Displaying publications 1 - 20 of 150 in total

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  1. Lee TP, Saad B, Ng EP, Salleh B
    J Chromatogr A, 2012 May 11;1237:46-54.
    PMID: 22444432 DOI: 10.1016/j.chroma.2012.03.031
    Zeolite Linde Type L (LTL) crystals with different length, diameter and particle size (nanosized LTL, rod LTL, cylinder LTL and needle LTL) were synthesized, characterized and were used as sorbent in the micro-solid phase extraction of ochratoxin A (OTA) before the high performance liquid chromatography detection. Under the optimized conditions, the detection limits of OTA for coffee and cereal were 0.09 ng g(-1) and 0.03 ng g(-1), respectively, while the quantification limits were 0.28 ng g(-1) and 0.08 ng g(-1), respectively. The recoveries of OTA of coffee and cereal spiked at 0.5, 10 and 25 ng g(-1) ranged from 91.7 to 101.0%. The proposed method was applied to forty-five samples of coffee and cereal. The presence of OTA was found in twenty-five samples, ranging from 0.28 to 9.33 ng g(-1).
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  2. Shalash M, Makahleh A, Salhimi SM, Saad B
    Talanta, 2017 Nov 01;174:428-435.
    PMID: 28738603 DOI: 10.1016/j.talanta.2017.06.039
    A vortex-assisted liquid-liquid-liquid microextraction method followed by high performance liquid chromatography-diode array detection for the determination of fourteen phenolic acids (cinnamic, m-coumaric, chlorogenic, syringic, ferulic, o-coumaric, p-coumaric, vanillic, p-hydroxybenzoic, caffeic, 2, 4-dihydroxybenzoic, sinapic, gentisic and gallic acids) in honey, iced tea and canned coffee drink samples has been developed. The separation was achieved using a Poroshell 120-EC-C18 column under a gradient elution at a flow rate of 0.6mLmin-1 and mobile phase composed of methanol and acetic acid (1%, v/v). Under the optimum chromatographic conditions, the fourteen phenolic acids were separated in less than 32min. The extraction was performed using a small volume (400µL) of ternary organic solvents (1-pentanol, propyl acetate and 1-hexanol) dispersed into the aqueous sample (10mL) and assisted by vortex agitation (2500rpm for 45s), the analytes were next back-extracted from the organic solvent using 0.02M KOH (40µL) with vortex speed and time of 2500rpm and 60s, respectively. Under these conditions, enrichment factors of 30-193-fold were achieved. The limits of detection (LODs) were 0.05-0.68µgL-1. Recoveries in honey, iced tea and canned coffee drinks were in the range 72.2-112%. The method was successfully applied for the determination of the phenolic acids in honey, iced tea and canned coffee drinks.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  3. 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
  4. Lai CS, Nair NK, Muniandy A, Mansor SM, Olliaro PL, Navaratnam V
    J Chromatogr B Analyt Technol Biomed Life Sci, 2009 Feb 15;877(5-6):558-62.
    PMID: 19147417 DOI: 10.1016/j.jchromb.2008.12.037
    With the expanded use of the combination of artesunate (AS) and amodiaquine (AQ) for the treatment of falciparum malaria and the abundance of products on the market, comes the need for rapid and reliable bioanalytical methods for the determination of the parent compounds and their metabolites. While the existing methods were developed for the determination of either AS or AQ in biological fluids, the current validated method allows simultaneous extraction and determination of AS and AQ in human plasma. Extraction is carried out on Supelclean LC-18 extraction cartridges where AS, its metabolite dihydroartemisinin (DHA) and the internal standard artemisinin (QHS) are separated from AQ, its metabolite desethylamodiaquine (DeAQ) and the internal standard, an isobutyl analogue of desethylamodiaquine (IB-DeAQ). AS, DHA and QHS are then analysed using Hypersil C4 column with acetonitrile-acetic acid (0.05M adjusted to pH 5.2 with 1.00M NaOH) (42:58, v/v) as mobile phase at flow rate 1.50ml/min. The analytes are detected with an electrochemical detector operating in the reductive mode. Chromatography of AQ, DeAQ and IB-DeAQ is carried out on an Inertsil C4 column with acetonitrile-KH(2)PO(4) (pH 4.0, 0.05M) (11:89, v/v) as mobile phase at flow rate 1.00ml/min. The analytes are detected by an electrochemical detector operating in the oxidative mode. The recoveries of AS, DHA, AQ and DeAQ vary between 79.1% and 104.0% over the concentration range of 50-1400ng/ml plasma. The accuracies of the determination of all the analytes are 96.8-103.9%, while the variation for within-day and day-to-day analysis are <15%. The lower limit of quantification for all the analytes is 20ng/ml and limit of detection is 8ng/ml. The method is sensitive, selective, accurate, reproducible and suited particularly for pharmacokinetic study of AS-AQ drug combination and can also be used to compare the bioavailability of different formulations, including a fixed-dose AS-AQ co-formulation.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  5. 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*
  6. Gan SH, Ismail R
    J Chromatogr B Biomed Sci Appl, 2001 Aug 15;759(2):325-35.
