;43(12):1763-72.
    PMID: 16019122
    Traditional herbal medicines, popularly known as 'jamu' and 'makjun' in Malaysia and Indonesia, are consumed regularly to promote health. In consideration of their frequent and prolonged consumption, the natural occurrence of aflatoxins (AF) in these products was determined using immunoaffinity column clean-up and high-performance liquid chromatography with pre-column derivatization. The evaluated method, which entails dilution of sample extracts with Tween 20-phosphate buffered saline (1:9, v/v) and a chromatographic system using isocratic mobile phase composed of water-methanol-acetonitrile (70:20:10, v/v/v), was effective in separating AFB1, AFG1 and AFG2 from interference at their retention times. Results were confirmed using post-column derivatization with photochemical reactor. For 23 commercial samples analyzed, mean levels (incidence) of AFB(1), AFB(2) and AFG1 in positive samples were 0.26 (70%), 0.07 (61%) and 0.10 (30%) microg/kg, respectively; one sample was positive for AFG2 at a level of 0.03 (4%) microg/kg. In contrast to the high levels of AF in crude herbal drugs and medicinal plants reported previously by other researchers, the low contamination levels reported in this study may be attributed to the higher selectivity to AF of the method applied. Based on the AFB1 levels and the daily consumption of positive samples, a mean probable daily intake of 0.022 ng/kg body weight was calculated.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  14. Ion-pair vortex assisted liquid-liquid microextraction with back extraction coupled with high performance liquid chromatography-UV for the determination of metformin in plasma
    Alshishani A, Makahleh A, Yap HF, Gubartallah EA, Salhimi SM, Saad B
    Talanta, 2016 Dec 01;161:398-404.
    PMID: 27769423 DOI: 10.1016/j.talanta.2016.08.067
    A new sample preparation method, ion-pair vortex assisted liquid-liquid microextraction (VALLME-BE), for the determination of a highly polar anti-diabetic drug (metformin) in plasma sample was developed. The VALLME-BE was performed by diluting the plasma in borate buffer and extracted to 150µL 1-octanol containing 0.2M di-(2-ethylhexyl)phosphoric acid as intermediate phase. The drug was next back-extracted into 20µL of 0.075M HCl solution. The effects of pH, ion-pair concentration, type of organic solvent, volume of extraction phases, ionic strength, vortexing and centrifugation times on the extraction efficiency were investigated. The optimum conditions were at pH 9.3, 60s vortexing and 2min centrifugation. The microextract, contained metformin and buformin (internal standard), was directly injected into a HPLC unit using C1 column (250mm×4.6mm×10µm) and detected at 235nm. The method was validated and calibration curve was linear with r2>0.99 over the range of 20-2000µgL-1. The limits of detection and quantitation were 1.4 and 4.1µgL-1, respectively. The accuracy was within 94.8-108% of the nominal concentration. The relative standard deviation for inter- and intra-day precision was less than 10.8%. The method was conveniently applied for the determination of metformin in plasma samples.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  15. Salting-out assisted liquid-liquid extraction coupled with hydrophilic interaction chromatography for the determination of biguanides in biological and environmental samples
    Alshishani A, Salhimi SM, Saad B
    J Chromatogr B Analyt Technol Biomed Life Sci, 2018 Jan 15;1073:51-59.
    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*
  16. Solid-phase extraction of non-steroidal anti-inflammatory drugs in human plasma and water samples using sol-gel-based metal-organic framework coating
    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: Chromatography, High Pressure Liquid/methods
  17. Validation of a HPLC method for determination of hydroxymethylfurfural in crude palm oil
    Ariffin AA, Ghazali HM, Kavousi P
    Food Chem, 2014 Jul 1;154:102-7.
    PMID: 24518321 DOI: 10.1016/j.foodchem.2013.12.082
    For the first time 5-hydroxymethyl-2-furaldehyde (HMF) was separated from crude palm oil (CPO), and its authenticity was determined using an RP-HPLC method. Separation was accomplished with isocratic elution of a mobile phase comprising water and methanol (92:8 v/v) on a Purospher Star RP-18e column (250mm×4.6mm, 5.0μm). The flow rate was adjusted to 1ml/min and detection was performed at 284nm. The method was validated, and results obtained exhibit a good recovery (95.58% to 98.39%). Assessment of precision showed that the relative standard deviations (RSD%) of retention times and peak areas of spiked samples were less than 0.59% and 2.66%, respectively. Further, the limit of detection (LOD) and LOQ were 0.02, 0.05mg/kg, respectively, and the response was linear across the applied ranges. The crude palm oil samples analysed exhibited HMF content less than 2.27mg/kg.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  18. Validation of a reverse-phase high-performance liquid chromatography method for the determination of amino acids in gelatins by application of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent
    Azilawati MI, Hashim DM, Jamilah B, Amin I
    J Chromatogr A, 2014 Aug 1;1353:49-56.
    PMID: 24797394 DOI: 10.1016/j.chroma.2014.04.050
    In-house method validation was conducted to determine amino acid composition in gelatin by a pre-column derivatization procedure with the 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent. The analytical parameters revealed that the validated method was capable of selectively performing a good chromatographic separation for 18 amino acids in less than 40 min; the overall detection and quantitation limit for amino acids fell into ranges of 5.68-12.48 and 36.0-39.0 pmol/μl, respectively; the matrix effect was not observed, and the linearity range was 37.5-1000 pmol/μl. The accuracy (precision and recovery) analyses of the method were conducted under repeatable conditions on different days in random order. Method precision revealed by HorRat values was significantly less than 2, except for histidine with a precision of 2.19, and the method recoveries had a range of 80-115% except for alanine which was recovered at 79.4%. The findings were reproducible and accurately defined, and the method was found to be suited to routine analysis of amino acid composition in gelatin-based ingredients.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  19. Organophosphorus Pesticide Multiresidues in Commercialized Asian Rice
    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
  20. Evaluation of role of HPLC (Merits & Pitfalls), in the diagnosis of various hemoglobinopathies & thalassemic syndromes
    Baig MA, Swamy KB, Baksh AD, Bahashwan A, Moshrif Y, Al Sawat A, et al.
    Indian J Pathol Microbiol, 2021 8 4;64(3):518-523.
    PMID: 34341263 DOI: 10.4103/IJPM.IJPM_709_20
    Background: : HPLC is one of the most important tools for accurate diagnosis of hemoglobinopathies and thalassemias. The advantage of the HPLC system is the excellent resolution, reproducibility &quantification of several normal and abnormal hemoglobin.

