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It seems probable that almost any particular purification requirement can be met by one or other of these methods, or by some combination of them. XD COLLECTION OF DETAILED RADIOCHEMICAL PROCEDURES (arranged in chronological order) Procedure 1 Procedure by: J. W. Irvine; J. Phys. Chem. 46, 810 (1942) Type pf procedure: With carrier Target material: Cyclotron targets Radioactivity production method: Cyclotron bombardment Purification method: Distillation of AsC1j. Approx. chemical yield: High Time taken for procedure: Not given Decontamination: "Free from radioactive contamination". 1. Place target material in C1aisen flask and add 0.5-2 mg sodium arsenite carrier. Add 25 ml. 12 M HC1 heat and add 30% H202 dropwise until target is dissolved (10-20 ml ^02 needed and the operation takes ~ 5m). 2. Distil off Ge with frequent addition of a few drops of Mfl2 to m'nimise reduction of As(V) to As(III) with consequent loss of AsC1j. When solids precipitate from the solution in the flask add 10 ml 12 M HC1 and repeat the distillation. Add glass beads or tile to prevent bumping if necessary. 3. Add 15 ml 12 M HC1 and then 10 ml 5 M HBr to reduce As(V) to As(III) and distil As into 10 ml of distilled water in an ice bath until bromine fumes appear. Add 10 ml 12 M HC1 + 5 ml 5 M HBr and repeat distillation until bromine fumes again appear. 4. Precipitate As metal from distillate by adding 1-2 g solid ammonium hypophosphito and warming on a steam bath 5-10 m. Do not heat too long or precipitate will coagulate too much: if this happens add a few mg of Duponol or other wetting agent. 5. Filter without allowing air to be sucked through the precipitate until it has been washed with 5-10 ml freshly boiled distilled water and with acetone. (This prevents oxidation). Procedure 2 Procedure by: H. Lanz and J. G. Hamilton, U.S.A.E.C. unpublished report \1DDC 15% (1948). Type of procedure: Carrier free Target material: Ge metal Radioactivity production method: 19 MeV deuterons Purification method: Distillation of Approx. chemical yield: Not given Time taken for procedure: Not given Decontamination: Not given 25

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1. After cooling for several days, dissolve Ge metal by refluxing in aqua regia for 24 h. 2. Add excess HC1 to destroy HNOj, bubble chlorine gas through to keep As in pentavalent state, and carry out four distillations of GeC1^ from solution, 7N HC1 being added each time just before solution goes to dryness. On last distillation add 50 mg Ge carrier to ensure a complete removal of radioactive Ge. 3. Stop chlorine stream, add 48% HBr and distil off AsC1j and collect in conc. HNOj. Two HBr distillations are needed to ensure complete As removal. 4. Evaporate HNOj distillate to dryness on a steam bath, converting As to arsenic acid. Take up As residue in 0.1 N HC1. Procedure 3 Procedure by: H. Hopkins; Reported by W.W. Meinke, U.S.A.E.C. unpublished report UCRL-432 Procedure 33-1. (1949). Type of procedure: With carrier Target material: As metal Radioactivity production method: 190 MeV deuterons Purification method: ^S2^5 Precipitation + Ge distilation. Approx. chemical yield: ~ 80%. Time taken for procedure: 1 h. Decontamination: Radiochemically pure by factor of ~ 100. 1. Dissolve As in conc. HNOj + HC1. Add carriers of Se and elements below (2 mg). 2. Evaporate to near dryness to remove excess HNOj, Make up to 5 ml with 1 N HC1, add N^OH.HC1 until Se starts to precipitate from hot solution. Add 1 ml 1 N KI, heat 5 m, and centrifuge off Se. 3. Add HC1 to make 3 N solution containing 10 mg As/ml. 4. Pass H2S take hot solution and stir vigorously. Repeat. 5. Centrifuge off precipitate and wash with water. 6. Dissolve As and Ge salts with dilute KOH, leaving CuS behind. 7. Separate Ge by distilling from 20 ml of boiling 6N HC1 in a slow stream of chlorine. When 14 volume remains, add 6N HC1 and repeat. 8. Precipitate As2S5 from 3N HC1. Remarks: Se and As may first be removed together by volatilising the elements along a quartz or pyrex tube. 26

