Mass spectrometry: a tool for enhanced detection of hemoglobin variants.

Background: More than 900 hemoglobin (Hb) variants are currently known. Common techniques used in Hb analysis are electrophoretic and chromatographic assays. In our laboratory, we routinely apply chromatographic methods.

Free 3-nitrotyrosine in exhaled breath condensates of children fails as a marker for oxidative stress in stable cystic fibrosis and asthma.

3-Nitrotyrosine (3-NT) is considered as a marker of oxidative stress, which occurs during inflammation. Since 3-NT levels in exhaled breath condensate (EBC) are very low, we applied a specific and sensitive gas chromatography-negative ion chemical ionization-mass spectrometry (GC-NICI-MS) method and high performance liquid chromatography (HPLC) with electrochemical detection for the analysis of free 3-NT in EBC. A total of 42 children (aged 5-17 years) were enrolled in this study, including children with asthma (n=12), cystic fibrosis (n=12), and healthy controls (n=18).

Analysis of minor hemoglobins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Background: Hemoglobin (Hb) heterogeneity arises mainly from posttranslational modifications of the globin chains, and cation-exchange chromatography reveals falsely increased concentrations of some minor Hbs in the presence of abnormal Hbs. Here we describe a method for identification of the globin chains and their posttranslational modifications contained in the Hb fractions.

Methods: We used cation-exchange HPLC (PolyCAT A column) for separation of Hb fractions and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for analysis of the separated globin chains.

Filter paper cards contaminated with EMLA cream produce artefacts on acylcarnitine analysis.

Electrospray ionization tandem mass spectrometry is a widely applied method for the analysis of acylcarnitines in blood samples spotted on filter paper cards (Guthrie cards). When the filter paper cards are contaminated by EMLA cream, highly intense signals at m/z 221 and 235 are detected under ESI-MS/MS conditions, monitoring for precursors of m/z 85. These signals correspond to the active ingredients prilocaine and lidocaine in EMLA and overlap with the signals from the isotopically labelled internal standards (2H3)propionyl carnitine and (2H3)butyrylcarnitine.

Mass spectrometric analysis of human transferrin in different body fluids.

In this study, we present a versatile new procedure for the analysis of transferrin and its isoforms isolated from human body fluids such as serum, plasma, and cerebrospinal fluid. This method is based on a three-step procedure: (i) isolation of transferrins using anion-exchange chromatography with UV detection; (ii) concentration of the transferrin fraction; (iii) detection of the transferrins with liquid chromatography-electrospray mass spectrometry. Pre-analytical sample procedures can be omitted and no immunoaffinity columns or transferrin-specific immunoassays were used.