scholarly journals Solid-Phase Extraction for Photometric Determination of Rosmarinic Acid in Lemon Balm (Melissa Officinalis) Extracts

2012 ◽  
Vol 11 (1) ◽  
pp. 62-72 ◽  
Author(s):  
Miroslav Ondrejovič ◽  
Tibor Maliar ◽  
Hana Benkovičová ◽  
Jana Kubincová
Keyword(s):  
Solid Phase Extraction ◽  
Flow Rate ◽  
Rosmarinic Acid ◽  
Mobile Phase ◽  
Solid Phase ◽  
Photometric Determination ◽  
Phase Extraction ◽  
Melissa Officinalis ◽  
Lemon Balm

Solid-Phase Extraction for Photometric Determination of Rosmarinic Acid in Lemon Balm (Melissa Officinalis) Extracts The aim of this study was evaluation of the solid-phase extraction for elimination of interference compounds from lemon balm extracts aimed for photometric determination of rosmarinic acid. In experiments, evaluated conditions were as follows: composition and volume of mobile phase, ratio between volume of sample and mass of stationary phase and flow rate of mobile phase during separation. The results indicated that interfered compounds were eliminated. The lemon balm extracts should be pretreated by adsorption on normal stationary phase (silica gel) in ratio sample volume to silica gel weight 1:1 (v/w) elution by mobile phase - diethyl ether: acetic acid (9:1; v/v) - volume - 40 times of crude extract volume - with flow rate 5 ml/min. After selection of SPE conditions, the method was validated with comparison to HPLC analysis. The results suggest that this method may be useable for determination of rosmarinic acid by photometric measurement based on the complexation of Fe2+ ions with rosmarinic acid.

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 Determination of Low Levels of Lead in Beer Using Solid-Phase Extraction and Detection by Flame Atomic Absorption Spectrometry

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Vanessa N. Alves ◽  
Simone S. O. Borges ◽  
Waldomiro B. Neto ◽  
Nívia M. M. Coelho
Keyword(s):  
Solid Phase Extraction ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Flow Rate ◽  
Flame Atomic Absorption Spectrometry ◽  
Solid Phase ◽  
Absorption Spectrometry ◽  
Phase Extraction ◽  
Flame Atomic Absorption

In this study, a method for the determination of low concentrations of lead in beer samples using solid-phase extraction with a flow injection analysis system and detection by flame atomic absorption spectrometry (FAAS) was developed.Moringa oleiferaseeds were used as a biosorbent material. Chemical and flow variables of the online preconcentration system, such as sample pH, preconcentration flow rate, eluent flow rate, eluent concentration, particle size, and sorbent mass, were studied. The optimum extraction conditions were obtained using a sample pH of 6.0, sample flow rate of 6.0 mL min−1, 63.0 mg of sorbent mass, and 2.0 mol L−1HNO3at a flow rate of 2.0 mL min−1as the eluent. With the optimized conditions, the preconcentration factor, precision, detection limit, consumption index, and sample throughput were estimated as 93, 0.3% (10.0 μg L−1,n=7), 7.5 μg L−1, 0.11 mL, and 23 samples per hour, respectively. The method developed was successfully applied to beer samples and recovery tests, with recovery ranging from 80% to 100%.

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 <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.

Simultaneous Preconcentration and Determination of Brilliant Blue and Sunset Yellow in Foodstuffs by Solid-Phase Extraction Combined UV-Vis Spectrophotometry

2018 ◽  
Vol 101 (6) ◽  
pp. 1850-1856 ◽  
Author(s):  
Abdullah Taner Bişgin
Keyword(s):  
Solid Phase Extraction ◽  
Flow Rate ◽  
Solid Phase ◽  
Ethanol Solution ◽  
Water Soluble ◽  
Brilliant Blue ◽  
Phase Extraction ◽  
Sunset Yellow ◽  
Food Dyes

