Serum cortisol and 11 deoxycortisol by liquid chromatography: clinical studies and comparison with radioimmunoassay.

1979 ◽  
Vol 25 (10) ◽  
pp. 1700-1703 ◽  
Author(s):  
E Canalis ◽  
A M Caldarella ◽  
G E Reardon
Keyword(s):  
Liquid Chromatography ◽  
Oral Administration ◽  
Serum Cortisol ◽  
Clinical Applications ◽  
Adrenal Function ◽  
Dynamic Tests ◽  
Oral Ingestion ◽  
Chromatographic Procedure ◽  
Normal Humans ◽  
Liquid Chromatographic

Abstract We describe a liquid-chromatographic procedure for separating and measuring cortisol and 11-deoxycortisol in serum. We quantitated these steroids in patients who were undergoing various tests of pituitary and (or) adrenal function and compared the results with those obtained by two radioimmunoassays done in two different laboratories. Results of 48 tests done in 37 functionally normal humans are presented. Cortisol values for sera collected in the morning as determined by liquid chromatography were (mean +/- SD) 134 +/- 54 micrograms/L. Serum cortisol concentrations increased from 136 +/- 65 to 321 +/- 80 micrograms/L 60 min after injecting synthetic corticotropin and increased from 107 +/- 46 to 242 +/- 31 micrograms/L after insulin-induced hypoglycemia. Serum cortisol decreased from 142 +/- 49 to 26 +/- 20 micrograms/L after oral administration of metyrapone, while 11-deoxycortisol increased from less than 10 to 210 +/- 53 micrograms/L. Serum cortisol measured less than 10 micrograms/L the morning after oral ingestion of dexamethasone. Results of the dynamic tests of adrenal function correlated well with previously reported studies. However, the cortisol values obtained by our technique were generally lower than those obtained by radioimmunoassay, possibly owing to lack of specificity of the latter methods used here for comparison. In contrast, values for 11-deoxycortisol were the same by both methods. The present studies confirm the usefulness of liquid chromatography for measuring these two steroids in serum during tests of pituitary and adrenal function. Future refinements of the technique should continue to increase its clinical applications.

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.

Gas Chromatographic and Gas Chromatographic-Mass Spectrometric Confirmation of 2,4- and 2,6-Toluenediamine Determined by Liquid Chromatography in Aqueous Extracts

1982 ◽  
Vol 65 (6) ◽  
pp. 1388-1394 ◽  
Author(s):  
Roger C Snyder ◽  
William C Brumley ◽  
Charles V Breder ◽  
Thomas Fazio
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Mass Spectrometric ◽  
Gas Liquid Chromatography ◽  
Aqueous Extracts ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract The confirmation of 2,4- and 2,6-toluenediamine (TDA) in aqueous extracts from boil-in-bags and retortable pouches is described. The extracts were initially analyzed by a high performance liquid chromatographic procedure and any apparent 2,4- and/or 2,6-TDA were quantitated. The liquid chromatographic effluent corresponding to any apparent 2,4- or 2,6-TDA was collected. TDA was then partitioned into ethyl acetate and reacted with trifluoroacetic anhydride (TFAA). The TDA-TFAA derivative formed was confirmed by gas-liquid chromatography (GLC) using a 1.2 m × 0.32 cm nickel column packed with 6% OV-17 on Superpak-20M. Results obtained from analyzing extracts of several retortable pouches and boil-in-bags showed levels of TDA migration ranging from <0.1 to 2.2 ppb (μg/L). Additional confirmation of the TDA-TFAA derivative from retortable pouches by multiple ion detection GC/mass spectrometry is also described.

Measurement of thiamylal and thiopental in plasma by electron capture and flame photometric gas-liquid chromatography.

1977 ◽  
Vol 23 (7) ◽  
pp. 1306-1309 ◽  
Author(s):  
R H Smith ◽  
J A MacDonald ◽  
D S Thompson ◽  
W E Flacke
Keyword(s):  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Electron Capture ◽  
Internal Standard ◽  
Chromatographic Column ◽  
Gas Liquid Chromatography ◽  
Unchanged Drug ◽  
Chromatographic Procedure ◽  
Isothermal Gas ◽  
Liquid Chromatographic

Abstract We describe an isothermal gas-liquid chromatographic procedure developed for measuring thiamylal and thiopental in plasma. The unchanged drug is extracted into ethyl acetate from acidified plasma, together with an internal standard. The solvent is removed, the residue methylated, aliquots, diluted with benzene, are injected into a 183-cm gas-liquid chromatographic column containing 3% OV-17. Sensitivity of detection is in the nanogram to picogram range.

Gas--liquid chromatographic microdetermination of underivatized ethosuximide (alpha-ethyl-alpha-methyl succinimide) in plasma or serum.

