We developed a method to separate anion complexes of sulfur, iodine, and phosphorus to enable determination by radiochemical techniques. This method involves ion chromatographic separation of the anion complexes from other highly emitting radioactive species such as cesium-137 and strontium-90 which interfere with radiochemical analysis. We essentially use the ion chromatograph as a sample pretreatment method. The samples are injected onto a cation exchange column which allows the anions to pass through while retaining the positively charged species. These anions are collected in the column effluent and measured by nuclear counting methods. The method was developed to enable measurement of trace radionuclides in radioactive waste. This report establishes the separation and collection protocol, collection efficiencies for sulfur, iodine, and phosphorus, which are dependent upon the sample matrix, and overall efficiencies and detection limits for the separation and subsequent radiochemical analysis

Dewberry, R. A.

Ekechukwu, A. A.

We developed a method to separate anion complexes of sulfur, iodine, and phosphorus to enable determination by radiochemical techniques. This method involves ion chromatographic separation of the anion complexes from other highly emitting radioactive species such as cesium-137 and strontium-90 which interfere with radiochemical analysis. We essentially use the ion chromatograph as a sample pretreatment method. The samples are injected onto a cation exchange column which allows the anions to pass through while retaining the positively charged species. These anions are collected in the column effluent and measured by nuclear counting methods. The method was developed to enable measurement of trace radionuclides in radioactive waste and in environmental samples. Trace radionuclides which are present in concentrations of only a few hundred disintegrations per minute per milliliter can be separated and then analyzed using liquid scintillation counting analysis. This paper establishes the separation and collection protocol, collection efficiencies for sulfur, iodine, and phosphorus anion standards, and overall efficiencies and detection limits for the separation and subsequent radiochemical analysis of iodine-129 from both environmental level and high salt waste samples

UNT Digital Library

WSRC-MS-96-0151, Rev .  1 C0MFdq60q/y&-2 Separation and Collection of Iodine, Sulfur, and Phosphorous Anion Complexes for Subsequent Radiochemical Analysis (U) by . A. A. Ekechukwu Westinghouse Savannah River Company Savannah River Site Aiken, South Carolina 29808 R. A Dewbeny \ . A document prepared for EMERGING TECHNOLOGIES IN HAZARDOUS WASTE MANAGEMENT Vlll at Birminghatp, AL, USA from 9/9/96 - 9/12/96. IA-f-i-pr*. r,r 77-n p , - e ) g ~ n ~ ) .  E.” ...* L -..._ . . ’ -. pf I5 IjqJ.4m ‘DOE Contract No. DE-AC09-89SR18035 This paper was prepared in connection with work done under the above contract number with the U. S. Department of Energy. By accepfance of this paper, the publisher and/or recipient acknowledges the U. S. Government’s right to retain a nonexclusive, royally-free license in and to any copyright covering this paper, along with the right to reproduce and to authorize others to reproduce all or part of the copyrighted paper. WSRC-MS-96-0 15 1 Red*  I / SEPARATION AND COLLECTION OF ANION COMPLEXES FOR SUBSEQUENT RADIOCHEMICAL ANALYSIS A.A. Ekechukwu, R.A. Dewberry Savannah River Technology Center SUMMARY We have developed a method t o  separate anion complexes o f  radioactive sulfur, iodine, and phosphorus t o  enable determination by radiochemical techniques. This method involves ion chromatographic separation of the anion complexes from other highly emitting radioactive species such as cesium-1 37 and strontium-90 which interfere with radiochemical analysis. We essentially use the ion. chromatograph as a sample pretreatment method. The samples are injected onto a cation exchange column which allows the anions t o  pass through while retaining the positively charged species. If more than one negatively charged radionuclide is present, the sample is injected onto an anion exchange column and the individual anions are separated. from each other as well as from the cations. These anions are collected in the column effluent and measured by nuclear counting methods. The method was developed t o  enable measurement of trace radionuclides in radioactive waste and in environmental samples. Trace radionuclides which are present in concentrations of only a few hundred disintegrations per minute per millil iter can be separated and then analyzed using liquid scinti l latkn counting analysis. This paper establishes the separation and collection protocol, collection efficiencies for sulfur, iodine, and phosphorus anion standards, and overall efficiencies and detection limits f o r  the separation and subsequent radiochemical analysis of iodine- 1 29 from both environmental level