THE DIFFERENTIAL DETERMINATION OF CONJUGATED HYDROXYSKATOLES IN HUMAN URINE

1967 ◽  
Vol 45 (9) ◽  
pp. 1317-1322 ◽  
Author(s):  
M. E. Mahon ◽  
G. L. Mattok
Keyword(s):  
Ethyl Acetate ◽  
Silica Gel ◽  
Human Urine ◽  
Thin Layers ◽  
Enzymic Hydrolysis ◽  
Sulfate Ester ◽  
Normal Controls

A method is described for the separation and estimation of 4-, 5-, 6-, and 7-hydroxyskatole sulfate esters in urine. After extraction from urine, the 5-, 6-, and 7-hydroxyskatole sulfate esters were hydrolyzed by a sulfatase preparation to the corresponding hydroxyskatoles. The 4-isomer was resistant to this enzymic hydrolysis. The hydroxyskatoles were then extracted by ethyl acetate from the hydrolyzate followed by extraction of the 4-sulfate ester by n-butanol. Each fraction was chromatographed on silica gel G thin layers, sprayed with a modified Ehrlich's reagent (p-N,N-bis(2-chloroethyl)aminobenzaldehyde), and the appropriate zones eluted from the chromatogram. The concentrations of each isomer originally present in the urine were estimated from the absorbances of the four eluates at their absorption maxima (ca. 600 mμ). The levels of the four isomeric skatolyl sulfates found in urines from 10 normal controls are given.

scholarly journals Determination of Delafloxacin in Pharmaceutical Formulations Using a Green RP-HPTLC and NP-HPTLC Methods: A Comparative Study

Antibiotics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 359 ◽  
Author(s):  
Prawez Alam ◽  
Essam Ezzeldin ◽  
Muzaffar Iqbal ◽  
Gamal A.E. Mostafa ◽  
Md. Khalid Anwer ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Silica Gel ◽  
Solid Lipid Nanoparticles ◽  
Ternary Mixture ◽  
Mobile Phase ◽  
Pharmaceutical Formulations ◽  
Lipid Nanoparticles ◽  
Ammonia Solution ◽  
Hptlc Method

In this work; delafloxacin (DLFX) was determined using a validated green RP-HPTLC and NP-HPTLC methods in commercial tablets and in-house developed solid lipid nanoparticles (SLNs). RP-HPTLC determination of DLFX was performed using “RP-18 silica gel 60 F254S HPTLC plates”. However; NP-HPTLC estimation of DLFX was performed using “silica gel 60 F254S HPTLC plates”. For a green RP-HPTLC method; the ternary combination of ethanol:water:ammonia solution (5:4:2 v/v/v) was used as green mobile phase. However; for NP-HPTLC method; the ternary mixture of ethyl acetate: methanol: ammonia solution (5:4:2 v/v/v) was used as normal mobile phase. The analysis of DLFX was conducted in absorbance/reflectance mode of densitometry at λmax = 295 nm for both methods. RP-HPTLC method was found more accurate, precise, robust and sensitive for the analysis of DLFX compared with the NP-HPTLC method. The % assay of DLFX in commercial tablets and in-house developed SLNs was determined as 98.2 and 101.0%, respectively, using the green RP-HPTLC technique, however; the % assay of DLFX in commercial tablets and in-house developed SLNs was found to be 94.4 and 95.0%, respectively, using the NP-HPTLC method. Overall, the green RP-HPTLC method was found superior over the NP-HPTLC. Therefore, the proposed green RP-HPTLC method can be successfully applied for analysis of DLFX in commercial tablets, SLNs and other formulations containing DLFX.

Quantitative Determination of Tris-(2,3,-dibromopropyl) Phosphate by Densitometry of Thin Layer Chromatograms

1979 ◽  
Vol 62 (6) ◽  
pp. 1315-1318
Author(s):  
Albert M Gardner
Keyword(s):  
Sewage Sludge ◽  
Thin Layer ◽  
Quantitative Determination ◽  
Ethyl Acetate ◽  
Silver Nitrate ◽  
Flame Retardant ◽  
Silica Gel ◽  
White Background ◽  
Ppm Level

Abstract The flame retardant tris-(2,3-dibromopropyl) phosphate (Tris) was chromatographed on silica gel thin layer plates, using ethyl acetate-hexane (30+70) as the developing solvent. Tris was visualized by spraying the chromatogram with 1% aqueous silver nitrate followed by exposure to ultraviolet light for 40 min. Tris appeared as dark gray spots on a white background; the spots were quantitated by densitometry at 600 nm. The lower level of sensitivity was 50 ng; calibration plots were linear from 50 to 800 ng. The procedure was developed to determine the levels of unmetabolized Tris remaining after exposure to sewage sludge suspensions. Recovery of Tris from 3 sewage sludge samples fortified at the 1.0 ppm level averaged 97%.

