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  1. High performance liquid chromatographic method optimized by Box-Behnken design model to determine caffeine in pharmaceutical preparations and urine samples
    Najmul Hejaz Azmi S, Aqib Nasir Al Rawahi W, Ibrahim Al Yahyai A, Ali Al Qasimi A, Saif Al Fuliti K, Said Al Qalhati O, et al.
    J Chromatogr B Analyt Technol Biomed Life Sci, 2024 Feb 15;1234:124035.
    PMID: 38309045 DOI: 10.1016/j.jchromb.2024.124035
    A UV-HPLC method optimized by Box-Behnken design model was developed to determine caffeine in pharmaceutical preparations and urine samples. The chromatographic conditions followed were mobile phase: methanol/water/ citrate buffer (pH 4.6) (40:25:35, v/v/v),AcclaimTMDionex C18 column (ODS 100A˚, 5 µm; 4.6 × 250 mm),flow rate (0.9 mL min-1), column temperature (30 °C) and UV-detection wavelength (204 nm). The chromatographic variables: pH (A), % methanol fraction (B), flow rate(C) and column temperature (D) were optimized at 50 μg mL-1caffeine using BBD model. The chromatogram resulted in the asymmetry factor (1.23), theoretical plate 13,786 and retention time (5.79 min). The proposed HPLC method's greenness point was assessed byAnalytical Eco-scale and found to be 78 (as per guidelines, ranked as excellent). The linearity was ranged from2.0 to 70 µg mL-1 with coefficient of correlation (r = 0.999) and detection limit of 0.19 µg mL-1. The proposedmethod was developed successfully and applied for the assay of active caffeine in pharmaceutical preparations and urine samples. The % recovery obtained by both (proposed and reference) methods ranged from 99.98 to 100.05 % followed the compliance (100 ± 2 %) with Canadian Health Protection regulatory guidelines. The performance of the proposed method was compared with published papers and found to be acceptable and superior. The proposed method was quite effective as the reference method, and hence can be used as an alternative method for the assay of active caffeine in pharmaceutical preparations and urine samples.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  2. In situ derivatization hollow fibre liquid-phase microextraction for the determination of biogenic amines in food samples
    Saaid M, Saad B, Ali AS, Saleh MI, Basheer C, Lee HK
    J Chromatogr A, 2009 Jul 3;1216(27):5165-70.
    PMID: 19481215 DOI: 10.1016/j.chroma.2009.04.091
    Hollow fibre liquid-phase microextraction with in situ derivatization using dansyl chloride has been successfully developed for the high-performance liquid chromatography-ultraviolet (HPLC-UV) determination of the biogenic amines (tryptamine, putrescine, cadaverine, histamine, tyramine, spermidine) in food samples. Parameters affecting the performance of the in situ derivatization process such as type of extraction solvent, temperature, extraction time, stirring speed and salt addition were studied and optimized. Under the optimized conditions (extraction solvent, dihexyl ether; acceptor phase, 0.1M HCl; extraction time, 30 min; extraction temperature, 26 degrees C; without addition of salt), enrichment factors varying from 47 to 456 were achieved. Good linearity of the analytes was obtained over a concentration range of 0.1-5 microg mL(-1) (with correlation coefficients of 0.9901-0.9974). The limits of detection and quantification based on a signal-to-noise ratio of 3-10, ranged from 0.0075 to 0.030 microg mL(-1) and 0.03 to 0.10 microg mL(-1), respectively. The relative standard deviations based on the peak areas for six replicate analysis of water spiked with 0.5 microg mL(-1) of each biogenic amine were lower than 7.5%. The method was successfully applied to shrimp sauce and tomato ketchup samples, offering an interesting alternative to liquid-liquid extraction and solid phase extraction for the analysis of biogenic amines in food samples.
    Matched MeSH terms: Chromatography, High Pressure Liquid/instrumentation; Chromatography, High Pressure Liquid/methods*
  3. Alpha-tocopherol content in 62 edible tropical plants
    Ching LS, Mohamed S
    J Agric Food Chem, 2001 Jun;49(6):3101-5.
