scholarly journals Gold nanoparticles grafted modified silica gel as a new stationary phase for separation and determination of steroid hormones by thin layer chromatography

2015 ◽  
Vol 23 (2) ◽  
pp. 279-286 ◽  
Author(s):  
Mitra Amoli-Diva ◽  
Kamyar Pourghazi
2019 ◽  
Vol 11 (43) ◽  
pp. 5511-5520 ◽  
Author(s):  
Sarah May Sibug-Torres ◽  
Isagani D. Padolina ◽  
Erwin P. Enriquez

A novel TLC plate design that features multiple screen printed phenyl- and octyl-modified silica gel stationary phases configured as radial sectors was developed for the in-field screening of herbal materials.


2010 ◽  
Vol 93 (3) ◽  
pp. 778-782 ◽  
Author(s):  
Tatána Gondová ◽  
Iveta Petríková

Abstract A new and simple TLC-densitometry method has been developed for the simultaneous separation of the two noradrenergic and specific serotonergic antidepressants mirtazapine and mianserine and validated for their determination in commercially available tablets. The method used TLC plates precoated with silica gel 60F254 as the stationary phase, and the mobile phase consisted of hexaneisopropanol25 ammonia (70 + 25 + 5, v/v/v). Densitometric analysis was carried out in the absorbance mode at 280 nm. The method was validated in accordance with International Conference on Harmonization guidelines in terms of linearity, LOD, LOQ, precision, and accuracy. Calibration curves were linear (R2 > 0.9970) with respect to peak area in the concentration range of 5002500 and 5005000 ng/spot for mirtazapine and mianserine, respectively. The LODs were 20 and 35 ng/spot for mirtazapine and mianserine, respectively. The described method was successfully applied to the determination of mirtazapine and mianserine in their pharmaceutical formulations with recovery ranging from 99.83 to 101.20 of the labeled amount of the compounds. The proposed method can be used in routine QC of these drugs in pharmaceutical formulations.


2005 ◽  
Vol 88 (5) ◽  
pp. 1562-1567 ◽  
Author(s):  
Valeria Widmer ◽  
Anne Schibli ◽  
Eike Reich

Abstract A quantitative high-performance thin-layer chromatographic method for determination of β-asarone in Calamus rhizome was developed and validated. The method is suitable for proper identification of Acorus calamus. Through the use of caffeine-modified silica gel as the stationary phase and toluene–ethyl acetate (93 + 7, v/v) as the mobile phase, β-asarone is baseline separated from its isomer α-asarone. Scanning densitometry with absorption measurement at 313 nm allows specific, accurate, and precise quantification of β-asarone. The working range of 40 to 200 ng absolute of the target substance is sufficient to establish whether a given sample passes the limit test of 0.5% maximum as required by the Swiss Pharmacopoeia.


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.


1999 ◽  
Vol 82 (2) ◽  
pp. 399-401 ◽  
Author(s):  
Constantin Marutoiu ◽  
Rodica Constantinescu ◽  
Florenta Dogar ◽  
Rodica Grecu

Abstract A polar silica gel R chemically modified with mercaptopropyltrimethoxysilane was prepared. Surface characteristics of the silica gel R before and after chemical modification were determinated by elemental analysis, specific surface area characterization, infrared spectroscopy, and thin-layer chromatography. Eight dyes were separated on the chemically modified silica gel R.


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