    PMID: 11499486
    An HPLC system using solid-phase extraction and HPLC with UV detection has been validated in order to determine tramadol and o-desmethyltramadol (M1) concentrations in human plasma. The method developed was selective and linear for concentrations ranging from 50 to 3,500 ng/ml (tramadol) and 50 to 500 ng/ml (M1) with mean recoveries of 94.36 +/- 12.53% and 93.52 +/- 7.88%, respectively. Limit of quantitation (LOQ) was 50 ng/ml. For tramadol, the intra-day accuracy ranged from 95.48 to 114.64% and the inter-day accuracy, 97.21 to 103.24%. Good precision (0.51 and 18.32% for intra- and inter-day, respectively) was obtained at LOQ. The system has been applied to determine tramadol concentrations in human plasma samples for a pharmacokinetic study.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  7. 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*
  8. Yodhnu S, Sirikatitham A, Wattanapiromsakul C
    J Chromatogr Sci, 2009 Mar;47(3):185-9.
    PMID: 19298703
    Mangosteen, Garcinia mangostana L., is known as the "Queen of fruits" and can be cultivated in the tropical rainforest such as Malaysia, Indonesia, and Thailand. Compounds isolated from the fruit peel of mangosteen contain abundant xanthones (especially alpha-mangostin). It has been used as traditional medicine such as anti-inflammatory and antibacterial and is popularly applied to cosmetic and pharmaceutical products. However, there is little information for quality and quantity determination of alpha-mangostin in mangosteen. Thus, the aim of this study was to set up a validated and stability-indicated isocratic reverse-phase high-performance liquid chromatographic (HPLC) method for quality control and quantity determination of a-mangostin from mangosteen peel extract. The assay was fully validated and shown to be linear (r(2) > 0.999), sensitive (LOD = 0.02 microg/mL and LOQ = 0.08 microg/mL), accurate (intra-day was between 98.1-100.8%, inter-day was between 90.0-101.3%), precise (intra-day variation < or = 1.8%, inter-day variation < or = 4.3%), specific, and with good recovery. Total analysis was approximately 8 min. The finalized method is also a stability-indicating assay. The present method should be useful for analytical research and for routine quality control analysis of alpha-mangostin in mangosteen peel extract and products of mangosteen.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  9. Ramanathan S, Parthasarathy S, Murugaiyah V, Magosso E, Tan SC, Mansor SM
    Molecules, 2015 Mar 18;20(3):4915-27.
    PMID: 25793541 DOI: 10.3390/molecules20034915
    Varied pharmacological responses have been reported for mitragynine in the literature, but no supportive scientific explanations have been given for this. These studies have been undertaken without a sufficient understanding of the physicochemical properties of mitragynine. In this work a UV spectrophotometer approach and HPLC-UV method were employed to ascertain the physicochemical properties of mitragynine. The pKa of mitragynine measured by conventional UV (8.11 ± 0.11) was in agreement with the microplate reader determination (8.08 ± 0.04). Mitragynine is a lipophilic alkaloid, as indicated by a logP value of 1.73. Mitragynine had poor solubility in water and basic media, and conversely in acidic environments, but it is acid labile. In an in vitro dissolution the total drug release was higher for the simulated gastric fluid but was prolonged and incomplete for the simulated intestinal fluid. The hydrophobicity, poor water solubility, high variability of drug release in simulated biological fluids and acid degradable characteristics of mitragynine probably explain the large variability of its pharmacological responses reported in the literature. The determined physicochemical properties of mitragynine will provide a basis for developing a suitable formulation to further improve its solubility, stability and oral absorption for better assessment of this compound in preclinical studies.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  10. Tahmasebi-Boldaji R, Hatamipour MS, Khanahmadi M, Sadeh P, Najafipour I
    Ultrason Sonochem, 2019 Oct;57:89-97.
