scholarly journals Analisis Pestisida Karbaril dengan metode KLT- Densitometri dalam matriks kedelai dan validasi metodenya

2010 ◽  
Vol 15 (2) ◽  
pp. 165-169 ◽  
Author(s):  
Sugijanto Sugijanto ◽  
Prihatin Prihatin ◽  
Noor Erma Sugijanto
Keyword(s):  
Ethyl Acetate ◽  
Silica Gel ◽  
Quantitative Evaluation ◽  
Sodium Sulphate ◽  
Chloroform Layer ◽  
Low Levels

A simple and rapid densitometric method has been developed for determination of low levels of carbaryl in soy bean matrix samples. Sample carbaryl in the soybean matrix was extracted with acetonitril, chloroform and NaCl 0.2 % solution, and the resulting chloroform layer was separated, added sodium sulphate anhydrous to get free of water than evaporated. After dissolution in methanol, the solutions were spotted on silica gel GF254 plates which were then eluted with toluene: ethyl acetate = 3:1 (v/v). Quantitative evaluation was performed by measuring the absorbance reflectance of the analyte spots at λ 280 nm. This densitometric method is selective, precise, accurate and can be used for the determination carbaryl in soy bean matrix.

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%.

scholarly journals IDENTIFICATION OF SOME CARCINOGENIC POLYCYCLIC AROMATIC HYDROCARBONS IN BANGLADESHI VEHICLES EXHAUST TAR BY GAS CHROMATOGRAPHY-MASS SPECTROPHOTOMETER

2010 ◽  
Vol 8 (3) ◽  
pp. 353-355 ◽  
Author(s):  
M. Amzad Hossain ◽  
S. M. Salehuddin
Keyword(s):  
Gas Chromatography ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Glass Fiber ◽  
Silica Gel ◽  
Aromatic Hydrocarbons ◽  
Solvent Mixture ◽  
Sodium Sulphate ◽  
Glass Fiber Filter ◽  
Polycyclic Aromatic

A more sensitive GC-MS method has been established for the determination of some carcinogenic polycyclic aromatic hydrocarbons (PAHs) in vehicles exhaust tar samples. The tar samples were extracted using dichloromethane (DMC): n-hexane solvent mixture. A multi-layer clean-up (silica gel/sodium sulphate) column was used, followed by glass fiber filter (GFF) paper. The method was successfully applied to determine a number of PAHs present in exhaust tar sample of different vehicles of the Atomic Energy Centre, Dhaka, Bangladesh.   Keywords: Carcinogenic polycyclic aromatic hydrocarbons, vehicles tar samples, identification, GC-MS/MS

scholarly journals Determination of Florfenicol, Thiamfenicol and Chloramfenicol at Trace Levels in Animal Feed by HPLC–MS/MS

Antibiotics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 59 ◽  
Author(s):  
Rosa Elvira Gavilán ◽  
Carolina Nebot ◽  
Ewelina Patyra ◽  
Beatriz Vazquez ◽  
Jose Manuel Miranda ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Animal Feed ◽  
Simultaneous Detection ◽  
The European Union ◽  
European Regulation ◽  
Official Control ◽  
Liquid Chromatography Tandem Mass ◽  
Residue Levels ◽  
Low Levels

Administration of florfenicol and thiamfenicol through medicated feed is permitted within the European Union, always following veterinary prescription and respecting the withdrawal periods. However, the presence of low levels of florfenicol, thiamfenicol, and chloramfenicol in non-target feed is prohibited. Since cross-contamination can occur during the production of medicated feed and according to Annex II of the European Regulation 2019/4/EC, the control of residue levels of florfenicol and thiamfenicol in non-target feed should be monitored and avoided. Based on all the above, a sensitive and reliable method using liquid chromatography tandem mass spectrometry was developed for the simultaneous detection of chloramfenicol, florfenicol, and thiamfenicol at trace levels in animal feed. Analytes were extracted from minced feed with ethyl acetate. Then, the ethyl acetate was evaporated, the residue was resuspended in Milli-Q water and the extract filtered. The method was in-house validated at carryover levels, with concentration ranging from 100 to 1000 µg/kg. The validation was conducted following the European Commission Decision 2002/657/EC and all performance characteristics were successfully satisfied. The capability of the method to detect amfenicols at lower levels than any prior perspective regulation literature guarantees its applicability in official control activities. The developed method has been applied to non-compliant feed samples with satisfactory results.

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%.

Determination of Eight Sulfonylurea Herbicide Residues by LC/MS/MS Using a Sample Separation Technique with Ethyl Acetate

2019 ◽  
Vol 102 (1) ◽  
pp. 239-245
Author(s):  
Eleftheria Bempelou ◽  
Petros Kappatos ◽  
Konstantinos Liapis
Keyword(s):  
Ethyl Acetate ◽  
Correlation Coefficients ◽  
Analytical Techniques ◽  
Growth Stages ◽  
Quechers Method ◽  
Validation Criteria ◽  
Maximum Residue Limits ◽  
Low Levels ◽  
Sample Separation

Abstract Background: Sulfonylureas are an important group of systemic herbicides mainly used for the control of weeds in cereals and other crops in early growth stages of their cultivations. Sulfonylureas are characterized by their broad spectrum weed control and their good crop selectivity. Objective: In the present study, the determination of eight sulfonylureas has been tested in wheat flour by applying the SweEt multiresidue method modified for dry products. Method: The method involves sample preparation with extraction with ethyl acetate (EEA) and determination of the analytes with LC/MS/MS-electrospray ionization. Its performance was compared with the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. Both methods were validated in three fortification levels according to European Union requirements. Results: The proposed method gave acceptable results as far as validation criteria are concerned, while QuEChERS did not result in successful recoveries in the lowest validation level, which is equal to the respective maximum residue limits (MRLs). Conclusions: The obtained results showed that the tested method showed good separation, sensitivity, linearity, precision, and accuracy for quantitative and qualitative analysis of sulfonylurea herbicides in cereals at low levels, as required by legislation. The analytical techniques were successfully applied to different samples of cereals, and no residues were determined above the reporting limit, as established at the lowest concentration level of each analyte being validated with acceptable accuracy. Highlights: Low recoveries for QuEChERS in the concentrations equal to the MRL. Acceptable recoveries for the EEA method in all fortification levels. Correlation coefficients above 0.99. Positive findings only with EEA in real samples.

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.

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.

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