Mass Spectrometry

Biography

Biography: Achille Cappiello

Abstract

A novel liquid chromatography-mass spectrometry (LC-MS) interfacing concept is presented and discussed. The new interface design is called “Liquid-EI”, LEI to distinguish it from previous attempts. In a LEI interface, vaporization of the HPLC eluate is carried out inside a suitable, independent micro-channel right before entering the ion source. An inert gas flow carries the gas phase molecules into the ion source. This approach moves the solute vaporization event immediately outside the ion source into a more suitable space in terms of dimensions, temperatures and surface materials, and free of sensitive components and electric potentials. The pressure drop and temperature gradients between LC and MS can be carefully monitored and controlled to enhance analyte response and reduce band broadening and/or solute carryovers. Preliminary results, carried out using an Agilent 7010 QqQ mass spectrometer and 5975 single quadrupole, gave us an optimistic impression, especially when the vaporization micro-channel was covered with a ceramic layer. Proof of concept and detailed description of the interface are presented. Preliminary experiments were conducted using PAHs (2-6 rings) and other compounds of environmental interest with and without column separation. Real world samples were analyzed using LEI with particular emphasis to address issues on identification of metabolites at low levels where mass spectral quality using high resolution accurate mass (HRAM) can be an issue and NMR may prove challenging, and further, complex sample matrix (soil, vegetable, food and other bio matrices, etc..) can give additional difficulties.