Anions in wastewaters - Determination of Anions in Natural and Treated Waters - page 543

oven waste effluents are reported in Table 8.16.
The results for samples A-D analysed by the headspace method [44] and the cyanogen
bromide method [43] are in good agreement. Samples E-H show good agreement when
analysed by the headspace method and

Table 8.16 Comparison with BrCN method and accuracy of proposed procedure

Sample CN−

determined
(mg L−1)

CN−
added

CN− recovered by HS
method (mg L−1)

BrCN
method

HS method

By calibration
graph

By standard
additions
method

By
calibration
graph

By standard
additions
method

A 53 52 - 25.0 25.1 -

B 65 65 - 20.0 20.0 -

C 42 43 - 20.0 25.2 -

D 58 57 - 5.00 5.04 -

E 0.20 0.23 0.21 0.150 - 0.150

F 0.37 0.41 0.38 0.150 - 0.150

G 0.25 0.28 0.25 0.150 - 0.149

H 0.30 0.34 0.30 0.020 - 0.021

Source: Reproduced with permission from Elsevier Science [43]

the standard additions method. The results obtained by using a calibration graph are
appreciably higher owing to the different matrix of the standards and the samples.
The accuracy of the procedure was tested by spiking samples A-H with a known
amount of cyanide; the recoveries, reported in the last two columns in Table 8.16 are
excellent.

8.8.8 Miscellaneous

da Nasciemento and Schwedt [47] have compared several methods for the determination
of cyanide in waste waters. See also section 14.12.5.1.

8.9 Cyanide (total)

Total cyanide includes free cyanide ions plus complexed metal cyanides, eg