Liquid Chromatographic Determination of 2,4-Dinitroaniline and 2-Naphthol in D&C Orange No. 17

1985 ◽  
Vol 68 (3) ◽  
pp. 474-477
Author(s):  
Alan L Scher
Keyword(s):  
Chromatographic Determination ◽  
Isocratic Elution ◽  
Reverse Phase ◽  
Column Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Prediction Limits ◽  
Liquid Chromatographic ◽  
Cellulose Column

Abstract A method is described for the determination of the intermediates in D&C Orange No. 17 by reverse phase liquid chromatography. The pigment is dissolved in boiling dioxane and then precipitated. The filtrate is chromatographed by isocratic elution, which is followed by a wash and equilibration. Peak area calibrations were linear. At the provisional specification levels, 99% prediction limits were 0.200 ± 0.0012% 2,4-dinitroaniIine (2,4-DNA) and 0.200 ± 0.006% 2-naphthol. The limits of determination were 0.0023% for 2,4-DNA and 0.013% for 2-naphthol at the 99.5% confidence level. Recoveries were 98- 100% for 2,4-DNA added at the 0.005-2% level, and 93-103% for 2- naphthol added at the 0.025-2% level. A survey of certified D&C Orange No. 17 samples showed that the lots contained higher levels of the intermediates than were determined previously by a cellulose column method, in which the pigment is not dissolved.

Liquid Chromatographic Determination of Lake Red C Amine and 2-Naphthol in D&C Red No. 8

1988 ◽  
Vol 71 (5) ◽  
pp. 1007-1011
Author(s):  
Alan L Scher ◽  
Robert J Calvey
Keyword(s):  
Chromatographic Determination ◽  
Gradient Elution ◽  
Column Method ◽  
Peak Areas ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Prediction Limits ◽  
Liquid Chromatographic ◽  
Cellulose Column

Abstract A method is described for the determination of the intermediates in D&C Red No. 8 by reverse-phase liquid chromatography (LC). The pigment is dissolved in boiling 95% ethanol-water (1 + 1) and then precipitated. The filtrate is chromatographed by gradient elution. Calibrations from peak areas at 254 nm for Lake Red C Amine sodium salt (LRCA-Na) and at 229 nm for 2-naphthol were linear, with prediction limits of 0.200 ± 0.006% and 0.200 ± 0.003%, respectively, for the maximum permitted levels. Calibration limits of determination were 0.01% for LRCA-Na and 0.006% for 2-naphthol. A 99% confidence level was used. Recoveries were 100.0-100.4% for LRCA-Na and 97.1-101.8% for 2-naphthol, each added at levels of 0.025-0.2%. Certified lots of D&C Red No. 8 that were analyzed by the LC method contained higher levels of LRCA-Na but the same levels of 2-naphthol when compared to results obtained previously by a cellulose column method, in which the pigment is not dissolved. The solubilities of D&C Red No. 8 in hot and room temperature solutions of 95% ethanol-water (1 + 1), water, and 95% ethanol were estimated.

Liquid Chromatographic Determination of Leuco Base in FD&C Blue No. 1

1986 ◽  
Vol 69 (3) ◽  
pp. 478-482
Author(s):  
Alan L Scher ◽  
H Dean Murray
Keyword(s):  
Liquid Chromatography ◽  
Chromatographic Determination ◽  
Isocratic Elution ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Prediction Limits ◽  
Liquid Chromatographic

Abstract Methods are described for the determination of leuco base in FD&C Blue No. 1 by reverse phase liquid chromatography and for the preparation and standardization of leuco base stock solution. The stock solution is prepared by reductive titration of the color with TiCl3. Solutions of the color and of leuco base are chromatographed by isocratic elution, which is followed by a wash and equilibration that can be omitted for screening. Peak area and height calibrations were linear. At the specification level, the 99% prediction limits were 5.00 ± 0.14% (area) and 5.00 ± 0.37% (height). Limits of determination were 0.29% (area) and 0.73% (height) at the 99.5% confidence level. Recoveries were 97-101% for leuco base added to FD&C Blue No. 1 at levels of 1-6%.

