a p p l i c at i o n N o t e                                                                                            Li...
Figure 1.                                                                 Figure 2.    Figure 1. Acid dependency of the th...
Table 1.                                                                 Ground water composition.                        ...
The data indicatesindicates a relationshipcontact time and time          The data a relationship between between contactur...
Table 8. 226R uptake from 100 mL simulated ground water matrix.                                                         Ta...
Figure 4. Comparison of paired results at varying TDS levels: LSC (left)Figure (right).                                   ...
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Application Note: Gross Alpha Measurements in Aqueous Samples Using Extraction Chromatography and Liquid Scintillation Counting

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A new approach to the measurement of gross alphas in liquid samples, which combines Eichrom's extraction technology with PerkinElmer's liquid scintillation analysis technology, is presented. Difficulties with sample preparation and detection efficiency have always been problematic with the traditional method of gas flow proportional counting (GPC). The use of Eichrom's extraction resins and alpha liquid scintillation counting (LCS) has resolved the sample preparation problems, associated with drying the sample on a planchet. With its superior detection efficiency over GPC, this combination provides a better counting platform. Thus, many of the inherent limitations associated with the traditional GPC method are overcome by using this new approach and results demonstrate faster sample preparation, lower detection limits and shorter counting times.

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Application Note: Gross Alpha Measurements in Aqueous Samples Using Extraction Chromatography and Liquid Scintillation Counting

  1. 1. a p p l i c at i o n N o t e Liquid Scintillation Counting Gross Alpha Measurements Author in Aqueous Samples Using Anil Thakkar, Michael Fern, Thomas Kupka, Extraction Chromatography and James Harvey Eichrom Industries Inc. and Charles J. Passo Jr. and Liquid Scintillation and James Thomson Packard Instrument Company CountingAbstract to reach a detection limit of 100 mBq/ L. Samples containing extremely high levels of dissolved solids may require even longerA new approach to the measurement of gross alphas in liquid counting times to achieve the desired detection limit since ansamples, which combines Eichrom’s extraction technology with even smaller sample size must be used. Alpha LSC has beenPerkinElmer’s liquid scintillation analysis technology, is presented. proposed as an alternate to GPC for gross alpha measurements.Difficulties with sample preparation and detection efficiency have The inherent counting efficiency for alpha particles by LSC isalways been problematic with the traditional method of gas flow in excess of 90%. Since it does not suffer from self absorptionproportional counting (GPC). The use of Eichrom’s extraction problems, LSC can handle higher levels of dissolved solids.resins and alpha liquid scintillation counting (LCS) has resolved the However, the sample size is limited by what can be put into ansample preparation problems, associated with drying the sample LSC vial, and so for samples larger than 10 mL, some form ofon a planchet. With its superior detection efficiency over GPC, sample concentration must be performed. As shown in Figures 1this combination provides a better counting platform. Thus, many and 2, Eichrom Industries actinide resin shows excellent uptakeof the inherent limitations associated with the traditional GPC for all the actinides and for radium under neutral to slightly acidicmethod are overcome by using this new approach and results conditions,1,2 and is therefore a good candidate to preconcentratedemonstrate faster sample preparation, lower detection limits samples prior to alpha LSC. The actinide resin (using the Dipex®and shorter counting times. extractant3) is an extraction chromatographic resin in which the functional group on the extractant molecule is a diphosphonateIntroduction moiety. The structure of this molecule is shown in Figure 3.The traditional method of gross alpha measurements for liquidsamples using GPC suffers from a number