    PMID: 11410015
    Vitamin E was determined by the high-performance liquid chromatography (HPLC) method. All the plants tested showed differences in their alpha-tocopherol content and the differences were significant (p < 0.05). The highest alpha-tocopherol content was in Sauropus androgynus leaves (426.8 mg/kg edible portion), followed by Citrus hystrix leaves (398.3 mg/kg), Calamus scipronum (193.8 mg/kg), starfruit leaves Averrhoa belimbi (168.3 mg/kg), red pepper Capsicum annum (155.4 mg/kg), local celery Apium graveolens (136.4 mg/kg), sweet potato shoots Ipomoea batatas (130.1 mg/kg), Pandanus odorus (131.5 mg/kg), Oenanthe javanica (146.8 mg/kg), black tea Camelia chinensis (183.3 mg/kg),papaya Carica papaya shoots (111.3 mg/kg), wolfberry leaves Lycium chinense (94.4 mg/kg), bird chili Capsicum frutescens leaves (95.4 mg/kg), drumstick Moringa oleifera leaves (90.0 mg/kg), green chili Capsicum annum (87 mg/kg), Allium fistulosum leaves (74.6 mg/kg), and bell pepper Capsicum annum (71.0 mg/kg). alpha-Tocopherol was not detected in Brassica oleracea, Phaeomeria speciosa, Pachyrrhizus speciosa, Pleurotus sajor-caju, and Solanum melongena.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  4. Improved high performance liquid chromatographic analysis of omeprazole in human plasma
    Yuen KH, Choy WP, Tan HY, Wong JW, Yap SP
    J Pharm Biomed Anal, 2001 Feb;24(4):715-9.
    PMID: 11272330
    A simple high-performance liquid chromatographic method was developed for the determination of omeprazole in human plasma. Omeprazole and the internal standard, chloramphenicol, were extracted from alkalinized plasma samples using dichloromethane. The mobile phase was 0.05 M Na2HPO4-ACN (65:35, v/v) adjusted to pH 6.5. Analysis was run at a flow rate of 1.0 ml/min at a detection wavelength of 302 nm. The method was specific and sensitive with a detection limit of 2.5 ng/ml at a signal-to-noise ratio of 4:1. The limit of quantification was set at 5 ng/ml. The calibration curve was linear over a concentration range of 5-1280 ng/ml. Mean recovery value of the extraction procedure was about 96%, while the within and between day coefficient of variation and percent error values of the assay method were all less than 14%.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  5. Determination of four lignans in Phyllanthus niruri L. by a simple high-performance liquid chromatography method with fluorescence detection
    Murugaiyah V, Chan KL
    J Chromatogr A, 2007 Jun 22;1154(1-2):198-204.
    PMID: 17418855 DOI: 10.1016/j.chroma.2007.03.079
    A new and simple analytical method using HPLC with fluorescence detection was developed for the simultaneous determination of four lignans (phyllanthin, hypophyllanthin, phyltetralin and niranthin) in Phyllanthus niruri L. plant samples. Optimal separation was achieved with an isocratic mobile phase consisting of acetonitrile-water (55:45 v/v). The method recorded limits of detection (S/N=5) for phyllanthin at 0.61 ng/mL, hypophyllanthin at 6.02 ng/mL, phyltetralin at 0.61 ng/mL and niranthin at 1.22 ng/mL, being 80, 8, 80 and 40 times, respectively, lower when compared with those derived using HPLC-UV detection. The limits of quantification (S/N=12) were 4.88 ng/mL for phyllanthin and phyltetralin, 9.76 ng/mL for niranthin and 24.4 ng/mL for hypophyllanthin showing 40, 8 and 20 times, respectively, lower than those from the UV detection method. The within-day and between-day accuracy for the four lignans were between 98.1% and 102.9% while their precision values were below 2.2%. The mean recovery was between 92.5% and 110.1%. The method was then successfully applied for the quantification of lignans in P. niruri plant samples. The highest amount of lignans was found in the leaves followed by fruits, branches and stem, whilst the roots have the least amount of lignans.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  6. Development and validation of a gradient HPLC-UV method for mitragynine following in vitro skin permeation studies
    Sim YS, Chong ZY, Azizi J, Goh CF
    J Chromatogr B Analyt Technol Biomed Life Sci, 2022 Jul 15;1204:123316.