    Results: BIO RAD Variant II analyzer was used. Sickle cell syndromes including double heterozygous states accounted for 56.13% of total cases. HbSS, HbS/β0-th, HbS/β+-th β-thal trait comprises 29%, 6.5%, 5.1%& 10% of total cases respectively with mean MCV (fl) = 84, 68,71,64 respectively. The Mean HbA2 for β-thal trait, HbE trait &HbE-β thal showed 5.1 ± 1.1, 19 ± 9 & 24 ± 8 respectively. HbF is increased in 8.6% case (excluding SC syndromes & β-thal disorders), of these 5.5% were infants & 12 cases of Aplastic Anemias. Peak P2 >7% (2.4% cases) was seen in uncontrolled diabetes mellitus which on quantification showed HbA1C = 8 ± 2.1 mmol/L.

    Discussion: : HPLC in correlation with CBC parameters & family studies can aid in the diagnosis of majority of Hemoglobinopathies and thalassemic syndrome. The CBC & HPLC parameters of the present study are in good correlation with the research conducted by Tejinder Sing, RiouJ & Alla Joutovsky. Present study showed HPLC comprehensively characterizing HbS, A, A2, F, S, C, D from each other & was also applicable for the quantification of HbA1c for the monitoring of Diabetes Mellitus.

    Conclusion: : The merits of HPLC are small quantity of sample required, economical, less TAT, accurate categorization of HbS, HbA2 & F. But one has to be aware of the limitations and problems associated with this method due to variant hemoglobin within the same retention windows. The present findings show HPLC as an excellent & powerful diagnostic tool for the direct identification of hemoglobin variants with a high degree of precision in the quantification of normal and abnormal hemoglobin fractions.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
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