of limitations. In order A method has been developed which combines this resin andto minimize the problem of self absorption, the volume of sample alpha LSC to measure total alpha activity in water samples.which can be analyzed is limited by the amount of dissolved The method is fast and simple. As many as 20 samples can besolids found in the aqueous samples (typically environmental and processed in 24 hours, requiring only one to two hours ofprocess waters). Counting efficiency of alpha particles by GPC hands-on time. Using 100 mL samples, a detection limit of 2 pCi/Lis 35% to 40% at best (0 mg residue) and declines to less than (75 mBq/L) can be reached with only 60 minutes counting time.10% when 100 mg of solids are left on the counting planchet.Counting times in excess of 1000 minutes are typically required
  2. 2. Figure 1. Figure 2. Figure 1. Acid dependency of the the uptake of several actinide species Acid dependency of uptake of several actinide species Figure 2. Acid dependency of the uptake of of several non-actinide species Acid dependency of the uptake several non-actinide species by the Dipex resin. Figure 1. resin. by the Dipex by the Dipex resin. Figure 2. resin. by the Dipex Acid dependency of the uptake of several actinide species Acid dependency of the uptake of several non-actinide species by the Dipex resin. by the Dipex resin.Experiment Experiment the same manner as the blanks except that the appropriate spike mL Ultima Gold LLT were added to a glass scintillation was also added directly to the scintillation vial. The simulated Experiment (0.5 g) was , and to one liter of a spiked mL vial.blanks except were prepared with two stockwas also theActinide resin (0.5 g) was added to one liter of a spiked watersample acidified to pH 2 with HNO addedstirred on a magnetic Actinide resin Ultima Gold LLT were prepared in the same manner as the Direct spikes ground water matrix was added to a glass scintillation that the appropriate spike solutions; vial. Direct spikes were in Table 1.in the same manner as composition is shown preparedstir plate. After the (0.5 g) was addedtime, the HNO3, and stirred the added directly that the appropriatevial. The simulated water sample acidified to pH 2 with resin a spiked blanks except to the scintillation spike was also 3 Actinide resin indicated contact to one liter of was collected wateronsample acidified to pH 2 with indicated contact time, a magnetic stir plate. After the HNO , and stirred ground water matrix was prepared with two stock solu-using a vacuum filtration apparatus and a 0.45 micron Gelman added directly to the scintillation vial. The simulated on athe resin was collected using a vacuum filtrationthe filter ground liter of compositionprepared with two stock solu- purity appara- One the each stock solution was prepared with high tions;water matrix was is shown in Table 1. 3filter. The resin a 0.45 micron Gelman indicated contact time, magnetic stir plate. After the tus and was rinsed with deionized (DI) water and rinsed filter. The resin was the resin was collected using atransferred to a watch glass vacuum filtration appara-containing the collected (DI) water and the filter containing the tions; theTwenty-five mL of each stock solution was added to 900 water. composition is shown in Table 1. with deionized resin was tus and a 0.45 micron Gelman filter. The resin was rinsed One liter of each stock solution was prepared with highand placed under a heat was transferred to a watch glass and collected resin lamp (approximately 75 cm above) for Onepurityof eachTwenty-five was prepared with high NaOH, mL of high purity water and mL of each pH of solution was liter water. stock solution mixed. The stock the resulting with deionized (DI) water and the filter containing the placedresin was transferred to a resin. The dried resin under a heat lamp (approximately 75 cmandapproximately 15 minutes to gently dry the watch glass collected above) solution to 900 mL ofto 9.8 using 0.1M HCl and 0.1M The added was adjusted high purity water and mixed. purity water. Twenty-five mL of each stock solution was carefully transferred into minutes to gently dry the resin. added to 900 mL of high puritythen diluted mixed. The for approximately 15 glass scintillation vial and the filter as necessary.resulting solution was adjusted tofinal volume ofwasplaced under a heat lampa(approximately 75 cm above) pH of the The solution was water and to a 9.8 using