Velp Scientifica
– UDK139 Operating Manual
10004762/B5
117
Begin the distillation by START.
100-120 ml of condensate are collected and the flask content can be adjusted to the
volume with the washings in a volumetric flask 200 ml (the same volume of the
sample). The quantitative determination of the cyanides can be performed by
titrimetry: add 10 drops of Rhodanine indicator into the flask and titrate by silver
nitrate.
The concentration of cyanides can be calculated as follows:
CN (µg/L) = (A-B) * D * 2 mole CN
-
* 26.02 g CN
-
* (1*10
6
µg)
C 1 eq. AgNO
3
1 mole
CN
-
1 g
A = ml AgNO3 for titration of sample
B = ml AgNO3 for titration of blank
C = ml of original sample before distillation (200 ml recommended).
D = actual normality of AgNO
3
(0.0192 N recommended)
References:
ENVIRONMENTAL PROTECTION AGENCY : Test method n. 9010.
APAT
Agenzia per la protezione dell’ambiente e per i servizi tecnici, IRSA-CNR
Istituto di Ricerca sulle Acque - Consiglio Nazionale delle Ricerche n° 4070.
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