V. Cheam et al., DIRECT DETERMINATION OF DISSOLVED AND TOTAL THALLIUM IN LAKE WATERS BY LASER-EXCITED ATOMIC FLUORESCENCE SPECTROMETRY, International journal of environmental analytical chemistry, 63(2), 1996, pp. 153-165
Thallium is a highly toxic, under-studied priority element. However, i
t has recently created much interest due to afresh and rapid improveme
nts in detection limit. It appears that there are no published Tl data
for Great Lakes waters, likely due to the poor sensitivity of classic
al methods. An electrothermal Laser-Excited Atomic Fluorescence Spectr
ometer has been optimized to detect sub-femtogram of thallium and used
to develop a method for direct determination of dissolved and total t
hallium in lake waters. The method voids the labor-intensive, contamin
ation-prone tasks of filtration, centrifugation and acid digestion of
collected particulates. Adequate precision and recoveries were achieve
d using several lake waters (undigested and digested) and a certified
reference material. The concentration of thallium in the acidified (0.
2% HNO3) Milli-Q-Water was monitored over a period of four months and
averaged 0.02 +/- 0.01 ng/l. The concentration in Hamilton Harbor rang
ed from 3 to 48 ng/l. The mean of dissolved/total fraction of Tl in th
e Harbor water was 80%.