    PMID: 31208622 DOI: 10.1016/j.ultsonch.2019.05.018
    This paper presents the successful application of ultrasound-assisted packed-bed (UAE-PB) method for the extraction of hypericin from the Hypericum perfuratum L. The Soxhlet system was utilized for the determination of suitable solvent from ethanol, methanol or from the mixture of different proportions of ethanol-methanol. The mixture of 50:50 v/v ethanol-methanol was obtained to be the most suitable solvent since it led to the highest extraction amount of hypericin. The extraction amount of hypericin increased by 13.6% and 21.4% when the solvent changed from pure methanol to the mixture of 50:50 v/v ethanol-methanol for the extraction time of 3 and 8 h, respectively. Subsequently, the extraction was conducted through the UAE-PB, and the effects of temperature, time, and the ratio of solvent to the dried plant were studied. The response surface method (RSM) was used to investigate the effect of parameters on the extraction in the UAE-PB system. At the temperature of 60 °C, extraction time of 105 min, and the solvent to plant ratio of 15.3, the maximum extraction yield of hypericin was achieved. In the optimal conditions, the amount of extraction was 0.112 mg hypericin/g dried plant, which was in accordance with the optimized predicted value (0.111 mg hypericin/g dried plant) from Design-Expert software.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  11. Che Zain MS, Osman MF, Lee SY, Shaari K
    Molecules, 2021 Feb 19;26(4).
    PMID: 33669484 DOI: 10.3390/molecules26041084
    Luteolin and apigenin derivatives present in oil palm (Elaeis guineensis) leaves (OPL) are reported to possess excellent antioxidant properties relating to numerous health benefits. To meet the global demand for flavonoids, OPL, which is plentifully generated as an agricultural by-product from oil palm plantations, can be further exploited as a new source of natural antioxidant compounds. However, to produce a standardized herbal preparation, validation of the quantification method for these compounds is required. Therefore, in this investigation, we developed and validated an improved and rapid analytical method, ultra-high-performance liquid chromatography equipped with ultraviolet/photodiode array (UHPLC-UV/PDA) for the quantification of 12 luteolin and apigenin derivatives, particularly focusing on flavonoid isomeric pairs: orientin/isoorientin and vitexin/isovitexin, present in various OPL extracts. Several validation parameters were assessed, resulting in the UHPLC-UV/PDA technique offering good specificity, linearity, accuracy, precision, and robustness, where the values were within acceptable limits. Subsequently, the validated method was employed to quantify luteolin and apigenin derivatives from OPL subjected to different drying treatments and extraction with various solvent systems, giving total luteolin (TLC) and apigenin content (TAC) in the range of 2.04-56.30 and 1.84-160.38 µg/mg extract, respectively. Additionally, partial least square (PLS) analysis disclosed the combination of freeze dry-aqueous methanol yielded OPL extracts with high TLC and TAC, which are strongly correlated with antioxidant activity. Therefore, we provide the first validation report of the UHPLC-UV/PDA method for quantification of luteolin and apigenin derivatives present in various OPL extracts, suggesting that this approach could be employed in standardized herbal preparations by adopting orientin, isoorientin, vitexin, and isovitexin as chemical markers.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  12. Saleem H, Sarfraz M, Khan KM, Anwar MA, Zengin G, Ahmad I, et al.
    Drug Dev Ind Pharm, 2020 May;46(5):861-868.
    PMID: 32352878 DOI: 10.1080/03639045.2020.1762199
    The biological, chemical, and in silico properties of methanol and dichloromethane (DCM) extracts of Alhagi maurorum roots with respect to the antioxidant, enzyme inhibition, and phytochemical composition were evaluated. Total bioactive contents were determined spectrophotometrically, and the individual secondary metabolites composition was assessed via ultra-high-performance liquid chromatography mass spectrometry (UHPLC-MS) analysis. Antioxidant capacities were evaluated using a panoply of assays (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging, ferric reducing antioxidant power (FRAP), cupric reducing antioxidant power (CUPRAC), phosphomolybdenum total antioxidant capacity (TAC), and metal chelating activity (MCA)). The enzyme inhibition potential was studied against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase, α-glucosidase, tyrosinase, urease and lipoxygenase (LOX) enzymes. The methanol extract was found to contain higher total phenolic (105.91 mg GAE/g extract) and flavonoid (2.27 mg RE/g extract) contents which can be correlated to its more substantial antioxidant potential as well as AChE, BChE, tyrosinase and α-glucosidase inhibition. However, the DCM extract was the most effective against α-amylase (1.86 mmol ACAE/g extract) enzyme inhibition. The UHPLC-MS analysis of methanol extract identified the tentative presence of a total of 18 secondary metabolites, including flavonoids, saponins, phenolic and terpenoid derivatives. Three compounds named emmotin A, luteolin 5,3'-dimethyl ether, and preferrugone were further investigated for their in silico molecular docking studies against the tested enzymes. The selected compounds were found to have higher binding interaction with AChE followed by BChE, α-glucosidase, α-amylase, and tyrosinase. The results of the present study have demonstrated A. mauroram to be considered as a lead source of natural antioxidant and enzyme inhibitor compounds.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  13. Hashim P, Sidek H, Helan MH, Sabery A, Palanisamy UD, Ilham M
    Molecules, 2011;16(2):1310-22.
