pH-Gradient Liquid Chromatography: Fundamentals and Examples

2017 ◽  
Vol 100 (6) ◽  
pp. 1590-1598 ◽  
Author(s):  
Łukasz Kubik ◽  
Paweł Wiczling ◽  
Roman Kaliszan
Keyword(s):  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Gradient Elution ◽  
Complex Mixtures ◽  
Ph Gradient ◽  
Organic Modifier ◽  
Ph Gradient Elution ◽  
Gradient Separation ◽  
Gradient Liquid Chromatography

Abstract In this paper, we acquaint the readers with the fundamentals of gradient separation, followed by the latest innovations in this field. We describe the principles of organic modifier- and pH-gradient elution emphasizing the differences and similarities with isocratic separation. The double organic modifier-/pH-gradient is also thoroughly reviewed as a useful method for the simultaneous determination of logkw (substitute of logP) and the pka of analytes present in complex mixtures.

scholarly journals A Simple High-Performance Liquid Chromatography Method for Simultaneous Determination of Three Triazole Antifungals in Human Plasma

2012 ◽  
Vol 57 (1) ◽  
pp. 484-489 ◽  
Author(s):  
Mei Zhang ◽  
Grant A. Moore ◽  
Murray L. Barclay ◽  
Evan J. Begg
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Human Plasma ◽  
High Performance ◽  
Internal Standard ◽  
Gradient Elution ◽  
Limit Of Quantification ◽  
Chromatography Method

ABSTRACTA rapid and simple high-performance liquid chromatography (HPLC) assay was developed for the simultaneous determination of three triazole antifungals (voriconazole, posaconazole, and itraconazole and the metabolite of itraconazole, hydroxyitraconazole) in human plasma. Sample preparation involved a simple one-step protein precipitation with 1.0 M perchloric acid and methanol. After centrifugation, the supernatant was injected directly into the HPLC system. Voriconazole, posaconazole, itraconazole, its metabolite hydroxyitraconazole, and the internal standard naproxen were resolved on a C6-phenyl column using gradient elution of 0.01 M phosphate buffer, pH 3.5, and acetonitrile and detected with UV detection at 262 nm. Standard curves were linear over the concentration range of 0.05 to 10 mg/liter (r2> 0.99). Bias was <8.0% from 0.05 to 10 mg/liter, intra- and interday coefficients of variation (imprecision) were <10%, and the limit of quantification was 0.05 mg/liter.

Simultaneous Determination of Seven Active Components in Desheng Pills by High-performance Liquid Chromatography

2020 ◽  
Vol 17 (1) ◽  
pp. 149-158
Author(s):  
Yang Xu ◽  
Huailei Yang ◽  
Baiyu Shan ◽  
Kuo Fang ◽  
Mingyu Li ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
High Performance ◽  
Blood Stasis ◽  
Gradient Elution ◽  
Phosphoric Acid Solution ◽  
Array Detector ◽  
Active Components

Background: Desheng pills (DSP) consist of six traditional Chinese medicine. This preparation is used fornourishing blood, eliminating stasis, soothing liver and regulating menstruation, and can also be used to treat menoxenia and dysmenorrhea caus ed by qi stagnation and blood stasis. Objective: In this paper, an accurate and sensitive high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed and validated for simultaneous determination of seven active components (gallic acid, paeoniflorin, costunolide, dehydrocostuslactone, rutin, leonurine hydrochloride and ferulic acid) in the traditional Chinese formula-Desheng pills. Methods: The seven analytes were separated on Agilent ZORBAX SB-C18 column (250mm× 4.6mm, 5μm) maintained at the temperature of 30.. Gradient elution was performed with the mobile phase of methanol (A)-0.1% phosphoric acid solution (B) at the flow rate of 1.0mL·min-1. The analysis was carried out at the wavelength of 225 nm, 256 nm, 277 nm and 320 nm with an injection volume of 10 μL. Results: The measured seven components showed good linear relationships within their own concentration ranges along with coefficients of determination ≥0.9996. The limits of detection and quantitation of all analytes were in the range of 0.19-13.51 μg/mL and 0.59-40.93 μg/mL, respectively. Average recoveries ranged from 98.82% to 102.01% with RSDs of 1.47%-1.99%. The content of tested components was in the range of 0.053-0.421 mg/g. Conclusion: The proposed method was found to be sensitive, accurate and reproducible, which provided an effective quantitative analytical method for quality control of Desheng pills.

Simultaneous determination of 8 fluoroquinolone antibiotics in sewage treatment plants by solid-phase extraction and liquid chromatography with fluorescence detection

2009 ◽  
Vol 59 (4) ◽  
pp. 805-813 ◽  
Author(s):  
L. Shi ◽  
X. F. Zhou ◽  
Y. L. Zhang ◽  
G. W. Gu
Keyword(s):  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Fluorescence Detection ◽  
Solid Phase ◽  
Sewage Treatment ◽  
Gradient Elution ◽  
Ammonium Bromide ◽  
Sewage Treatment Plants ◽  
Relative Standard

Fluoroquinolones (FQs) are among the most important antibiotics used in human and veterinary medicines. A simple and effective analytical method based on reversed-phased liquid chromatography with fluorescence was developed and validated for the simultaneous determination of eight FQs in wastewater at trace level. Aqueous samples were extracted using AnpelTM MEP cartridges where they were subsequently eluted by formic acid in methanol. The aqueous extracts were analyzed by gradient elution Liquid Chromatography with Fluorescence Detection (LC–FLD), whose mobile phase was composed of acetonitrile and 10 mM tetrabutyl ammonium bromide (TBAB). The limits of detection (LOD) and the relative standard deviation (RSD) were as low as 0.11–1.06 μg/L and 2–5%, respectively. The presented method was successfully applied to quantify FQs in the influent and effluent of several typical Sewage Treatment Plants (STPs) in Shanghai. For the extraction of 100 mL influent and 500 mL effluent sewage water samples, recoveries obtained were between 79–109% and 80%–105%, respectively. 7 FQs were occurred and identified in the STPs with the concentrations varying from 7 ng/L to 1 μg/L. Norfloxacin, ciprofloxacin and lomefloxacin were the most frequently detected antibiotics occurring in the wastewaters. The analytical procedure developed may be used for more in-depth studies on the occurrences and the fate of these commonly used pharmaceuticals in the sewage treatment plants and in the aquatic environment.

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