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.

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.

Determination of Diacetyl in Butter as 2,3-Diaminonaphthalene Derivative, Using a Fluorometric Procedure or Reverse Phase Liquid Chromatography with Fluorescence Detection

1988 ◽  
Vol 71 (3) ◽  
pp. 462-465
Author(s):  
Pietro Damiani ◽  
Giovanni Burini
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
The Other ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Fluorescence Characteristics ◽  
Chromatographic Procedure ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Two procedures, one fluorometric and the other reverse phase liquid chromatographic, for determination of a derivative of diacetyl are described. Exploratory work on diacetyl standard solutions to establish the best conditions for the derivatization with 2,3-diaminonaphthalene (DAN) to yield 2,3-dimethylbenzo[g]-quinoxaline (DMBQ) is discussed, as well as the fluorescence characteristics of the DMBQ derivative. Diacetyl was determined in 10 commercial butter samples by the proposed procedures and by other known methods (determination of o-phenylenediamine and 3,3-diaminobenzidinederivatives). Recoveries from butter samples spiked with known amounts of diacetyl ranged from 96.9 to 101.8% (with CVs ranging from 0.3 to 2.1%) for the fluorometric procedure and from 96.9 to 102.7% (with CVs ranging from 0.5 to 2.4%) for the chromatographic procedure. These results agree well with those obtained with o-phenylenediamine and 3,3-diaminobenzidine methods on the same butter samples. The proposed methods have the advantages of improved detectability and specificity.

Quantitative Analysis of Methionine, Cysteine, and Lysine in Feeds by Reversephase Liquid Chromatography Using Precolumn Derivatization with 9- Fluorenylmethyl Chloroformate: Preliminary Study

1990 ◽  
Vol 73 (6) ◽  
pp. 935-939 ◽  
Author(s):  
Angel Cubedo Fernández-Trapiella
Keyword(s):  
Amino Acids ◽  
Liquid Chromatography ◽  
Quantitative Analysis ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Precolumn Derivatization ◽  
Fluorescence Detector ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Phase Liquid

Abstract An Improved analytical method based on precolumn derivatization with 9-fluorenylmethyl chloroformate (9-FMC) and reverse- phase liquid chromatography was developed for quantitative analysis of methionine, cysteine, and lysine In feeds. Samples of corn, whey powder, soybean meal, meat meal, and fish meal were selected for an accurate determination of these 3 amino acids. A portion of each finely ground sample was weighed and subjected to oxidation with performic acid for 16 h before hydrolysis with 6N HCI for 24 h. An aliquot of each hydrolysate was evaporated, dissolved, and diluted with 0.2M pH 7.85 borate buffer. An aliquot of each final solution was derlvatlzed with 9-FMC and analyzed by reverse- phase liquid chromatography using a fluorescence detector with a 254 nm excitation filter and a 313 nm emission filter. The 2 sulfur amino acids and lysine were perfectly separated from all other amino acids with a simple binary gradient. Cysteine (analyzed as cysteic acid), methionine (as methionine sulfone), and lysine were quantltated using internal standard calibration. Hydrolysates were also analyzed by conventional Ion-exchange chromatography (IEC). Amino acid values as obtained by the proposed LC method were close to IEC data. Considering IEC results as reference values, the differences In recovery of amino acids In feedstuffs determined by both methods were not more than 7.5%. Precision of the LC method was evaluated within a single hydrolysate and between different hydrolysates of a single sample. Coefficients of variation (CV) were not more than 4.1 and 5.9%, respectively.

Sign in / Sign up

Export Citation Format

Share Document