An initial assessment of the use of gradient elution in microemulsion and micellar liquid chromatography

2004 ◽  
Vol 27 (17-18) ◽  
pp. 1498-1502 ◽  
Author(s):  
Simon M. Bryant ◽  
Kevin D. Altria
Keyword(s):  
Liquid Chromatography ◽  
Gradient Elution ◽  
Micellar Liquid Chromatography ◽  
Initial Assessment

Gradient elution in micellar liquid chromatography I. Micelle concentration gradient

1994 ◽  
Vol 683 (2) ◽  
pp. 321-334 ◽  
Author(s):  
Lillian S. Madamba-Tan ◽  
Joost K. Strasters ◽  
Morteza G. Khaledi
Keyword(s):  
Liquid Chromatography ◽  
Concentration Gradient ◽  
Gradient Elution ◽  
Micellar Liquid Chromatography

Gradient elution in micellar liquid chromatography II. Organic modifier gradients

1994 ◽  
Vol 683 (2) ◽  
pp. 335-345 ◽  
Author(s):  
Lillian S. Madamba-Tan ◽  
Joost K. Strasters ◽  
Morteza G. Khaledi
Keyword(s):  
Liquid Chromatography ◽  
Gradient Elution ◽  
Micellar Liquid Chromatography ◽  
Organic Modifier

Isocratic and gradient elution in micellar liquid chromatography with Brij-35

2015 ◽  
Vol 38 (12) ◽  
pp. 2059-2067 ◽  
Author(s):  
Ester Peris-García ◽  
Casandra Ortiz-Bolsico ◽  
Juan José Baeza-Baeza ◽  
María Celia García-Alvarez-Coque
Keyword(s):  
Liquid Chromatography ◽  
Gradient Elution ◽  
Micellar Liquid Chromatography ◽  
Brij 35 ◽  
Isocratic And Gradient Elution

Gradient elution micellar liquid chromatography

1984 ◽  
Vol 316 ◽  
pp. 183-191 ◽  
Author(s):  
John G. Dorsey ◽  
Morteza G. Khaledi ◽  
John S. Landy ◽  
Jun-Liang Lin
Keyword(s):  
Liquid Chromatography ◽  
Gradient Elution ◽  
Micellar Liquid Chromatography

Micellar liquid chromatography of plant extracts components

2014 ◽  
Vol 27 (6) ◽  
pp. 420-427 ◽  
Author(s):  
Katarzyna Stępnik ◽  
Irena Malinowska ◽  
Edward Rój
Keyword(s):  
Liquid Chromatography ◽  
Plant Extracts ◽  
Micellar Liquid Chromatography

Simultaneous Determination of Methocarbamol and Paracetamol in the Presence of Three Related Substances by Ultra Performance Liquid Chromatography

2019 ◽  
Vol 15 (5) ◽  
pp. 505-510
Author(s):  
Yanjuan Zheng ◽  
Qiushi Peng ◽  
Rui Dong ◽  
Tingyu Chen ◽  
Yi Bao ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Pharmaceutical Preparations ◽  
Gradient Elution ◽  
Ultra Performance Liquid Chromatography ◽  
Related Substances ◽  
Bulk Powder ◽  
Highly Sensitive ◽  
Optimal Protocol ◽  
Acquity Uplc

Introduction: A rapid, and accurate Ultra Performance Liquid Chromatography (UPLC) method was developed to simultaneously analyze Methocarbamol, Paracetamol and the related substances Materials and Methods: Waters ACQUITY UPLC® BEH Phenyl C18 column was used in conjunction with UV detection at 225nm. Gradient elution with 0.05M, pH 6 phosphate buffer and acetonitrile flow at 0.3mL /min rate were used to separate the substances. The retention times for 4-Aminopheno, Paracetamol, Guaifenesin, Methocarbamol, and 4-Chloroacetanilide were 1.319 minute, 2.224 minute, 4.467 minute, 4.769 minute and 5.433 minute respectively. The concentration was linear in the range of 2-100 µg/ml for Methocarbamol, and 1-100 µg/mL for Paracetamol. The percentage recoveries were between 99.28±1.23% to 100.57±0.99% for Methocarbamol, and between 99.08±1.23% to 101.23±1.39% for Paracetamol. Results and Discussion: The validated optimal protocol is robust and accurate for simultaneous analysis of Methocarbamol, Paracetamol and the related substances, applicable for bulk powder as well as pharmaceutical formulation. Conclusion: In this paper, a highly sensitive, accurate, and precise UPLC method with UV-Vis detection was developed and validated for quality control of MET and PAR in bulk as well as in pharmaceutical preparations.

Analysis of organic impurities of besifloxacin hydrochloride by high performance liquid chromatography with isocratic and gradient elution.

