Liquid chromatographic determination of guanidines with an anion exchange column used simultaneously as separator and postcolumn reagent generator

1986 ◽  
Vol 58 (7) ◽  
pp. 1380-1383 ◽  
Author(s):  
Hans. Jansen ◽  
Elisabeth G. Van der Velde ◽  
Udo A. T. Brinkman ◽  
Roland W. Frei ◽  
Hans. Veening
Keyword(s):  
Anion Exchange ◽  
Chromatographic Determination ◽  
Anion Exchange Column ◽  
Exchange Column ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Liquid Chromatographic Determination of Thiamine in Infant Formula Products by Using Ultraviolet Detection

1985 ◽  
Vol 68 (6) ◽  
pp. 1087-1092
Author(s):  
Benjamin K Ayi ◽  
David A Yuhas ◽  
Kathryn S Moffett ◽  
Deidre M Joyce ◽  
Nicholas J Deangelis
Keyword(s):  
Infant Formula ◽  
Chromatographic Determination ◽  
Phosphate Esters ◽  
Exchange Column ◽  
Relative Standard ◽  
Cation Exchange Column ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Different Levels

Abstract A liquid chromatographic (LC) method has been developed for determination of thiamine in infant formula products. The method involves the following steps: (a) dissolution of the formula with water, (b) pH adjustment to induce protein precipitation, (c) filtration, (d) concentration of thiamine by using a cation exchange column and extraction system, (e) cleanup of adsorbed thiamine and other contaminants on the ion exchange column by washing with water and then methanol, (f) elution of thiamine with a mixture of methanol-2M potassium chloride buffer, (g) analysis for thiamine by liquid chromatography. Thiamine is separated from its phosphate esters, the mono-, di-, and triphosphates, as well as its antagonists oxythiamine and pyrithiamine on a 6 p-m particle size column and a mobile phase of 40mM triethylammonium phosphate buffer-methanol (pH 7.7) (90 + 10). The method is reproducible, with relative standard deviations ranging from ± 0.76 to ± 1.2%, depending on the infant formula product tested. Recovery of thiamine from various infant formula products is greater than 99%. Analysis for thiamine of several commercially available infant formulas at different levels of fortification gave results that ranged from 122 to 216% of the declared levels. These results agree well with those obtained using the AOAC fluorometric method.

High Pressure Liquid Chromatographic Determination of Nifursol in Finished Feeds

1981 ◽  
Vol 64 (4) ◽  
pp. 969-972
Author(s):  
Glenn M George ◽  
Larry J Frahm ◽  
J Patrick Mcdonnell
Keyword(s):  
High Pressure ◽  
Chromatographic Determination ◽  
Anion Exchange Column ◽  
Photometric Detection ◽  
Average Coefficient ◽  
Strong Anion Exchange ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Feed Samples

Abstract Nifursol is extracted from feed with acetonitrile, and then washed with carbon disulfide to remove feed interferences. An aliquot is concentrated, diluted with 5% NaCl solution, filtered, and then subjected to high pressure liquid chromatography on a strong anion exchange column, using 365 nm photometric detection. The average recovery of nifursol from fortified feed samples was 100.6% with an average coefficient of variation of 3.5%. The nifursol determination is not subject to interference from the other commonly used nitrofurans.

Rapid Liquid Chromatographic Determination of Clopidol in Chicken Muscles

1984 ◽  
Vol 67 (2) ◽  
pp. 334-336
Author(s):  
Canutte A Mtema ◽  
Hiroyuki Nakazawa ◽  
Eigo Takabatake
Keyword(s):  
Internal Standard ◽  
Chromatographic Determination ◽  
Alumina Column ◽  
Anion Exchange Column ◽  
Chicken Muscle ◽  
Liquid Chromatographic Method ◽  
Chicken Muscles ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple, rapid, and sensitive liquid chromatographic method is described for the quantitative determination of trace amounts of clopidol (3,5- dichloro-2,6-dimethyl-4-pyridinol) in chicken muscles. Clopidol was extracted from tissues with acetonitrile and the extract was cleaned up on an alumina column and separated on an anion exchange column, using 0.5% acetic acid in methanol as eluant. The solvent in the eluate was evaporated and the residue was dissolved in methanol containing benzamide as internal standard. Clopidol was separated on a Zorbax ODS column (4.6 × 250 mm) by using acetonitrile–0.05M phosphate buffer, pH 7.0 (15 + 85 v/v%), and detected at 270 nm with 0.005 AUFS. Recoveries of clopidol added to chicken tissues at levels of 0.02, 0.05, and 0.1 μg/g were 94.8, 94.8, and 97.0%, respectively. This method is applicable to levels as low as 0.01 ppm clopidol in chicken muscle.

