scholarly journals Evaluation of radiochemical purities of routinely used radiopharmaceuticals: Three years’ experience of a single institute

2019 ◽  
Author(s):  
Hameed Ullah ◽  
Iftikhar Ahmad ◽  
Muhammad Rauf Khattak ◽  
Shoab Shah ◽  
Shakil Ahmad ◽  
...  
Keyword(s):  
Radiochemical Purity ◽  
Chemical Species ◽  
Retention Factor ◽  
Chemical Impurities ◽  
Mobile Phases ◽  
Rf Values ◽  
Permissible Levels ◽  
Solvent Systems ◽  
Specific Paper ◽  
Quality Control Test

Introduction: Radiochemical purity (RCP) is a routine quality control test carried out at nuclear medicine to determine the concentration of various chemical species present in the radiopharmaceuticals (RPs). The present work describes three years of experience in a single institute for the measurement of these impurities in the RPs preparations. Methods: The RCP of different cold kit preparations were performed by chromatographic methods. Specifically, a small drop of the aliquot was spotted on the specific paper acting as the stationary phase and then developed in different solvents as mobile phases. The developed chromatograms were then quantified for various chemical species by Mini TLC scanner or well type counter. Results: The retention factor (Rf) values for the different chemical species in the labeling of RP were measured by using single, double or triple solvent systems. It was observed that 2.70% of the kits had RCP less than the acceptable limit whereas 97.30% kits were found within the permissible levels. Conclusion: Chromatographic techniques used for the assessment of RCP offer sufficiently good results for identification and separation of different chemical impurities.

Reverse Phase Thin Layer Chromatography of Some Aroclors, Halowaxes, and Pesticides

1973 ◽  
Vol 56 (2) ◽  
pp. 367-372
Author(s):  
David L Stalling ◽  
James N Huckins
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Mobile Phase ◽  
Gas Liquid Chromatography ◽  
Chlorinated Pesticides ◽  
Reverse Phase ◽  
Mobile Phases ◽  
Rf Values ◽  
Solvent Systems ◽  
Layer Chromatography

Abstract The components of Aroclors® 1232, 1248, 1254, and 1260; Halowaxes® 1099, 1013, and 1014; and several chlorinated pesticides are resolved by reverse phase thin layer chromatography (RPTLC), which permits component separation by partition between a nonpolar stationary phase and a polar mobile phase. Rf values of resulting spots were calculated for 2 of 4 new solvent systems (mobile phases). RPTLC patterns were reproducible and characteristic of each material examined. The spots were recovered from the plates and characterized by gas-liquid chromatography (GLC) and/or GLC-mass spectrometry. In some cases, single GLC peaks of Aroclor standards were resolved into more than one component by RPTLC, whereas some RPTLC spots of Halowaxes were resolved into as many as 4 GLC peaks. The analysis of environmental residues of chlorinated compounds was facilitated by this technique.

OPTIMIZATION OF THIN LAYER CHROMATOGRAPHY METHODS FOR SEPARATION AND IDENTIFICATION OF ANTIDEPRESSANTS IN THEIR MIXTURE

2014 ◽  
Vol 21 (1) ◽  
pp. 11-15
Author(s):  
Daiva Kazlauskienė ◽  
Guoda Kiliuvienė ◽  
Palma Nenortienė ◽  
Giedrė Kasparavičienė ◽  
Ieva Matukaitytė
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Solvent System ◽  
Ammonia Solution ◽  
Relative Standard ◽  
Rf Values ◽  
Solvent Systems ◽  
Paroxetine Hydrochloride ◽  
Fluvoxamine Maleate ◽  
Layer Chromatography

