Thin Layer Chromatographic Determination of Subsidiary Dyes in D&amp;C Red No. 19 and D&amp;C Red No. 37

10.1093/jaoac/57.4.957 ◽

1974 ◽

Vol 57 (4) ◽

pp. 957-960

Author(s):

Sandra Bell

Keyword(s):

Thin Layer ◽

Silica Gel ◽

Chromatographic Method ◽

Chromatographic Determination

Abstract A thin layer chromatographic method is presented by which triethylrhodamine and other lower ethylated subsidiary colors are separated from D&C Red No. 19 and D&C Red No. 37. After removal from the plate, subsidiary dyes are extracted from silica gel C adsorbent and quantitated spectrophotometrically. Recoveries of 1, 2, and 5% of added triethylrhodamine ranged from 89 to 1 0 3% for D&C Red No. 19 and from 85 to 1 0 2% for D&C Red No. 37.

Thin Layer Chromatographic Determination of Citrinin

10.1093/jaoac/62.1.201 ◽

1979 ◽

Vol 62 (1) ◽

pp. 201-202 ◽

Cited By ~ 2

Author(s):

Robert D Stubblefield

Keyword(s):

Acetic Acid ◽

Thin Layer ◽

Linear Relationship ◽

Silica Gel ◽

Coefficient Of Variation ◽

Ethylenediaminetetraacetic Acid ◽

Limit Of Detection ◽

Tlc Plates

Abstract Clearly defined zones of citrinin can be obtained on thin layer chromatographic (TLC) plates and measured by fluorodensitometry. Silica gel plates were prepared as a slurry with aqueous 0.05M Na2EDTA (ethylenediaminetetraacetic acid), spread at 0.5 mm wet thickness, and activated at 105°C for 1 hr. Plates were developed in acetic acid-benzene (5+95). The limit of detection was 10 ng citrinin/zone. Densitometric analysis (365 nm excitation, 505 nm emission) revealed that a linear relationship exists for levels of 10 ng to at least 100 ng/zone wtih a coefficient of variation of ±5%.

Thin-Layer Chromatographic Determination of Carbaryl (Sevin) in Some Foods

10.1093/jaoac/48.4.736 ◽

1965 ◽

Vol 48 (4) ◽

pp. 736-738

Author(s):

Josephine M Finocchiaro ◽

Walter R Benson

Keyword(s):

Aluminum Oxide ◽

Thin Layer ◽

Chromatographic Method ◽

Semiquantitative Determination

Abstract A thin-layer chromatographic method is described for the semiquantitative determination of the insecticide carbaryl. Acceptable recoveries ranging from 0.05 to 0.2 ppm have been obtained from nine crops. The Rf value of carbaryl ranged from 0.52 to 0.60 on aluminum oxide G plates.

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

10.1093/jaoac/56.4.813 ◽

1973 ◽

Vol 56 (4) ◽

pp. 813-816 ◽

Cited By ~ 7

Author(s):

Peter M Scott ◽

Barry P C Kennedy

Keyword(s):

Thin Layer ◽

Ethyl Acetate ◽

Thin Layer Chromatography ◽

Silica Gel ◽

Apple Juice ◽

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.

Collaborative Study of a Fluorometric and Thin Layer Chromatographic Determination of Aminacrine and Its Salts in Drug Preparations

10.1093/jaoac/50.3.680 ◽

1967 ◽

Vol 50 (3) ◽

pp. 680-682

Author(s):

Laura A Roberts

Keyword(s):

Standard Deviation ◽

Thin Layer ◽

Chromatographic Method ◽

Collaborative Study ◽

Assay Method ◽

The Mean ◽

Layer Chromatography ◽

Mean Concentration

Abstract Eight collaborators studied a fluoromelric and thin layer chromatographic method for aminacrine and its salts in powder and cream drug preparations. Recovery of aminacrine.HCI by fluorometer in both preparations averaged 100% for powder and 102% for cream. The mean concentration of aminacrine.HCI found in the powder was 0.108% with a standard deviation of ± 0.001%. The mean concentration of aminacrine found in the cream was 0.191% with a standard deviation of ± 0.003%. Seven of the 8 collaborators successfully used thin layer chromatography to identify the aminacrine in both sample forms supplied. The assay method for aminacrine and its salts in drug preparations is recommended for adoption as official, first action

Gas Chromatographic Determination of Mecarbam and Its Metabolites Mecarboxon, Diethoate, and Diethoxon in Cottonseeds

10.1093/jaoac/70.5.870 ◽

1987 ◽

Vol 70 (5) ◽

pp. 870-874

Author(s):

Rachel S Greenberg

Keyword(s):

Silica Gel ◽

Propylene Carbonate ◽

Chromatographic Method ◽

Soxhlet Extraction ◽

Alumina Column ◽

Flame Photometric Detector ◽

Average Recovery ◽

Gas Chromatographic Method

Abstract A gas chromatographic method is described for determining residues of mecarbam and 3 of its metabolites, mecarboxon, diethoate, and diethoxon, in cottonseeds. For mecarbam analysis, following Soxhlet extraction with chloroform (after blending), the oily extract is partitioned with propylene carbonate and cleaned up on a silica gel column. Metabolites are extracted by the same method, followed by cleanup of mecarboxon on a silica gel column or diethoxon on an alumina column; cleanup of diethoate can be performed on either column. AH 4 compounds are determined using a flame photometric detector equipped with a phosphorus filter. Average recoveries for cottonseed samples fortified with 0.03-1.0 ppm mecarbam ranged from 80 to 88%. Average recoveries were 81-88% for mecarboxon and 90-92% for diethoate (alumina column) and diethoxon from samples fortified with 0.05-1.0 ppm. Average recovery of diethoate from samples cleaned up on the silica gel column were 84-88% in the range of 0.05-0.2 ppm. Values obtained for mecarbam residues in field-treated samples are also presented.

