The temperature of the atomization surface at which analyte loss becomes statistically significant.
Source:
PAC, 1992, 64, 253. 'Nomenclature, symbols, units and their usage in spectrochemical analysis - XII. Terms related to electrothermal atomization (IUPAC Recommendations 1992)' on page 257 (https://doi.org/10.1351/pac199264020253)