Comparative studies on the high-performance liquid chromatographic determination of thiamine and its phosphate esters with chloroethylthiamine as an internal standard using pre- and post-column derivatization procedures

1991 ◽  
Vol 558 (1) ◽  
pp. 115-124 ◽  
Author(s):  
S. Sander ◽  
A. Hahn ◽  
J. Stein ◽  
G. Rehner
2003 ◽  
Vol 68 (11) ◽  
pp. 883-892 ◽  
Author(s):  
Dragica Zendelovska ◽  
Trajce Stafilov

A rapid, specific and sensitive high-performance liquid chromatographic method for the determination of famotidine in human plasma has been developed. Famotidine and the internal standard were chromatographically separated from plasma components using a Lichrocart Lichrospher 60 RP select B cartridge for solid-phase separation with a mobile phase composed of 0.1 % (v/v) triethylamine in water (pH 3) and acetonitrile (92:8, v/v). UV detection was set at 270 nm. The calibration curve was linear in the concentration range of 10.0 ? 350.0 ng mL-1. The method was implemented to monitor the famotidine levels in patient samples.


1982 ◽  
Vol 65 (3) ◽  
pp. 753-756
Author(s):  
Walter F Schmidt

Abstract A high performance liquid chromatographic procedure has been developed for the assay of phenprocoumon in tablets. In comparison to the present official USP assay procedure, it is equivalent in precision and accuracy and is faster and more specific. A mobile phase consisting of a 1% solution of acetic acid in acetonitrile-water (4 + 3) separates phenprocoumon from warfarin internal standard on a 6 μm octadecylsilane (ODS) column with UV detection at 311 nm. The method enables the concurrent determination of phenprocoumon and possible contaminants such as salicylic acid.


1982 ◽  
Vol 28 (10) ◽  
pp. 2143-2148 ◽  
Author(s):  
P M Edelbroek ◽  
E J de Haas ◽  
F A de Wolff

Abstract To study correlations between the concentrations, in serum, of amitriptyline and its most important metabolites with clinical response in patients, we developed a "high-performance" liquid-chromatographic method for routine determination of amitriptyline, nortriptyline, total 10-hydroxy-amitriptyline, desmethylnortriptyline, and E(trans)- and Z(cis)-10-hydroxynortriptyline. These compounds are extracted from 1 mL of alkalinized serum into hexane/isoamyl alcohol (99/1 by vol). Perazine is the internal standard. To minimize irreversible adsorption of the drugs onto the glassware, 5 micrograms of maprotiline is added to the organic phase just before evaporation. After a 10-min resolution on a silica column eluted with acetonitrile/methanol/NH4OH (1 mol/L), absorbance is measured at 240 nm. Only chlorimipramine, doxepin, procainamide, and N-acetylprocainamide may interfere with assay of the compounds that probably are therapeutically relevant: amitriptyline, nortriptyline, and E-10-hydroxynortriptyline. Uremia, lipemia, and icterus also do not affect the analysis.


1981 ◽  
Vol 27 (3) ◽  
pp. 437-440 ◽  
Author(s):  
D R Uges ◽  
P Bouma

Abstract We have developed "high-performance" liquid-chromatographic methods for determining 4-aminopyridine, an acetylcholine-releasing drug, in serum, saliva, and urine. As little as 1 microgram/L can be detected by extracting the alkalinized sample plus the internal standard (3,4-diaminopyridine) into dichloromethane, mixing the organic phase with 1-pentanol, evaporating the dichloromethane, and injecting the residue onto a reversed-phase column, where it is eluted with acetonitrile/methanol/aqueous ammonium carbonate, with detection at 245 nm. Analytical recoveries from serum averaged 86.7%. The CV at 50 micrograms/L was 2.9% (n = 8). For urine samples containing very high concentrations of 4-aminopyridine, we mixed urine and potassium carbonate in an automatic injector vial, extracted the drug into dichloromethane, centrifuged, and injected an aliquot of the extract into the chromatograph. Analytical recoveries averaged 92%, and the CV was about 2% for drug concentrations of 0.1-8 mg/L of urine.


