Search results for "Liquid Chromatography"

Determination of ascorbic acid in plasma and urine by high performance liquid chromatography with ultraviolet detection.

1999

Abstract A reliable simple reversed-phase liquid chromatographic method for the routine determination of ascorbic acid in plasma and urine with ultraviolet detection is described. This method enables the complete separation of the ascorbic acid peak from others with a recovery of above 95 % within 8 minutes. The method can be used for analysing multiple samples within a day. In addition, the storage conditions and stability of ascorbic acid in plasma and urine were investigated. Samples of plasma and urine can be stored on ice in darkness for at least 60 min without reduction of ascorbic acid concentration. Prepared samples can be stored in darkness at 4 °C for at least 120 min and in liqui…

A simple high-performance liquid chromatography (HPLC) method for the measurement of pyridoxal-5-phosphate and 4-pyridoxic acid in human plasma.

2014

Abstract Background Low concentration of plasma pyridoxal-5-phosphate (PLP) is associated with hyperhomocysteinemia and inflammation. Most methods for the measurement of plasma PLP require large specimen volume and involve the use of toxic reagents. Methods We have developed a HPLC method for the measurement of PLP and 4-pyridoxic acid (4-PA) in plasma, which requires small specimen volume. The samples are prepared without adding any toxic reagents. Furthermore, we have examined whether intake of vitamin B 6 affects the concentration of plasma PLP and 4-PA. Results The coefficient of variation of the method was 6% and the recovery of the added vitamin in plasma was about 100%. The concentra…

Purification and structural characterisation of lipid transfer protein from red wine and grapes

2012

Lipid transfer proteins (LTP) play a major role in plant defence and are of particular interest due to their known ability to cause allergic reactions. These proteins are expressed in grapes and also remain detectable after vinification, especially in red wine. However, it remains unknown whether the protein undergoes any changes during the vinification process. Here, we present a purification method for LTPs from Dornfelder grapes and wine. By liquid-chromatography-mass spectroscopy (LC-MS/MS) we identified LTPs from two different species (Vitis vinifera and Vitis aestivalis). Additionally, the purified LTPs were characterised using spectrometric methods, confirming their high purity and s…

Retention pharmacokinetic and pharmacodynamic parameter relationships of antihistamine drugs using biopartitioning micellar chromatography

2001

Abstract Antihistamines are drugs which act by competitive inhibition of the H1 or H2 histamine receptors. Little has been known about their clinical pharmacokinetics and biological responses until the last few years. In this paper, we propose quantitative retention–activity relationship, QRAR, models based on the retention data of antihistamines in a biopartitioning micellar chromatography (BMC) system using a Brij35 mobile phase for describing pharmacokinetic parameters such as half-life and volume of distribution, or the pharmacodynamic parameters, therapeutic plasma levels, lethal doses and drug-receptor dissociation constant. The predictive ability of these models is statistically vali…

Adding the Mureş River Basin (Transylvania, Romania) to the List of Hotspots with High Contamination with Pharmaceuticals

2020

Background: The Mureș River Basin is a long-term heavily polluted watershed, in a situation of climate changes with increasing water flow and related decreasing dilution capacity. Here, a mixture of emerging pollutants such as pharmaceuticals were targeted to reveal potential risks regarding the natural lotic ecosystems. Due to the continuous discharge into the environment, pharmaceuticals are gaining persistent organic pollutant characteristics and are considered emerging pollutants. Based on the hazard quotient, this research highlights the dangerous concentrations of carbamazepine, ibuprofen, furosemide, and enalapril in river water. Results: High levels of four pharmaceutical compounds …

Determination of 5-nitrofurylacrylic acid in wines by high-performance liquid chromatography

1988

HPLC determination of volatile phenols in wines

1993

An alternative to the traditional solvent extraction method used to extract and rapidly quantify ethyl-and vinylphenol and ethyl-and vinylgaiacol from wine is presented. The method is based on retention of volatile phenols on adsorbants. Among the tested resins, the most efficient, AG 2-X8 (anion exchange resin), worked as well with a synthetic solution as with wines. The percolation of clarified wine adjusted to pH 9 on this resin permits, in particular, the elimination of organic acids. Phenols are not eluted after rinsing the column with 1N HCl, but are eluted with methanol after this treatment. Good recovery (91 %) and good repeatability are observed. The eluate is directly analysed by …

Quantitative determination of sotolon in wines by high-performance liquid chromatography

1993

Sotolon (4,5-dimethyl-3-hydroxy-2(5H)-furanone) is a key flavour compound in the french flor-sherry “Vin jaune”. This compound was determined quantitatively by extraction of 25 ml of wine on a XAD-4 resin, elution with diethyl ether, separation by HPLC on a Lichrospher 100 Diol column, elution with dichloromethane/hexane (60/40) and UV detection at 232 nm. The amount of sotolon in “Vin jaune” (120 to 268 μg/l) was related to the development of the yeast film over a period of 6 years. Only 6 to 51 μg/l were found in the “Vin de paille” which is made with overmaturated grapes of the same Savagnin vine-plant but without development of yeasts, and 80 to 140 μg/l in “Tokai” which are partly grow…

High Performance Liquid Chromatography Analysis of Grape and Wine Polyphenols

2008

Integrating analytical resolutions in non-targeted wine metabolomics

2015

Direct injection Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), and ultra-high performance liquid chromatography coupled to mass spectrometry (UPLC/MS) were combined for the non-targeted analysis of wine metabolites. The unrivalled resolution on mass measurement allowed by the former and the separation ability of isomeric and isobaric substances by the latter, clearly increases the scope of detectable unknown metabolites in wines. Such methodology is illustrated through the comparison of chemical spaces of a young and an older Pinot noir wine. RP and HILIC chromatography could reveal up to five isomers for a given mass, throughout the explored mass range. CHO, CHOS …