3. System Performance

In order to quantify the performance of the technique, sensitivity is defined as the concentration of the element, in μg·L ^–1 (or in μg for electrothermal spectrometry, given the fixed and limited amount of the element introduced into the furnace), required to produce 1% absorption, i.e., to generate an absorbance of 0.0044. This is referred to as concentration, or characteristic mass. These values, which vary greatly depending on the elements and are generally specified by the manufacturer, must be approximated (a 20% deviation is generally tolerated) during instrument optimization, until the instrument gradually ages. Any deterioration in these performance metrics on a relatively new instrument is then indicative of a problem (lamp alignment or condition, clogged nebulizer, surface condition of the graphite carbon furnace, etc.).