model and the fact that dierent atomization temperatures
were used, the agreement between the intrinsic mass for
LS-AAS and CS-AAS is very reasonable.
The lack of dependence of CS-AAS on the source and
detection parameters places new emphasis on the performance
of the furnace. Absorbances for any CS-AAS instrument can
be directly compared and absorbance will have a fixed relation-
ship to concentration. The only variable that can cause a
change in sensitivity is the furnace. The number of atoms in
the light path is dependent on the temperature, the furnace
length and matrix interferences. A two-step furnace24 will
allow better control of two of these variables; temperature and
matrix interferences. Since a two-step furnace does not require
a rapid temperature ramp, accurate and reproducible tempera-
tures should be easier to achieve. Volatilization of the sample
into a constant temperature should alleviate many of the
chemical interferences arising from the sample matrix. Only
the furnace length would have to be standardized to obtain a
Fig. 3 Absorbance map for the same data as shown in Fig. 2 (250 pg uniform response between dierent instruments.
of Cu). Absorbance was computed using the intensities from the first
and last column (perpendicular to wavelength axis) as reference
intensities. There was no stray light correction for these data. Noise characteristics