    PMID: 21278681 DOI: 10.3390/molecules16021310
    Leaves of Centella asiatica (Centella) were analysed for their triterpene composition and bioactivity such as collagen enhancement, antioxidant, anticellulite and UV protection capacity properties. Triterpenes of Centella were measured using HPLC-PAD on an Excil ODS 5 mm (C18) column for the simultaneous determination of asiatic acid, madecassic acid, asiaticoside and madecassoside. Centella was found to contain significant amounts of madecassoside (3.10 ± 4.58 mg/mL) and asiaticoside (1.97 ± 2.65 mg/mL), but was low in asiatic and madecassic acid. The highest collagen synthesis was found at 50 mg/mL of Centella extracts. The antioxidant activity of Centella (84%) was compared to grape seed extract (83%) and Vitamin C (88%). Its lipolytic activity was observed by the release of glycerol (115.9 µmol/L) at 0.02% concentration. Centella extracts exhibited similar UV protection effect to OMC at 10% concentration. In view of these results, the potential application of Centella in food and pharmaceutical industries is now widely open.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  14. Mahyudin NA, Blunt JW, Cole AL, Munro MH
    J Biomed Biotechnol, 2012;2012:894708.
    PMID: 22291452 DOI: 10.1155/2012/894708
    The application of an HPLC bioactivity profiling/microtiter plate technique in conjunction with microprobe NMR instrumentation and access to the AntiMarin database has led to the isolation of a new 1. In this example, 1 was isolated from a cytotoxic fraction of an extract obtained from marine-derived Streptomyces sp. cultured on Starch Casein Agar (SCA) medium. The 1D and 2D (1)H NMR and ESIMS data obtained from 20 μg of compound 1 fully defined the structure. The known 2 was also isolated and readily dereplicated using this approach.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  15. 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
  16. Mendes K, Harmanjeet H, Sedeeq M, Modi A, Wanandy T, Zaidi STR, et al.
    Perit Dial Int, 2018 07 10;38(6):430-440.
    PMID: 29991562 DOI: 10.3747/pdi.2017.00274
    BACKGROUND: Infections caused by ceftazidime-resistant Pseudomonas and extended-spectrum beta-lactamase (ESBL)-producing gram-negative bacteria are increasing worldwide. Meropenem and piperacillin/tazobactam (PIP/TZB) are recommended for the treatment of peritoneal dialysis-associated peritonitis (PDAP) caused by ceftazidime-resistant Pseudomonas and other resistant gram-negative bacteria. Patients may also receive intraperitoneal heparin to prevent occlusion of their catheters. However, the stability of meropenem or PIP/TZB, in combination with heparin, in different types of peritoneal dialysis (PD) solutions used in clinical practice is currently unknown. Therefore, we investigated the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions.

    METHODS: A total of 15 PD bags (3 bags for each type of PD solution) containing meropenem and heparin and 24 PD bags (3 bags for each type of PD solution) containing PIP/TZB and heparin were prepared and stored at 4°C for 168 hours. The same bags were stored at 25°C for 3 hours followed by 10 hours at 37°C. An aliquot withdrawn before storage and at defined time points was analyzed for the concentration of meropenem, PIP, TZB, and heparin using high-performance liquid chromatography. Samples were also analysed for particle content, pH and color change, and the anticoagulant activity of heparin.

    RESULTS: Meropenem and heparin retained more than 90% of their initial concentration in 4 out of 5 types of PD solutions when stored at 4°C for 168 hours, followed by storage at 25°C for 3 hours and then at 37°C for 10 hours. Piperacillin/tazobactam and heparin were found to be stable in all 8 types of PD solutions when stored under the same conditions. Heparin retained more than 98% of its initial anticoagulant activity throughout the study period. No evidence of particle formation, color change, or pH change was observed at any time under the storage conditions employed in the study.

    CONCLUSIONS: This study provides clinically important information on the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions. The use of meropenem-heparin admixed in pH-neutral PD solutions for the treatment of PDAP should be avoided, given the observed suboptimal stability of meropenem.