Liquid Chromatographic Determination of Zoalene in Medicated Feeds

1984 ◽  
Vol 67 (5) ◽  
pp. 861-862 ◽  
Author(s):  
John Morawski ◽  
Glenn Kyle
Keyword(s):  
Colorimetric Method ◽  
Chromatographic Determination ◽  
Activated Alumina ◽  
Reverse Phase ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Aoac Official ◽  
Liquid Chromatographic ◽  
Medicated Feeds

Abstract A rapid, reliable separation and quantitation of zoalene (3,5-dinitroo-toluamide) from feeds is accomplished by using reverse phase liquid chromatography (LC) and ultraviolet detection. An extraction technique which is similar to the present AOAC official colorimetric method is used before chromatographic analysis. This extraction is followed by an activated alumina cleanup and LC to separate zoalene from feed matrix. The methodology was applied to a variety of spiked feed matrices, and yielded good recoveries. Liquid chromatographic results were shown to correlate with colorimetric determinations.

Reverse Phase Liquid Chromatographic Determination of Chlorophacinone and Diphacinone in Bait Formulations

1982 ◽  
Vol 65 (4) ◽  
pp. 927-929
Author(s):  
Brian R Bennett ◽  
Gregory S Grimes
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Target Concentration ◽  
External Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Chlorophacinone and diphacinone are extracted at the 0.005% level from grain or paraffinized baits with glacial acetic acid. The target concentration is 0.01 mg/mL. The filtered supernate is chromatographed on a Partisil PXS ODS10/25 liquid chromatography column with premixed and degassed glacial acetic acid-tetrahydrofuran-water (14 + 2 + 9) and detected at 288 nm. The concentration is calculated by using an external standard. The recovery from spiked samples averaged 96.6% for both analytes. The response is linear from 0.001 to 0.040 mg/mL. The coefficient of variation of within-day replicates ranged from 1.1 to 2.5%.

Liquid Chromatographic Determination of Carminic Acid in Yogurt

1989 ◽  
Vol 72 (2) ◽  
pp. 231-234 ◽  
Author(s):  
Mercedes Jalón ◽  
Majesús Peńa ◽  
Julián C Rivas
Keyword(s):  
Chromatographic Determination ◽  
Carminic Acid ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Array Detection ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A reverse-phase liquid chromatographic method is described for the determination of carminic acid in yogurt. A C18 column is used with acetonitrile-1.19M formic acid (19 + 81) as mobile phase and diode array detection. Sample preparation includes deproteinization with papain and purification in a polyamide column. The relative standard deviation for repeated determinations of carminic acid in a commercial strawberry-flavored yogurt was 3.0%. Recoveries of carminic acid added to a natural-flavored yogurt ranged from 87.2 to 95.3% with a mean of 90.2%. The method permits measurement of amounts as low as 0.10 mg/kg.

Rapid Method for Extraction and Reverse Phase Liquid Chromatographic Determination of Paraquat Residues in Water

1983 ◽  
Vol 66 (3) ◽  
pp. 663-666
Author(s):  
Ijaz Ahmad
Keyword(s):  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reverse Phase ◽  
Ultraviolet Detection ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Low Levels ◽  
Liquid Chromatographic

Abstract A simple and fast analytical method is described for the quantitative determination of low levels of paraquat residues in water. The method involves extraction and concentration of paraquat in water by using a C18 Sep-Pak cartridge followed by reverse phase high performance liquid chromatographic determination with ultraviolet detection at 257 nm. Recoveries of paraquat from spiked samples were above 93% with a coefficient of variation of 6.1%. The method can be used for water samples with paraquat concentrations as low as 0.05 ppm.

