33. assay Analytical method for detecting or measuring the presence, amount,
state or functional activity of an analyte or other
compound of interest. An assay is a component of a test, tool or instrument.
34. assay-appropriate scientific validation One process of scientific validation where, irrespective of the stage of development in which the study is supported, assay criteria for scientific validation are defined to allow valid and documented decisions to be made from the reported concentrations (or ‘fit-for- purpose validation’).
35. atmospheric pressure chemical ionization (APCI) A soft ionization technique for the production of gas-phase ions, typically most efficient with nonpolar small molecules. It involves nebulization of a liquid flow, application of a sheath gas and a corona discharge needle with applied current in the order of µA to place a charge on vaporized molecules. The produced ions are transferred into the vacuum interface region of a mass spectrometer for subsequent analysis.