    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  17. Syed HK, Liew KB, Loh GO, Peh KK
    Food Chem, 2015 Mar 1;170:321-6.
    PMID: 25306352 DOI: 10.1016/j.foodchem.2014.08.066
    A stability-indicating HPLC-UV method for the determination of curcumin in Curcuma longa extract and emulsion was developed. The system suitability parameters, theoretical plates (N), tailing factor (T), capacity factor (K'), height equivalent of a theoretical plate (H) and resolution (Rs) were calculated. Stress degradation studies (acid, base, oxidation, heat and UV light) of curcumin were performed in emulsion. It was found that N>6500, T<1.1, K' was 2.68-3.75, HETP about 37 and Rs was 1.8. The method was linear from 2 to 200 μg/mL with a correlation coefficient of 0.9998. The intra-day precision and accuracy for curcumin were ⩽0.87% and ⩽2.0%, while the inter-day precision and accuracy values were ⩽2.1% and ⩽-1.92. Curcumin degraded in emulsion under acid, alkali and UV light. In conclusion, the stability-indicating method could be employed to determine curcumin in bulk and emulsions.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  18. 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
  19. Mohd Hazli UHA, Abdul-Aziz A, Mat-Junit S, Chee CF, Kong KW
    Food Res Int, 2019 01;115:241-250.
    PMID: 30599938 DOI: 10.1016/j.foodres.2018.08.094
    Alternanthera sessilis (red) (ASR) is an edible herbal plant with many beneficial health effects. This study aimed to investigate the antioxidant components and antioxidant activities of the edible leaves and stems of ASR extracted using solvent of varying polarities namely water, ethanol, ethyl acetate and hexane. ASR leaf extracts showed higher in both antioxidant components and activities than the stem extracts. Among the antioxidant components, the ethanol leaf extract showed higher phenolic (77.29 ± 1.02 mg GAE/g extract) content while the ethyl acetate leaf extract was rich in flavonoids (157.44 ± 10.19 mg RE/g extract), carotenoids (782.97 ± 10.78 mg BE/g extract) and betalains (betanin: 67.08 ± 0.49 mg/g extract; amaranthin: 93.94 ± 0.68 mg/g extract and betaxanthin: 53.92 ± 0.88 mg/g extract). Nevertheless, the ethanol leaf extract showed the highest DPPH radical scavenging activity and ABTS radical cation scavenging activity. It also exhibited highest ferric reducing activity among all the extracts. Four polyphenolic compounds from ASR leaf, namely ferulic acid, rutin, quercetin and apigenin, were identified and quantified using ultra high performance liquid chromatography. The existence of these compounds was further verified using tandem mass spectrometry. These current results indicate that ASR leaf particularly the ethanol extract has the potential to be exploited as a source of natural antioxidants.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  20. Sharma A, Kamble SH, León F, Chear NJ, King TI, Berthold EC, et al.
    Drug Test Anal, 2019 Aug;11(8):1162-1171.
    PMID: 30997725 DOI: 10.1002/dta.2604
    Kratom (Mitragyna speciosa) is a psychoactive plant popular in the United States for the self-treatment of pain and opioid addiction. For standardization and quality control of raw and commercial kratom products, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantification of ten key alkaloids, namely: corynantheidine, corynoxine, corynoxine B, 7-hydroxymitragynine, isocorynantheidine, mitragynine, mitraphylline, paynantheine, speciociliatine, and speciogynine. Chromatographic separation of diastereomers, or alkaloids sharing same ion transitions, was achieved on an Acquity BEH C18 column with a gradient elution using a mobile phase containing acetonitrile and aqueous ammonium acetate buffer (10mM, pH 3.5). The developed method was linear over a concentration range of 1-200 ng/mL for each alkaloid. The total analysis time per sample was 22.5 minutes. The analytical method was validated for accuracy, precision, robustness, and stability. After successful validation, the method was applied for the quantification of kratom alkaloids in alkaloid-rich fractions, ethanolic extracts, lyophilized teas, and commercial products. Mitragynine (0.7%-38.7% w/w), paynantheine (0.3%-12.8% w/w), speciociliatine (0.4%-12.3% w/w), and speciogynine (0.1%-5.3% w/w) were the major alkaloids in the analyzed kratom products/extracts. Minor kratom alkaloids (corynantheidine, corynoxine, corynoxine B, 7-hydroxymitragynine, isocorynantheidine) were also quantified (0.01%-2.8% w/w) in the analyzed products; however mitraphylline was below the lower limit of quantification in all analyses.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
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