scholarly journals Development of Chromatographic Methods for Determination of Agrimoniin and Related Polyphenols in Pharmaceutical Products

2009 ◽  
Vol 92 (2) ◽  
pp. 410-418 ◽  
Author(s):  
Izabela Fecka
Keyword(s):  
Silica Gel ◽  
Extraction Procedure ◽  
Pharmaceutical Products ◽  
Hplc Method ◽  
Mobile Phases ◽  
Sample Extraction ◽  
Unmodified Silica ◽  
Short Time ◽  
Layer Chromatography

Abstract Thin-layer chromatography (TLC) and liquid chromatography (LC) methods were developed for the qualitative and quantitative determination of agrimoniin, pedunculagin, ellagic acid, gallic acid, and catechin in selected herbal medicinal products from Rosaceae: Anserinae herba, Tormentillae rhizoma, Alchemillae herba, Agrimoniae herba, and Fragariae folium. Unmodified silica gel (TLC Si60, HPTLC LiChrospher Si60) and silica gel chemically modified with octadecyl or aminopropyl groups (HPTLC RP18W and HPTLC NH2) were used for TLC. The best resolution and selectivity were achieved with the following mobile phases: diisopropyl etheracetoneformic acidwater (40 30 20 10, v/v/v/v), tetrahydrofuranacetonitrilewater (30 10 60, v/v/v), and acetoneformic acid (60 40, v/v). Concentrations of the studied herbal drugs were determined by using a Chromolith Performance RP-18e column with acetonitrilewaterformic acid as the mobile phase. Determinations of linearity, range, detection and quantitation limits, accuracy, precision, and robustness showed that the HPLC method was sufficiently precise for estimation of the tannins and related polyphenols mentioned above. Investigations of suitable solvent selection, sample extraction procedure, and short-time stability of analytes at storage temperatures of 4 and 20C were also performed. The percentage of agrimoniin in pharmaceutical products was between 0.57 and 3.23.

scholarly journals Identification and Quantitation of Polymyxin B, Framycetin, and Dexamethasone in an Ointment by Using Thin-Layer Chromatography with Densitometry

2005 ◽  
Vol 88 (5) ◽  
pp. 1549-1554 ◽  
Author(s):  
Jan Krzek ◽  
Anna Maślanka ◽  
Pawel Lipner
Keyword(s):  
Thin Layer ◽  
Silica Gel ◽  
Polymyxin B ◽  
Rapid Identification ◽  
Mobile Phases ◽  
Relative Standard ◽  
Dexamethasone Acetate ◽  
Similar Accuracy ◽  
Layer Chromatography

Abstract A new thin-layer chromatographic-densitometric method has been developed for rapid identification and quantitative determination of polymyxin B, framycetin, and dexamethasone in a dental ointment. Silica gel 60 and F254 silica gel 60 plates were used for separating antibiotics and dexamethasone acetate, respectively. When determining framycetin and polymyxin B, chromatograms were developed by using 2 mobile phases, namely methanol and methanol–n-butanol–ammonia (25%)–chloroform (14 + 4 + 9 + 12, v/v/v/v/). The densitometric measurements were made at 550 nm after detection with 0.3% ninhydrin solution. Dexamethasone was determined by using the mobile phase cyclohexane–ethyl acetate (2 + 3, v/v) and ultraviolet densitometric recording at 245 nm. The results obtained for individual constituents with the chromatographic-densitometric method demonstrate similar accuracy, relative standard deviation values from 1.49 to 2.47%, and relative error values from 0.02 to 0.81% and are comparable to those obtained with the reference methods.

Comparison of Different Methods for the Determination of Phenylalanine Hydroxylase Activity in Rat Liver and Euglena gracilis

1984 ◽  
Vol 39 (7-8) ◽  
pp. 728-733 ◽  
Author(s):  
Rita M. Fink ◽  
Erich F. Elstner
Keyword(s):  
Rat Liver ◽  
Euglena Gracilis ◽  
Phenylalanine Hydroxylase ◽  
Hplc Method ◽  
Enzymic Activity ◽  
Hydroxylase Activity ◽  
Product Separation ◽  
Tyrosine Concentration ◽  
Layer Chromatography

Abstract Three different methods for the determination of phenylalanine hydroxylase activity have been compared: a) Differential photometric assay of the increase in tyrosine concentration in the presence of phenylalanine; b) Product separation by thin layer chromatography and scintillation counting of the [14C]tyrosine formed;c) HPLC separation and spectrofluorometric quantification of derivatized amino acids. A comparison of the activities of phenylalanine hydroxylase in rat liver and Euglena gracilis clearly showed that only rat liver contains this enzymic activity as shown by methods b) and c) although pseudo-activity of Euglena gracilis preparations was found during the spectrophotometric test a). The HPLC method proved to be the fastest, most reliable and convenient method for direct tyrosine determination and thus for measuring phenylalanine hydroxylase activity.

scholarly journals Normal and reversed phase thin-layer chromatography of new 16, 17-secoestrone derivatives

2003 ◽  
Vol 68 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Marijana Acanski ◽  
Suzana Jovanovic-Santa ◽  
Lidija Jevric
Keyword(s):  
Thin Layer ◽  
Stationary Phase ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Reversed Phase ◽  
Retention Behavior ◽  
Mobile Phases ◽  
Layer Chromatography

The retention behavior and separation ability of a series of new 16,17-secoestrone derivatives has been studied on silica gel, alumina and C-18 silica gel layers with non-aqueous and aqueous-organic mobile phases. The retention behavior and separation ability are discussed in terms of the nature of the solute, eluent and stationary phase.

