TEST PLAN
CAPILLARY ELECTROPHORESIS METHOD FOR THE DETERMINATION
OF FREE HYDROXIDE AND COMPLEXANTS IN HANFORD NUCLEAR
WASTE
1. 0 INTRODUCTION
The challenges of maintaining tank safety, waste processing and waste cleanup make
routine characterization of the waste indispensable. The Hanford nuclear waste is very
complex, highly caustic, has many radionuclides, metal ions, organic compounds and
many inorganic anions. The determination of free hydroxide and thus estimating free
acid in the tanks are paramount and particularly of vital attention because of their
relevance to tank corrosion. In addition, pH information is necessary in waste processing,
treatment and eventual disposal. Tanks must be characterized for their
ethylenediaminetetraacetic acid (EDTA) and N-hydroxyethylethylenediaminetriacetic
acid (HEDTA) contents because these complexants profoundly affect the chemistry of
metals, thus radionuclides. In addition, the presence of these complexants adds large
amounts of organic material to the tanks, which greatly impacts waste management,
treatment and disposal.
The current method for the determination of hydroxide ion at the Hanford Site is
potentiometric titration. However, potentiometric titration is not selective. It gives false
high concentrations in the presence of certain concentrations of aluminate, carbonate,
phosphate, and chromate, which also consume acid during the titration. The maximum
tolerable mole ratio of anion to OH- for these anions are 0.5 for aluminate, 2.5 for
carbonate and 0.6 for phosphate. In addition to the interference problem discussed above,
potentiometric titration is time consuming, consumes high amounts of acid and generates
large volumes of additional mixed waste.
Capillary zone electrophoresis methods have been shown to have high promise for anion
analysis by indirect detection for non-UV absorbing species. Chromate ion has been
widely used as the absorbing background electrolyte (BGE). Okemgbo and others have
shown successful applications of CZE methods for the analyses of the Hanford nuclear
waste for EDTA, HEDTA and nitrates. They discussed the high ionic strength
requirement for the electrolyte used for the CE separation of these compounds due to the
high ionic strength and high pH of the matrix.
A Fluor Hanford Inc. contract at Washington State University Tri-Cities (WSUTC) will be
used to improve and expand analytical procedures and instrumentation. Special attention
will be devoted to determination of free hydroxide, EDTA and HEDTA in tank waste.
Fluor Hanford Inc. and Washington State University Tri-Cities have conducted tank waste
projects as a joint team effort. This approach takes advantage of the natural synergy of
multiple partnerships and of the unique strengths of each team member. In addition, total
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costs are reduced by use of low academic charge-out rates, and WSU staff gains real world
chemistry experience. The WSUTC researcher will work in conjunction with the PHMC
responsible scientist (S. G. Metcalf).
Dr. Asopuru Okemgbo of WSUTC brings in a wealth of experience in analytical
chemistry, kinetics, and Hanford mixed waste chemistry. He is uniquely qualified to
perform this work. Hanford waste chemistry is unique and challenging; the usual
analytical methods simply don't work. He possesses a unique combination of knowledge
and is the only scientist available with graduate level university training analytical
chemistry and physical chemistry. He is qualified to work at the 222-S laboratory where
this work will be conducted. He has a proven 7-year track record of developing analytical
methods to analyze Hanford waste.
2.0
OBJECTIVE
This amendment adds two tasks to an existing Statement of Work. In task 1 an existing
instrument will be updated and placed into service for the determination of EDTA and
HEDTA. Task 2 is to develop and evaluate capillary electrophoresis methodology for
rapid determination of free hydroxide ion in Hanford nuclear waste. After development
and testing are complete the method will be implemented for routine use at 222-S.
3.0
TASKS
TASK 1:
Assist with Determination of EDTA and HEDTA by CZE
Activity 1
WSUTC will assist and advise FH staff as requested. WSUTC will design
and perform laboratory experiments at 222-S, review data and train 222-S
staff.
Restart of WATERS Capillary Ion Analyzer involved talking with Jann Frey
and visiting at 222-S laboratory.
Review of capillary zone electrophoretic purge, rinse, injection, and run
programmes.
Review composition of electrolyte and rinse solutions.
Review Test electropherograms
TASK 2:
Develop New Analytical Method to Determine Hydroxide by CZE
Activity 1:
Test Plan, restarting CE equipment, and calibration:
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Restart CE equipment, the Waters Capillary Ion Analyzer (CIA), at
Washington State University Tri-Cities
Review of capillary zone electrophoretic purge, rinse, injection, and run
programmes.
Review composition of electrolyte and rinse solutions.
Prepare electrolytes and buffer solutions.
Evaluate polybrine and bromide electrolyte
Evaluate polybrine and thiosulfate electrolye
Evaluate other electrolytes
Calibrate CIA, run standards, establish optimal conditions.
Activity 2:
Analytical parameters/conditions for free OH- determination:
Evaluate methods of injection for free hydroxide and other relevant anions
Evaluate gravity injection method under different ionic strength
conditions.
Evaluate electromigration injection method under different ionic
strength conditions.
Calibration curves for free hydroxide and other anions will be established for
testing with synthetic Hanford waste.
Establish reliable calibration curves for free hydroxides under
various ionic strength conditions.
Evaluate standard addition methods as a function of changes in ionic
strength.
Test calibration with synthetic Hanford waste samples.
Prepare 1:10, 1:102, 1:103, and 1:104 dilutions of the synthetic waste.
Quantify at the dilution levels.
Establish detection limits.
Activity 3:
Investigation of potential interferences and testing of candidate method with
synthetic Hanford waste:
Evaluate the effects of added carbonate, phosphate, and aluminate in
the quantification of free hydroxide in the synthetic waste.
Evaluate effects of precipitation of potential interfering ions with
barium sulfate.
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Activity 4:
Technology transfer and Hot Test at 222-S Laboratory:
WSUTC will work in conjunction with the PHMC staff to test the method
with actual hot samples at 222-S Laboratory. Detection limit and
concentration range will be determined and documented.
Activity 5:
Provide Training and write procedure
Washington State University will train one chemist and technician on the
use of the methodology. WSUTC in conjunction with the PHMC staff will
write the final procedure to be used at 222-S Laboratory for the
determination of free hydroxide ions in the tank waste.
Activity 6:
Final Report:
WSUTC will provide a well-documented final report summarizing the
findings of all experiments and tasks performed.
Deliverable:
The report shall include details of the tests performed, established optimal
injection method for the determination of free hydroxide in synthetic
Hanford waste. The final report will be issued or publications will be
submitted to refereed scientific journal by September 30, 2002.
Technical Point of Contact:
Management.
Steven G. Metcalf, Technical Program
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