St. Nelson et D. Dettman, Improving hydrogen isotope ratio measurements for on-line chromium reduction systems, RAP C MASS, 15(23), 2001, pp. 2301-2306
Recent advances in on-line metal [U, Mn, Cr] reduction systems for the auto
mated analysis of deltaD(VSMOW) in water and organic solvents greatly incre
ases sample throughput. However, several sources of uncertainty are inheren
t in these systems, including analytical reproducibility, fractionation of
reference gas in the inlet system, and memory effects, as well as error int
roduced during data normalization that must be quantified. A careful consid
eration of these sources of uncertainty suggests that accuracy to <1 parts
per thousand may be difficult to achieve due to the combined effects of ana
lytical error and uncertainty in the calibration of secondary laboratory st
andards. However, for internally consistent data sets, it may be possible t
o measure relative differences between samples at the similar to0.5 parts p
er thousand level or below. In addition to describing methods for data redu
ction, strategies for minimizing and managing uncertainty are presented alo
ng with a recipe for greatly increasing reactor life in Cr-reduction system
s. Increased reactor life reduces consumable costs by a factor of 10. Copyr
ight (C) 2001 John Wiley & Sons, Ltd.