Abstract Background: Brilliant Blue and Sunset Yellow, two highly water-soluble synthetic food dyes, are the most popular food dyes used and consumed. Although they are not highly toxic, some health problems can be observed when excessive amounts of food products containing these dyes are consumed. Objectives: The aim of the study was to develop a simultaneous UV-Vis combined solid-phase extraction method, based on the adsorption onto Amberlite XAD-8 resin, for determination of Brilliant Blue and Sunset Yellow dyes. Methods: Sample solution was poured into the reservoir of the column and permitted to gravitationally pass through the column at 2 mL/min flow rate. Adsorbed dyes were eluted to 5 mL of final volume with 1 mol/L HNO3 in ethanol solution by applying a 2 mL/min flow rate. Dye concentrations of the solution were determined at 483 and 630 nm for Sunset Yellow and Brilliant Blue, respectively. Results: The detection limits of the method for Brilliant Blue and Sunset Yellow were determined as 0.13 and 0.66 ng/mL, respectively. Preconcentration factor was 80. Brilliant Blue contents of real food samples were found to be between 11 and 240 μg/g. Sunset Yellow concentrations of foodstuffs were determined to be between 19 and 331 μg/g. Conclusions: Economical, effective, and simple simultaneous determination of Brilliant Blue and Sunset Yellow was achieved by using a solid-phase extraction combined UV-Vis spectrometry method. Highlights: The method is applicable and suitable for routine analysis in quality control laboratories without the need for expert personnel and high operational costs because the instrumentation is simple and inexpensive.

A multidrug LC–MS/MS method for the determination of five immunosuppressants in oral fluid

Bioanalysis ◽  
2019 ◽  
Vol 11 (16) ◽  
pp. 1509-1521 ◽  
Author(s):  
Lucía Paniagua-González ◽  
Elena Lendoiro ◽  
Esteban Otero-Antón ◽  
Esther Molina-Pérez ◽  
Evaristo Varo-Pérez ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Solid Phase Extraction ◽  
Mobile Phase ◽  
Oral Fluid ◽  
Solid Phase ◽  
Therapeutic Drug ◽  
Phase Extraction ◽  
Trough Concentrations ◽  
First Time

Aim: This study aimed: to develop and validate an LC–MS/MS method for mycophenolic acid, tacrolimus, sirolimus, everolimus and cyclosporin A in oral fluid (OF), as an essential tool to study the usefulness of OF as an alternative matrix for immunossuppressants’ therapeutic drug monitoring; and to find the best OF collector for these analytes. Materials & Methods: Chromatographic separation was achieved using an XBridge® Shield RP18 analytical column maintained at 65ºC, using 2 mM ammonium formate and 0.1% formic acid in water (A) and acetonitrile (B) as mobile phase. OF sample was extracted with solid phase extraction after sonication and protein precipitation. Results & Conclusions: Method validation met all the acceptance criteria. LODs were 0.05–1 ng/ml, and LOQs 0.1–5 ng/ml. Silanized tubes offered the best recoveries. The method was successfully applied to 31 OF specimens, describing everolimus detection in OF for the first time. Conclusion: The proposed method is sensitive enough for the detection of OF trough concentrations in patients receiving immunosuppressants when using an appropriate OF collector.

scholarly journals Solid Phase Extraction of Trace Amounts of Praseodymium Using Transcarpathian Clinoptilolite

2019 ◽  
Vol 3 (1) ◽  
pp. 27 ◽  
Author(s):  
Olha Stashkiv ◽  
Volodymyr Vasylechko ◽  
Galyna Gryshchouk ◽  
Ihor Patsay
Keyword(s):  
Detection Limit ◽  
Solid Phase Extraction ◽  
Sorption Capacity ◽  
Flow Rate ◽  
Salt Solution ◽  
Ph Value ◽  
Solid Phase ◽  
Phase Extraction ◽  
Optimal Conditions

Sorptive properties of the Transcarpathian clinoptilolite towards Pr(III) were studied under dynamic conditions. The sorption capacity of clinoptilolite under optimal conditions (sorbent grain diameter of 0.20–0.31 mm; pH 9.0, temperature of preliminary precalcination of 350 °C, and flow rate of the Pr(III) salt solution with the concentration of 1.0 μg·mL−1 through the sorbent of 5 mL·min−1) was equal to 47.5 mg·g−1. The best desorbent of Pr from the clinoptilolite was the 1 M solution of KCl acidified with HCl to a pH value of 3.0. The method of Pr(III) trace amounts preconcentration in a solid phase extraction mode with further determination of this REE via spectrophotometric technique was developed. The linearity of the proposed method was evaluated in the range of 2–100 ng·mL−1 with detection limit of 0.7 ng·mL−1.

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