The1dried resin15HCl.carefullygentlyrinse was collected was The 0.5Mtransferredthe resin. into a glass 1000 mL. Aliquots of this solution were spikedThe solution therinsed with mL of 0.5M minutes to HCl dry for approximately pH 0.1M HCl and 0.1M NaOH, as necessary.9.8 using in of the resulting solution was adjusted to and used scintillation vial and the filter rinsedLLT was mLglass with 1 added 0.5M procedure as the simulated ground water matrix. Aliquots ofin the scintillation vial. Tencarefully transferred into a The dried resin was mL Ultima Gold 0.1M HCl and 0.1M NaOH, volume of 1000 mL. was then diluted to a finalas necessary. The solution scintillation vial andHCl filter rinsed with 1 mL the 0.5M HCl. The 0.5M the rinse was collected in of scintilla-and the alpha activity was counted on a PerkinElmer Tri-Carb wasof this solution were spiked and used inmL. procedure as then diluted to a final volume of 1000 the Aliquots HCl. The 0.5M HCl rinse wasGold LLT times added30 orthe of this solution were spiked and used in the procedure as tion vial. Ten mL Ultima collected in the scintilla- was and ® the simulated ground water matrix.2550TR/AB liquid scintillation counted Count Packard Tri-Carb ® tionalpha Ten mL Ultima Gold LLT was added and the vial. activity was counter. on a were60 minutes as indicated and the alpha region of interest was®set the simulated ground water matrix. alpha activity was counted on a Packard Tri-Carbtimes 2550TR/AB liquid scintillation counter. Countbetween 90 and or 60keV. The alpha/beta discriminator setting 2550TR/AB 500 minutes as indicated and Count times were 30 liquid scintillation counter. the alpha region(124) was30 or 60 minutes between procedure inalpha The alpha/ were determined following the 90 and 500 keV.instrument of interest was set as indicated and the the regioninstruction manual, set between 90(124)500 keV. The alpha/ beta discriminator setting and was determined follow- of interest was using 210Po as the pure alpha source and90 90 Y ing the procedure in the instrument instruction manual, Sr/betaas the 210 beta source. Vialswas determined follow- discriminator setting (124) used in the discriminator pure ing procedure had thethe instrument instructionSr/ Y as the using Po as the pure alpha source and 90 manual, 90setting the procedure in same composition as the actual pure Po assource. Vials used in the discriminator the 210 beta Y as settingsamplesprocedure the pure resin, 1source andHCl, and the mL using (i.e., 0.5 g actinide alpha mL 0.5M Sr/as 10 actual 90 90 had theused in composition pure Gold LLT). Blank beta source. Vials same the discriminator settingUltimasamples (i.e., 0.5samples were prepared as follows: 0.5 g procedure had the same compositionmL 0.5Mactual and g actinide resin, 1 as the HCl,actinide10 mL1 mL 0.5 M HCl, andBlank samples were prepared resin, Ultima Gold LLT). 10 samples (i.e., 0.5 g actinide resin, mL Ultima Gold LLT were 1 mL 0.5M HCl, and Figure 3.added to afollows:Gold LLT). Blank samples0.5 Mprepared in 10 mL Ultima 0.5 g actinideDirect spikes were prepared 10 as glass scintillation vial. resin, 1 mL were HCl, and Figure 3. Eichrom Dipex extractant. Eichrom Dipex extractant. as follows: 0.5 g actinide resin, 1 mL 0.5 M HCl, and 10 Figure 3. Eichrom Dipex extractant. Page 2 – Application Note Page 2 – Application Note 2
  3. 3. Table 1. Ground water composition. Table 1. Ground water composition. Table 1. Ground water composition. Results and Discussion Results and Discussion Table 1. Ground water composition. Percentageand Discussion Results uptake of various spikes of alpha emitters of Percentage uptake of various spikes of alpha emitters of interest interest were measured using the procedure, previously were measured using the procedure, previously described. 241Am, Resultsof500Am ofof variouswith aprocedure, emitters time Percentage241Am, 234/238U,used.spikes226Ra were used. The described. uptake were 232ThThe uptake of Am and Discussion the 30 alphaofcontact of and of and mL and 234/238U from 500minute previously 234/238 U, 232Th and 226Ra 241 uptake were measured using interest 241 234/238 U from DI water mL DI water is shownain Tables 2of234/238U, 232Th is shown in emitters2of with 30 241Am, contact spikes of alpha Tables and described.minuteand 3. time and 226Ra were used. The Percentage uptake various uptake of 241Am and 234/238 the procedure, of DI water 3. interest were measured usingU from 500 mLpreviously described. 