Adsorption Isotherms of Substituted Benzophenones on a Reverse-Phase Liquid Chromatography System: Effect of the Mobile-Phase Composition

2010 ◽  
Vol 55 (11) ◽  
pp. 4768-4774 ◽  
Author(s):  
Matias I. Sancho ◽  
Sonia E. Blanco ◽  
Eduardo A. Castro
Keyword(s):  
Liquid Chromatography ◽  
Phase Composition ◽  
Adsorption Isotherms ◽  
Mobile Phase ◽  
Mobile Phase Composition ◽  
Reverse Phase ◽  
System Effect ◽  
Reverse Phase Liquid Chromatography ◽  
Phase Liquid ◽  
Liquid Chromatography System

Determination of Seven Artificial Sweeteners in Diet Food Preparations by Reverse-Phase Liquid Chromatography with Absorbance Detection

1988 ◽  
Vol 71 (5) ◽  
pp. 934-937 ◽  
Author(s):  
James F Lawrence ◽  
Claudette F Charbonneau
Keyword(s):  
Liquid Chromatography ◽  
Mobile Phase ◽  
Sorbic Acid ◽  
Artificial Sweeteners ◽  
Reverse Phase ◽  
Phase Gradient ◽  
Reverse Phase Liquid Chromatography ◽  
Absorbance Detection ◽  
Phase Liquid

Abstract The artificial sweeteners aspartame, saccharin, cyclamate, alitame, acesulfam-K, sucralose, and dulcin are determined in diet soft drinks and tabletop sweetener preparations. Samples are diluted, filtered, and analyzed directly by liquid chromatography on a C-18 reversephase column with a mobile phase gradient ranging from 3% acetonitrile in 0.02M KH2P04 (pH 5) to 20% acetonitrile in 0.02M KH2P04 (pH 3.5). Diet puddings and dessert toppings are extracted with ethanol, filtered, and diluted with mobile phase for analysis. The sweeteners, except sucralose and cyclamate, were detected by UV absorbance at either 200 or 210 nm. Sucralose was determined at 200 nm or by refractive index. Cyclamate was determined after post-column ion-pair extraction. The sweeteners stevioside and talin were not detected. Additives such as caffeine, sorbic acid, and benzoic acid did not interfere.

Sulfated Polyborate, a novel buffer for low pH mobile phase on a non-end capped stationary phase in reverse phase liquid chromatography

2021 ◽  
Vol 08 ◽  
Author(s):  
Purushottam Sutar ◽  
Pravin Khedkar ◽  
Ganesh Chaturbhuj
Keyword(s):  
Liquid Chromatography ◽  
Stationary Phase ◽  
Mobile Phase ◽  
Basic Drugs ◽  
Buffer Concentration ◽  
Organic Modifier ◽  
Reverse Phase ◽  
Sulfated Polyborate ◽  
Reverse Phase Liquid Chromatography ◽  
Phase Liquid

Background: Sulfated Polyborate, a novel inorganic material primarily designed as a catalyst, has shown properties such as high solubility in organic solvents, low U.V. cut-off, and pKa ≈2.0, which suggests its potential as a mobile phase buffer for reverse-phase liquid chromatography. Objective: This study aims to substantiate the role of Sulfated Polyborate as mobile phase buffer for reverse-phase liquid chromatographic analysis of basic drugs with high pKa values viz. Bisoprolol fumarate, Timolol maleate, Verapamil hydrochloride, and Carvedilol. Methods: Solubilities, U.V. cut-offs, and pKa of Sulfated Polyborate was first experimentally confirmed. The behaviour of Sulfated Polyborate as mobile phase buffer at pH 3.0 was ascertained by varying the buffer concentration, flow rates, and percent organic modifier for elution of the four basic drugs on a non-end capped octyl silyl (C8) column. Similarly, the study was performed with KH2PO4 as a reference buffer. The column performance and conductometric measurements ascertained the impact of Sulfated Polyborate on the stationary phase. Results: Sulfated Polyborate and KH2PO4 buffers showed correlation coefficients of 0.99 and 1.00 for analyte retention factors for variation of buffer concentration and organic modifier composition, respectively. Peak symmetries and the number of theoretical plates were improved from > 2.0 to < 2.0 and ≈1000 to ≈3000, respectively, for Variation in buffer concentrations. Similar Van Deemter plots indicated equivalency of Sulfated Polyborate and KH2PO4 buffers. The column performance and conductometric measurements depicted no adsorption on the stationary phase. Conclusion: The present study demonstrates Sulfated Polyborate as a novel buffer for analytes with higher pKa on reverse-phase liquid chromatography.

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