    PMID: 35700649 DOI: 10.1016/j.jchromb.2022.123316
    Mitragynine is a promising candidate for pain relief and opiate replacement but the investigations for drug delivery are lacking. This study aims to investigate the potential of mitragynine to be delivered through the skin with an emphasis on developing and validating a gradient HPLC-UV analytical method to determine mitragynine in the samples collected during in vitro skin permeation studies. The optimised method involves a gradient elution using a C18 column with a mobile phase comprising acetonitrile and 0.1 %v/v of formic acid (0-1 min: 30:70 to 70:30 (v/v) and hold up to 4 min; 4-6 min: return to 30:70 (v/v) and hold up to 10 min) at a flow rate of 1.2 mL/min. This method was validated based on the standards set by the International Council on Harmonisation guidelines. The method showed mitragynine elution at ∼ 4 min with adequate linearity (R2 ≥ 0.999 for concentration ranges of 0.5-10 and 10-175 μg/mL) and acceptable limits of detection and quantification at 0.47 and 1.43 μg/mL, respectively. The analytical performance is robust with excellent precision and accuracy. This method was used to evaluate the in vitro skin permeation of mitragynine (5 %w/v) from simple solvent systems over 48 hr. The results showed a cumulative amount of mitragynine permeated at ∼ 11 μg/cm2 for dimethyl sulfoxide and ∼ 4 μg/cm2 for propylene glycol. The study not only addressed the issues of the currently available HPLC-UV methods that limit the direct application but also affirmed the potential of mitragynine to be delivered through the skin.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  7. Fulltext Fast and Sensitive HPLC-ESI-MS/MS Method for Etoricoxib Quantification in Human Plasma and Application to Bioequivalence Study
    Loh GOK, Wong EYL, Tan YTF, Heng SC, Saaid M, Cheah KY, et al.
    Molecules, 2022 Sep 04;27(17).
    PMID: 36080473 DOI: 10.3390/molecules27175706
    Etoricoxib is a non-steroidal anti-inflammatory drug (NSAID) used to treat pain and inflammation. The objective of the current study was to develop a sensitive, fast and high-throughput HPLC-ESI-MS/MS method to measure etoricoxib levels in human plasma using a one-step methanol protein precipitation technique. A tandem mass spectrometer equipped with an electrospray ionization (ESI) source operated in a positive mode and multiple reaction monitoring (MRM) were used for data collection. The quantitative MRM transition ions were m/z 359.15 > 279.10 and m/z 363.10 > 282.10 for etoricoxib and IS. The linear range was from 10.00 to 4000.39 ng/mL and the validation parameters were within the acceptance limits of the European Medicine Agency (EMA) and Food and Drug Analysis (FDA) guidelines. The present method was sensitive (10.00 ng/mL with S/N > 40), simple, selective (K prime > 2), and fast (short run time of 2 min), with negligible matrix effect and consistent recovery, suitable for high throughput analysis. The method was used to quantitate etoricoxib plasma concentrations in a bioequivalence study of two 120 mg etoricoxib formulations. Incurred sample reanalysis results further supported that the method was robust and reproducible.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods
  8. Fulltext Caffeine and theobromine levels in chocolate couverture and coating products
    Ramli N, Abdul Rahman S, Hassan O, Mohd Yatim A, Said M, Lim LS, et al.
    Malays J Nutr, 2000 Mar;6(1):55-63.
