Rapid Separation and Determination of Thyromimetic Iodoamino Acids by Gradient Elution Reverse Phase Liquid Chromatography with Electrochemical Detection

1983 ◽  
Vol 6 (3) ◽  
pp. 511-526 ◽  
Author(s):  
M. R. Hadj-mohammadi ◽  
Jimmie L. Ward ◽  
John G. Dorsey
Keyword(s):  
Liquid Chromatography ◽  
Electrochemical Detection ◽  
Gradient Elution ◽  
Reverse Phase ◽  
Rapid Separation ◽  
Reverse Phase Liquid Chromatography ◽  
Phase Liquid

Determination of Diacetyl in Butter as 2,3-Diaminonaphthalene Derivative, Using a Fluorometric Procedure or Reverse Phase Liquid Chromatography with Fluorescence Detection

1988 ◽  
Vol 71 (3) ◽  
pp. 462-465
Author(s):  
Pietro Damiani ◽  
Giovanni Burini
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
The Other ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Fluorescence Characteristics ◽  
Chromatographic Procedure ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Two procedures, one fluorometric and the other reverse phase liquid chromatographic, for determination of a derivative of diacetyl are described. Exploratory work on diacetyl standard solutions to establish the best conditions for the derivatization with 2,3-diaminonaphthalene (DAN) to yield 2,3-dimethylbenzo[g]-quinoxaline (DMBQ) is discussed, as well as the fluorescence characteristics of the DMBQ derivative. Diacetyl was determined in 10 commercial butter samples by the proposed procedures and by other known methods (determination of o-phenylenediamine and 3,3-diaminobenzidinederivatives). Recoveries from butter samples spiked with known amounts of diacetyl ranged from 96.9 to 101.8% (with CVs ranging from 0.3 to 2.1%) for the fluorometric procedure and from 96.9 to 102.7% (with CVs ranging from 0.5 to 2.4%) for the chromatographic procedure. These results agree well with those obtained with o-phenylenediamine and 3,3-diaminobenzidine methods on the same butter samples. The proposed methods have the advantages of improved detectability and specificity.

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.

Simultaneous Analysis of Nivalenol and Deoxynivalenol in Cereals by Liquid Chromatography

1987 ◽  
Vol 70 (3) ◽  
pp. 479-483 ◽  
Author(s):  
Denis R Lauren ◽  
Roy Greenhalgh
Keyword(s):  
Liquid Chromatography ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Relative Standard ◽  
Phase Liquid ◽  
Cereal Samples ◽  
Sensitive Method

Abstract A sensitive method is described for determination of nivalenol (NIV) and deoxynivalenol (DON) in cereals by using reverse phase liquid chromatography and UV detection at 222 nm. The sample is extracted with acetonitrile-water (85 + 15) and an aliquot is purified by passage through a combined column of cation exchange resin and alumina-carbon (20 + 1). Analysis at this stage is possible with some samples but the method recommends passing an aliquot through a carbon minicolumn after evaporation and solubilization in methanol. Interference from coextracted compounds at this point is negligible. Recoveries of both NIV and DON from spiked extracts taken through the full method were in the range 83-94%. The relative standard deviation, based on 5 replicate determinations from each of 2 corn samples, was approximately 5% for both NIV and DON. With a 10 fiL injection, the minimum contamination (3 x signal/noise ratio) able to be detected in cereal samples was about 0.015 μ NIV/g and 0.05 μ DON/g. The cleaned up extracts are also suitable for analysis by gas chromatography.

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