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Procedure 4 Procedure by: H. Goeckermann; Reported by W.W. Meinke, U.S.A.E.C. unpublished report UCRL-432, Procedure 33-2 (1949). Type of procedure: With carrier Target material: ~ Ig Bi metal Radioactivity production method: 184" cyclotron, all particles. Purification method: Distillation of AsC1j + sulfide precipitation. Approx. chemical yield: Not given. Time taken for procedure: Few hrs. Decontamination: Factor ~ 10 from fission and spallation products. 1. To aliquot of HNOj solution of target, add 10 mg As and ~ 10 mg Ge carriers: boil nearly to dryness, take up in 15 ml 6N HC1, add crystal of NH^I, and saturate with F^S at ice temperature: wash with F^S saturated 6N t^SO^ 2. Dissolve precipitate in 1 ml conc. NH^OH and dilute to 10 ml (discard any residue). Transfer to a glass still and add ~ 10 mg each of Te, Sb and Sn carriers. Add 10 ml conc. HC1 and distil all but 5 ml in a chlorine stream into 5 ml water in an ice bath. Add 5 ml conc. HC1 and ~ 10 mg Ge to residue in flask and repeat distillation. 3. To residue from GeC1^ distillation, pass in HC1 gas to remove C^, add 1 ml saturated CuC1 in conc. HC1, and distil over 5 ml in an HC1 stream into 10 ml conc. HC1 in an ice bath. Add CuC1-HC1 to residue and distil further. 4. Pass r^S into distillate and centrifuge out As2Sj. Dissolve in 1 ml conc. NH^OH, add ~ 10 mg Te, Sb and Sn carriers and repeat AsC1j distillation. 5. Precipitate As2Sj again, dissolve in 1 ml conc. NH^OH, add 10 ml conc. HC1, saturate with r^S, filter, wash with water, ethyl alcohol and ether, dry 10 min at 110°C. Weigh as As2Sj (16.4 mg per 10 mg As). Remarks: Cylinder HC1 and C\^ are rather unpleasant and corrosive to work with. Procedure is fairly slow. Ge can be separated along with As as indicated. Procedure 5 Procedure by: A.S. Newton: Reported by W.W. Meinke, U.S.A.E.C. unpublished report UCRL-432, Procedure 33-3 (1949). Type of procedure: With carrier Target material: 0.1-lg Th. metal Radioactivity production method: 60" cyclotron a particles Purification method: Distillation of Approx. chemical yield: Undetermined. Time taken for procedure: ~ 2-3 h. Decontamination: 105-106. 27

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1. Dissolve Th metal in conc. HC1 + a few drops 0.2 M (NH4>2SiF6 to clear up black residue: Dilute HC1 to 2N and take aliquot. 2. Add 10 mg Ge and As carriers and make up to 15 ml. 6N in HG1. Add crystal of NH4I and treat with H2S at ice temperature. Wash with 6N H2S04 saturated with H2S. 3. Dissolve precipitate in 1 ml conc. NH^OH and dilute to 10 ml. Discard any residue. Transfer to glass still and add 10 mg each of Te, Sb and Sn carriers. Add 10 ml conc. HC1 and a crystal of KCIOj. Distil all but 5 ml into 5 ml water in an ice bath. 4. Add 5 ml conc. HC1, 10 ml Ge carrier and KC1Oj to remaining solution in still and repeat. 5. To residue from GeC14 distillation, pass in HC1 gas to remove C12- 6. Add 1 ml saturated CuC1 solution in conc. HC1 and distil over 5 ml in HC1 stream into 10 ml conc. HC1 in ice bath. 7. Add CuC1 -HCl and distil again. Pass H2S into distillate and precipitate As2Sj. 8. Dissolve in 1 ml conc. NH^OH, add 10 mg. Te, Sb and Sn carriers and repeat distillation. Precipitate As2Sj again, dissolve in 1 ml conc. NH^OH, add 10 ml conc. HC1 saturated with H2S. Filter, wash with water, ethy alcohol and ether. Dry at 110°. Weigh as As2Sj. Procedure 6 Procedure by: L. Winsberg, Radiochemical studies: the fission products; Book 3i Paper 228, pp. 1440; McGraw-Hill; New York, 1951. Type of procedure: With carrier Target material: Freshly irradiated uranium Radioactivity production method: Reactor neutrons Purification method: Distillation of AsC1j Approx. chemical yield: Not given. Time taken for procedure: Not given. Decontamination: > 10 for As . 1. To an appropriate amount of neutron-irradiated uranyl nitrate solution in a 50 ml centrifuge tube, add 2 ml each of standardised Ge and As carrier solution and boil nearly to dryness to remove excess HNOj. Take up in 15 ml 6N HC1, place in an ice bath, and pass in H2S, adding a few crystals of NH^I to aid precipitation if necessary. 2. Dissolve mixed precipitate in 1 ml conc. NH4OH and dilute to 10 ml, add 0.5 ml Zr carrier solution. Centrifuge and discard Zr(OH)4 precipitate. Add 10 ml conc. HC1 and pass in H2S. Centrifuge and wash the precipitate with 10-15 ml. of H2S04-H2S solution. Add 5 ml H20 and heat to expel excess H2S. Add 1 ml conc. NH^OH to dissolve any GeS2 or As2Sj remaining, and transfer to a still. Add 10 mg. each of Te, Sb and Sn carriers. (Disregard the sulfides that form in the still). 28

