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Application Bulletin 176/4 eDetermination of lead and tin by anodic stripping voltammetryPage 8/8AppendixFull Report of a determination of Pb and Sn acc. to method 2 with the 746 VA Trace Analyzer================== METROHM 746 VA TRACE ANALYZER (5.746.0101) ==================Determ. : 03111419 User: Date: 1999-03-11Modified : 2000-12-05 19:30:39 Run : 0 Time: 14:19:11Sample table: ---------------------------------------------------------------------------------Pos. Ident.1/S1 Ident.2/S2 Ident.3/S3 Method.call Sample size/S0sample5 mL--------------------------------------------------------------------------------Method : AB176_2Title : Det.of Sn and Pb with methylene blue. AB176 part 2Remark1 : 5 ml sample + 5 ml electrolyte + 50 µl methylene blue (1g/l)Remark2 : el.: 0.14mol/l oxalate + 0.17mol/l NH4Cl + 0.15mol/l HCl--------------------------------------------------------------------------------Substance : SnCommentsMass conc.: 27.41 ug/L Mass : 137.1 ng ------------------MC.dev. : 0.904 ug/L (3.3%) Add.mass : 100 ngCal.dev. : - V0.sample: 5 mLVR U/mV I/nA I.mean Std.dev. I.delta Comments--- ----- ------ ------ ------- ------- ------------------00 -537 4.808 4.824 0.022201 -537 4.83910 -536 8.227 8.166 0.0871 3.34211 -536 8.10420 -536 11.41 11.55 0.1883 3.38121 -536 11.68Substance : PbCommentsMass conc.: 5.068 ug/L Mass : 25.34 ng ------------------MC.dev. : 0.228 ug/L (4.51%) Add.mass : 25 ngCal.dev. : - V0.sample: 5 mLVR U/mV I/nA I.mean Std.dev. I.delta Comments--- ----- ------ ------ ------- ------- ------------------00 -412 4.895 4.965 0.098701 -413 5.03410 -412 9.579 9.435 0.2038 4.47011 -412 9.29120 -412 14.24 14.26 0.0323 4.82321 -412 14.28Substance Techn. Y.reg/offset Slope Nonlin. Mean deviat.--------- -------- ------------ ---------- ---------- ------------Sn std.add. 4.804e-09 3.522e-04 1.114e-10Pb std.add. 4.888e-09 0.001938 1.789e-10Final results +/- Res.dev. % Comments--------------------------------- ----------------- ------------------Sn = 27.414 ug/L 0.904 3.30Pb = 5.0681 ug/L 0.228 4.51Method parameters of a determination of Pb and Sn acc. to method 2 with the 746 VA Trace Analyzer================== METROHM 746 VA TRACE ANALYZER (5.746.0101) ==================Method: AB176_2 .mthOPERATION SEQUENCETitle : Det.of Sn and Pb with methylene blue. AB176 part 2--------------------------------------------------------------------------------Instructions t/s Main parameters Auxiliary parameters------------- ----- ------------------------- -------------------------1 DOS/M V.added 5.050 mL2 REM 5mL sample + 5 mL electrolyte + 50 µL meth. blue3 SMPL/M V.fraction mL V.total L4 PURGE5 STIR 300.0 Rot.speed 2000 /min6 (ADD7 PURGE8 STIR 30.0 Rot.speed 2000 /min9 0PURGE10 (REP11 SEGMENT Segm.name asvSn12 REP)113 PURGE14 STIR Rot.speed 2000 /min15 ADD>M Soln.name Pb-std V.add 0.025 mL16 ADD>M Soln.name Sn-std V.add 0.100 mL17 ADD)218 END
Application Bulletin 176/4 eDetermination of lead and tin by anodic stripping voltammetryPage 9/9Method: AB176_2SEGMENTasvSn--------------------------------------------------------------------------------Instructions t/s Main parameters Auxiliary parameters------------- ----- ------------------------- -------------------------1 STIR 2.0 Rot.speed 2000 /min2 HMDE Drop size 4 Meas.cell normal3 DPMODE U.ampl 50 mV t.meas 20.0 mst.step 0.20 s t.pulse 40.0 ms4 MEAS 90.0 U.meas -800 mV5 MEAS 20.0 U.meas -580 mV6 0STIR 10.07 SWEEP 28.2 U.start -800 mV U.step 4 mVU.end -250 mV Sweep rate 20 mV/s8 0MEAS U.standby mV9 ENDMethod: AB176_2CALCULATIONmax. 15 lines--------------------------------------------------------------------------------Quantity Formula (R##, C##, A##) Res.unit Sig.dig.------------ ---------------------------------------- -------- --------Sn R1000=MC:Sn #g/L 5Pb R1001=MC:Pb #g/L 5Method 3: Determination of Sn(II) besidesSn(IV) in an electrolyte containing NaFPrincipleIn weak alkaline solutions, containing sodium fluorideit is possible to determine Sn(II) besides Sn(IV) byDPASV. The Sn(IV) ions do not give any voltammetricsignal under these conditions. The detection limit is2.5 µg/L.Accessories• 6.1450.210 Measuring vessel of PFAReagentsAll of the used reagents must be of purest qualitypossible (analytical grade or suprapur). Only ultrapurewater should be used.• Piperazine-1,4-bis(2-ethane sulfonic acid), PIPES,CAS 5625-37-6• Sodium hydroxide solution, suprapur, w(NaOH) =30%• Ammonia solution, suprapur, w(NH 3) = 25%• Hydrochloric acid, suprapur, w(HCl) = 30%• NaNO 3, suprapur, CAS 7631-99-4• NaF suprapur, CAS 7681-49-4• SnCl 2 dihydrate, p.a., CAS 10025-69-1NaNO 3 solutionNaF solutionSn standardstock solutionSn(II) standardsolutionc(NaNO 3) = 1 mol/L4.25 g NaNO 3 are dissolved in50 mL ultrapure water.c(NaF) = 1 mol/L2.1 g NaF are dissolved in 50mL ultrapure water.c(Sn 2+ ) = 1 g/L0.190 g SnCl 2 are dissolved in50 mL oxygen free water. 10mL hydrochlorid acid are addedang the solution is made up to100 mL using oxygen free water.The solution is sensitiveagainst oxidtion and shouldprepared freshly in regularintervals.c(Sn 2+ ) = 1 mg/LThe diluted working solutionsare prepared from standardstock solutions by dilution inc(HCl) = 0.01 mol/L. Oxygenfree water has to be used.Ready-to-use solutions:PIPES buffer c(PIPES) = 1 mol/L, pH 87.6 g PIPES are mixed with1 mL sodium hydroxide solutioniand 5 mL high purity water.The pH is adjusted to 8 ± 0.1with ammonia solution. Thesolution is filled up to 25 mL.Analysis5 mL sample+ 0.5 mL NaNO3 solution+ 3.5 mL NaF solution+ 0.5 mL PIPES bufferThe pH is adjusted to 8.0 with ammonia solution.
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