By conducting the toxicological analysis it is meaningful to determine the analytical system that could identify simultaneously several medicinal preparations quickly and precisely. The purpose of this work was to create and validate the method of thin-layer chromatography that would be suitable to separate the components of antidepressant mixture (amitriptyline hydrochloride, paroxetine hydrochloride, sertraline hydrochloride, fluvoxamine maleate and buspirone hydrochloride) and to identify them. The system was validated with regard to the sensitivity, repetition of data, resistance and particularity. The solvent systems with potential of high separation of components in their mixture were created: acetonitrile, methanol, ammonia solution 25 percent (85:10:5); acetonitrile, methanol, ammonia solution 25 percent (75:20:5); dichlormethane, 1,4-dioxane, ammonia solution 25 percent (50:45:5); dichlormethane, 1,4-dioxane, ammonia solution 25 percent (42:55:3); trichlormethane, 1,4-dioxane, ammonia solution 25 percent (25:70:5); trichlormethane, 1,4-dioxane, ammonia solution 25 percent (60:36:4). One of the most suitable solvent systems for separation of the analyzed mixture (sertraline, amitriptyline, paroxetine, buspirone, fluvoxamine) was determined – acetonitrile, methanol, ammonia solution 25 percent (85:10:5). When this solvent system was used, the average Rf values of the analyzed compounds differed the most. Validation was conducted – the relative standard deviation (RSD, percent) of the average Rf value of the analyzed compounds varied from 0,6 to 1,8 percent and did not exceed the permissible error of 5 percent. The sensitivity of methodology was determined by assessing the intensity of the mixture’s spots on the chromatographic plate. The detection limit of buspirone was 0,0012 µg; sertraline – 0,0008 µg; amitriptyline – 0,0004 µg; fluvoxamine – 0,0004 µg; paroxetine – 0,0008 µg. The resistance of results to the changed conditions – it was determined that when the amounts of the solvents acetonitrile and methanol were increased or decreased to two milliliters, the average Rf values of the analyzed compounds did not change statistically significantly

scholarly journals Profile of Thin-Layer Chromatography and UV-Vis Spectrophotometry of Akar Kuning Stem Extract (Arcangelisia flava)

2018 ◽  
Vol 1 (2) ◽  
pp. 72-76 ◽  
Author(s):  
Mohammad Rizki Fadhil Pratama ◽  
Suratno Suratno ◽  
Evi Mulyani
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Ethanol Extract ◽  
Retention Factor ◽  
Polar Solvents ◽  
Central Kalimantan ◽  
Stem Extract ◽  
Rf Values ◽  
Layer Chromatography ◽  
Chloroform Methanol

This study aims to obtain the profile of Thin-Layer Chromatography (TLC) and Ultraviolet-Visible (UV-Vis) spectrophotometry from ethanol extract of akar kuning stems (Arcangelisia flava) from Central Kalimantan. The TLC method is used with the orientation phase of the combination of polar-non-polar solvents resulting from orientation, while ethanol is used as the solvent for UV-Vis spectrophotometers. TLC results showed the formation of 3 stains on a combination of polar solvents chloroform : methanol : water while in a non-polar solvent combination n-hexane : ethyl acetate did not show any stains. Comparison of retention factor (Rf) values show the best combination of polar solvents to separate stains at a ratio of 5 : 2 : 1, respectively. Separation in 2-dimensional TLC with polar solvents showed a similar pattern with 1-dimensional separation in the form of 3 stains. UV-Vis spectrophotometer results showed 4 main peaks with wavelength 227.2; 267.4; 345.2; and 425.3 nm, respectively. The profile of the peak formed is very similar to that shown by berberine, one of the main metabolites of akar kuning. TLC and UV-Vis spectrophotometers profiles obtained are expected to support further research using akar kuning stems, especially those from Central Kalimantan.

DDT-Type Compounds: Separation and Identification by a System Combining Thin Layer Chromatography, Gas Chromatography, and Infrared Spectroscopy

1968 ◽  
Vol 51 (6) ◽  
pp. 1247-1260
Author(s):  
M B Abou-Donia ◽  
D B Menzel
Keyword(s):  
Gas Chromatography ◽  
Infrared Spectroscopy ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Electron Capture ◽  
Structural Changes ◽  
Effective Technique ◽  
Rf Values ◽  
Solvent Systems ◽  
Layer Chromatography

Abstract Infrared spectroscopy, in combination with TLC and GLC, offers an effective technique for isolation, separation, and identification of DDT-type compounds. Rf values for DDT and 13 other compounds, most of which have been reported as DDT breakdown products, have been determined in 27 solvent systems, using TLC techniques. Three columns, in combination with the electron capture detector, have been experimentally studied to analyze the 13 DDT-like compounds. The positions and intensities of the infrared bands of the 14 compounds have been measured in KBr. The variations of these measurements have been discussed in relation to the structural changes of DDT-type compounds.

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.

