High-performance Liquid Chromatography-mass Spectrometer Research Articles

On-line derivatization of eluted substances in dynamic high-performance liquid chromatography-mass spectrometry through the particle-beam interface

Derivatization reagents were added through the particle beam high-performance liquid chromatograph-mass spectrometer interface in order to improve the detectability of polar compounds separated by high-performance liquid chromatography and detected by mass spectrometry by formation of the corresponding derivative. Mainly qualitative aspects are considered in this work. Dynamic derivatization in the gas phase of several substances containing carboxylic, sulphonic, hydroxy and other acidic or basic functional groups is described.

Influence of the packing material and the column filters on the reliability of a high-performance liquid chromatograph—mass spectrometer interface based on the direct liquid inlet principle

The direct liquid introduction interface for coupled high-performance liquid chromatography(HPLC)-mass spectrometry consists of a 1–3-μm pinhole in a nickel diaphragm. This interface produces an axial jet of HPLC eluent into the ionization source. Variations in the jet affect the mass fragmentation pattern. Physical modifications of the pinhole also induce substantial changes in the jet. The influence of the packing material and the column filters has been examined and solution are given for preventing plugging of the pinhole.

The use of combined high performance liquid chromatography negative ion chemical ionization mass spectrometry to confirm the administration of synthetic corticosteroids to horses

Negative ion chemical ionization mass spectra of some corticosteroids have been obtained by direct syringe introduction on to the Finnigan moving belt high-performance liquid chromatography-mass spectrometer interface. Proprietary preparations based upon dexamethasone, betamethasone and prednisolone were administered to horses at therapeutic dose level. Urine samples were extracted, the extracts purified by Sephadex LH-20 chromatography and the presence of the parent steroids in the eluates was confirmed by combined high-performance liquid chromatography negative ion chemical ionization mass spectrometry using ammonia as reagent gas.