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3. Add 10 ml. conc. HC1, pass in C12 gas, and distil all but 5 ml. of the solution into a centrifuge tube containing 5 ml. of H20 cooled in an ice bath. Set aside the distillate for Ge separation, if desired. 4. Add 5 ml. conc. HC1 and 1 ml. Ge carrier solution, and distil GeCL again, as in step 3. 5. Remove C12 gas, and pass in air. Add 1 ml. of a saturated solution of CuC1 in conc. HC1 and 5 ml. conc. HC1 and distil to about 1 ml., taking care not to heat to dryness or Sb may distil. Add 5 ml. of conc. HC1 and 1 ml. of CuC1-HC1 solution, and distil again to about 1 ml. Catch the distillates in 10 ml. of H20 in a centrifuge tube cooled in an ice bath. 6. Pass H2S into the combined distillate to precipitate As2Sj. Centrifuge, dissolve in 1 ml. NH^OH, add 10 mg. each Te, Sb and Sn and distil as in step 5. 7. Precipitate the As in the distillate as As2Sj, dissolve in 1 ml. conc. NH^OH and dilute to 10 ml. (If a precipitate returns, centrifuge and discard it). Add 10 ml. conc. HC1, pass in H-S to complete the precipitation and then filter. Wash several times with H20, ethyl alcohol, and ether. Dry at 110° for 10 m. Weigh as As2S3. Procedure 7 Procedure by; A. A. Smales and B. D. Pate: Anal. Chem. 24 717 (1952). Type of procedure: With carrier Target material: General samples, including GeC^. Radioactivity production method: Reactor neutrons Purification method: Distillation of AsC1j. Approx. chemical yield: Not given Time taken for procedure: Not given Decontamination: Not given 1. Irradiate simultaneously for period of up to 30 h., sealed silica containers, each about 0.5 ml capacity and containing a weighed amount (approx. 0.1 ml.) of the solution under test, and also one containing standard arsenic solution (1 fig As/ml). Transfer contents of each silica container to a distillation flask together with ~ 0.5 g NaOH. 2. Add by pipette 5 ml. sodium arsenite solution containing 10 mg As/ml and wash this, together with a few drops of H202 solution through the dropping funnel into the flask. Warm gently and add gradually via the dropping funnel 10 ml. conc. HC1 to which has been added 5 ml. of 30% H202, followed by a little distilled water. 3. Distil down to 2-3 ml., adding H202 dropwise from time to time. Repeat twice more the addition of acid and peroxide and distillation to a small volume. 4. Add 10 ml. 40% HBr and distil AsC1j into 10 ml. cold water. Distil to low volume and repeat addition of HBr and distillation twice more. 29

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5. Add to distillate a few mg of Ge carrier and 1/2 g solid ammonium hypophosphite: heat to 90-95°C for 30 m to precipitate and coagulate As metal. 6. Centrifuge, wash with water and mount. 7. Standard and sample are counted under identical conditions to reduce counting corrections. Procedure 8 Procedure by: A. A. Smales and B. D. Pate: Analyst 77 188 (1952) Type of procedure: With carrier Target material: Sea water + trace As Radioactivity production method: Reactor neutrons. Purification method: Distillation of AsC1j Approx. chemical yield: Not given Time taken for procedure: Not given Decontamination: Not given 1. Transfer activated sea water sample to the distillation flask and add 1 ml 10% NaOH solution, followed by 5.0 ml of sodium arsenite carrier solution (10 mg As/ml). Add a few drops 30% F^O^ and wash down dropping funnel with a little water. Reduce volume to ~ 2 ml by boiling and add a mixture of 10 ml conc. HC1 + 5 ml 30% K^C^ which is freely evolving chlorine. Distil to 2 ml. This procedure destroys any organic- arsenic compounds which may be present. 2. The remainder of the procedure is identical with steps 4-7 of procedure 7. Procedure 9 Procedure by: A. A. Samles and B. D. Pate; Analyst 77 196 (1952). Type of procedure: With carrier Target material: Biological material + trace As Radioactivity production method: Reactor neutrons Purification method: Distillation of AsC1j Approx. chemical yield: Not given Time taken for procedure: Not given Decontamination: Not given 1. Transfer weighed sample after irradiation to a 250 ml beaker. Add 5.0 ml of a standard arsenic solution (10 mg/ml As) followed by 2 ml 30% f^C^, 5 ml HNOj (S.G. 1.42), 5 ml H2S04 (S.G. 1.84) and 2 ml HC104. Gently heat solution until initial reaction subsides and then more strongly, adding further HNOj if necessary to prevent charring. Finally heat until F^SO^ + HC104 fumes appear and until all organic matter is completely oxidised. 30