    PMID: 22692392
    Thirty-two samples of chocolate products were analysed by HPLC for caffeine and theobromine contents. Defatted residues of samples were extracted with 80% aqueous acetone. After extraction into boiling water, the methylxanthines were identified and quantified with the use of μ-Bondapak column and mobile phase of methanol:water:acetic acid (20:79:1). Levels of caffein and theobromine in 32 samples of chocolate products averaged 0.62-1.14 mg/g and 0.026-0.153 mg/g respectively. Mean values for theobromine and caffeine content for chocolate coating were 0.82 and 0.07 mg/g respectively. The chocolate coating made from fat substitute had theobromine and caffeine levels ranging from 0.36-0.70 mg/g and 0.027-0.061 mg/g respectively, with mean values of 0.49 mg theobromine/g and 0.039 mg caffeine/g. In local chocolate, the mean theobromine and caffeine levels respectively were 0.72 mg/g and 0.04 mg/g in milk chocolate, and 0.85 mg/g and 0.06 mg/g in dark chocolate. Meanwhile, for imported chocolate, the mean theobromine and caffeine levels respectively were 1.05 mg/g and 0.12 mg/g in dark chocolate; 0.76 mg/g and 0.04 mg/g in milk chocolate; and 0.74 mg/g and 0.03 mg/g in white chocolate. Compared with the local chocolates, imported chocolates had higher levels of theobromine and caffeine at 1.141 mg/g and 0.1533mg/g. The average theobromine and caffeine concentrations in local chocolate were 0.082mg/g and 0.066mg/g. Theobromine concentration in chocolate samples is within the range of 0.62mg/g-1.141mg/g and the range of caffeine concentration is 0.026mg/g-0.153mg/g respectively. Bittersweet chocolates were found to have higher theobromine and caffeine concentrations than normal sweet chocolates and milk chocolates.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  9. Fulltext Supercritical fluid extraction of bioactive flavonoid from Strobilanthes crispus (pecah kaca) and its comparison with solvent extraction
    Liza, M.S., Abdul Rahman, R., Mandana, B., Jinap, S., Rahmat, A., Zaidul, I.S.M., et al.
    International Food Research Journal, 2012;19(2):503-508.
    MyJurnal
    Supercritical carbon dioxide extraction (SC-CO2) of bioactive flavonoid from Strobilanthes crispus (Pecah Kaca) was performed to study the effects of various parameters such as pressure, temperature and dynamic extraction time on the yield and composition of bioactive flavonoid. The results were also compared with those obtained by conventional Soxhlet extraction in lab conditions. The results from SFE showed that the effect of extraction variables on extraction yields decreased in the following order: pressure, temperature and dynamic extraction time. The extraction pressure played a dominant role in the yield of the sample while the effect of time could be ignored. This study also revealed that both Soxhlet extraction and SC-CO2 extraction can be used to obtain flavonoid compound. Under the optimum conditions, the highest bioactive flavonoid compound content was obtained at 3.98% and eight flavonoid compounds were identified by HPLC.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  10. Kesan kepekatan asid performik terhadap pengepoksidaan minyak sawit olein
    Darfizzi Derawi, Jumat Salimon
    Sains Malaysiana, 2011;40:1123-1127.
    Kajian pengoptimuman tindak balas pengepoksidaan minyak sawit olein (POo) dengan menggunakan mangkin asid performik (HCOOOH) telah dijalankan. Kesan tindak balas terhadap nisbah kepekatan HCOOH : H2O2 dan masa tindak balas telah dikaji pada suhu 45oC. Kandungan oksigen oksirana (OOC) optimum sebanyak 3.61% diperoleh dengan menggunakan nisbah mol 1 : 5 : 2 pada 150 min dan sebanyak 96.5% penukaran dapat dicapai. Hasil tindak balas adalah sebanyak 91.3%. Puncak kromatografi cecair berprestasi tinggi (HPLC) bagi minyak sawit olein terepoksida (EPOo) telah berubah sepenuhnya berbanding puncak HPLC POo. Spektrum transformasi Fourier infra-merah (FTIR) telah menunjukkan kehadiran puncak ikatan gelang oksirana pada 844 cm-1.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  11. Fulltext Simple and sensitive method for the analysis of ketorolac in human plasma using high-performance liquid chromatography
    Muralidharan S, Jayaraja Kumar K, Parasuraman S
    J Young Pharm, 2013 Sep;5(3):98-101.
