Effect of inorganic salts as mobile-phase additives on lipophilicity values determined by reversed-phase thin-layer chromatography for new 1,2,4-triazole derivatives

2006 ◽  
Vol 19 (111) ◽  
pp. 386-392 ◽  
Author(s):  
Jolanta Flieger ◽  
Małgorzata Tatarczak
2011 ◽  
Vol 4 (2) ◽  
pp. 113-117 ◽  
Author(s):  
D. Larionova ◽  
I. Goryacheva ◽  
C. Van Peteghem ◽  
S. De Saeger

The conditions of thin-layer chromatography separation of related aflatoxins and zearalenones in the presence of β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin were studied. Effects of the stationary phase and mobile phase composition were investigated. Analytical conditions for the separation and simultaneous semi-quantitative fluorescence detection of aflatoxins B1, B2, G1 and G2, zearalenone and α-zearalenol on normal-phase plates (silica gel, polyamide) and reversed-phase plates (C18) with cyclodextrin modified mobile phase were optimised. The limit of quantification was found 2 ng per spot for aflatoxin G1 and aflatoxin B2, 3.5 ng for aflatoxin B1 and aflatoxin G2 and 100 ng per spot for zearalenone and α-zearalenol. Addition of cyclodextrins to the mobile phase allowed a decrease in the amount of toxic solvents, and improved separation characteristics, but did not improve the limit of quantification.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Beata Polak ◽  
Adam Traczuk ◽  
Sylwia Misztal

AbstractThe problems with separation of amino acid mixtures in reversed-phase mode are the result of their hydrophilic nature. The derivatisation of the amino group of mentioned above solutes leads to their solution. For this purpose, 9-fluorenylmethoxycarbonyl chloroformate (f-moc-Cl) as the derivatisation reagent is often used. In our study, the separation of some f-moc- amino acid derivatives (alanine, phenylalanine, leucine, methionine, proline and tryptophan) with the use of micellar systems of reversed-phase high-performance thin-layer chromatography (HPTLC) and pressurized planar electrochromatography (PPEC) is investigated. The effect of surfactant concentration, its type (anionic, cationic and non-ionic) and mobile phase buffer pH on the discussed above solute migration distances are presented. Our work reveals that the increase of sodium dodecylsulphate concentration in the mobile phase has a different effect on solute retention in HPTLC and PPEC. Moreover, it also affects the order of solutes in both techniques. In PPEC, in contrast to the HPTLC technique, the mobile phase pH affects solute retention. The type of surfactant in the mobile phase also impacts solute retention and migration distances. A mobile phase containing SDS improves system efficiency in both techniques. Herein, such an effect is presented for the first time.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Beata Polak ◽  
Emilia Pajurek

AbstractThe separation of some water- and fat-soluble vitamins via micellar systems of reversed-phase high-performance thin-layer chromatography (HPTLC) and pressurized planar electrochromatography (PPEC) was subjected to research. Hence, the influence of the mobile phase composition (surfactant and acetonitrile concentration, eluent buffer pH) on the migration distances and zone separation of some vitamins (thiamine, riboflavin, niacin, pyridoxine, cyanocobalamin, folic acid, ergocalciferol and α-tocopherol) was investigated. Our results indicated that the applied technique has an impact on the solute order. Comparing the system capacity of HPLC and PPEC (measured as height of the theoretical plate) for the mobile phase systems with and without surfactant shows differences, especially for fat-soluble vitamin. The variances and reproducibilities (% RDS) values of the vitamin are less in PPEC than in TLC. Moreover, the migration distances of water-soluble vitamins are longer than fat-soluble ones. Overall, eluent consisting of 50% acetonitrile, 18.75 mM SDS, the buffer of pH 6.99 via the PPEC technique was most appropriate for determining the investigated vitamins in the artificial mixture and the two commercially available vitamin combinations.


1999 ◽  
Vol 82 (2) ◽  
pp. 244-247 ◽  
Author(s):  
M H Guermouche ◽  
D Habel ◽  
S Guermouche

Abstract Determination of tinidazole in human serum by high-performance thin-layer chromatography (HPTLC) is presented. It includes use of 10 × 10 cm plates coated with silica gel 60 and chloroform-acetonitrile-acetic acid (60 + 40 + 2) as mobile phase. Quantitation was performed by densitometry at 320 nm. The linearity (1-10 ng), precision (6%), reproducibility (5%), recovery (96%), and detection limit (1 mg/L) of tinidazole determination by HPTLC were comparable with corresponding method parameters by reversed-phase HPLC. A satisfactory correlation was found between the 2 analytical methods. The procedure was used to quantitate tinidazole in patient sera.


2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Andrzej Czyrski

The lipophilicity is an important parameter that influences the activity of the drugs in the human body. The reversed phase high performance thin layer chromatography was applied to determine the Log P values of ibuprofen, ketoprofen, naproxen, and flurbiprofen. The stationary phase used in the study was silica-gel coated plates. The mobile phase was the mixture of acetonitrile and water in different proportions. The content of acetonitrile varied in 5% increments from 50% to 80%. The Rm0 values were determined for the compounds with a known Log P and for the analyzed substances (ibuprofen, naproxen, ketoprofen, and flurbiprofen). The Log P values were calculated for the analyzed compounds using the regression curve Rm0 = f(Log P) parameters for the compounds with the known lipophilicity. Flurbiprofen is characterized by the highest Log P value: 3.82. The lowest one is noted for ketoprofen: 2.66. The determined Log P values of tested compounds were similar to the values calculated by the software.


Author(s):  
Kavitha Jayaseelan ◽  
Karunanidhi Santhana Lakshmi

  Objective: The current study was framed with a view to develop a simple, sensitive and a rapid reversed-phase thin-layer chromatography (RP-TLC)/ densitometry method for quantification of parabens (methyl, ethyl, propyl, and butyl) in various cosmetic preparations available in local market. Moreover, robustness testing was planned to be performed applying a central composite design (CCD).Methods: The desired chromatographic separation was achieved on RP-TLC/densitometry plates precoated with Silica gel 60 GF254 on aluminum sheet, employing methanol:toluene:acetonitrile:glacial acetic acid as mobile phase in the ratio of 3:5:1.8:0.2 v/v/v/v and detection was carried out at 256 nm.Results: The mobile phase used gave an excellent resolution of all the four separated parabens. The method was found linear over a wide range of 6.25- 400 ng/spot. The optimized method was validated by measuring various validation parameters. CCD was employed to check the robustness of the method at three-factor levels. The developed and optimized method was used to quantify parabens in 30 different cosmetic products procured from local market.Conclusion: The proposed and developed RP-TLC/densitometry method can be applied for routine analysis of all the parabens in cosmetic products and can also be extended to the analysis in pharmaceuticals and food products.


2017 ◽  
Vol 30 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Aneta Hałka-Grysińska ◽  
Radosław Ł. Gwarda ◽  
Krzysztof Pawełek ◽  
Tomasz Baj ◽  
Tadeusz H. Dzido

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