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2. Dilute, after cooling, to 20 ml, add 20 ml HC1 (S.G. 1.19) and precipitate As by adding Ig solid ammonium hypophosphite and heating to 90-95°C to coagulate As. 3. Centrifuge of precipitate, wash with water, and dissolve by adding 5 ml water, 2 ml 1^02 and 2 ml HC1. Transfer solution to distillation vessel and proceed with distillation etc. as in procedure 7. Procedure 10 Procedure by: L. Salmon; U.K.A.E.A. unpublished report AERE C/M 154 (1952). Type of procedure: Target material: Radioactivity production method: Purification method: Approx. chemical yield: Time taken for procedure: Decontamination: With carrier Sulfur + trace As. Reactor neutrons Distillation of AsC1- Not given Not given Not given 1. Dissolve sulfur target in a mixture containing 10 ml CC1^, 1 ml bromine, 5 ml HN03 (S.G. 1.42) and 5.0 ml. As carrier (made by dissolving 1.32g As203 in a little NaOH and making up to 100 ml with water: 1 ml = 10.0 mg As). Warm gently until all sulfur is dissolved, evaporate off CC1^f bromine gently and finally evaporate to fumes of H2SO4. Cool, add, 5 ml water and 1 ml 3N NaOH. Transfer to distillation flask. 2. Distil down to 2 ml and reject distillate. Add 10 ml conc. HC1 + 5 ml 100 vol ^2^2. Again evaporate to 2 ml and reject distillate. 3. Add 10 ml 40% HBr and distil into 10 ml of cold water. Repeat with 10 ml of HBr twice more. 4. Add l-2g solid ammonium hypophosphite to distillate and warm to 90°-95° for 30 m to precipitate As metal. Centrifuge and wash with water. Mount. Procedure 11 Procedure by: J. G. Cuninghame; Phil. Mag. 44 900 (1953). Type of procedure: Target material: Radioactivity production method: Purification method: Approx. chemical yield: Time taken for procedure: Decontamination: With carrier Natural uranium Reactor neutrons Evolution of AsH3 + AsC1j distillation 35% 45m 77 78 7Q Gives radiochemically pure As , As and As from fresh mixed fission products. 31

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1. Add irradiated uranium solution to standardised arsenite carrier in dilute r^SO^, oxidise to As(V) with potassium bromate and then reduce to As(III) with potassium metabisulphite. 2. Place in operating arsine generator with mercury cathode* and generate arsine for 15 m with cell at ~ 80°C at cathode current density of ~ 2.5 amp/cm . Pass AsHj through lead acetate solution to absorb any Se and Te and collect in 3. Add Sb carrier to AgNOj, followed by NaC1, filter and carry out ferric hydroxide scavenge on supernate. 4. Make supernate 1:1 in HC1 and add Sb hold back carrier. Precipitate As metal by adding ~ Ig solid ammonium hypophosphite and bringing solution to the boil. 5. Dissolve As metal in brominated HC1 and distil As from concentrated HBr in presence of Sb, Te and Sn hold-back carriers. Collect As in concentrated HC1. 6. Reprecipitate As metal, filter and mount. * As used by D. Rogers and A. E. Heron; Analyst 71 4 '4 (1946). Procedure 12 Procedure by: J. A. James and D. H. Richards: Anal. Chem. Acta 15 118 (1956). Type of procedure: With carrier Target material: Tungsten metal + trace As Radioactivity production method: Reactor neutrons Purification method: Distillation of AsC1j Approx. chemical yield: Not given Time taken for procedure: Not given Decontamination: Not given 1. Irradiate simultaneously W sample and As standard. Transfer W sample to KOH-F mixture containing 60mg As20j carrier and warm until dissolution complete ( ~ 30 m). 2. Distil to low volume, discard distillate, acidify with HC1-F^C^, and again distil to low volume. Discard distillate. 3. Add HBr and distil into cold water. 4. Take distillate, add inactive WOj and repeat the HBr distillation. 5. Add a solution of sodium tungstate complexed with excess tartaric acid to distillate, then add solid ammonium hypophosphite and boil for 30 m to coagulate As. Centrifuge and mount. 6. Dissolve the As standard into a KOH-r^C^ solution containing a known amount of ~ 100 mg As20j and make up to 100 ml. Take a suitable aliquot of this solution and add to an alkaline peroxide solution containing 60 mg As-,0-,. Precipitate As and mount as in step 5. 32