    PMID: 24396250 DOI: 10.1016/j.jyp.2013.06.007
    To develop a simple and sensitive method of ketorolac in drug free human plasma using high-performance liquid chromatographic (HPLC).
    Matched MeSH terms: Chromatography, High Pressure Liquid
  12. 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/economics; Chromatography, High Pressure Liquid/methods*; Chromatography, High Pressure Liquid/standards*
  13. Your mycotoxins in water paper
    Paterson RRM, Buddie A
    Environ Sci Pollut Res Int, 2019 05;26(13):13676.
    PMID: 30357675 DOI: 10.1007/s11356-018-3544-3
    Matched MeSH terms: Chromatography, High Pressure Liquid
  14. Frying performance of palm-based solid frying shortening
    Omar MN, Nor-Nazuha MN, Nor-Dalilah MN, Sahri MM
    Pak J Biol Sci, 2010 Mar 15;13(6):298-302.
    PMID: 20506718
    In order to evaluate the frying performance of palm-based solid frying shortening against standard olein, the fresh potato chips were fried in both frying media using an open fryer. After frying the chips for 40 h in an open batch fryer, it was found that the frying quality of palm-based solid frying shortening was better than standard palm olein in terms of Free Fatty Acid (FFA) values, Total Polar Content (TPC) and Total Polymeric Material (TPM). Solid shortening gave FFA, TPC and TPM values of 0.7, 15.3 and 2.67%, respectively, whilst standard palm olein gave values for FFA, TPC and TPM of 1.2, 19.6 and 3.10%, respectively. In terms of sensory mean scores, sensory panelists preferred the color of potato chips fried in solid shortening on the first day of frying, while on the third and fifth day of frying there were no significant differences (p < 0.05) in the sensory scores of fried products in both frying mediums. However, on the fifth day of frying, panelists gave higher scores in terms of taste, flavor and crispness for potato chips fried in solid shortening. These findings show that the palm-based solid shortening is better than palm olein when used for deep fat frying in terms of FFA values, total polar content and total polymeric material, especially for starch-based products such as potato chips. The result also shows that, in terms of sensory mean scores, after frying for 40 h, the sensory panelists gave higher scores in terms of taste, flavor and crispiness for potato chips fried in palm-based solid shortening.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  15. Detection of dynorphin 1-17 biotransformation fragments in human nasal polyps by UPLC-QTOF-MS
    Ballouze R, Ismail MN, Abu Kassim NS, Salhimi SM, Mohamad I, Abd Mutalib NS, et al.
    Anal Bioanal Chem, 2024 Jan;416(2):545-557.
    PMID: 38040942 DOI: 10.1007/s00216-023-05061-3
    Chronic rhinosinusitis with nasal polyps (CRSwNP) is a persistent inflammation of the sinonasal mucosa. CRSwNP treatments are associated with inconsistent efficacy and recurrence of symptoms. Dynorphin 1-17 (DYN 1-17) and its fragments have been shown to modulate the immune response in various inflammatory conditions. This study aimed to investigate the effect of different pH and degrees of inflammation on DYN 1-17 metabolism in human CRSwNP tissues. DYN 1-17 was incubated with grade 3 and grade 4 inflamed tissues of CRSwNP patients at pH 5.5 and pH 7.4 over a range of incubation periods. The resulting fragments were identified using an ultra-performance liquid chromatography (UPLC) system coupled to quadrupole-time of flight (QTOF) mass spectrometry based on their accurate mass. The rate of DYN 1-17 fragmentation was slower at pH 5.5 in comparison to pH 7.4. The extent and rate of metabolism of DYN 1-17 were much lower in grade 3 inflamed tissue (31-32 fragments) than in grade 4 (34-41 fragments). N-Terminal fragments (DYN 1-15, 1-11, 1-10, and 1-6) were metabolized slower at pH 5.5 as compared to pH 7.4. DYN 1-12, 1-8, 2-10, 4-10, 5-10, and 8-14 were only observed under the inflammatory pH while DYN 5-17 and 6-17 were only identified upon incubation with grade 4 CRSwNP tissues. DYN 1-17 metabolism was significantly affected by the pH level and the severity of the inflammation of CRSwNP tissues, indicating the potential roles of DYN 1-17 and its fragments in modulating the inflammatory response and their avenue as therapeutics in future studies.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  16. Stability indicating HPLC-UV method for detection of curcumin in Curcuma longa extract and emulsion formulation
    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*
  17. Effect of deprotenizing agent and quantification of donepezil hydrochloride in human plasma
    Liew KB, Peh KK, Fung Tan YT
    Pak J Pharm Sci, 2014 Sep;27(5):1303-7.
