scholarly journals HPLC determination of hydrochlorothiazide in urine after solid-phase extraction

2005 ◽  
Vol 51 ◽  
pp. 23-28 ◽  
Author(s):  
Violeta Ivanova ◽  
Dragica Zendelovska ◽  
Marina Stefova
Keyword(s):  
Particle Size ◽  
Solid Phase Extraction ◽  
Mobile Phase ◽  
Solid Phase ◽  
Hplc Method ◽  
Phase Extraction ◽  
Hplc Separation ◽  
Isocratic Elution ◽  
Extraction Recovery

A simple, rapid and precise HPLC method has been developed for the assay of hydrochlorothiazide in urine. The clean-up of the urine samples was carried out by solid-phase extraction using HLB cartridges. Extraction recovery was 94.00-100.28 %. HPLC separation was performed with isocratic elution on Hypersil BDS C18 column (100 x 4.0 mm I.D., 3 µm particle size) protected with appropriate guard column. The mobile phase was 18 % acetonitrile and 0.025 mol/L solution of KH2PO4, pH 4 at flow rate of 0.3 mL/min. Detection of the substances was performed at 220 nm. The calibration curves were linear in the range of 2-50 µg/mL. The developed method is validated by checking its accuracy, precision and stability. The detection limit is 2 µg/mL hydrochlorothiazide. The method is proved to be convenient for routine analysis of hydrochlorothiazide in urine.

scholarly journals HPLC method validation and application for organic acid analysis in wine after solid-phase extraction

2016 ◽  
Vol 35 (2) ◽  
pp. 225 ◽  
Author(s):  
Violeta Ivanova-Petropulos ◽  
Krste Tašev ◽  
Marina Stefova
Keyword(s):  
Solid Phase Extraction ◽  
Organic Acids ◽  
High Performance ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Hplc Method ◽  
Phase Extraction ◽  
Hplc Separation ◽  
Limit Of Quantification

<p>A solid-phase extraction method followed by reverse phase high-performance liquid chromatography (RP-HPLC) was optimized and validated for the quantitative determination of tartaric, malic, shikimic, lactic, citric and succinic acids in wine. Solid-phase extraction was carried out with C18 cartridges and extraction recoveries for all acids ranging from 98.3 to 103% were obtained. HPLC separation was performed with isocratic elution on a LiChrosorb RP-18 column (250 × 4.6 mm I.D., 5 µm) protected with the appropriate guard column. The mobile phase was a 5 mM solution of H<sub>3</sub>PO<sub>4</sub> with pH 2.1 at a flow rate of 1 ml/min. Detection of the organic acids was performed at 210 nm. The developed method was validated by checking its linearity, limit of detection (LOD), limit of quantification (LOQ), precision and recovery. The method was applied to the analysis of organic acids in Macedonian red and white wines.</p>

scholarly journals Determination of urinary free cortisol by HPLC

1997 ◽  
Vol 43 (8) ◽  
pp. 1386-1391 ◽  
Author(s):  
Ursula Turpeinen ◽  
Helene Markkanen ◽  
Matti Välimäki ◽  
Ulf-Håkan Stenman
Keyword(s):  
Solid Phase Extraction ◽  
Mobile Phase ◽  
Solid Phase ◽  
Internal Standard ◽  
Reversed Phase ◽  
Hplc Method ◽  
Extraction Column ◽  
Phase Extraction ◽  
Free Cortisol

Abstract We here report a reversed-phase HPLC method for the determination of free cortisol in human urine, using methylprednisolone as the internal standard. Before chromatography, samples were extracted with a C18 solid-phase extraction column and the steroids were separated on a LiChrospher 100 C18 column with a mobile phase of methanol/acetonitrile/water (43/3/54 by vol). Linearity, precision, and accuracy of the method were established. The detection limit was 10 pmol of cortisol, and total CVs were &lt;8%. With various solid-phase extraction columns the recovery of cortisol was 36–97%; recovery of the internal standard was 43–85%. Study of interference by 6 other steroids and metabolites and 24 drugs showed that carbamazepine and digoxin partly overlapped with cortisol, but this interference could be reduced by modification of the mobile phase. The HPLC method was compared with an RIA and an automated immunoassay method. The results obtained by HPLC averaged 40% of the RIA values.

scholarly journals A Rapid HPLC Method for Monitoring Plasma Levels of Caffeine and Theophylline Using Solid Phase Extraction Columns

1986 ◽  
Vol 23 (4) ◽  
pp. 440-446 ◽  
Author(s):  
Clare E Pickard ◽  
A D Stewart ◽  
R Hartley ◽  
M D Lucock
Keyword(s):  
Acetic Acid ◽  
Sample Preparation ◽  
Solid Phase Extraction ◽  
Mobile Phase ◽  
Solid Phase ◽  
Hplc Method ◽  
Phase Extraction ◽  
The Cost ◽  
Good Agreement

A simple HPLC method for the determination of caffeine and theophylline in plasma is described. Separation of theobromine, paraxanthine, theophylline, β-hydroxyethyltheophylline and caffeine is obtained using a mobile phase of 1% acetic acid/methanol (83:17, v/v) and a Waters Associates NOVA-PAK C18 column protected by a Guard-PAK precolumn module containing a Guard-PAK CN cartridge. Rapid sample preparation is achieved by solid-phase extraction columns (Bond-Elut C18, 1 mL capacity) which provide excellent recovery values for both drugs. The cost per sample using this approach can be minimised by column regeneration and re-use. Results obtained for theophylline are in good agreement with values determined by other techniques.

scholarly journals Development and validation of a bioanalytical LC-UV method with solid-phase extraction for determination of valproic acid in saliva

2012 ◽  
Vol 62 (2) ◽  
pp. 211-220 ◽  
Author(s):  
Jasmina Tonic-Ribarska ◽  
Arlinda Haxhiu ◽  
Zoran Sterjev ◽  
Gordana Kiteva ◽  
Ljubica Suturkova ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Human Saliva ◽  
Hplc Method ◽  
Therapeutic Monitoring ◽  
Phase Extraction ◽  
Free Drug Concentration ◽  
Development And Validation

Development and validation of a bioanalytical LC-UV method with solid-phase extraction for determination of valproic acid in saliva A bioanalytical HPLC method with UV detection for the determination of the antiepileptic drug valproic acid in human saliva has been developed and validated. Saliva represents an alternative matrix for therapeutic monitoring of antiepileptic drugs due to the increasing interest in free drug concentration. The proposed method involved solid-phase extraction for sample preparation and yielded very good mean recoveries of 99.4 % and 97.9 % for valproic acid and IS, respectively. The calibration function for valproic acid was linear over the concentration range of 1.0-50.0 μg mL-1 (R2 = 0.9989). Within-run and between-run precision and accuracy were studied at four concentrations and RSDs were less than 7.3 and 2.2 %, while accuracy values were higher than 96.8 and 97.5 %, respectively. The described method provides sensitivity, linearity, precision, accuracy and is suitable for analyses of valproic acid in saliva samples.

Development of an HPLC method for the determination of nifedipine in human plasma by solid-phase extraction

2006 ◽  
Vol 839 (1-2) ◽  
pp. 85-88 ◽  
Author(s):  
Dragica Zendelovska ◽  
Suzana Simeska ◽  
Olgica Sibinovska ◽  
Elena Kostova ◽  
Kalina Miloševska ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Human Plasma ◽  
Solid Phase ◽  
Hplc Method ◽  
Phase Extraction
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