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Results for “NICOTINIC ACID”

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At least 847 records · Page 47Linked to original sources
PubMed1995

High-performance liquid chromatographic determination of nicotinic acid and nicotinamide in biological samples applying post-column derivatization resulting in bathmochrome absorption shifts.

An ion-pair reversed-phase high-performance liquid chromatographic procedure for the rapid separation and sensitive quantitation of nicotinic acid (NA) and nicotinamide (NAM) in biological samples was developed. The vitamers were separated within 10 min on an octadecylsilica column applying a linear gradient of tetrabutylammonium phosphate and methanol. NA and NAM were converted to highly absorbing derivatives by a modified König's reaction using a double post-column derivatization arrangement consisting of two pumps and two knitted tubular reactors. The proposed method is highly sensitive and specific and applicable to biological materials as was shown by the analysis of rat intestinal tissue.

Animals↗
PubMed2005

Simultaneous determination of nicotinic acid and its metabolites using hydrophilic interaction chromatography with tandem mass spectrometry.

A hydrophilic interaction chromatographic (HILIC) system interfaced with atmospheric pressure ionization (API) sources and a tandem mass spectrometer (MS/MS) was developed for the simultaneous determination of nicotinic acid (NiAc) and its metabolites in dog plasma in support of a pharmacokinetic study. A silica column was adapted for separation of NiAc and its two metabolites, nicotinamide (NiNH2) and nicotinuric acid (NiUAc), under HILIC conditions. The influence of experimental factors such as the composition of mobile phase on ionization efficiency and chromatographic performance of all analytes was investigated. The feasibility of the proposed HILIC/MS/MS methods was explored by comparing the plasma levels of NiAc, NiNH2, and NiUAc in dog obtained by using either electrospray ionization or atmospheric pressure chemical ionization interfaces in positive ion mode. The methods were partially validated in terms of inter-day accuracy and precision, extraction recovery, benchtop and freeze/thaw stability. Further, the potential of ionization suppression resulting from endogenous components of the biological matrixes on the HILIC/API-MS/MS methods were investigated using the post-column infusion technique.

Animals↗