Chemistry Reference
In-Depth Information
In 1992, Cordera et al. described a FI system with an on-line ion-exchange col-
umn to preconcentrate uranium and thorium prior to reaction with Arsenazo III for
spectrophotometric determination.
21
In 1995, Grudpan et al. incorporated an ion-
exchange preconcentration column as part of the injection valve of a FI system for
colorimetric determination of uranium using 4-(2-pyridylazo)resorcinol.
18
In 1998,
Grudpan's group described a similar FI system for uranium analysis using UTEVA-
Resin packing in a preconcentrating minicolumn.
19,20
In 1994, Dadfarnia and McLeod described the analysis of uranium in surface
waters and sea water using a simple FI system with an alumina column for pre-
concentration.
77
Species eluted from this column were delivered to an ICP-MS as
the detector. Also in 1994, Hollenbach et al. described the automation of extraction
chromatographic methods based on TRU-Resin and TEVA-Resin to separate and
preconcentrate U, Th, and Tc from soil samples, using ICP-MS for detection.
49,125
In
1996, Aldstadt et al. described the use of FI and extraction chromatography using
TRU-Resin to determine U in environmental samples by ICP-MS.
78
In 1995, Nevissi and Strebin described a simple fluidic system to deliver sample
and reagents to a TRU-Resin column for the separation of Pu and Am.
79
A filter was
included on-line to capture a precipitate containing the actinides; dissolution of the
precipitate transferred the sample onto the column downstream. Radionuclides were
detected with α-spectrometry off-line.
In 1996, Grate et al. described a SI method to automate a Sr-Resin extraction
chromatographic separation of
90
Sr from tank-waste samples, with on-line detection
using a flow-through scintillation detector.
80
This report was followed by several
additional papers within a few years, which described on-line extraction chromato-
graphic separations for
99
Tc or actinides in FI and SI systems using TEVA-Resin or
TRU-Resin.
44,47,48,81-83
The use of FI and SI methods to automate radiochemistry was
summarized in the journal
Analytical Chemistry
in 1998,
84
and was later described
in additional detail in a book chapter
46
and in ACS Symposium Series papers.
85,86
This group described the use of a SI extraction chromatographic separation involv-
ing TRU-Resin as a front end for ICP-MS in 2001.
87
By the late 1990s and into the 2000s, a number of additional groups became
involved in automated fluidic separations for radiochemical analysis, especially as
a front end for ICP-MS. Published journal articles on fluidic separations for radio-
metric or mass spectrometric detection are summarized in Tables 9.1 through 9.5.
The majority of such studies have used extraction chromatographic separations, and
these will be the main focus of the remainder of this chapter. Section 9.4 describes
methods that combine separation and detection. Section 9.5 describes a fully auto-
mated system that combines sample preparation, separation, and detection.
Although the automated extraction chromatographic separations are designed
from existing separation chemistry and manual procedures, several issues are typi-
cally investigated when they are automated. These investigations ensure that the sep-
arations are performing satisfactorily, help to define parameters for the automated
procedure, and provide confidence that the automated method will perform properly
over and over again while unattended. Separation issues examined include solution
compositions for the load, wash, and elute steps; column crossover effects, removal
of interferences during the wash step, and analyte recoveries. Sample issues are