Trace Analysis of Zearalenone and/or Zearalanol in Animal Chow by High Pressure Liquid Chromatography and Gas-Liquid Chromatography

1977 ◽  
Vol 60 (2) ◽  
pp. 272-278 ◽  
Author(s):  
Claude L Holder ◽  
Charles R Nony ◽  
Malcolm C Bowman
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Silica Gel ◽  
High Pressure Liquid Chromatography ◽  
Additional Data ◽  
Gas Liquid Chromatography ◽  
Step Procedure ◽  
Rf Values ◽  
Solvent Systems ◽  
Layer Chromatography

Abstract An analytical method is described for determining residues of the estrogens zearalenone and/or zearalanol in animal chow at levels as low as 10 ppb. The chow is extracted with methanol and cleaned up by a 3-step procedure employing a Sephadex LH-20 column, liquid-liquid partitioning at pH 13 and 8.3, and a silica gel column. Residues of the 2 compounds, separated on silica gel, are assayed by using high pressure liquid chromatography with ultraviolet detection. Additional data are also included concerning p-values of the compounds in several solvent systems, Rf values from thin layer chromatography with 9 solvent systems, solubilities in 3 solvents, and a procedure for preparing their pentafluoropropionyl derivatives for analysis by electron capture gas-liquid chromatography.

Liquid Chromatographic Determination of Phenolic Impurities in Technical MCPA Using Electrochemical Detection (Coulometric Mode)

1988 ◽  
Vol 71 (2) ◽  
pp. 325-327
Author(s):  
Yuk Y Wigfield ◽  
Monique Lanouette
Keyword(s):  
Acetic Acid ◽  
Flow Rate ◽  
Chromatographic Determination ◽  
Gradient System ◽  
Mobile Phases ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Solvent Systems ◽  
Liquid Chromatographic

Abstract Fifteen samples of technical 4-chloro-2-methylphenoxy acetic acid (MCPA) from 6 manufacturers were analyzed for the presence of 13 different phenolic impurities. Reverse-phase liquid chromatography with an electrochemical (coulometric mode) detector was used for qualitative and quantitative determinations. The phenols were separated using a 40-70% methanol and 60-30% 0.02M KH2P04 (pH 4.0) 35 min gradient system on a Spheri-5-RP-18 column. Confirmation of the phenols present was done by retention time comparison with the corresponding standards, using 2 other isocratic mobile phases, methanol-0.2M acetic acid (60 + 40) at a flow rate of 1.3 mL/min and acetonitrile-0.02M KH2P04 (45 + 55) (pH 3.0) at a flow rate of 0.90 mL/min. The similarity of results on 3 different solvent systems demonstrates the absence of any interfering responses. 2-Methyl-4-chlorophenol (average 0.168%) and 2-methyl- 4,6-dichlorophenol (average 0.004%) were detected in all 15 samples. 3-Methylphenol (0.002%) and 2,6-dimethyl-4-chlorophenol (0.002%) were detected in one sample only. The minimum detectable amount ranged from 0.1 to 0.6 ng, depending on the phenol. This corresponds to less than 0.002% when expressed relative to the weight of sample. The coefficient of variation for multiple analyses of the same sample (n = 6) is 1% for 2-methyl-4-chlorophenol and 3% for 2-methy 1-4,6- dichlorophenol.

scholarly journals Identification and Determination of Oxytetracycline, Tiamulin, Lincomycin, and Spectinomycin in Veterinary Preparations by Thin-Layer Chromatography/Densitometry

2000 ◽  
Vol 83 (6) ◽  
pp. 1502-1506 ◽  
Author(s):  
Jan Krzek ◽  
Anna Kwiecień ◽  
Małgorzata Starek ◽  
Anna Kierszniewska ◽  
Włodzimierz Rzeszutko
Keyword(s):  
Quantitative Analysis ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Citric Acid Solution ◽  
Active Constituents ◽  
Mobile Phases ◽  
Rf Values ◽  
Layer Chromatography ◽  
Small Confidence Interval

Abstract A thin-layer chromatographic/densitometric method was developed for the identification and quantitation of oxytetracycline, tiamulin, lincomycin, and spectinomycin in veterinary preparations. Silica gel-coated thin layer chromatography plates and 2 mobile phases were used to separate these constituents. The appropriate compositions of the suitable mobile phases were established: 10% citric acid solution–n-hexane–ethanol (80 + 1 + 1, v/v) and n–butanol–ethanol–chloroform– 25% ammonia (4 + 5 + 2 + 5, v/v). Along with Rf values and spot colors, direct UV and visual densitometric measurements were used for identification. Similar measuring ranges were used for quantitative analysis to obtain repeatable and reliable results for the preparations examined. The results of the quantitative analysis are characterized by a small confidence interval and are close to the declared contents of active constituents: oxytetracycline 30.01 ± 0.38 g at λ = 350 nm and 30.24 ± 0.86 g at λ = 430 nm; tiamulin, 10.19 ± 0.86 g at λ = 450 nm; lincomycin, 2.27 ± 0.08 g at λ = 278 nm; and spectinomycin, 2.18 ± 0.07 g at λ = 421 nm. The recoveries for all antibiotics ranged from 100.01 to 102.54%.

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