241minute contact Th and 226Ra wereTables the with a 30 Am, 234/238U, 232 time is shown in used. 2 and Americium uptake was 234/238 excellent asexpected fromThe uptake of behavior of 241Am on241 500 wasresin. The uranium Americium uptake was U fromwas mL of DI water 3. expected from excellent as 241 Am and the theoretical contact time isAm on in Tables 2 and theoretical with a 30 minute behavior of the actinide actinide resin. shown the recoveries were uptake expected. Sinceas as expected. Since The uranium recoveries were not was expected from 3. Americium not as was excellent thermodynamically, the actinidetheoretical behavior actinideall of the uranium, resin. thermodynamically, the of up resin should have the resin should have taken241Am on the actinide taken Table 3. Uptake of 234/238U at 30 minute contact time. we The uraniumuranium, wewere as was expected from to Americium uptake was excellent notkinetic issuethere was up all of the recoverieswas some as expected. Since evaluated whether there evaluated whether related Table 3. the theoretical issue related to uptake onto the have of some kineticbehavior of 241Am resin actinide timeCor- thermodynamically, the actinideon theshould resin.taken Uptake of 234/238U at 30 minute contact time. uptake onto the resin. Correspondingly, the contact resin. respondingly, the contact evaluated whether Since up all of the uranium, we time of the sample with the The uranium the actinide resin was extended. Inthere was Table 3. the sample withrecoveries were not as expected. Table 4, thermodynamically, related to uptakeshould contact times some kinetic issue extended. resin onto4, have uranium actinide resin was actinide In Table the resin. Cor- the taken Uptake of 234/238U at 30 minute contact time. the respondingly, the thevarious sample contact times are up spike recoveries at we evaluated whether there wasthe uranium spike recoveries at time of sample contact various the sample with all of the uranium, Table 3. shown. are actinide resin was extended. In Table 4, the uranium shown. some kinetic issue related to uptake onto the resin. Cor- Uptake of 234/238U at 30 minute contact time. respondingly, the contact time samplesample with the spike recoveries at various of the contact times are shown. actinide resin was extended. In Table 4, the uranium spike recoveries at various sample contact times are shown. Table 4. Effect of contact time on 234/238U spike recovery. Table 4. Effect of contact time on 234/238U spike recovery. Table 2. Table 4. Uptake of 241Am (91.6% efficiency). Effect of contact time on 234/238U spike recovery. Table 2. Table 4. Uptake of 241Am (91.6% efficiency). Application Note Effect of contact time on 234/238U spike recovery. – Page 3 Table 2. Uptake of Am (91.6% efficiency). 241 Table 2. Uptake of 241Am (91.6% efficiency). Application Note – Page 33 Application Note – Page 3
  4. 4. The data indicatesindicates a relationshipcontact time and time The data a relationship between between contacturanium spike recovery. At recovery. At four hours the and uranium spike four hours contact time, contact time,recovery is quantitative. quantitative. contact period represents the recovery is The 18 hour The 18 hour contact periodovernight (unattended) contact of the resin with the sample. resin represents overnight (unattended) contact of theUnattended operations which can be carried out overnight can be with the sample. Unattended operations which are carried out overnight are attractive to routine productionattractive to routine production laboratories because of the laboratories because of the effective use of space andeffective use of space and time. This contact time period was time. This contact time period was chosen for all futurechosen experiments. experiments. Based in Table 4, it is expected for all future Based on the data on the data in Table4, it is expected that four hour contact time is also adequate. re- that four hour contact time is also adequate. Spike coveries of thorium and radium from DI water (18 hourSpike recoveries of thorium and radium from DI water (18 hourcontactcontact time) were acceptable. See Table 5. time) were acceptable. See Table 5.The one lowone low recovery forrepresented a sample in sample The recovery for thorium thorium represented awhich there was non-quantitative transfer of the actinide resin ac- in which there was non-quantitative transfer of thefrom the filter resin from the