Quantitative Determination of Carbaryl in Apples, Lettuce, and Water by Densitometry of Thin Layer Chromatograms

10.1093/jaoac/61.3.616 ◽

1978 ◽

Vol 61 (3) ◽

pp. 616-620

Author(s):

Joseph Sherma ◽

Andrew J Kovalchick ◽

Richard Mack

Keyword(s):

Thin Layer ◽

Quantitative Determination ◽

Fiber Optics ◽

Silica Gel ◽

Chromatographic Method ◽

Visual Estimation ◽

Carbamate Insecticides

Abstract A method for the quantitative determination of carbaryl insecticide by in situ densitometry was developed. After separation on silica gel thin layer plates, carbaryl residues were detected by using p-nitrobenzenediazonium fluoborate reagent and quantitated by scanning the resultant blue spots with a fiber optics densitometer and comparing them with standards. The method was applied to water fortified with carbaryl at 8 ppb and apples and lettuce fortified at 0.10 ppm; all recoveries were greater than 89%. The 2 crop extracts were cleaned up by using the AOAC thin layer chromatographic method for visual estimation of carbaryl. Related carbamate insecticides were detected by using the same reagent, and the potential for quantitation was demonstrated.

Use of Small Charcoal/Alumina Cleanup Columns in Determination of Trichothecene Mycotoxins in Foods and Feeds

10.1093/jaoac/69.4.699 ◽

1986 ◽

Vol 69 (4) ◽

pp. 699-703 ◽

Cited By ~ 8

Author(s):

Thomas R Romer

Keyword(s):

Gas Chromatography ◽

Liquid Chromatography ◽

Thin Layer ◽

Chromatographic Method ◽

Food And Feed ◽

Feed Samples

Abstract Small charcoal/alumina cleanup columns have been effectively used to remove interfering materials from grain, feed, and food extracts prior to chromatographic determination of trichothecene mycotoxins. A thin layer chromatographic method has been developed that can simultaneously detect part per billion concentrations of deoxynivalenol, fusarenon X, nivalenol, T-2 toxin, HT-2 toxin, neosolaniol, and diacetoxyscirpenol in food and feed samples. Recoveries of 90-99% can be obtained. The use of charcoal/alumina cleanup columns in conjunction with liquid chromatography and gas chromatography of trichothecenes is also discussed.

Thin Layer Chromatographic Determination of Sterigmatocystin in Cheese

10.1093/jaoac/68.4.643 ◽

1985 ◽

Vol 68 (4) ◽

pp. 643-645

Author(s):

Octave J Francis ◽

George M Ware ◽

Allens Carman ◽

Shia S Kuan

Keyword(s):

Thin Layer ◽

Aluminum Chloride ◽

Chromatographic Method ◽

One Dimensional ◽

Sample Extract ◽

Ether Mixture ◽

Final Purification

Abstract A one-dimensional thin layer chromatographic method has been developed for determining sterigmatocystin in cheese. Cheese is extracted with acetonitrile—4% KC1 (85 + 15). A simplified liquid-liquid partition cleanup is used, and the sample extract is passed through a cupric carbonate column for final purification. Sterigmatocystin is visualized by spraying the plate with aluminum chloride. The fluorescence of the : spot is enhanced 10-fold by additional plate spraying with a silicone- ' ether mixture, enabling sterigmatocystin detection and quantitation at 2 land5 μg/kg, respectively. Average recoveries were 88.3 and 86.4% at the 10 and 25 μg/kg levels, respectively.

Thin Layer Chromatographic Determination of Aflatoxin in Eggs: Collaborative Study

10.1093/jaoac/61.3.569 ◽

1978 ◽

Vol 61 (3) ◽

pp. 569-573

Author(s):

Stanley Nesheim ◽

Mary W Trucksess

Keyword(s):

Thin Layer ◽

Coefficient Of Variation ◽

Chromatographic Method ◽

Collaborative Study ◽

Chromatographic Determination

Abstract The thin layer chromatographic method of Trucksess et al. for aflatoxin Bx in eggs was collaboratively studied. Each collaborator analyzed 3 known practice samples and 9 unknown samples containing added aflatoxin Bx at 0, 0.05, 0.10, and 0.30 ng/g. For 9 collaborators, recoveries for the 3 positive levels were: 0–0.13 ng/g (average 98%, coefficient of variation (C.V.) 83%), 0.05-0.18 ng/g (average 102%, C.V. 36%), and 0.11-0.42 ng/g (average 93%, C.V. 31%), respectively. The method has been adopted as official first action.