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Procedure 13 Procedure by; O.R.N.L. Master Analytical Manual Method 5-110600 (1957). Type of procedure: With carrier Target material: Metals, alloys, fine chemicals, other solid materials or liquids + trace As. Radioactivity production method: Reactor neutrons Purification method: AsC1j distillation + As2Sj precipitation. Approx. chemical yield: 70% Time taken for procedure: Not given Decontamination: "Adequate" 1. Irradiate sample and standard As20j simultaneously and prepare for analysis as follows:- (a) Metals, alloys, fine chemicals, or other solid materials Transfer to 60 ml distilling flask and pipette in 2 ml standard As carrier solution. Add 25 ml conc. HC1 and heat to dissolve: during dissolving make repeated dropwise additions of 30% F^C^ until sample is completely dissolved. (b) Liquid samples Pipette aliquot into 60 ml distilling flask and add 2 ml standard As carrier. (c) Standard As2Oj Place 100 mg As20j in 100 ml volumetric flask, dissolve in 2M NaOH and dilute to mark. Mix, take aliquot and add to distilling flask, together with 2 ml standard As carrier. 2. Add to distilling flask 2-5 mg each of Fe, Co,Cu, Sr and Na carriers. Add 15 ml conc. HC1 + 10 ml 5M HBr and distil into 10 ml of water in an ice bath. When bromine fumes appear in distillate add 10 ml conc. HC1 + 5 ml 5M HBr to distilling flask and distil again. 3. Make distillate 1M in HC1 and precipitate As2Sj. Wash precipitate with 1M HC1. 4. Dissolve in small amount conc. HNOj; add 5 mg Se carrier and evaporate to dryness to remove excess HNOj. Take up in 10 ml 1M HC1 heat to near boiling and add 5M hydroxylamine hydrochloride dropwise until all Se is precipitated. Allow precipitate to settle and add a further 5 mg of Se. Centrifuge and wash with two 5 ml portions of hot water. Add washes to supernate. 5. Add 5 mg Sb carrier to combined supernate and add enough conc. HF to make 7M in HF by adding conc. HF. Cool and precipitate As2Sy Wash with two 5 ml portions of water. 33

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6. Precipitation of As (a) As2S3 Dissolve precipitate from step 5 in 1 ml. conc. NH^OH. Add 10 ml conc. HC1. Precipitate with H2S; wash with three 5 ml portions of water and three 5 ml portions absolute ethanol; dry at 110° for 15 m. (b) MgNH4As04.H20 (i) Dissolve precipitate from step 5 in 5 ml. conc. HNOj, transfer to 50 ml beaker and add 1-2 ml. bromine water. Heat to destroy sulfur and oxidise to As(V). (ii) Cool and add 10 ml. magnesium mixture to the solution. Neutralise with conc. NH4OH and add excess until a precipitate forms. Digest 15 m. (iii) Filter and wash with three 5 ml. portions 2.5% NH^OH, three 5 ml. portions of absolute ethanol and three 5 ml. portions ether. Dry at 110° for 30 m. Weigh as MgNH4As04.V$ H20. (c) As metal (i) Dissolve precipitate from step 5 in 0.5 ml. conc. HC1 + 0.5 ml. conc. HNOj + 1.0 ml. HC1O4. Heat for 5 m and fume. When fumes arise from top of tube, discontinue heating. (ii) Cool and add 10 ml. 6M HC1. Heat to boiling and add 5 ml. CrC12. Digest in steam bath until precipitate forms, then add additional 5 ml. CrC12. Heat 5 m more. (iii) Filter, wash with three 5 ml. portions water and three 5 ml. portions absolute ethanol. Dry at 110° for 15 m. Procedure 14 Procedure by: R. J. Prestwood; U.S.A.E.C. Unpublished report LA 1721 2nd ed. (1958). Type of procedure: With carrier Target material: Fissile material Radioactivity production method: Fission Purification method: Extraction of Asl, into CHCU + As2S, precipitation. Approx. chemical yield: 80% Time taken for procedure: 4h for quadruplicate analyses. Decontamination: ~ 6000 1. Make sample acid and precipitate As2Sj. Chief contaminants are Ge, Te, Mo and Cd. Fume with mixture of HN03/HC1/HC104 to remove Ge. 34