1978 ◽  
Vol 24 (10) ◽  
pp. 1821-1823 ◽  
Author(s):  
A J Fellenberg ◽  
A C Pollard
Keyword(s):  
Liquid Chromatography ◽  
Detection Threshold ◽  
Internal Standard ◽  
Chloroform Extract ◽  
Gas Liquid Chromatography ◽  
Clinical Use ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic procedure for the microdetermination of ethosuximide is described. Ethosuximide is extracted from acidified plasma or serum into chloroform containing an internal standard alpha,alpha-dimethyl-beta-methyl succinimide. Part of the initial chloroform extract is gently evaporated, the residue redissolved in n-heptane at 60 degrees C, and an aliquot analyzed by gas-liquid chromatography. The procedure is rapid, reliable, sensitive, and specific. It requires a 25--50 microliter sample for a single estimation, has a detection threshold of less than 10 micromol/liter, and is suitable for routine clinical use.

Ascorbate in plasma as measured by liquid chromatography and by dichlorophenolindophenol colorimetry.

1986 ◽  
Vol 32 (6) ◽  
pp. 1004-1006 ◽  
Author(s):  
D J VanderJagt ◽  
P J Garry ◽  
W C Hunt
Keyword(s):  
Ascorbic Acid ◽  
Liquid Chromatography ◽  
Electrochemical Detection ◽  
High Performance ◽  
Colorimetric Method ◽  
Dehydroascorbic Acid ◽  
High Performance Liquid Chromatographic ◽  
Plasma Samples ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract Ascorbic acid was measured in 125 plasma samples by an automated colorimetric method involving dichlorophenolindophenol and by a "high-performance" liquid-chromatographic procedure with electrochemical detection. The two methods gave comparable results for samples with ascorbate concentrations of 1 to 20 mg/L (r = 0.97). We also measured the amount of total ascorbate (ascorbic acid + dehydroascorbic acid) in the same samples by a liquid-chromatographic procedure with precolumn derivitization of ascorbic acid. We confirmed that plasma contains little dehydroascorbic acid.

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%.

Measurement of chloroprocaine and procaine in plasma by flame ionization gas-liquid chromatography.

1978 ◽  
Vol 24 (9) ◽  
pp. 1599-1602 ◽  
Author(s):  
R H Smith ◽  
M A Brewster ◽  
J A MacDonald ◽  
D S Thompson
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Chromatographic Column ◽  
Gas Liquid Chromatography ◽  
Unchanged Drug ◽  
Flame Ionization ◽  
Chromatographic Procedure ◽  
Isothermal Gas ◽  
Liquid Chromatographic

Abstract We describe an isothermal gas-liquid chromatographic procedure developed for measuring procaine and chloroprocaine in plasma. The unchanged drug is extracted into toluene from alkalinized plasma, together with an internal standard. The solvent is removed, the residue redissolved in methanol, and aliquots are injected into a 91.5-cm gas-liquid chromatographic column containing 3% OV-210. Sensitivity of detection is in the nanogram range.

Liquid-chromatographic detection of thiazide diuretics in urine.

1980 ◽  
Vol 26 (6) ◽  
pp. 702-706 ◽  
Author(s):  
P A Tisdall ◽  
T P Moyer ◽  
J P Anhalt
Keyword(s):  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Spectrophotometric Method ◽  
Mobile Phase ◽  
Reversed Phase ◽  
Analytical Recovery ◽  
Two Samples ◽  
Chromatographic Procedure ◽  
Chromatographic Detection ◽  
Liquid Chromatographic

Abstract We describe a liquid-chromatographic procedure for detection in urine of all thiazide drugs currently used clinically. Urine is treated initially with NaBH4 to convert any chlorothiazide present to hydrochlorothiazide. The urine is acidified with NaH2PO4 (1.0 mol/L, pH 5), and thiazides are extracted with ethyl acetate. Interfering substances are then removed in two washes with 0.1 mol/L Na2HPO4 at pH 8. The ethyl acetate is evaporated and the residue redissolved in mobile phase. Thiazides are assayed by reversed-phase chromatography, with detection by ultraviolet absorption. Analytical recovery of thiazides ranged from 53 to 93%. Urines from 48 patients were so studied, and the results were compared with results by the currently used spectrophotometric method. The two methods agreed for 56% of samples. Evaluation of the discrepancies by review of patients’ histories clearly showed liquid chromatography to have correctly identified seven of eight positive urines that the spectrophotometric method failed to detect. Ultraviolet scanning incorrectly identified as positive two samples, whereas liquid chromatography did not falsely identify any urines as positive. Our method was more sensitive and more specific than the spectrophotometric method.

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.

Liquid chromatography of synthetic polymers under limiting conditions of insolubility. I. Principle of the method

2006 ◽  
Vol 60 (1) ◽  
Author(s):  
D. Berek
Keyword(s):  
Liquid Chromatography ◽  
Small Molecules ◽  
Fast Moving ◽  
Synthetic Polymers ◽  
Sample Solution ◽  
New Approach ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

AbstractA novel liquid chromatographic procedure is presented. It is based on differences in the transport velocities of the fast-moving, pore-excluded macromolecules and slow-progressing, pore-permeating small molecules of an auxiliary liquid. A barrier of small molecules selectively decelerates certain kind of macromolecules while other kind remains unhindered. As a result, polymers of different nature are efficiently separated. In this new approach, the barrier is formed by a zone of a non-solvent injected immediately before the sample solution. The resulting method is denoted liquid chromatography under limiting conditions of insolubility.

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