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<br />~~) D 4374
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<br />11.4:1 Run' the system'.witlt ;theccLemicalzneagents, no
<br />sample or CN standards. Wait about l2 mra for the reagents
<br />to flow through the colorimeter f]ovhoe11:1iI'trm the.colorim-
<br />eter display rotary switch.to Dainp:il:and:theixorder Chart
<br />Drive to ON position. Adjust the baselin~~ She.colorim-
<br />eter baseline control to read zeio onKhe rleoorder: d 1'
<br />11.4.2 Put successively in .the :sampleaitrny:4,cvps of 50
<br />µg/L CN standard, 2 cups of 100 µg/L~C1N standard, 2 cups
<br />of 100 µgJL'CN. complex standard;-:(cobalt;•Terro,'or
<br />ferricyanide), and 2 nrps of distiIIexl water: Start She sampler.
<br />l 1.4.3 It takes.about 25 min.forlthb first.ptak to appear.
<br />While the first peak is in prggtrss adjust the colorimeter Std
<br />Cal control so that at the plateau Of the 50 µg/L•(TI peak
<br />reads 50 (or the assigned value).on'fhe i•~art•recorder. Use
<br />the next peak for exact •adjustmeuts.. T'he:third and. fourth
<br />peaks should prove to be satisfactoryffs~rdn_:dl '.'.
<br />11.4.4 The next two peaks belong to. the 100 µg/L CN and
<br />should read 100 (or az assigned); within the experimental
<br />variation.'. q+., ~ . •,7„u; yl~;aq~• dq sdt rhi~H 6_nsr. ~~'+.,
<br />11.4.5 Now the last two peals correspond to the strong
<br />complex cyanide and should give a concentration of 100
<br />µg/L CN. If those peaks are lower than expected then the U V
<br />irradiation may not be effective`andsltduld'be ofieeked.
<br />11.4.6 The water in the last two •sample cups should not
<br />give any response, and the base line stiotild return to zero,
<br />otherwise minor adjustmenu should ba made %•1 "
<br />11.5 Analysis ojField Samples' gtnuq ;rlr ncr' _
<br />11.5.1 The system is now ready and calibrated to measure
<br />total cyanides. The samples have beeri'clixke•11 and treated
<br />for interferences, if found (az in Section 6) ;~?r.~•~ ••
<br />11.5.2 Homogenize the samples by a bltndei, sonifier, or
<br />by shaking well. This is in addition to.the"sampler stirrer
<br />used during the run. .;' r•'1 ,oittR+u;~ta,;•. ,
<br />11.5.3 Fill an identified cup or two iF analytirig sample in
<br />duplicate and load the sample tray.'tr0itnlGlri rr.:u .
<br />11.5:4 Follow goad quality confrdl'piactides and include
<br />check cyanide standards and distillea~water as"necessary.
<br />11.5.5 Avoid introducing samples containing high-cya-
<br />nide concentrations (100 µgJl,)'withotft proper dilution.
<br />Otherwise the peaks shoot off scale; and Ute system may need
<br />a suitable wash (sce' 14.1) to roturn'ttl"base line.`Reanalyze
<br />any samples affected by carryoveY~contad$natibn: t ;~
<br />• 11.5.6 Results arc read directly'fi~6ID the recorder chart
<br />(linear absorption), or from a'talibiatioa''eurvei'in cases
<br />where the working`codcentration "range is`high and the
<br />response is not ideally finear.'_rnooi ht ztcc ~ r 11;+ ti., .
<br />11.6 Sbur Down Slaps and Rotttr`ile'Wash''ii%'l'..-
<br />11.6:1 After the last sample analysis cbmp~leted'keep the
<br />pump on and tins off all other equipriient, that is, recorder,
<br />colorimeter (the sampler is off automatically); variable trans-
<br />former, UV irradiator, and close the uitrogeri gas. cylinder.