    PMID: 25176366
    The effect of deprotenizing agents on recovery of donepezil hydrochloride in the development of a simple, rapid, selective and sensitive high performance liquid chromatography method for quantification of donepezil hydrochloride in human plasma was described. The deprotenizing agents were comprised of, perchloric acid, methanol, acetonitrile, chloroform and their mixtures. The chromatographic separation was carried out using reversed phase C18 column (Agilent Eclipse Plus C18) with UV detection at 268 nm. The mobile phase was comprised of 0.01 M potassium dihydrogen phosphate buffer, methanol and acetronitrile (50:30:20, v/v) adjusted to pH 2.7 with phosphoric acid (80%). A combination of perchloric acid and methanol gave a cleaner sample with a good recovery of donepezil hydrochloride of above 96%. The method showed intraday precision and accuracy in the range of 6.82% to 1.5% and 3.13% to 1.12% respectively, while interday precision and accuracy ranged between 1.06% to 4.71% and 13.01% to 6.43% respectively. The standard calibration curve was linear from 30ng/mL to 4000ng/mL, with a correlation coefficient of 0.9965±0.0034. The retention time of donepezil was 5.9 min with a run time of 7.0 min. The method can be applied to analyze large batch plasma samples in pharmacokinetic studies.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
  18. A simple semi-preparative reversed-phase HPLC/PDA method for separation and quantification of glycyrrhizin in nine samples of Glycyrrhiza glabra root collected from different geographical origins
    Basar N, Talukdar AD, Nahar L, Stafford A, Kushiev H, Kan A, et al.
    Phytochem Anal, 2014 Sep-Oct;25(5):399-404.
    PMID: 24585378 DOI: 10.1002/pca.2507
    Glycyrrhiza glabra L. (Fabaceae), commonly known as 'liquorice', is one of the most popular ingredients in several traditional herbal medicinal preparations, and glycyrrhizin is the major glycoside present in this plant. The content of glycyrrhizin may vary among G. glabra samples collected from various geographical origins, which may affect the therapeutic efficacy. Thus, quantification of glycyrrhizin in G. glabra samples is important.
    Matched MeSH terms: Chromatography, High Pressure Liquid*
  19. 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*
  20. Development and validation of an ion-pair chromatographic method for simultaneous determination of trans- and cis-urocanic acid in fish samples
    Zare D, Muhammad K, Bejo MH, Ghazali HM
    J Chromatogr A, 2012 Sep 21;1256:144-9.
    PMID: 22885043 DOI: 10.1016/j.chroma.2012.07.083
    Urocanic acid (UCA) has been reported to be a mast cell degranulator and has also been suggested as a complementary agent in implicated scombroid fish poisoning. In this research, a new method is described to extract, clean up and perform simultaneous ion-pair chromatographic analysis of trans- and cis-urocanic acid (UCA) in fish samples. UCA was extracted using 0.05 M HCl and protein was removed from the extract by precipitation with 10% trisodium citrate and 10% citric acid. The HPLC method that is developed showed a rapid, precise and sensitive method with short retention time for simultaneous separation of UCA isomers in fish samples. Estimation of trans- and cis-UCA in the muscle of Indian mackerel, tuna and sardine showed that, as expected, no cis-UCA existed in fish muscles and the highest concentration of trans-UCA was found in Indian mackerel with 118.8 mg kg(-1) while the highest concentrations of trans-UCA in tuna and sardine were 12.1 and 17.5 mg kg(-1), respectively.
    Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
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