filter paper to The next step in the tinide paper to the scintillation vial. the scintillation vial. The next step in the evaluation of this procedure was toevaluation of this procedure was to test it on samples of the test it on samples of the simulated ground water matrix. Table 5. Spike recoveries with 232Th and 226Ra. Table 5. See Tables 6 and 7.simulated ground water matrix. See Tables 6 and 7. Spike recoveries with 232Th and 226Ra. The data indicates a relationship between contact timeAll the actinides show good uptake from 500 mL samples. All uranium spike recovery. At four hours contact time, and the actinides show good uptake from 500 mLThorium recoveries, while not quantitative, werenot quantitative, samples. indicates a relationship18 hour contact period the data Thorium recoveries, between contact time Therecovery is quantitative. Thewhile equivalentto the recoveries observed fromrecoveries Radium recoveries,resin were equivalent to recovery. At four hours contact time, and uranium spike the DI water. observed from DI wa- represents overnight (unattended) contact of thehowever, were poor recoveries, however, were poor (seecan be ter. recovery (see Table 7). As The 18be predicted period withRadium is quantitative. might hour contact Table the the sample. Unattended operations whichfrom the data in Table 7,predicted from thetoin the simulated the 7). As might be the calcium presentcontact Table 7, carried out overnight are attractive data in of the resin represents overnight (unattended) routine productionground calcium present in the simulated ground which matrix, with the sample. Unattended operations water canand laboratories because of prevent (or possiblyof space be water matrix, appears to the effective use block) theuptake appearsout contact timepossiblywas to routine production carried to prevent (or period block) the uptake future of radium overnight are attractive chosen for all of ra- time. Thison the actinide resin. Subsequent experiments dium on the actinide resin. Subsequent experiments fromfrom 100 mL samplesBased on the data in Table 4, ofis expected experiments. becausesimulated matrix showed much and laboratories of the of the effective use it space 100 mL samples of thetime is wasmatrix showed much time. This contact time simulated adequate. calcium that four hour contact period also chosen for Spike re-better uptake,uptake, probablythe lower overall level of all future better probably due on the datathe lower overall(18 hour experiments. Based anddue to from DI water expected level of to coveries of thorium radiumpresent. The results are equivalent to thein Table 4,5. isto the DI it calciumtime) were acceptable.are equivalent Spike re- contact present. The results alsowater recoveries in See Table DI that four hour contact time is adequate.Table 5. See Table 8 for these results. See Table 8 for these re- water recoveries in Table 5. coveries of thorium and radium from DI water (18 hour sults. time) recovery for thorium represented a sample The one low were acceptable. See Table 5. contact in which there was non-quantitative transfer of the ac-The final test of the method was to analyze actual Table 6.environmentalresin from the method was to the scintillationenvi- The finallow recoveryhad been previously characterized The one test of the for paper to analyze actual vial. tinide samples whichfilter thorium represented a sample U uptake from simulated ground water matrix. 234/238for gross alpha activityin thewhich had been previously charac- ronmentalthere by theevaluation of this procedure the ac- in which samples traditional evaporation/ GPC The next step was non-quantitative transfer of was tomethod. Twenty-four (24)the the simulated the traditional matrix. terizedresingross alpha activity by ground water evapo- tinide for from samples paper to the scintillation test it on samples of filter were received from the vial. Table 5. ration/GPC 6 andSurveys National Watersamples Lab re- The Tables method. Twenty-four (24) Quality were See next step in 7.United States Geological the evaluation of this procedure was to Spike recoveries with 232Th and 226Ra. ceivedon samplesUnited States Geological Surveys Na- from the of(NWQL)testArvada, Colorado.the simulated ground water matrix. in it tional Water Quality Lab (NWQL) in Arvada, Colorado. These samples represented Table 6. 