and high salt waste samples. I NTRO DUCT10 N Our laboratory provides analytica support for many different types of research programs within the Savannah River Technology Center and throughout the Savannah Rivtr Site. A wide variety of sample types including ground water, organics, laboratory waste, process control, sludge, soils, and others are received for many aif ferent analyses. These samples are both radioactive and non-radioactive and may contain hazardous materials such as RCRA metals, organics, WSRC-MS-9 6-0 15 1 and flammable solvents. Often these' analyses involve measurement of trace constituents in the presence of higher concentrations o f  interfering species. This is especially common when measuring trace radionuclides in the presence of high concentrations o f  radioactive cesium and strontium. _.. ~ We have developed a method for analysis of low levels of radioactive phosphorus, sulfur, and iodine in waste and environmental samples. This method involves ion chromatographic separation from radioactive cesium and strontium isotopes by passage through a cation exchange column. The cesium and strontium (cations) are retained by the column while the iodine, sulfur, and phosphorus, present as anion complexes pass through unretained. The radionuclides of the separated species are then measured using liquid scintillation counting and gamma spectroscopy. Currently available methods for determination of low-level radionuclides involve chemical separation of each element individually . and subsequent radioichemical analysis using nuclear counting techniques. The ion chromatographic method separates a I I of the elements simultaneously including ones which cannot be determined using existing wet chemical methods. This decreases the length of time required for analysis and the amount of waste generated, as well as limiting personnel radiation and chemical exposure. EXPERIMENTAL SECTION I n s t r u m e n t a t i o n  All chromatographic separations were performed using a Dionex Series 4500 Ion Chromatograph (Dionex Corporation, Sunnyvale, Ca) which included the basic chromatography module, gradient pump, conductivity and spectrophotometric detectors, reagent delivery module, regenerant pump, post column reactor, and eluent degas module. The chromatograph was interfaced with a Spectra Physics Integrator for data acquisition, manipulation, and storage. The sample was injected using a Dionex 4000 psi injection valve which was plumbed for a 500 UL sample size. The large sample size (1 0 times larger than the standard Injection size of 50 uL) was necessary to  recover a sufficient volume of the separated sample for subsequent analysis by LSC. WSRC-MS-96-015 1, R e J ,  1 The columns used were 'CG3/CS3 separator columns for * cation separation and AG5/AS5 separator columns for anion separation, both from Dionex. The columns were conditioned for a t  least 30 minutes at the start of each day's experiments and a t  least 10 minutes between each run by flowing fresh eluent through the column. _.. ~ For conductivity detection of nonradioactive standards, a Dionex basic conductivity module and conductivity cell were used. The column effluent was passed through a suppressor membrane which ' converts the eluent t o  water by ion exchange with an electrochemically generated regenerant solution running counter current t o  the eluent stream. Radioactive samples were separated chromatographicaily into ion fractions. These fractions were collected and subsequently analyzed using LSC and gamma spectroscopic analysis. Liquid scint i l lat ion measurements (alpha and beta emission data) were done using a Packard 2250CA Tricarb Liquid Scintillation Analyzer (Packard Instrument Co., Downers Grove, 11). Gamma spectroscopy was done using a germanium gamma detector (EG&G Ortec). The separation and collection method is diagrammed in Figure 1. Reagents All chemicals and reagents met the applicable specifications of the Committee on Analytical Reagents of the American Chemical Society. Eluents and regenerant solutions were prepared from u l t ra  pure deionized water (18 MQ resistivity) which had been passed through a Millipore system for purification. The eluent reservoirs were degassed and kept under a pressurized reservoir of 20 psi  nitrogen. Unless otherwise noted, all reagents were used as received from the manufacturer. The liquid scintillation cocktail used was Optifluor (Packard, #6013425). Nonradioactive IC anion standards were prepared by volumetric dilution with ultrapure deionized water of 1000 ppm stock standard solutions which were procured from Spex Industries and traceable t o  the National Institute of Standards Technology. These diluted standard solutions were prepared fresh for each experiment. Procedure The separation was achieved by elution off of a low capacity ion exchange resin. The eluent used was 50 mM sodium carbonate/50 WSRC-MS-96-0 15 1 m M  sodium bicarbonate for anion separation