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2. Convert As to tri-iodide by treatment with HI and extract into CHC1j; Te, Mo and Cd are not extracted; the decontamination in this step is ~ 6000. 3. Wash solvent phase and back-extract As with dilute 142804. Repeat extraction and back-extraction. 4. Precipitate As2Sj and dissolve. Precipitate As by adding CrC^ and mount. Procedure 15 Procedure by: G. F. Shipman and 0. I. Milner; Anal. Chem. 30 211 (1958). Type of procedure: With carrier Target material: Hydrocarbon reforming catalyst + trace As Radioactivity production method: Reactor neutrons Purification method: Distillation of AsBrj Approx. chemical yield: Not given Time taken for procedure: 15 h for batch of four samples Decontamination: Not given 1. Place sample into nickel crucible and weigh. For each gramme of sample, add lOg Na202, mix intimately, and sprinkle a layer of Na20. on top of the mixture. Place in a muffle furnace at 500° ± 25°C for 1 h. Remove, cool and leach with ~ 30 ml water. Add 1:1 ^SO^ cautiously until precipitate of aluminium hydroxide redissolves and then add 5 ml excess. Transfer to 50 ml volumetric flask, cool and make up to the mark. 2. Place 20 ml conc. ^SO^ in a distilling flask and add 2.00 ml of carrier As solution (5.00 mg As/ml.) and an aliquot of the sample sufficient to give a final activity of 10,000 c.p.m. Rinse with two 2 ml washes. Finally add 2 ml 47% HBr. Bubble nitrogen at a rate of 1 bubble/s. Heat to 120°, and stop distillation when temperature begins to fall. 3. Make distillate 7-8N in HC1 and add 2-3g ammonium hypophosphite. Digest in steam bath 45 m. Filter and mount. Procedure 16 Procedure by: U. Schindewolf and J. W. Irvine; Anal. Chem. 30 906 (1958). Type of procedure: Carrier free Target material: Ge Radioactivity production method: Cyclotron Purification method: Anion exchange Approx. chemical yield: Not given Time taken for purification: Not given Decontamination: Estimated as > 10 from 6c 1. Dissolve Ge target in a few ml of conc. HC1/HNOj, heating in a steam bath if necessary. 2. Reduce As(V) and excess acid with SO2 and dilute to 0.25-2.5M HC1. 35

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3. Pass through anion exchange column equilibrated with dilute HF. For absorption of Ig of Ge, use a column 1.3 cm diameter, 25 cm. long. Elute As with about 5 column volumes of dilute HF. Concentrate eluate in steam bath if desired. Note: Volatile AsFj does not form as long as a liquid phase is present. However, with the disappearance of the last drop of solution, there is a substantial loss of activity. This loss can be eliminated by adding 1 ml. conc. HNOj to the solution to oxidise As to As(V), which remains on evaporation to dryness. Procedure 17 Procedure by: 1. J. Gruverman & P. Kruger; Inter. J. Appl. Rad. and Isotopes 5 28 (1959). Type of procedure: Target material: Radioactivity production method: Purification method: Approx. chemical yield: Time taken for purification: Decontamination: Carrier free Ge Ge72(d,n)As73: Ge73(d,2n)As73: Ge73(d,n)As74: Ge74(d,2n)As74. Distillation of AsC1j Recovery 90% Not given Product 98% (As7J + As'4). 1. Age Ge target, about 5g, 10-15 days to allow As to decay and dissolve in aqua regia. Evaporate nearly to dryness twice while passing chlorine gas through rapidly. 2. Dilute with 15 ml HC1 and transfer to distilling flask. Distil Ge into trap contain- ing 6N NaOH while passing chlorine through still. Evaporate to near dryness several times, with additions of HC1 between evaporations. A total of 25-35 ml is distilled. 3. Now distil As into ice-cooled water trap by adding 5 ml of a saturated solution of CuC1 to the still and passing HC1 gas through. Continue distillation until activity cannot be detected in the still. 4. Evaporate active distillate to desired volume while bubbling chlorine into the liquid. Procedure 18 Procedure by: H. Smith; Anal. Chem. 31 1362 (1959). Type of procedure: Target material: Radioactivity production method: Purification method: Approx. chemical yield: Time taken for purification: Decontamination: With carrier Biological tissue + trace As Reactor neutrons Evolution of AsHj Not given Not given Not given 1. Wash digested sample into 200ml. flask and add 10 p.g. As carrier, followed by 2 ml. conc. H2S04, 4 ml. conc. HC1, 5 ml of a 15% solution of Nal, and 0.4 ml. of a 40% solution SnC12 in 50% HC1. Dilute to 150 ml. and place in water bath for 5m. 36