2019 ◽  
Vol 16 ◽  
Author(s):  
Joanna Wittckind Manoel ◽  
Camila Ferrazza Alves Giordani ◽  
Livia Maronesi Bueno ◽  
Sarah Chagas Campanharo ◽  
Elfrides Eva Sherman Schapoval ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Gradient Elution ◽  
Pharmaceutical Product ◽  
Raw Material ◽  
Isocratic Elution ◽  
Organic Impurities ◽  
Elution Method

Introduction: Impurity analysis is an important step in the quality control of pharmaceutical ingredients and final product. Impurities can arise from drug synthesis or excipients and even at small concentrations may affect product efficacy and safety. In this work two methods using high performance liquid chromatography (HPLC) were developed and validated for the evaluation of besifloxacin and its impurity synthesis, with isocratic elution and another with gradient elution. Method: The analysis by HPLC in isocratic elution mode was performed using a cyano column maintained at 25 °C. The mobile phase was composed by 0.5% triethylamine (pH 3.0): acetonitrile (88:12 v/v) eluted at a flow rate of 1.0 ml/min with detection at 330 nm. The gradient elution method was carried out with the same column and mobile phase components only modifying the rate between organic and aqueous phase during analysis. The procedures have been validated according to internationally accepted guidelines, observing results within acceptable limits. Results: The methods presented were found to be linear in the 140 to 260 µg/ml range for besifloxacin and 0.3 to 2.3 µg/ml for an impurity named A. The limits of detection and quantification were respectively 0.07 and 0.3 µg/ml for impurity A, with a 20 µL injection volume. The precision achieved for all analyses performed provided RSD inter-day equal to 6.47 and 6.36% for impurity A with isocratic elution and gradient, respectively. The accuracy was higher than 99% and robustness exhibited satisfactory results. In the isocratic method an analysis time of 25 min and 15 min was obtained for gradient. For impurity A, the number of theoretical plates in the isocratic mode was about 5000 while in the gradient mode it was about 45000, hence, it made the column more efficient by changing the mobile phase composition during elution. In besifloxacin raw material and in pharmaceutical product used in this study, other related impurities were present but but impurity A was searched for and not detected Conclusion: The proposed methods can be applied for quantitative determination of impurities in the analysis of the besifloxacin raw material, as well as in ophthalmic suspension of the drug, considering the quantitation limit.

Simultaneous Determination of Six Components in Jingzhiguanxin Tablet by High-Performance Liquid Chromatography

2019 ◽  
Vol 15 (2) ◽  
pp. 130-137
Author(s):  
Hui Jiang ◽  
Lianhao Fu ◽  
Yu Wang ◽  
Shaozhi Wang ◽  
Xiaoxu Zhang ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Gradient Elution ◽  
Tanshinone Iia ◽  
Array Detector ◽  
Control Analysis ◽  
Active Components ◽  
Quality Control Analysis

Background: Jingzhiguanxin (JZGX) tablet, a traditional Chinese prescription, is commonly used for treating coronary heart disease and angina pectoris in the clinic. There are six active components (Danshensu (DSS), Protocatechuic aldehyde (PD), Paeoniflorin (PF), Ferulic acid (FA), Salvianolic acid B (Sal B) and Tanshinone IIA (TA)) in JZGX tablet. </P><P> Objective: In this paper, a simple and reliable method was used for simultaneous determining the six active components by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). Methods: These six active components were separated on an Agilent Zorbax Eclipse XDB-C18 column (150 mmx4.6 mm, 5 µm) at 30 °C. Acetonitrile (A), methanol (B) and 0.5% H3PO4 aqueous solution (C) were used as mobile phase for gradient elution. The flow rate was 1 mL/min and the detection wavelengths were set at 280 nm for DSS, PD and Sal B, 230 nm for PF, 320 nm for FA and 270 nm for TA, respectively. Results: All of the six components showed good linearity regressions (r2≥0.9997) in the detected concentration range. The recovery rates and coefficient of variation (CV) for all analytes were 98.66%- 100.18% and 0.75%-1.89%, respectively. This method was successfully applied to simultaneously determine the six components in JZGX tablet from different batches and manufacturers. Conclusion: The validated method can be used in routine quality control analysis of JZGX tablet without any interference.

scholarly journals Determination of Antiviral Drugs and Their Metabolites Using Micro-Solid Phase Extraction and UHPLC-MS/MS in Reversed-Phase and Hydrophilic Interaction Chromatography Modes

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2123
Author(s):  
Luboš Fical ◽  
Maria Khalikova ◽  
Hana Kočová Vlčková ◽  
Ivona Lhotská ◽  
Zuzana Hadysová ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Tandem Mass ◽  
Phase Extraction ◽  
Hydrophilic Interaction

Two new ultra-high performance liquid chromatography (UHPLC) methods for analyzing 21 selected antivirals and their metabolites were optimized, including sample preparation step, LC separation conditions, and tandem mass spectrometry detection. Micro-solid phase extraction in pipette tips was used to extract antivirals from the biological material of Hanks balanced salt medium of pH 7.4 and 6.5. These media were used in experiments to evaluate the membrane transport of antiviral drugs. Challenging diversity of physicochemical properties was overcome using combined sorbent composed of C18 and ion exchange moiety, which finally allowed to cover the whole range of tested antivirals. For separation, reversed-phase (RP) chromatography and hydrophilic interaction liquid chromatography (HILIC), were optimized using extensive screening of stationary and mobile phase combinations. Optimized RP-UHPLC separation was carried out using BEH Shield RP18 stationary phase and gradient elution with 25 mmol/L formic acid in acetonitrile and in water. HILIC separation was accomplished with a Cortecs HILIC column and gradient elution with 25 mmol/L ammonium formate pH 3 and acetonitrile. Tandem mass spectrometry (MS/MS) conditions were optimized in both chromatographic modes, but obtained results revealed only a little difference in parameters of capillary voltage and cone voltage. While RP-UHPLC-MS/MS exhibited superior separation selectivity, HILIC-UHPLC-MS/MS has shown substantially higher sensitivity of two orders of magnitude for many compounds. Method validation results indicated that HILIC mode was more suitable for multianalyte methods. Despite better separation selectivity achieved in RP-UHPLC-MS/MS, the matrix effects were noticed while using both chromatographic modes leading to signal enhancement in RP and signal suppression in HILIC.

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