The Ektachem clinical chemistry slide for simultaneous determination of unconjugated and sugar-conjugated bilirubin.

1984 ◽  
Vol 30 (8) ◽  
pp. 1304-1309 ◽  
Author(s):  
T W Wu ◽  
G M Dappen ◽  
R W Spayd ◽  
M W Sundberg ◽  
D M Powers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Liquid Chromatography ◽  
Magnetic Resonance ◽  
Total Bilirubin ◽  
Clinical Chemistry ◽  
Average Concentration ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic ◽  
Conjugated Bilirubin

Abstract Using dual-wavelength spectrometry, we have refined the mordant-based bilirubin slide method (Clin Chem 28:2366-2372, 1982) to co-detect unconjugated bilirubin (Bu) and its sugar conjugates (Bc) in 10 microL of serum. The assay is based on three principles: (a) mono- and diconjugated bilirubins behave spectrally like one fraction (Bc) when bound to the mordant, (b) Bu and Bc are spectrally distinct, and (c) B delta (the bilirubin-albumin complex) is not measured in the film. With known bilirubin mixtures, results by the assay agree with those by nuclear magnetic resonance, by a Jendrassik-Gróf method for total bilirubin, and by a liquid-chromatographic procedure. With patients' sera, the slide correlates with a liquid-chromatography-augmented Jendrassik-Gróf method, according to the following typical regression statistics (in mumol/L): for Bu, slope = 0.992, r = 0.996, intercept = -0.376, Sy X x = 5.08; for Bc, slope = 0.970, r = 0.985, intercept = -0.735, Sy X x = 8.16. The method is precise (for Bu, CV = 5.2% at an average concentration of 16.4 mumol/L, and 4.1% at 66.7 mumol/L; for Bc, CV = 6.5% at 23.4 mumol/L, and 3.8% at 151.7 mumol/L for pools of patients' sera), is relatively interference free, and has potential for extension to further applications.

Gas—Liquid Chromatographic Measurement of Guanidino Acids

1975 ◽  
Vol 21 (7) ◽  
pp. 838-843 ◽  
Author(s):  
Harini Patel ◽  
Burton D Cohen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Liquid Chromatography ◽  
Liquid Phase ◽  
Magnetic Resonance ◽  
Gas Liquid Chromatography ◽  
Butyl Esters ◽  
Silicone Liquid ◽  
Chromatographic Measurement ◽  
Liquid Chromatographic

Abstract We present a method for separating and measuring guanidino acids by gas—liquid chromatography. Compared to ion-exchange techniques, this system is faster, more sensitive, requires smaller sample volumes, is independent of colorimetric reactions, and permits simultaneous determination of both amino and guanidino acids. N-Trifluoroacetyl-n-butyl esters are formed and then are separated by using a column containing a mixed silicone liquid phase coated on Chromosorb W-HP. Analytical recoveries from plasma ranged from 86 to 112% and were optimal when purification and derivatization were done without prior protein precipitation. Speculations as to the cause of this interference by protein include coprecipitation, protein-binding, and cyclization of the guanidines in the acids used for denaturation. Evidence presented suggests that all three occur: ultrafiltrability is diminished in the presence of protein and nuclear magnetic resonance demonstrates cyclization of some of these esters.

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.

High-Pressure Liquid Chromatography of Benzo (a) pyrene and Benzo(ghi)perylene in Oil-Contaminated Shellfish

1976 ◽  
Vol 59 (5) ◽  
pp. 989-992 ◽  
Author(s):  
Humberto Guerrero ◽  
Edward R Biehl ◽  
Charles T Kenner
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Petroleum Ether ◽  
Silica Gel ◽  
High Pressure Liquid Chromatography ◽  
High Pressure Liquid Chromatographic ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic ◽  
Polynuclear Aromatics

Abstract A high-pressure liquid chromatographic procedure is described for the determination of benzo (a) pyrene and benzo(ghi)perylene. These polynuclear aromatics are extracted with acetonitrile and partitioned into petroleum ether, the petroleum ether is removed, and the residue is saponified. The compounds are purified and isolated by passing the residue through a silica gel column and a high-pressure liquid chromatographic column, and detected by their ultraviolet absorption. Recoveries of standards through the procedure averaged 104%.

Direct determination of the linoleate/oleate ratio in serum cholesterol esters by liquid chromatography.

1982 ◽  
Vol 28 (4) ◽  
pp. 676-680 ◽  
Author(s):  
J T Bernert ◽  
J R Akins ◽  
D T Miller
Keyword(s):  
Liquid Chromatography ◽  
Serum Cholesterol ◽  
Methyl Esters ◽  
Direct Determination ◽  
Reversed Phase ◽  
Cholesterol Esters ◽  
Serum Samples ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract We describe a convenient method for the direct determination of the serum cholesterol linoleate/cholesterol oleate (L/O) ratio by reversed-phase "high-performance" liquid chromatography. After removal of phospholipids by silicic acid chromatography, a serum extract is analyzed on a 5-micrometers particle size Ultrasphere-ODS column, eluted isocratically with acetonitrile/isopropanol (30/70, by vol). Detection is at 200 nm. Cholesterol palmitoleate interferes with the measurement when the analysis is based on peak area, but not when peak height is used. The overall precision of L/O measurements by this method was very similar to that observed with a gas-liquid chromatographic procedure, in which the cholesterol esters are first isolated and transesterified to the methyl esters. In both cases, the within-run CV for six replicate analyses was less than 2%. Analysis of 53 human serum samples by both methods yielded very similar L/O ratios. A plot of the data (our method = y) vs the usual gas-liquid chromatographic procedure gave a correlation coefficient of 0.988 and a regression equation of y = 1.03x + 0.013. Furthermore, direct analysis of serum cholesterol ester L/O ratios by our liquid-chromatographic method is simpler, quicker, and more readily adaptable to automation.

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