Liquid Chromatographic Determination of Fluridone Aquatic Herbicide and Its Metabolite in Fish and Crayfish

1986 ◽  
Vol 69 (5) ◽  
pp. 856-859 ◽  
Author(s):  
Sheldon D West ◽  
Edgar W Day
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Aquatic Herbicide ◽  
Liquid Chromatographic

Abstract A residue method is described for determination of the aquatic herbicide fluridone (1-methy1-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)- pyridinone) and its metabolite (1-methy1-3-(4-hydroxyphenyl)-5-[3- (trifluoromethyl)phenyl]-4(1H)-pyridinone) in fish and crayfish tissues. Both compounds are extracted from tissues with methanol, and the extracts are subjected to acidic hydrolysis to release conjugated forms of fluridone and the metabolite. Sample extracts are purified by liquidliquid partitioning and Florisil Sep-Pak® column chromatography. Both compounds are separated and measured by reverse phase liquid chromatography with UV detection at 313 nm. In the absence of interfering peaks, the method has a detection limit of approximately 0.04 ppm of either compound. Overall, recoveries averaged 96% for fluridone and 78% for the metabolite for all tissue types combined.

Liquid Chromatographic Determination of Primary and Secondary Amines as 8-Quinolinesulfonyl Chloride Derivatives

1984 ◽  
Vol 67 (4) ◽  
pp. 687-691
Author(s):  
F Taylor Noggle ◽  
C Randall Clark
Keyword(s):  
Chromatographic Determination ◽  
Secondary Amines ◽  
Absorption Bands ◽  
Reverse Phase ◽  
Primary And Secondary Amines ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Derivatives Of

Abstract The normal phase and reverse phase liquid chromatographic properties of seven 8-quinolinesulfonyl derivatives of primary and secondary amines are examined using dual wavelength ultraviolet detection. The amines are further identified by infrared spectrophotometry with emphasis on structural elucidation based on absorption bands at characteristic wavelengths.

Ion-Pair Extraction Cleanup for Liquid Chromatographic Determination of Bentazon in Crops and Soil

1984 ◽  
Vol 67 (3) ◽  
pp. 653-655
Author(s):  
Malin Åkerblom ◽  
Gunborg Alex
Keyword(s):  
Clay Soil ◽  
Chromatographic Determination ◽  
Ion Pair ◽  
Wheat Grain ◽  
Reverse Phase ◽  
Tetrabutylammonium Ion ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Bentazon was selectively extracted as an ion pair with tetrabutylammonium ion into dichloromethane. This technique was used to clean up crop and soil samples before determination of bentazon by reverse phase liquid chromatography and UV detection. Recoveries from potatoes, cucumbers, wheat grain, and clay soil were 77–103%, with a detection limit of 0.02 mg/kg.

Reverse-Phase Liquid Chromatographic Determination of Paraquat and Diquat in Agricultural Products

1987 ◽  
Vol 70 (6) ◽  
pp. 1008-1011 ◽  
Author(s):  
Toshihiro Nagayama ◽  
Toshio Maki ◽  
Kimiko Kan ◽  
Mami Iida ◽  
Taichiro Nishima
Keyword(s):  
Chromatographic Determination ◽  
Agricultural Products ◽  
Minimum Detectable Concentration ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Detectable Concentration ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A simple, rapid, highly sensitive liquid chromatographic method is described for the quantitative determination of paraquat and diquat residues in agricultural products. Paraquat and diquat are extracted with hot dilute hydrochloric acid and are cleaned up on an Amberlite CG-50 column, followed by reverse-phase liquid chromatography on an NH, column, with ultraviolet detection at 257 nm (paraquat) and 310 nm (diquat). The minimum detectable concentration of both paraquat and diquat was 0.5 ng per injection, which corresponds to a lower detection limit of approximately 0.02 fjg/g in the original samples. Recoveries of paraquat and diquat added to various samples were greater than 79%, and averaged 91 and 90%, respectively, at the 0.1 and 1.0 μg/g spiking levels.

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