Determination of -Aminobutyric Acid in Food Matrices by Isotope Dilution Hydrophilic Interaction Chromatography Coupled to Mass Spectrometry

Determination of niacin in food materials by liquid chromatography using isotope dilution mass spectrometry.

The availability of deuterium-labeled nicotinic acid makes stable isotope dilution mass spectromerty (MS) coupled with liquid chromatography (LC) an attractive option for the determination of the water-soluble B-vitamin niacin in food samples. A method was developed based on acid digestion, solid-phase extraction with a strong cation exchange column, and reversed-phase chromatography with a C18...

Determination of Oxidized Phosphatidylcholines by Hydrophilic Interaction Liquid Chromatography Coupled to Fourier Transform Mass Spectrometry

A novel liquid chromatography-mass spectrometry (LC-MS) approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI) coupled to hydrophilic interaction liquid chromatography (HILIC) was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass a...

Determination of perchlorate in infant formula by isotope dilution ion chromatography/tandem mass spectrometry

A sensitive and selective isotope dilution ion chromatography/tandem mass spectrometry (ID IC-MS/MS) method was developed and validated for the determination of perchlorate in infant formula. The perchlorate was extracted from infant formula by using 20 ml of methanol and 5 ml of 1% acetic acid. All samples were spiked with (18)O(4) isotope-labelled perchlorate internal standard prior to extrac...

Determination of selenium in biological materials by stable isotope dilution gas chromatography-mass spectrometry.

Determination of sulfur in fossil fuels by isotope dilution electrothermal vaporization inductively coupled plasma mass spectrometry

The determination of S by solution nebulization quadrupole inductively coupled plasma mass spectrometry (ICP-MS) is dif®cult because of interferences from oxygen dimer ions. The large O2 z ion current from the solvent water is a serious interference at S, the most abundant of the four isotopes, and precludes its measurement. The isotopic composition of S varies in nature as a consequence of nat...