Single-run separation of closely related cationic and anionic compounds by CE-ESI-MS: application to the simultaneous analysis of melamine and its analogs in milk.

In recent years, two adulteration incidents concerning the addition of melamine, a nitrogen-rich industrial small polar compound, to pet food and infant formula products have occurred in China. These issues prompted laboratories to develop methods for the analysis of melamine and related compounds in a wide variety of food products and ingredients. In this context, a CE-ESI-MS method was developed to simultaneously analyze melamine and its related products (ammeline, ammelide and cyanuric acid) that possess close physico-chemical properties.

Characterization and classification of matrix effects in biological samples analyses.

An exhaustive classification of matrix effects occurring when a sample preparation is performed prior to liquid-chromatography coupled to mass spectrometry (LC-MS) analyses was proposed. A total of eight different situations were identified allowing the recognition of the matrix effect typology via the calculation of four recovery values. A set of 198 compounds was used to evaluate matrix effects after solid phase extraction (SPE) from plasma or urine samples prior to LC-ESI-MS analysis.

Atmospheric pressure photoionization for coupling liquid-chromatography to mass spectrometry: a review.

This review presents the state-of-the-art techniques that couple liquid chromatography (LC) and mass spectrometry (MS) via atmospheric pressure photoionization (APPI). The different ionization mechanisms are discussed as well as the influence of the mobile phase composition, the nature of the dopant, etc. A comparison with other ionization sources, such as electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), is reported, and the combination of APPI with these sources is also discussed.

Sample preparation development and matrix effects evaluation for multianalyte determination in urine.

The development of a generic analytical method remains difficult when a high number of compounds has to be simultaneously considered. This study proposes an innovative strategy for the development of a solid phase extraction (SPE) procedure before liquid chromatography-mass spectrometry analysis of 34 diuretics and beta-blockers in urine samples. These compounds have been selected since they are often encountered in anti-doping control.

Development and validation of a liquid chromatography-atmospheric pressure photoionization-mass spectrometry method for the quantification of alprazolam, flunitrazepam, and their main metabolites in haemolysed blood.

A LC-APPI-MS method was developed and validated for the detection of alprazolam, flunitrazepam and their major metabolites in haemolysed blood. Samples were diluted with water (2:1, v:v) and extracted with a hydrophobic-lipophilic balanced copolymer. The method was fully validated according to ICH guidelines and SFSTP protocols.

Evaluation of the influence of protein precipitation prior to on-line SPE-LC-API/MS procedures using multivariate data analysis.

Matrix effects on mass spectrometry (MS) response were investigated with three atmospheric pressure ionization (API) sources after on-line solid-phase extraction (SPE) of human plasma. On-line SPE was evaluated with one restricted access material (RAM), two large particle supports (LPS) and one monolith. A sample protein precipitation (PP) with acetonitrile (2:1) and a direct injection were tested.