and 1.6 mM HCI fo r  ' cation separation. The sample was injected a t  0.5 minutes  with an eluent flow rate of 1 mL per minute and allowed to elute for 1 5  minutes. Figure 2 is an ion chromatogram showing the retention t imes for  standard anion complexes including iodate, sulfate, and phosphate. The location and intensity of t h e  peak are dependent upon both t h e  identity and concentration of the eluent solution. The separation protocol and column conditions are listed in Figure 2. During the chromatographic separation of nonradioactive standards, eluted ions were detected using conductivity detection. The radionuclides separated from t h e  waste solutions were collected by hand in 1 mL (1 minute) fractions and subsequently analyzed using LSC. For LSC, the fractions were collected directly into vials containing 1 4  mL of Optifluor. DISCUSSION Principle of t h e  Method and Experimental Details The method essentially uses the  ion chromatograph as  a sample preparation tool. The sample is injected onto the column and the different ions in solution are separated. The separated ions a re  collected a s  they exit the column in eluent fractions. These fractions are collected into liquid scintillation coctail and the radionuclides present are measured by liquid scintillation counting. Two routes for separation were pursued. The first involved injecting the  sample onto a low capacity anion exchange resin column and collecting the individual ions a s  one-minute fractions. The collection efficiency of nonradioactive standards of iodate, sulfate, and phosphate ranged between 93 and 97% (see Table 1). The collection efficiency for an iodine-I 29 standard collected w a s  94% overall, including the collection and subsequent liquid scintillation analysis. The liquid scintillation spectrum from the I - 1 2 9  fraction is shown in Figure 3. The other separation strategie was to inject the sample onto a low capacity cation exchange resin column. Anions are unretained on this  column and pass through in t h e  column void volume. The cations are retained on the column and t h u s  separated completely from the anions. This strategie was used when t h e  anion radioisotopes did not interfere with each other's detection. The collection efficiency of non-radioactive standards is between 97 and 99% using t h i s  WSRC-MS-9 6-0 15 1, AeJ I method (see Table 2). The collection efficiency for an iodine-I 29 standard collected was 97% overall, including the collection and subsequent liquid scintillation analysis. Preparation o f  a Standard Curve For nonradioactive elemental analyses, standard curves are -prepared by plotting the concentration of known standards versus the peak height in conductivity units. The standard curves for each of the elements were made by the ion chromatograph usin9 one standard and one blank and are stored in the instruments memory. These calibration curves are verified by running a check standard each time the analysis is run. For radioactive standards, the overall efficiency is determined by measuring sample spike recoveries using standards of known activity. Length o f  Time Required for Analysis The length of time for analysis depends on the elution times for the individual anion. After a sample has been properly prepared, the chromatographic run to  elute all 3 anions takes 10 minutes. Liquid scintillation measurements were made using a 10  minute count. Separation o f  Interfering Species Samples which contain many different species present in widely differing concentrations are particularly difficult t o  analyze. As stated earlier, this chromatographic method was developed t o  be used in the analysis of high activity SRS waste. This waste contains low levels of radioactive iodine, phosphorus, and sulfur in the presence of high levels of radioactive cesium and strontium. Tables 3 and 4 show the activity and half lives of various radioisotopes present in SRS waste. Two of these isotopes, Cs-I37 and Sr-90, are high energy beta emmiters. This activity masks the signal from these low-level isotopes and thus prevent their detection and quantitation. Qualitative identification of the radionuclides in the separated ion fractions was done by liquid scintillation counting. Standards and spiked samples were run to  determine collection efficiency, counting efficiency, and overall recovery o f  radioisotopes. After the chromatographic separation was complete, the column was flushed with concentrated eluent t o  remove any remaining species which may have been retained by the column. This wash was counted by LSC and no activity was found. The major difficulty encountered with this analysis is the nature o f  the samples. High level nuclear waste contains many cationic and WSRC-MS-96-0 15 1 anionic species a t  widely differing concentration levels 'including ' . chemicals from plant separation processes, laboratory waste, fission products, neutron activation products, uranium, plutonium, and