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2. Add lOg 16-22 mesh zinc pellets and allow evolution of hydrogen to continue 15m. Pass evolved AsHj through lead acetate on a cotton wool filter, and collect As in 1 ml. of a 1.6% solution of Hg C12. Add 5 ml. of 0.001 N iodine in 40% Nal solution to help solution of any solids formed. Wash delivery tube well into trap. Procedure 19 Procedure by: A. Kjelberg & A. C. Pappas; J. Inorg. Nucl. Chem. 11 173 (1959). Type of procedure: With carrier Target material: 2.0g uranyl nitrate Radioactivity production method: Reactor neutrons Purification method: ^6^6 extraction Approx. chemical yield: Not given Time taken for purification: ~ 2m for separation from Ge by solvent extraction steps. Time not given for full procedure. Decontamination: > 10 for Ge: "sufficient" for other fission products. 1. Dissolve sample (without heating) in 6.5 ml water to which is added 20 mg Ba + 20 mg As(V) carriers and 3 drops conc. HC1. Transfer to separating funnel containing 20 ml. CgH^. Add 4.5 ml. 10.2 N HI (commercial 67%) and shake 10 s. Reserve aqueous for Ba. 2. Back extract with 6.5 ml. water for 30 s and wash aqueous phase with 10 ml C^H/- for 5 s. 3. Repeat extraction and back extraction. 4. Add 10 mg Te(IV) carrier + 3.5 ml conc. HC1. Heat nearly to boiling and reduce with S02. Filter Te and boil supernate to drive off SC^. Cool and add 20 ml. conc. HC1. 5. Precipitate As with ^S, centrifuge,and wash with 6N HC1 saturated with ^S. 6. Dissolve sulfide in 0.5 ml conc. HC1 + 0.5 ml conc. HN03 + 1.0 ml HC104, heat in water bath 5 m and then to strong fumes. Cool. 7. Re-extract with C^H^ and back extract as in steps 1 and 2. 8. Reprecipitate As as sulfide and redissolve. Dilute to 20 ml with 6N HC1 and precipitate As metal by adding 100 mg KI + Ig sodium hypophosphite, and heat until coagulated. Wash with hot water and mount. Procedure 20 Procedure by: A. E. Greendale & D. L. Love; Anal. Chem. 35 632 (1963). Type of procedure: With carrier Target material: Fissile material Radioactivity production method: Reactor neutrons Purification method: Evolution of 37

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Approx. chemical yield: 70-80% Time taken for purification: 10 s. Decontamination: Mixed fission products (2 weeks old) 10 ; Sb 2 x 103; Sn = ~ 106. 1. Add sample to 4 ml. of a 30% solution of r^SO^ containing 1 mg each Sb and As carriers. 2. Drop solution into flask containing 5g granular zinc held at 100°C in a water bath, with dry nitrogen flushing through. 3. Pass N2 + SbHj + AsHj through a tube of drying agent, followed by a quartz tube in a furnace held at 600°C. The Sb metal deposits on this tube and on a sintered glass filter which follows it. The As metal deposits on a second quartz tube heated to a reddish glow by a burner, which follows the sinter. Procedure 21 Procedure by: L. Tomlinson; Anal. Chim. Acta, 32 157 (1965). Type of Procedure: With carrier Target material: Fissile material Radioactivity production method: Reactor neutrons Purification method: Evolution of AsHj Approx. chemical yields: ~ 50% Time taken for purification: ~ 45 s. Decontamination: Br > 3 x 103: I > 4 x 104; Te 2 x 105; Se 9 x 104; Sn 2 x 103; Sb 2.5 x 103; Ge not measured. 1. Dissolve radioactive mixture containing As in HC1 or H^SO^ and add O.Smg Sb(IlI) (SbC1j dissolved in HC1) and 0.5 mg As(III) (As20j dissolved in NaOH solution and excess HC1 added). Adjust acidity to 5N and volume to 5.5 ml. 2. Add mixture to the cathode compartment of a diaphragm type electrolytic cell having a graphite cathode and a platinum gauze anode through whose cathode compartment pure He or N2 has been flowing for several minutes at 250 ml/m. 3. Pass a current of 50 amps for 10 s, flush for a further period and turn off gas flow. 4. The mixture of carrier gas, hydrogen, arsine, stibine, germane and stannane passes out from the cell and through a calcium sulphate column which removes any moisture and mostof the stannane, a silica tube at 480°C followed by a 40 m.m. diameter sintered glass filter of 20-30 n pore size on which is deposited Sb and Ge, and then through a second silica tube and sinter at 950°C on which metallic As is deposited as a mirror. 5. Count As in situ or dissolve in HC1/F^C^ an^ count as a liquid, or reprecipitated As metal. 38

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REFERENCES 1. Sneed, M. C. & Brasted, R. C. "Comprehensive inorganic chemistry". Vol. 5 p. 5. Van Nostrand, Princeton, 1956. 2. Chariot, G. & Bejier, D. "Quantitative Inorganic Analysis", Methuen & Co. London 1957. 3. Walton, H. F. "Principles and methods of chemical analysis". Prentice-Hall, Inc., New York 1952. 4. Beard, H. C. & Lyerly, L. A. Anal. Chem. 33 1781 1961. 5. Saito, K., Ikeda, S., Saito, M. Bull Chem. Soc. Japan, 33 884 1960. 6. Goto, H., Kakita, Y., Furukawa, T. Nippon Kagaku Zasshi 79 1513 1958. 7. Kitahara, S. Kagaku Kenyusho Hokoku 25 165 1950. 8. Prestwood, R. J. L. A. 1721 2nd ed. (1958). 9. Moustafa, Z. Thesis, Mainz 1952. (N.S.A. 17 243 1963). 10. Sherma, J., Evans, G. H., Frame, H. D., Strain, H. H. Anal. Chem. 33 224 1963. 11. Cvjeticanin, N., Jovanovic, V. Bull. Inst. Nuc. Sci. "Boris Kidrich". 13 270 1962. 12. Fidelis, L, Gwozdz and Siekierski, S. Nukleonika 8 319 1963. 13. Preobrazenskii, B. K., Moskvin, L. N. Radiokhimiya 3 309 1961. 14. Seyl, K. E., Herrmann, G. H., Z. Elektrochem 67 1065 (1960). USAEC Division of Technical 1nformation Extension, Oak Ridge, Tennessee 39

