Analysis of in-bottle digestate by using
the inductively coupled plasma?mass
spectrometric (ICP?MS) method has been
expanded to include arsenic, boron, and
vanadium. Whole-water samples are
digested by using either the hydrochloric acid
in-bottle digestion procedure or the nitric acid
in-bottle digestion procedure. When the
hydrochloric acid in-bottle digestion
procedure is used, chloride must be removed
from the digestate by subboiling evaporation
before arsenic and vanadium can be
accurately determined. Method detection
limits for these elements are now 10 to 100
times lower than U.S. Geological Survey
(USGS) methods using hydride generation?
atomic absorption spectrophotometry (HG?
AAS) and inductively coupled plasma?
atomic emission spectrometry (ICP?AES),
thus providing lower variability at ambient
concentrations. The bias and variability of
the methods were determined by using results
from spike recoveries, standard reference
materials, and validation samples. Spike
recoveries in reagent-water, surface-water,
ground-water, and whole-water recoverable
matrices averaged 90 percent for seven
replicates; spike recoveries were biased from
25 to 35 percent low for the ground-water
matrix because of the abnormally high iron
concentration. Results for reference material
were within one standard deviation of the
most probable value. There was no
significant difference between the results
from ICP?MS and HG?AAS or ICP?AES
methods for the natural whole-water samples
that were analyzed.