other actinides. Environmental samples often contain high levels of nitrates and chlorides. The high concentrations o f  individual anions and cations prevent the trace constituents f rom completely interacting with the column stationary phase and thus inhibit separation into discrete fractions. To counteract this effect, nonradioactive carriers (10 UL of the 1000 ppm standards of stable elemental isotopes per 1 mL of sample) were added t o  the samples. This enabled the trace constituents to  more effectively compete with the column surface. For radionuclide analysis, ion chromatography was used only t o  separate the ions into discrete fractions for subsequent analysis by liquid scintillation counting and gamma spectroscopy. The ions were collected in 1 mL fractions. Since only a 50 UL sample volume had been injected onto the column, this represented a 20 fold dilution which prevented detection of most of the trace constituents. To compensate for this, the injection valve was replumbed with a 500 uL injection loop, thus increasing the amount of sample injected onto the column. and then recovered by ten-fold. Comparison o f  chromatographic runs using 1 -ppm nonradioactive standard solutions showed no effect in precision of accuracy of the data or the effectiveness of the separation. Analysis of Waste Tank Samples Increasing the size of the sample loop proved problematic when analyzing waste samples of sample with high salt content. The large amount of anions exceeded the separation capacity of the column and prevented the collection of discrete anion complexes. A waste tank sample with high salt content which had been spiked with a known activity of 1-129 was injected onto an anion separation column. The 1-1 29 did not elute in a discrete fraction, as was seen with the 1-129 standard. Instead, the 1-129 activity bled out over several minutes and could not be collected efficiently. The anion separation method is not suitable for high salt content samples. The same sample was injected onto a cation separator column using a 0.5 mL sampie loop and much better results were obtained. The I - 129 eluted in the column void volume (the first minute after sample injection) and was recovered with an overall recovery of 84%. WSRC-MS-96-0151, 1 CONCLUSION We have developed a method which can separate low levels o f  radioactive anions from high levels of radioactive cations which would othennrise prohibit their analysis. The method can be-used f o r  both environmental and waste samples which are very difficult t o  analyze because of the wide variety of species found in thein i n  varying concentrations. As with any chrcmatographic separation, high concentrations of elements in the sample will saturate the column stationary phase and must be removed from the sample prior t o  analysis. This method appears applicable t o  the analysis of trace radionuclides which can be separated and analyzed using I i q u i d scintillation counting and gamma counting. Future work includes measuring the separation and collection efficiencies of S-35 and P -  32. WSRC-MS-96-015 1 References 1. 2. 3. 4. 5. 6. 7. 8. 9. Bibler, N.E., “Radionuclide Analyses Required f o r  DWPF Product“ ,  , MCC Meeting on Analytical Methods, January 16-17, 1990, Pleasanton,  Ca. Almon, A.C., Kinard, W.F, Dewberry, R.A., Bibler, N.E., “Mult imodal  Separat ion Of Alkali, Alkaline Earth, Transition, P o s t - T r a n s i t i o n ,  Lanthanide,  And Actinide Metal Cations In W a s t e  Sludge”, Ion Chromatography Forum, New Orleans, La, May 15, 1991. _.. - . W a s t e  Compliance Procedures, WSRC-SW4-6, March 1 990. Pohl, C.A., J-ohnson, E.L., J. Chromatogr. Sci. 18 (1 980) 442. Dionex Corporation, Application Note No. 6, Sunnyvale, CA, 19i8. Takata ,  Y., Mizuniwa, F., and Maekoya, C., Anal. Chem. 46 (1 974) 262. Dionex Corporation, Application Note No. 6, Sunnyvale, CA, 1986. Sevenich, G.J., Fritz, Anal. Chem. 55 (1 983) 12. Hamilton, V.T., Spall, D.W., Smith, B.F., Peterson,  E.J., J. Chrom., 469 (1989) 369-377. WSRC-MS-96-015 1, A ~ J  1 Figure 1 : Basic Ion Chromatography Ins t rument  Diagram - Eluent is pumped through a separator column. The sample is injected into t h i s  stream and passes through the column which separates the anions in the sample. The separated anions pass through a Conductivity cell, the conductivity is recorded and the chromatogram generated. When collecting anion fractions for LSC, the column is disconnected from the conductivity cell and the effluent is collected into LSC cocktail. sample inject eluent reservoir instrument + control to waste separator column suppressor membrane I compvter a- I data generation I conductivity detector - eluent path .)- - e -  data signal Y - Nirrite (10 ppm) WSRC-MS-96-015 1 Figure 2: Ion Chromatogram of Nonradioactive Anion Standards. 2 -89 detector range = 30 US integrator at@nuation = 1024 _ I  9 i 6 0 0  C 0 U N T S WSRC-MS-96-0 15 1 , fled I Figure 3: LSC Spectrum of 1-129 Fraction - Standard' w a s  injected onto cation column and the first 1 minute of eluent was collected. .:. . . - .  ! ,  . . .. .. . - - .  -3 I ! I c Anion Complex I -  S 0 4 - 2  P04-3  WSRC-MS-96-015 1 E f f i c i e n c y  %RSD on 5 Reps. 9 4  3.8 9 3  4.6 9 7  2.9 _.. -Table 1: Collection Eff iciencies of  Anion Complexes a s  Measured by Ion Chromatography, Anion Exchange Column. Anion Complex I -  S 0 4 - 2  P04-3 E f f i c i e n c y  %RSD on 5 Reps. 97  2.3 99  2.8 9 8  2.1 Table 2: Collection Eff iciencies of  Anion Complexes a s  Measured by  Ion Chromatography, Cation Exchange Column. c NUCLIDE Ni-5 9 Ni-63 Se-79 Sr-90 Nb-93m Zr-93 Tc-9 9 Pd-107 SII-1 26 cs-135 cs-137 Sm-15 1 Th-230 U-234 U-238 Np-237 Pu-238 Pu-239 Pu-240 Pu-241 Pu-242 Am-241 Am-243 Cm-244 WSRC-MS-9 6-0 15 1, &J 1 HALF LIFE vears 8E04 92 7E04 28 12 1 E06 2.1 E05 7E06 1 E05 2E06 30 93 80 2E05 5E09 2E06 89 2E04 7E03 13 4E05 5E02 8E03 18 Table ' 3: Radionuclides Required t o  h e  Measured in SRS * . . -  WSRC-MS-96-0 151 Table 4: Radinuclide Concentrations Measured in SRS Sludge Isotope Concentration Ni59 19  9-90 1.9 3-93 1.1 _.- - Tc99 2.8 PdlO7 12.4 Snl26 0.01 - Csl35 1.2 Csl37 7.0 Sml51 0.2 ’ Th230 0.0 . U234 1.4 U238 10.9 Np237 106 Pu239 3 6  Pu240 3 Am243 0.3 Cm244 0.09 Pm147 2.5 Eul54 0.0 

Separation and collection of iodine, sulfur, and phosphorous anion complexes for subsequent radiochemical analysis

Separation and Collection of Iodine, Sulfur, and Phosphorous Anion Complexes for Subsequent Radiochemical Analysis (U) 9 by A. A. Ekechukwu Westinghouse Savannah River Company Savannah River Site Aiken, South Carolina 29808 R. A Dewberry M A document prepared for EMERGING TECHNOLOGIES IN HAZARDOUS WASTE MANAGEMENT VI11 at Birmingham from 09/09/96 - 09/12/96. DOE Contract No. DE-AC09-89SR18035 This paper was prepared in connection with work don und the ab ve contract numbs with the U. S. Department of Energy. By acceptance of this paper, the publisher and/or recipient acknowledges the U. S. Government‘s right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper, along with the right to reproduce and to authorize others to reproduce all or part of the copyrighted paper. I DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United.States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not iniiinge privately owned righp. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. This report has been reproduced directly from the best available copy. Available to DOE and DOE contractors fiom the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831; prices available from (615) 576-8401. Available to the public from the National Technical Information Service, U.S. Department of Commercet 5285 Port Royal Road, Springfield, VA 22161. WSRC-MS-96-015 1 PREPRINT EXTENDED ABSTRACT Presented at the I&EC Special Symposium American Chemical Society Birmingham, AL September 9-12, 1996 SEPARATION AND COLLECTION OF IODINE, SULFUR, AND PHOSPHORUS ANION COMPLEXES FOR SUBSEQUENT RADIOCHEMICAL ANALYSIS A.A. Ekechukwu, R.A. Dewberry Savannah River Technology Center  SUMMARY We developed a method to separate anion complexes of radioactive sulfur, iodine, and phosphorus to enable determination by radiochemical techniques. This method involves ion chromatographic separation of the anion complexes from other highly emitting radioactive species such as cesium-137 and strontium-90 which interfere with radiochemical analysis. We essentially use the ion ' chromatograph as a sample pretreatment method. The samples are injected onto a cation exchange column which allows the anions to pass through while retaining the positively charged species. If more than one negatively charged radioisotope is present, the sample is injected onto an anion exchange column and the individual anions separated from each other as well as from the cations. These anions are collected in the column effluent and measured by nuclear counting methods. The method was developed to enable measurement of trace radionuclides in radioactive waste and in environmental samples. Trace radionuclides which are present in concentrations of only a few hundred disintegrations per rninute per milliliter can be separated and then analyzed using liquid scintillation countjng analysis. This paper establishes the separation and collection protocol, collection efficiencies for sulfur, iodine, and phosphorus, and overall efficiencies and detection limits for the separation and subsequent radiochemical analysis. WSRC-MS-96-015 1 INTRODUCTION Our laboratory provides analytical support for many different types of research programs within SRTC and throughout the Savannah River Site. A wide variety of sample types including ground water, organics, laboratory waste, process control, sludge, soils, and others are received for many Werent analyses. These samples are both radioactive and non-radioactive and may contain hazardous materials such as RCRA metals, organics, and flammable