1988 ◽  
Vol 34 (9) ◽  
pp. 1897-1899 ◽  
Author(s):  
M H Cheng ◽  
W Y Huang ◽  
A I Lipsey

Abstract This high-performance liquid-chromatographic (HPLC) method for simultaneous determination of prednisone and its metabolite, prednisolone, in plasma is a modification of the method of Frey et al. (Clin Chem 1979;25:1944-7). Heparinized plasma (1.0 mL) with 0.1 mL of internal standard solution (11-deoxy-17-hydroxycorticosterone, 2 mg/L) is extracted with 7.0 mL of dichloromethane, then washed sequentially with 0.1 mol/L HCl, 0.1 mol/L NaOH, and deionized water, 2.0 mL each. The extract is evaporated and the residue reconstituted with 75 microL of mobile phase, methanol/H2O (40/60 by vol). Thirty microliters of this is injected onto a reversed-phase C6 column, which is eluted at 1.4 mL/min. Analytical recoveries of prednisone and prednisolone were 94-98% and 102-106%, respectively. Day-to-day precision (CV) was 3.8% for prednisone, 6.1% for prednisolone. We encountered no interference from the 21 other steroids and 25 drugs tested. This method is simple, accurate, and precise.


1977 ◽  
Vol 60 (1) ◽  
pp. 71-72
Author(s):  
Mark A McCalla ◽  
Frances G Mark ◽  
William H Kipp

Abstract A method is described for the qualitative and quantitative determination of 2,4-hexadienoic acid (sorbic acid) by high performance liquid chromatography (HPLC). The results show excellent reproducibility (±2.55%) and agree well with values obtained using the official AOAC ultraviolet method for both fortified wine and commercial wines. Sorbic acid is separated by HPLC, using a strong anion exchange resin, Zipax SAX, eluted with 0.01M Na2B4O7, and detected using UV (254 nm) detector. Sodium benzoate is used as an internal standard.


1983 ◽  
Vol 29 (10) ◽  
pp. 1840-1842 ◽  
Author(s):  
J Lehmann ◽  
H L Martin

Abstract We have adapted to erythrocytes a method for the determination of alpha- and gamma-tocopherols in plasma and platelets. Erythrocytes (50 microL) were extracted with methanol containing tocol (internal standard) and pyrogallol. Tocopherols were partitioned into chloroform, washed, and injected in methanol onto a reversed-phase (C18) "high-performance" liquid-chromatographic column. The mobile phase was methanol/water (99/1 by vol) at a flow rate of 2 mL/min and detection was with a "high-performance" spectrophotofluorometer. The limit of detection for either tocopherol is 0.10 microgram/mL of packed cells. Analytical recoveries ranged from 93 to 104%. Some values for tocopherols in human erythrocytes are presented.


1982 ◽  
Vol 65 (3) ◽  
pp. 706-710
Author(s):  
Aziz Geahchan ◽  
Paul Chambon ◽  
Pierre Genoux

Abstract A high performance liquid chromatographic method is described for the determination of clocapramine in animal feed and plasma. Samples are made alkaline and then extracted with chloroform containing opipramol as internal standard. For plasma samples, the organic phase is evaporated to dryness under a stream of nitrogen, and the residue is dissolved in dichloromethane-methanol. Extracts are chromatographed on silica gel with dichloromethane-methanol-ammonia (100 + 10 + 0.25) as eluant, and quantitated using an internal standard. Within-day precision for plasma extracts (n = 15) was 3.39, 5.7, and 4.13% at 5,10, and 15 mg clocapramine/L plasma, respectively, and day-to-day precision was 4.6, 6.8, and 4.4% at the same levels. The detection limit was 0.5 mg/L. Recovery from feed over the concentration range 2-6 g/kg was >96%.


1985 ◽  
Vol 31 (7) ◽  
pp. 1222-1224 ◽  
Author(s):  
G Houin ◽  
J P Jeanniot ◽  
P Ledudal ◽  
J Barré ◽  
J P Tillement

Abstract We describe a "high-performance" liquid-chromatographic assay for simultaneously determining propisomide and its mono-N-dealkylated metabolite in plasma and urine. After extraction with dichloromethane at alkaline pH, the unchanged drug, its metabolite, and the internal standard are separated by liquid chromatography on a reversed-phase column and the absorbance of the eluate is measured at 254 nm. Selectivity, sensitivity, and reproducibility are excellent. Results are similar to those by gas chromatography for propisomide but, in addition, the metabolite can be simultaneously measured in the same clinical sample. We also report results by this method for blood and plasma samples from a volunteer receiving a single 200-mg dose of propisomide.


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