Rapid analysis for iodotyrosines and iodothyronines in thyroglobulin by reversed-phase liquid chromatography.

1979 ◽  
Vol 25 (10) ◽  
pp. 1757-1760 ◽  
Author(s):  
N M Alexander ◽  
M Nishimoto
Keyword(s):  
Anion Exchange ◽  
Anion Exchange Chromatography ◽  
Reversed Phase ◽  
Exchange Chromatography ◽  
Chart Recorder ◽  
Chromatographic Procedure ◽  
Phase Liquid ◽  
Flow Through ◽  
Sequential Digestion ◽  
Liquid Chromatographic

Abstract We describe a 10-min reversed-phase "high-pressure' liquid-chromatographic procedure for measuring tyrosine, monoiodotyrosine, diiodotyrosine, 3,5-diiodothyronine, 3,5,3'-triiodothyronine, 3,3',5'-triiodothyronine, and thyroxine. Resolution and quantitation of a mixture of these amino acids were excellent on LiChrosorb (Altex) RP-8 with isocratic elution (1.5 mL/min) with acetonitrile/water/glacial acetic acid (50/49/1 by vol). As little as 100 ng of each iodoamino acid could be detected and quantitated with a conventional 1-cm, flow-through spectrophotometric (254-nm) detector coupled to a 10-mV strip-chart recorder. Analyses for monoiodotyrosine, diiodotyrosine, 3,5,3'-triiodothyronine, and thyroxine in hog and beef thyroglobulin hydrolysates (sequential digestion with pronase and aminopeptidase) agreed well with results by anion-exchange chromatography and by competitive radioassays. To prevent interference by tryptophan in the analysis for diiodotyrosine, we batch-separated the iodoamino acids by anion-exchange chromatography before the procedure. The procedure we describe seems generally useful for detection and quantitation of thyroid hormones, thyroid hormone metabolites, and iodotyrosines.

Uric acid determinations: reversed-phase liquid chromatography with ultraviolet detection compared with kinetic and equilibrium adaptations of the uricase method.

1982 ◽  
Vol 28 (3) ◽  
pp. 496-498 ◽  
Author(s):  
O C Ingebretsen ◽  
J Borgen ◽  
M Farstad
Keyword(s):  
Uric Acid ◽  
Serum Proteins ◽  
Reversed Phase ◽  
Uric Acid Concentration ◽  
Liquid Chromatograph ◽  
Serum Uric Acid Concentration ◽  
Chromatographic Procedure ◽  
Absorbance Reading ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A reversed-phase liquid-chromatographic procedure is presented for quantitation or uric acid in human serum, with absorbance measured at 292 nm. The mobile phase was sodium acetate (35 mmol/L, pH 5.0)/acetonitrile (9/1 by vol). Complete precipitation of serum proteins was obtained by mixing serum (50-500 microL) with an equal volume of acetonitrile, and the precipitate was removed by centrifugation. Aliquots (20 microL) of the supernate were injected directly into the liquid chromatograph, which was adjusted so that the absorbance reading of the uric acid peak was as high as possible. Routinely, a full-scale deflection of 1.28 absorbance units was used. The within-run precision (CV) was 0.6% for a serum uric acid concentration of 227 mumol/L and day-to-day precision over a 15-day period was 0.8% for uric acid of 345 mumol/L. No interferences from related compounds were observed. We compared results by this method with those by kinetic (aca, Du Pont) and equilibrium adaptations (Ames kit; Nyco-test, Nyegaard; and Monotest, Boehringer Mannheim) of uricase methods. The method we report is simple, and can be used in a fully automatic liquid-chromatographic system.

Elimination of caffeine interference in HPLC determination of urinary nicotine and cotinine.

1989 ◽  
Vol 35 (7) ◽  
pp. 1456-1459 ◽  
Author(s):  
N T Thuan ◽  
M L Migueres ◽  
D Roche ◽  
G Roussel ◽  
G Mahuzier ◽  
...  
Keyword(s):  
Reversed Phase ◽  
Gas Liquid Chromatography ◽  
Tobacco Exposure ◽  
Coefficients Of Variation ◽  
Chromatographic Procedure ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Minimum Detectable Amount ◽  
Column Extraction

Abstract We report an analytical reversed-phase liquid-chromatographic procedure for quantifying nicotine and cotinine in urine, taking into account the presence of interfering caffeine frequently encountered in such specimens. These analytes are extracted from the alkalinized urine with chloroform. After evaporation of the chloroform, the residue is dissolved in methanol and injected into a chromatographic C18 column. Extraction recoveries averaged 80% to 97%. Chromatographic conditions were investigated to obviate caffeine interference. The proposed eluent mobile phase is a polar mixture of water, acetonitrile, methanol, and a pH 4 acetoacetate buffer (65/2/29/4 by vol) adjusted to pH 4.30 +/- 0.02 with triethylamine. High resolution and linearity were obtained for each analyte up to a concentration of 200 mg/L. The minimum detectable amount of each compound was 20 ng per injection, corresponding to 10 micrograms per liter of urine. Correlation with results of gas-liquid chromatography was excellent (r = 0.99). This simple, rapid procedure allows routine screening of tobacco exposure with acceptable precision: within- and between-run coefficients of variation were less than 2% and less than 5%, respectively.

Determination of urinary placental estriol by reversed-phase liquid chromatography with fluorescence detection.

1980 ◽  
Vol 26 (1) ◽  
pp. 130-132
Author(s):  
J T Taylor ◽  
J G Knotts ◽  
G J Schmidt
Keyword(s):  
Reversed Phase ◽  
Excitation Wavelength ◽  
Fluorescence Detector ◽  
Liquid Chromatograph ◽  
Chromatographic Procedure ◽  
Natural Fluorescence ◽  
Phase Liquid ◽  
Near Term ◽  
Far Ultraviolet ◽  
Liquid Chromatographic

Abstract We describe a liquid-chromatographic procedure for determining urinary estriol concentrations. The urine sample, after enzymatic hydrolysis to free the conjugated estrogen, is extracted with ether, and an aliquot of the resulting extraction residue is injected into the liquid chromatograph. Sample components are separated with a reversed-phase C18 column and isocratic elution with an acetonitrile/water mobile phase. Using a far-ultraviolet excitation wavelength, we measure the natural fluorescence of the eluted estrogen with a fluorescence detector. The procedure provides excellent sensitivity for determing near-term pregnancy concentrations of urinary estriol. The selectivity of the method limits the effect of potentially interfering compounds.

Development of an acidic/neutral antibody flow-through polishing step using salt-tolerant anion exchange chromatography

2015 ◽  
Vol 3 (8) ◽  
pp. 477-487 ◽  
Author(s):  
Yun (Kenneth) Kang ◽  
Rajesh Ambat ◽  
Troii Hall ◽  
Matthew D Sauffer ◽  
Stanley Ng ◽  
...  
Keyword(s):  
Anion Exchange ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Salt Tolerant ◽  
Flow Through
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