Quantitative determination of α-tocopherol on thin layers of silica gel

1977 ◽  
Vol 83 (2) ◽  
pp. 401-407 ◽  
Author(s):  
John L. Hess ◽  
Mark A. Pallansch ◽  
Kim Harich ◽  
G.E. Bunce
Keyword(s):  
Quantitative Determination ◽  
Silica Gel ◽  
Thin Layers

Improved Method for the Thin Layer Chromatographic Determination of Patulin in Apple Juice

1973 ◽  
Vol 56 (4) ◽  
pp. 813-816 ◽  
Author(s):  
Peter M Scott ◽  
Barry P C Kennedy
Keyword(s):  
Thin Layer ◽  
Ethyl Acetate ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Apple Juice ◽  
Chromatographic Determination ◽  
Improved Method ◽  
Layer Chromatography ◽  
Hydrochloride Solution

Abstract Apple juice from a freshly opened container is extracted 3 times with ethyl acetate. The extract is dried, concentrated, diluted with benzene, and added to a silica gel column. Patulin is eluted by benzene-ethyl acetate (75+25) and detected by thin layer chromatography, using a 3-methyl-2-benzothiazolinone hydrazone hydrochloride solution as the spray reagent. Satisfactory recoveries were obtained for patulin added to apple juice at levels of 25–400 μg/L.

Gas-Liquid Chromatographic Determination of Captan and Two Metabolites in Milk and Meat

1977 ◽  
Vol 60 (3) ◽  
pp. 679-681
Author(s):  
John H Onley
Keyword(s):  
Ethyl Acetate ◽  
Silica Gel ◽  
Chromatographic Determination ◽  
Gel Chromatography ◽  
Milk Samples ◽  
Liquid Chromatographic Determination ◽  
Meat Samples ◽  
Silica Gel Chromatography ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method has been developed for the determination of captan (N-trichloromethylthio-4-cyclohexene-1, 2-dicarboximide) and 2 metabolites, tetrahydrophthalimide (THPI) and tetrahydrophthalamic acid (THPMA), in milk and meat. The sample is extracted with ethyl acetate and is cleaned up by acetonitrile partition and silica gel chromatography where captan, THPI, and THPMA are separated. Captan is directly determined by GLC. THPI and THPMA are separately derivatized in an acetone solution of penta fluorobenzyl bromide. The resultant derivatives are purified separately on an Al2O3, column and quantitated by GLC, using an electron capture detector. Recoveries from milk samples fortified at 0.02–10 ppm ranged from 71 to 102%; recoveries from meat samples fortified at 0.04–10 ppm ranged from 75 to 99%.

Evaluation of Liquid Chromatographic Methods for Analysis of Chlorphoxim Formulations

1985 ◽  
Vol 68 (5) ◽  
pp. 887-890
Author(s):  
Dwight L Mount ◽  
James W Miles
Keyword(s):  
Ethyl Acetate ◽  
Disease Control ◽  
Silica Gel ◽  
Active Ingredient ◽  
Internal Standard ◽  
Emulsifiable Concentrate ◽  
Water Dispersible ◽  
External Standard ◽  
Liquid Chromatographic

Abstract Liquid chromatographic (LC) methods for determination of active ingredient in chlorphoxim formulations have been developed independently by Bayer AG and the Centers for Disease Control (CDC). Both methods specify separation on a silica gel column. The Bayer method uses a 5% solution of tetrahydrofuran in hexane as the eluting solvent and quantitates results on the basis of an external standard. The CDC method uses a 5% solution of ethyl acetate in hexane as the eluting solvent and uses 4-fluorophenyl sulfone as an internal standard. The 2 methods were compared by replicate analyses of samples of chlorphoxim technical and water-dispersible powder and emulsifiable concentrate formulations. The precision of both methods was acceptable