Liquid Chromatographic Determination of Sucralfate in Dental Cream

1992 ◽  
Vol 75 (5) ◽  
pp. 809-811 ◽  
Author(s):  
Robert J Gargiullo
Keyword(s):  
Mobile Phase ◽  
Chromatographic Method ◽  
Chromatographic Determination ◽  
Anion Exchange Column ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Tetrabutylammonium Hydrogen Sulfate ◽  
Refractive Index Detection

Abstract A simple, rapid liquid chromatographic method is described for quantitative determination of sucralfate in dental cream. Analyses were performed on a weak anion exchange column with 0.6M ammonium sulfate-0.005M tetrabutylammonium hydrogen sulfate as the mobile phase and refractive index detection. The method was linear over a range of 0.0 to 20.0% sucralfate in dental cream. The coefficient of variation was 3.2%. Standard recoveries were concentration dependent and ranged from 97.2 to 104.9%.

Liquid Chromatographic Determination of Folic Acid in Infant Formula and Adult Medical Nutritionals

1992 ◽  
Vol 75 (5) ◽  
pp. 891-897 ◽  
Author(s):  
Bart T Jacoby ◽  
Franklin T Henry
Keyword(s):  
Folic Acid ◽  
Infant Formula ◽  
Chromatographic Determination ◽  
Enzymatic Digestion ◽  
Anion Exchange Column ◽  
Liquid Chromatographic Method ◽  
Strong Anion Exchange ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for the determination of pteroylglutamic acid (folic acid) in infant formula and liquid medical nutritional diets is described. Extraction of folic acid from the sample matrix is facilitated by a partial enzymatic digestion of the sample proteins. An aliquot of the sample preparation is injected onto a strong anion exchange column (SAX) for preliminary separation, using a pH 5.3 mobile phase of 0.02M sodium acetate and 0.02M sodium sulfate. Before the elution of the folic acid from the SAX column, the eluant is directed onto an octyl bonded-phase column (C8) by using automated switching valves. After the folic acid has been transferred to the C8 column, the SAX column is removed from the flow path. The folic acid is eluted from the Cs column by using an acetonitrile gradient. Detection is by absorption at 345 nm. The mean coefficient of variation is 3.6%, and the range of the recoveries of added folic acid is 95.5-100.2%. The method detection limit and method quantitation limit for infant formula are 10 and 28 µg/kg, respectively. This method is used routinely for the determination of folic acid in infant formula and liquid medical nutritional diets.

Anion-exchange chromatographic determination of bromide in serum.

1984 ◽  
Vol 30 (5) ◽  
pp. 781-783 ◽  
Author(s):  
M E Miller ◽  
C J Cappon
Keyword(s):  
Anion Exchange ◽  
Unique Feature ◽  
Chromatographic Determination ◽  
Serum Samples ◽  
Anion Exchange Column ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Absolute Detection Limit ◽  
Liquid Chromatographic

Abstract In this liquid-chromatographic method for the determination of bromide in human serum, an important and unique feature is pre-analysis ultrafiltration of the sample, which effectively removes proteins. The chromatographic system consists of an anion-exchange column (Whatman Partisil SAX 10-micron particles), an isocratic phosphate-buffered mobile phase, and ultraviolet detection at 195 nm. The absolute detection limit, 0.6 ng of bromide, makes this method the most sensitive assay for serum bromide yet reported. The day-to-day CV ranged from 1.6% to 4.9%. Analytical recovery of bromide added to serum samples ranged from 96.2% to 108.8%. Data on bromide in serum are presented for adults and newborns and for adults given bromide orally.

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