Pulse introduction of a sample into a graphite furnace requires that the sample be heated rapidly enough that the evaporation time is much shorter than the retention time. To achieve that condition, in the graphite cuvette L'vov used an additional power source. In a Mass-mann-type furnace the graphite tube containing the dried sample is heated quickly by a powerful ac current to obtain the desired short evaporation time. The simplest way of sample heating is in a Woodriff constant-temperature furnace. The furnace is kept continuously at high temperature and a graphite crucible containing the dried sample is introduced into the furnace. The crucible is heated by conduction and radiation fast enough that the evaporation time is short compared to the residence time. This technique has been applied to a number of problems.
Momir Marinkoviá and Ray Woodriff, "Optimization of Sample Introduction into Constant Temperature Graphite Furnace for Atomic Absorption Spectroscopy," Appl. Spectrosc. 30, 458-459 (1976)