234/238U uptake from simulated ground water matrix. Table 5. All Tables 6 and 7.show good uptake from 500 mL the actinides See samples from across the United States. Totalground These samples represented ground water samples from water samples. Thorium recoveries, while not quantitative, Spike recoveries with 232Th and 226Ra.dissolved solidsthe United States. been measured onfromof(TDS) across (TDS) content had Total dissolved solids DI wa- were equivalent to show good observed ten All the actinides the recoveriesuptake from 500 mLthese samples, ranging asmeasured on ten of these samples,Table content had been high as 1700 mg/L. Overall the results samples. Thorium recoveries, while poor (see rang- ter. Radium recoveries, however, werenot quantitative, ing As high as 1700 mg/L.from the the results obtained 7). as might be to the recoveries observed method the were equivalent predicted Overall data in Table 7,obtained for the 24 samples using the proposed LSC from DI wa-agreed for the 24 samplesthe simulated ground water method extremely well with using the proposed LSC matrix, calcium present in thosehowever, were poorusing Table ter. Radium recoveries, previously obtained (see agreed might be predicted in Table 9 previously obtained appears to prevent (or with those data in Table 7). As extremely wellpossibly the are the results of ra-the GPC method. The data shown from block) the uptake 7, the using on the dium thepresentmethod. The data shown intotal 9 are calcium GPC in resin. Subsequent experiments from Tabledetermined by each actinidethe simulated ground water matrix, method along with the 2 sigma the results determined by each method theshowed of ra- 100 mL to prevent (or possibly block) along with much appears samples of the simulated matrix uptake the 2propagated uncertainty (TPU). uncertainty (TPU). sigmaon the propagated due to the lower overall level of dium total actinide resin. better uptake, probably Subsequent experiments from calcium present. The results are matrix showed much 100 mL samples of the simulated equivalent to the DI water uptake, probably due5. See lower overallthese re- better recoveries in Table to the Table 8 for level of Table 7. sults. calcium present. The results are equivalent to the DI 232 Th and 226Ra uptake from simulated ground water matrix. Table 7. 232Th and 226Ra uptake from simulated ground water matrix. water recoveries in Table 5. See Table 8 for these re- Table 6. The final test of the method was to analyze actual envi- sults. 234/238 U uptake from simulated ground water matrix. ronmental samples which had been previously charac- Table 6. terized for gross the method was to analyze actual envi- The final test of alpha activity by the traditional evapo- 234/238 U uptake from simulated ground water matrix. ration/GPCsamples which had been previouslywere re- ronmental method. Twenty-four (24) samples charac- ceived for gross United States Geological Surveys Na- terized from the alpha activity by the traditional evapo- tional Watermethod. Twenty-four (24) samples were re- ration/GPC Quality Lab (NWQL) in Arvada, Colorado. These samples represented ground water samples from ceived from the United States Geological Surveys Na- acrossWater Quality Lab (NWQL) in Arvada, Colorado. tional the United States. Total dissolved solids (TDS) content had been measured ground these samples from These samples representedon ten of water samples, rang- ing as4the Application Note dissolved solids (TDS) across highUnited States. Total Page – as 1700 mg/L. Overall the results obtained for the had samples using on ten of these samples, rang- content 24 been measured the proposed LSC method agreed high as 1700 mg/L. Overall previously obtained ing as extremely well with those the results obtained using the GPC method. The data shown LSC method for the 24 samples using the proposed in Table 9 are 4 the results determined by each method along with the 2
  5. 5. Table 8. 226R uptake from 100 mL simulated ground water matrix. Table 8. Table 8. R uptake from 100 mL simulated ground water matrix. 226 R uptake from 100 mL simulated ground water matrix. 226 Table 9. Comparative results for NWQL water samples using GPC and LSC. Table 9. Table 9. Comparative results for NWQL water samples using GPC and LSC. Comparative results for NWQL water samples using GPC and LSC. Application Note – Page 55