solvents. Often these analyses involve measurement of trace constituents in the presence of higher concentrations of interfering species. This is especially cornmon when measuring trace radionuclides due to the high concentration of radioactive cesium and strontium isotopes. We have developed a method for analysis of low levels of radioactive phosphorus, sulfur, and iodine in the waste and environmental samples. This method involves ion chromatographic separation of isotopes from radioactive cesium and strontium isotopes by passage through a cation exchange column. The cesium and strontium (cations) are retained by the colurnn while the iodine, sulfur, and phosphorus, present as anion complexes, pass through unretained. The radionuclides of the separated species are then analyzed using liquid scintillation counting and gamma spectroscopy. Currently available methods for determination of low-level radionuclides involve chemical separation of each element individually and subsequent radioisotope analysis using nuclear counting techniques. The ion chromatographic method separates all of the elements simultaneously including ones which cannot be determined using existing wet chemical methods. This decreases the length of time required for analysis and the amount of waste generated, as well as limiting personnel radiation and chemical exposure. DISCUSSION Separation of Interfering Species Samples which contain many different species present in widely differing concentrations are particularly difficult to analyze. As stated earlier, this chromatographic method was developed to be used in the analysis of low levels of radioactive iodine, phosphorus, and sulfur in the presence of high levels of radioactive cesium and strontium. Cs-137 and Sr-90 activity mask the signal fkom'these WSRC-MS-9 6-0 15 1 isotopes thus preventing their detection and quantitation. Qualitative identification of the separated isotopes was done by liquid scintillation counting. Standards and spikes samples were run to determine collection efficiency, counting efficiency, and overall recovery of radioisotopes. After the chromatographic separation was complete, the column was flushed with concentrated eluent to remove any remaining species which may have been retained by the column. This wash was counted by LSC and no radionuclides were found. Problems and Interferences The major difficulty encountered with this analysis is the nature of the waste samples themselves. High level nuclear waste contajns many cationic and anionic species at widely differing concentration levels including chemicals from plant separation processes, laboratory waste, fission products, neutron activation products, uranium, plutonium, and other actinides. Environmental samples often contain high levels of nitrates and chlorides. The high concentrations of individual anions and cations prevent the trace constituents from completely interacting with the column stationary phase and thus inhibit separation into discreet fractions. To counteract this effect, nonradioactive carriers (10 mL of the 1000 ppm standards of stable elemental isotopes per 1 mL of sample) were added to the samples. This enabled the trace constituents to more effectively compete with the column surface and separate effectively. For radionuclide analysis, ion chromatography was used only to separate the cations into discreet fraction for subsequent analysis by liquid scintillation counting and gamma spectroscopy. The ions were collected in 1 mL fractions. Since only a 50 mL sample volume had been injected onto the column, this represented a 20 fold dilution which prevented detection of most of the trace constituents. To compensate for this, the injection valve was replumbed with a 500 mL injection loop, thus increasing the amount of sample injected onto the column and then recovered by ten-fold. Comparison of chromatographic runs using l-ppm nonradioactive standard solutions showed no effect in precision of accuracy of the data or the effectiveness of the separation. WSRC-MS-96-015 1 CONCLUSION We have developed a method which can separate low levels of radioactive anions from high levels of radioactive cations which would prohibit their analysis. The method can be used for both environmental and waste samples which are very difficult to analyze because of the wide variety of species found in them in varying concentrations. As with any chromatographic separation, high concentrations of elements in the sample will saturate the column stationary phase and must be removed from the sample prior to analysis. This method appears applicable to the analysis of trace radionuclides which can be separated and analyzed using liquid scintillation counting and gamma counting. 

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Separation and collection of iodine, sulfur, and phosphorous anion complexes for subsequent radiochemical analysis

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