Development and application of a multiple reaction monitoring method for the simultaneous quantification of sodium channels Na 1.1, Na 1.2, and Na 1.6 in solubilized membrane proteins from stable HEK293 cell lines, rodents, and human brain tissues.

Rationale: Na 1.1, 1.2, and 1.

On the feasibility of quantifying sodium channel Na 1.6 protein in mouse brain using targeted ultra-high-performance/electrospray ionization multiple reaction monitoring mass spectrometry.

Rationale: Na 1.6 is a transmembrane voltage gated sodium channel implicated in various forms of epilepsy. Modulation of its activity in epilepsy animal models can be accomplished using inhibitors which may result in changes in its expression.

Selective Na1.7 Antagonists with Long Residence Time Show Improved Efficacy against Inflammatory and Neuropathic Pain.

Selective block of Na1.7 promises to produce non-narcotic analgesic activity without motor or cognitive impairment. Several Na1.

Oxidation of catechols during positive ion electrospray mass spectrometric analysis: evidence for in-source oxidative dimerization.

Rationale: Catechols are an important class of analytes occurring in many natural and synthetic products. Electrospray ionization in negative mode is the preferred way of ion generation for these compounds; however, studies in positive ion mode can reveal their potential for in-source oxidation and further structural changes, some of which may also occur in the solution phase. Therefore in-source oxidation can provide a forward look into the potential for solution oxidation.

Internal standard signal suppression by co-eluting analyte in isotope dilution LC-ESI-MS.

The suppression of the internal standard by increasing concentrations of the co-eluting analyte in calibration series and plasma samples analysed by LC-ESI-MS was studied using the isotope dilution technique. A series of three analyte/deuterated analyte pairs including fexofenadine/d6-fexofenadine, dapsone/d4-dapsone and peudoephedrine/d3-ephedrine were investigated. Suppression of the internal standard signal was noticed in extracted plasma samples containing fexofenadine and d6-fexofenadine as internal standard, as well as in solvent based calibration solutions of the three pair of compounds noted above during LC-ESI-MS analysis at flow rates greater than 100 microL min(-1).