Thin Layer Chromatographic Method for Determination of Deoxynivalenol in Wheat: Collaborative Study

1986 ◽  
Vol 69 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Robert M Eppley ◽  
Mary W Trucksess ◽  
Stanley Nesheim ◽  
Charles W Thorpe ◽  
Albert E Pohland ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Aluminum Chloride ◽  
Chloride Solution ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Sample Extraction ◽  
Layer Chromatography

Abstract A collaborative study of a rapid method for the determination of deoxynivalenol (DON) in winter wheat was successfully completed. The method involves sample extraction with acetonitrile-water (84 + 16), cleanup using a disposable column of charcoal, Celite, and alumina, and detection by thin layer chromatography after spraying with an aluminum chloride solution. Each of the 15 collaborators analyzed 12 samples, 2 of which were naturally contaminated, and 10 to which DON was added, in duplicate, at levels of 0,50,100,300, and 1000 ng/ g. Average recoveries of DON ranged from 78 to 96% with repeatabilities of 30-64% and reproducibilities of 33-87%. The results of the study show that false positives were not a problem and that all of the analysts could detect DON at the 300 ng/g level or higher. The method has been adopted official first action.

scholarly journals Development of a Rapid and Sensitive HPLC Assay Method for Lenalidomide Capsules and Its Related Substances

2012 ◽  
Vol 9 (3) ◽  
pp. 1165-1174 ◽  
Author(s):  
L. Maheshwara Reddy ◽  
K. Janardhan Reddy ◽  
L. Bhaskar Reddy ◽  
P. Raveendra Reddy
Keyword(s):  
Wave Length ◽  
Hplc Method ◽  
Assay Method ◽  
Hplc Assay ◽  
Stability Studies ◽  
Related Substances ◽  
Mobile Phases ◽  
Acid Sodium Salt ◽  
Sun Light

A chromatographic method was established for the determination of lenalidomide and related substances in 10 mg and 5 mg capsules using Sunfire C-18(250×4.6 mm ID, 5 μm) HPCL column with 85:15 v/v ratio of mobile phases A (mixture of phosphoric acid buffer and 1-octane sulphonic acid sodium salt) and B(55: 45 v/v ratio of methanol and acetonitrile) at 40°C and 210 nm wave length. The degradation studies were performed using 0.1N HCl, 0.1 N NaOH, 1% v/v hydrogen peroxide, humidity, UV at 254 nm, Sun light, and heat to 60°C. No significant degradation of lenalidomide was observed. However, the slight degradation was observed in presence of NaOH. The developed HPLC method gave the peaks purity angle was less their threshold angle, indicating it to be suitable for stability studies. It was validated with respect to linearity, accuracy, precision, ruggedness, and robustness.

The Identification of Rubber Compounding Ingredients by Using Thin Layer Chromatography

1983 ◽  
Vol 56 (5) ◽  
pp. 1080-1095 ◽  
Author(s):  
B. J. Gedeon ◽  
T. Chu ◽  
S. Copeland
Keyword(s):  
Molecular Weight ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Easy Method ◽  
Mobile Phases ◽  
Rf Values ◽  
Visualization Systems ◽  
Layer Chromatography

Abstract TLC is a quick, easy method to the identification of rubber compounding ingredients. Both silica gel absorbent and C18 absorbent are suitable for these identifications. With the mobile phases used in this study, a better separation of antioxidants is possible using silica gel absorbent. Work should be continued on finding suitable mobile phases for the C18 absorbent, since the Rf values are more reproducible. For those separations that require a separation of compounds of varying molecular weight, the C18 absorbent is superior to silica gel absorbent. The visualization systems that have been developed for use with silica gel absorbent are suitable for use with C18 absorbent. These systems give the same colors for either absorbent.

scholarly journals Spectrophotometric Determination of Iron(II) after Solid Phase Extraction of Its 2,2′ Bipyridine Complex on Silica Gel-Polyethylene Glycol

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Nahid Pourreza ◽  
Saadat Rastegarzadeh ◽  
Ali Reza Kiasat ◽  
Hossein Yahyavi
Keyword(s):  
Polyethylene Glycol ◽  
Solid Phase Extraction ◽  
Silica Gel ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Calibration Graph ◽  
Phase Extraction ◽  
Relative Standard

A new solid phase extraction procedure was developed for preconcentration of iron(II) using silica gel-polyethylene glycol (silica-PEG) as an adsorbent. The method is based on retention of iron(II) as 2,2′ bipyridine complex on silica-PEG. The retained complex is eluted by 1.0 mol L−1of sulfuric acid-acetone mixture (1:2) and its absorbance is measured at 518 nm, spectrophotometrically. The effects of different parameters such as pH, concentration of the reagent, eluting reagent, sample volume, amount of adsorbent, and interfering ions were investigated. The calibration graph was linear in the range of 1–60 ng mL−1of iron(II). The limit of detection based on3Sbwas 0.57 ng mL−1and relative standard deviations (R.S.D) for ten replicate measurements of 12 and 42 ng mL−1of iron(II) were 2.4 and 1.7%, respectively. The method was applied to the determination of of iron(II) in water, multivitamin tablet, and spinach samples.

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