One reason why many persons have met with difficulties
in determining cadmium in urine may be interference
from the rather high and variable concentration
of salt. Some workers-e.g., Liebermann (10)
and Kubasik and Volosin (11)-have tried to circumvent
this by making an extraction before analysis.
Others have tried to eliminate interference by (e.g.) use
of ion exchangers (8). However, aside from their being
time consuming, these procedures pose risks of variable
recovery and contamination. Pitfalls with flameless
atomic absorption spectroscopy have been described in
a recently published critical study (16). Explanations
for failure when urine is directly injected may be that
undiluted urine has been used, or drying, ashing, and
atomization have not been made optimum, or both. In
part, such conditions may be critical because irregular
amounts of cadmium may be lost at temperatures above
400 #{176d}uCring ashing.