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01/1J/92 11:25 'ae04 0a4 a12e ASCI VA.\COUVER +++ P Y H&S ®001/Old h A S C 1 Numerous studies have been pariormad on the eHiesey of the autoanalyssr method for cyanide analysls on mining relaud aqueow solutions. The reaulU of some of these studies ars reported by Smith and Muddar, 110811. Appended to this letter ars data from two such studies, which are described below. Study f1: Table 2.3 Oivaa • comparison of total Nanide determinatlons In mining rotated solutions by the manual method and tM sutoanalyaer method, IUSEPA Methods 8010 and 8012 retpactivelyl. While the manual method pave cyanlde values In the range antielpatsd at 0.006 to 0.020 mplL, the sutoanalyaar values wan often order of magnitude higher. Study /2: Table 2.4 hat day Nom an Interlaboratory study where two laboratories used the manual total cyanide method and a third laboratory the autoanalyssr method. Ths autoanalyssr values were found to bs two to three times the values obUinsd by both laboratories using the manual method. Smith end Mutldar conclude from their studies end experience that: '..If It Is proposed to use the sutosnslyssr technique for routine determination of total cyanlde, a comparative study should ba made with msnual dlstlllatlon dau to ensure that the autosnalyar method Is appropriate for the ssmpls matrix being evaluated', (page 30, section 2.3.21. They tontluds also that the manwl method, when performed by • skilled technician, fa more reliable than the sutosnslyssr method. This la particularly true at very !ow levels of Nanlda 3.4.2 Lyslmeter L3 samples eaaetl on the above description, it is apparent that the samples tolletted from the L3 lysimeter are not amenable t0 securers analysls for total ryanfde using en autoarolyser technique at the detection lavsls required, i.a 0.005 to 0.075 mp/L. The highly Hlins matrix will have viscosity affects In the photometer used for masuremant end will result In decrease in the transmitted light though the call. As such, this will give • positive readln0 for cyanide unlecs the standartls used for dstsrminatlon era of matched Ionic strength. In the ease of the Aeeu~Labs analysac, the matrix of the sUntlardl was not matched with the ssmpls matrix. The same applies to panieulsta matter, particularly eotioids, in the sample. Their pnsenee will result in light seettsrlnp In the photometric measurement cell, again resulting in s potitlve Intsrfsrsncs In the snelytical method pivtnp a false detection for cyanlde.