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MONOGRAPHS IN THE RADIOCHEMISTRY AND THE RADIOCHEMICAL TECHNIQUE SERIES Copies of the following monographs are available from the Clearinghouse for1 Federal Scientific and Technical Informa- tion, National Bureau of Standards, U. S. Department of Com- merce, Springfield, Va. Aluminum and Gallium, NAS-NS-3032, $0.50 Americium and Curium, NAS-NS-3006, $0.75 Antimony, NAS-NS-3033, $0.50 Arsenic, NAS-NS-3002 (Rev.) 1965 $1.00 Astatine, NAS-NS-3012, $0.50 Barium, Calcium, and Strontium, NAS-NS- 3010, $1.25 Beryllium, NAS-NS-3013, $0.75 Cadmium, NAS-NS-3001, $0.75 Carbon, Nitrogen, and Oxygen, NAS-NS- 3019, $0.50 Cesium, NAS-NS-3035, $0.75 Chromium, NAS-NS-3007, (Rev.)1964 $0.75 Cobalt, NAS-NS-3041, $1.00 Copper, NAS-NS-3027, $0.75 Fluorine, Chlorine, Bromine, and Iodine, NAS-NS-3005, $0.50 Francium, NAS-NS-3003, $0.50 Germanium, NAS-NS-3043, $0.50 Gold, NAS-NS-3036, $0.50 Indium, NAS-NS-3014, $0.50 Iridium, NAS-NS-3045, $0.50 Iron, NAS-NS-3017, $0.50 Lead, NAS-NS-3040, $1.75 Magnesium, NAS-NS-3024, $0.50 Manganese, NAS-NS-3018, $0.50 Mercury, NAS-NS-3026, $0.50 Molybdenum, NAS-NS-3009, $0.50 Nickel, NAS-NS-3051, $0.50 Niobium and Tantalum, NAS-NS-3039, $0.75 Osmium, NAS-NS-3046, $0.50 Palladium, NAS-NS-3052, $0.75 Phosphorus, NAS-NS-3056, $0.50 Platinum, NAS-NS-3044, $0.50 Polonium, NAS-NS-3037, $0.75 Potassium, NAS-NS-3048, $0.50 Protactinium, NAS-NS-3016, $1.00 Radium, NAS-NS-3057, $2.25 Rare Earths — Scandium, Yttrium, and Ac- tinium, NAS-NS-3020, $3.00 Rare Gases, NAS-NS-3025, $0.75 Rhenium, NAS-NS-3028, $0.50 Rhodium, NAS-NS-3008, (Rev.)1965 $1.00 Rubidium, NAS-NS-3053, $0.50 Ruthenium, NAS-NS-3029, $1.00 Selenium, NAS-NS-3030,(Rev.)l965$1.00 Silicon, NAS-NS-3049, $0.50 Silver, NAS-NS-3047, $0.75 Sodium, NAS-NS-3055, $0.50 Sulfur, NAS-NS-3054, $0.50 Technetium, NAS-NS-3021, $0.50 Tellurium, NAS-NS-3038, $0.50 Thorium, NAS-NS-3004, $0.75 Tin, NAS-NS-3023, $0.75 Titanium, NAS-NS-3034, $0.50 Transcurium Elements, NAS-NS-3031, $0.50 Tungsten, NAS-NS-3042, $0.50 Uranium, NAS-NS-3050, $3.50 Vanadium, NAS-NS-3022, $0.75 Zinc, NAS-NS-3015, $0.75 Zirconium and Hafnium, NAS-NS-3011, $0.50 Applications of Computers to Nuclear and Radiochemistry, NAS-NS-3107, $2.50 Application of Distillation Techniques to Radiochemical Separations, NAS-NS- 3108, $0.50 Detection and Measurement of Nuclear Ra- diation, NAS-NS-3105, $1.50 Liquid-liquid Extraction with High- molecular-weight Amines, NAS-NS- 3101, $1.00 Low-level Radiochemical Separations, NAS- NS-3103, $0.50 Paper Chromatographic and Electromigra- tion Techniques in Radiochemistry, NAS- NS-3106, $0.50 Rapid Radiochemical Separations, NAS-NS- 3104, $1.25 Separations by Solvent Extraction with Tri- n-octylphosphlne Oxide, NAS-NS-3102, $0.75