<br />11.6.2•$odium,Hydrozide [i!asfi•;'-~Plaoe"'all"fibre; reagent
<br />tubes, az well az the sample lin y~~0~. )!(aOHrfo} 10 min
<br />to rinse the system.; .,;, ~14~ ,,, •,_,iMl(nrt,i~nrtr:,t,
<br />11.63 Warer, Wash-Place a~ ant tubes m water for
<br />20 min.',-. , ..~.. ,~; ~,t,.,.d r.. ' uf, t7+t'MY~r# i'. rot+
<br />11.6.4 Turo 'off (he pump,~e~t release t~'e platen and
<br />r sJ. j,:l. r.: ~.J. .. ....,.lieu HJ~. ~ 7•, 1: i1..
<br />pump tubes; sdT..-~c,ss,ir;'•3v~;liii~i~}q~ttafl:)
<br />.. ~ .. ~ 3'.r1ORC ^I qn ^A hlhmf itd~tn8liac: _
<br />J2.. Procedar~e for;pissocisblg,_ ,~ u o . , ,
<br />.71a .
<br />12.1f All the steps prescribed.fondete~injrrigltotabcyanide
<br />.:,ys '~ ..:.
<br />apply for the dissociable cyanide, with the exception of the
<br />following.
<br />12.1.1 The UV irradiator must be turned off in order to
<br />determine the dissociable cyanides. The unit can be bypassed
<br />completely, this will reduce the run-time approximately 10
<br />min.
<br />12.1.2 A separate chemical standard calibration is neces-
<br />sary. The system must be recalibrated betbre determination
<br />oC dissociable cyanide. No response will be noted for the
<br />strong cobalt-cyanide complex. Ferro-Cerri+;yanide complexes
<br />may give a small response due to some decomposition. The
<br />response should be e5 % of the total cyanide employing the
<br />UV irradiation.
<br />13. Maintenance
<br />13.1 Daily-After use wash the system Cor 10 min with
<br />0.02 M NaOH, followed by 20 min with +vater.
<br />13.2 Monrhly:
<br />13.2.1 Before changing pump tubes, w:uh the UV quartz
<br />coil using both acid tube and sample pump tube with 5
<br />HCI for 10 min, 10 min with 0.02 M N.tOH, and l0 min
<br />more with water.
<br />13.2.2 Now change all pump tubes.
<br />13.2.3 Change any transmission tubin@ which appears to
<br />be dirty, colored or sticky, az well az any loose sleeves.
<br />13.3 Routine periodic maintenance for all automated
<br />continuous flow modules according to manufacturer man-
<br />uals should be followed, with special emphasis on pump
<br />lubrication.
<br />14. Trouble Shooting
<br />14.1 Conraminarion-Samples containing high concen-
<br />trations of cyanide may result in system contamination az
<br />noted by persistent color in the glass coils (also the recorder
<br />tracing does not come back to baseline).
<br />14.1.1 Rinse the system with one or mere of the following
<br />wash solutions until the color is removed from the system:
<br />(a) 0.02 M NaOH, (b) l.0 M NaOH, or (c i HCI acid, 5 % by
<br />volume.
<br />14.1.2 Rinse the system for 10 min with water.
<br />14.2 Waste Trap Failure-Excessive amounts of gases
<br />may escape from the waste tmp acct interrupt the flow
<br />pattern. This rarely occurs, and is the result of evolution of
<br />gases from samples extremely high in cyanide or carbonate,
<br />which will cause losses in analysis of the soettific sample and
<br />next few to follow.
<br />14.2.1 The waste trap is designed to lee self filling, and
<br />should correct itself in a few minutes.
<br />14.2.2 Verify that the system is batik to normal by
<br />checking the distillation ratio (see 11.4.2).
<br />14.2.3 Repeat the analysis of the samples affected by
<br />improper operation of the wazte trap.
<br />15. Precision and Biasr=
<br />15.1 A collaborative study was conducted to evaluate the
<br />performance of both methods, namely the dissociable cya-
<br />nide and total cyanide. Four Iaboratorie:; from the United
<br />States and Canada participated with eight analysts. Four
<br />"Supposing dau are on fde az ASTM Headquarters Request RR:619-1092.
<br />. ~: ,., . n . '°t+.~>.:. 110
<br />:yWi . ~~lf' . al.-'s~"fill '1~ i
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