Determination of 3-Methoxy-4-Hydroxymandelic Acid (VMA) in Urine by Thin-Layer Chromatography

1965 ◽  
Vol 11 (10) ◽  
pp. 905-913 ◽  
Author(s):  
J S Annino ◽  
M Lipson ◽  
L A Williams
Keyword(s):  
Thin Layer ◽  
Ethyl Acetate ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Potassium Carbonate ◽  
Several Variables ◽  
Fast Red ◽  
Layer Chromatography

Abstract From studies of several variables, a method has been developed for the separation and quantitation of 3-methoxy-4-hydroxymandelic acid (VMA) in urine by thin-layer chromatography. The urine is pretreated with acid and Florisil, and then extracted with ethyl acetate. Thin-layer chromatography is performed on silica gel with a butanol: acetic acid:water solution. The VMA spot is located by spraying with fast red GG and potassium carbonate. After removal from the plate, maximum color is developed and quantitated by reading in a spectrophotometer at 510 mµ.

scholarly journals TLC determination of some flavanones in the buds of different genus Populus species and hybrids

2018 ◽  
Vol 68 (2) ◽  
pp. 199-210 ◽  
Author(s):  
Loretta Pobłocka-Olech ◽  
Piotr Migas ◽  
Mirosława Krauze-Baranowska
Keyword(s):  
Quantitative Analysis ◽  
Formic Acid ◽  
Ethyl Acetate ◽  
Silica Gel ◽  
Mobile Phase ◽  
Flavonoid Aglycones ◽  
Evaluation Mode ◽  
Populus Species

Abstract Flavonoids in the buds of eight Populus species and hybrids were detected and compared with the aid of an optimized TLC method. Separation of 17 flavonoid aglycones belonging to different groups, namely, flavones, flavonols, flavanones and flavanonols, previously described as constituents of poplar buds, was performed on silica gel plates using a hexane/ethyl acetate/formic acid (60:40:1.3, V/V/V) mixture as the mobile phase. Pinocembrin and pinostrobin were found in the majority of analyzed poplar buds. For quantitative analysis of both compounds, two TLC evaluation modes, densitometric and videodensitometric, were compared and the established methods were validated. Concentrations of flavanones in some extracts differed slightly or significantly due to the analyzed plant matrix complexity and the TLC evaluation mode applied. Poplar buds rich in flavanones originated from P. × canadensis ‘Robusta’ (1.82 and 2.23 g per 100 g, resp.) and P. balsamifera (1.17 and 2.24 g per 100 g, resp.).

PREGNANETRIOL IN URINE: DETERMINATION AS A 17-KETOGENIC STEROID

1959 ◽  
Vol XXXII (IV) ◽  
pp. 596-605 ◽  
Author(s):  
R. Morris
Keyword(s):  
Congenital Adrenal Hyperplasia ◽  
Silica Gel ◽  
New Method ◽  
Adrenal Hyperplasia ◽  
Enzymic Hydrolysis ◽  
Normal Individuals ◽  
Hydrolysis Of

ABSTRACT A new method has been described for the determination of pregnanetriol in urine. It depends on the oxidation of pregnanetriol glucuronide to aetiocholanolone and its measurement as a Zimmermann chromogen after chromatography on silica gel. The method was applied to the urine from normal individuals and patients with congenital adrenal hyperplasia and the results were compared with a method using enzymic hydrolysis of the steroid conjugate.

Screening of Chloramphenicol Residues in Pork Muscle by Planar Chromatography

1994 ◽  
Vol 77 (5) ◽  
pp. 1101-1104 ◽  
Author(s):  
J P Abjean
Keyword(s):  
Solid Phase Extraction ◽  
Ethyl Acetate ◽  
Silica Gel ◽  
Chromatographic Method ◽  
Solid Phase ◽  
Phase Extraction ◽  
Planar Chromatography ◽  
Sample Throughput ◽  
Qualitative Determination

Abstract A rapid planar chromatographic method is described for the qualitative determination of chloramphenicol residues in muscle. The drug is extracted with ethyl acetate and purified by solid-phase extraction. After elution, the collected phase is evaporated to dryness. The residue is dissolved in methanol, spotted on a silica gel plate, and chromato-graphed. After elution, the chloramphenicol is visualized after reduction with fluorescamine. This method detects chloramphenicol in meat at 10 μg/kg and has a sample throughput of about 25 samples per analyst per day.

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