  6. 6. Figure 4. Comparison of paired results at varying TDS levels: LSC (left)Figure (right). and GPC 4. Comparison of paired results at varying TDS levels: LSC (left) and GPC (right).TDS content are shown in Figure 4. In this figure, the gross (75 mBq/L)can be achieved with a 60 minute count time and aalpha activity for each the ten which hadby the characterized for The results for sample measured been two methods References 100mL sample. Process samples (non-environmental) in whichis plotted oncontent are shown in Figure 4. In this figure, the TDS the y-axis versus the TDS content on the x-axis. the alpha activity is due only to the actinides and not to radium gross alpha activity for each sample measured by the 1. Horwitz, E.P. et al. (1993). Separation andResults by the two methods are plotted in pairs: the left-hand can bepreconcentration of actinidesusing 500 mL aliquots. ex- analyzed by this procedure from acidic media by two methods is plotted on the y-axis versus the TDS con-data point in each x-axis. the LSC result; the right-hand dataplot- tent on the pair is Results by the two methods are Detection limits chromatography. AnalyticaChimica lower, in traction for these sample sizes would be much Acta.point in each pairs: the left-hand data point in each pair2is the 281:361-372. ted in pair is the GPC result. The error bars reflect the range of 15 mBq/L.sigma total propagatedright-hand data point in each interval). LSC result; the uncertainty (95% confidence pair is the 2. Burnett, W. and Cable, P. (1995). Determination of ra-Note that in result.case, the agreement between the total propa- GPC every The error bars reflect 2 sigma 95% dium-228 in natural waters using extraction chromato- References resins. Radioactivity & Radiochemistry. Vol 6. graphicconfidence intervals is excellent and appears interval). Note that gated uncertainty (95% confidence to be unaffectedby the in everyof dissolvedagreement between the 95% confi- amount case, the solids in the samples. Also the TPU 1. Horwitz,3:36-44.al. (1993). Separation and preconcentration No. E.P. et dence intervals is excellent and appears to be unaffectedof the LSC results is lower in all cases. 3. actinides from et al. (1997). Dipex: A newchromatography. of Horwitz, E.P. acidic media by extraction extraction chro- by the amount of dissolved solids in the samples. Also Analytica Chimica Acta. 281:361-372. separation and matographic material for the the TPU of the LSC results is lower in all cases. preconcentration of actinides from aqueous solution. Re- 2. Burnett, W. and Cable, Polymers. Determination of active & Functional P. (1995).Conclusion ConclusionIn conclusion, the proposed method for measuring gross alpha radium-228 in natural waters using extraction chromatographic resins. Radioactivity & Radiochemistry.activityIn conclusion,chromatography and liquidmeasuring gross Vol 6. No. 3:36-44. by extraction the proposed method for scintillationcounting is quick and by extraction chromatography and liquid 3. Horwitz, E.P. et al. (1997). Dipex: A new extraction alpha activity allows for lower detection limits withshorterscintillation counting is quick andactinidesfor lower is count times. The measurement of allows elements de- chromatographic material for the separation andexcellent using 500 mL sample aliquots.times. Themeasurement tection limits with shorter count Accurate measurement of actinides elements is excellent using 500 mL sample preconcentration of actinides from aqueous solution. of alpha activity due to radium requires a sample aliquot of aliquots. Accurate measurement of alpha activity due to Reactive & Functional Polymers.100 mL if calcium content is high. A detection limit of 2 pCi/L radium requires a sample aliquot of 100 mL if calcium content is high. A detection limit of 2 pCi/L (75 mBq/L)PerkinElmer, Inc.be achieved with a 60 minute count time and a 100 can mL sample. Process samples (non-environmental) in940 Winter StreetWaltham, MA 02451 USA P: (800) 762-4000 or the alpha activity is due only to the actinides and which not to radium can be analyzed by this procedure using(+1) 203-925-4602www.perkinelmer.com 500 mL aliquots. Detection limits for these sample sizes would be much lower, in the range of 15 mBq/L.For a complete listing of our global offices, visit www.perkinelmer.com/ContactUsCopyright ©2011, PerkinElmer, Inc. All rights reserved. PerkinElmer® is a registered trademark of PerkinElmer, Inc. All other trademarks are the property of their respective owners.009601_01 Page 6Printed in USA – Application 2011 April Note

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