Conclusions
The graphical representations of sample mass versus
concentration can be used as a guide toward the true
mercury concentration with highly contaminated soil,
sediment, and plant samples. Student’s t test for pooled
data confirms that there is no significant difference
between RA-915+ and ICP-AES and CVAAS at the
99% confidence level when sample masses are optimized.
Thus, in addition to favorable attributes, such
as portability, direct analysis without acid digestion, and
short time required for analysis, the RA-915+ mercury
concentration values obtained are comparable to those
of ICP-AES and of CVAAS. The RA-915+ should be
frequently cleaned to remove dust accumulation inside
the combustion chamber and on the windows. The RA-
915+ should not be operated for too long periods for
solid samples containing high moisture and for liquid
samples, which cause condensed water to accumulate in
the tubing. Both condensed water and dust accumulation
inside the combustion chambers and tubing resulted
in deforming the peak.