9012B­
1
Revision
2
August
2002
METHOD
9012B
TOTAL
AND
AMENABLE
CYANIDE
(
AUTOMATED
COLORIMETRIC,
WITH
OFF­
LINE
DISTILLATION)

1.0
SCOPE
AND
APPLICATION
1.1
Method
9012
is
used
to
determine
the
concentration
of
inorganic
cyanide
(
CAS
Registry
Number
57­
12­
5)
in
wastes
or
leachate.
The
method
detects
inorganic
cyanides
that
are
present
as
either
soluble
salts
or
complexes.
It
is
used
to
determine
values
for
both
total
cyanide
and
cyanide
amenable
to
chlorination.
The
"
reactive"
cyanide
content
of
a
waste
is
not
determined
by
this
method.
Refer
to
40
CFR
261.23
for
information
on
the
characteristic
of
reactivity.

2.0
SUMMARY
OF
METHOD
2.1
The
cyanide,
as
hydrocyanic
acid
(
HCN),
is
released
from
samples
containing
cyanide
by
means
of
a
reflux­
distillation
operation
under
acidic
conditions
and
absorbed
in
a
scrubber
containing
sodium
hydroxide
solution.
The
cyanide
ion
in
the
absorbing
solution
is
then
determined
by
automated
UV
colorimetry.

2.2
In
the
automated
colorimetric
measurement,
the
cyanide
is
converted
to
cyanogen
chloride
(
CNCl)
by
reaction
with
Chloramine­
T
at
a
pH
less
than
8
without
hydrolyzing
to
the
cyanate.
After
the
reaction
is
complete,
color
is
formed
on
the
addition
of
pyridine­
barbituric
acid
reagent.
The
concentration
of
NaOH
must
be
the
same
in
the
standards,
the
scrubber
solutions,
and
any
dilution
of
the
original
scrubber
solution
to
obtain
colors
of
comparable
intensity.

3.0
INTERFERENCES
3.1
Interferences
are
eliminated
or
reduced
by
using
the
distillation
procedure.
Chlorine
and
sulfide
are
interferences
in
Method
9012.

3.2
Oxidizing
agents
such
as
chlorine
decompose
most
cyanides.
Chlorine
interferences
can
be
removed
by
adding
an
excess
of
sodium
arsenite
to
the
waste
prior
to
preservation
and
storage
of
the
sample
to
reduce
the
chlorine
to
chloride
which
does
not
interfere.

3.3
Sulfide
interference
can
be
removed
by
adding
an
excess
of
bismuth
nitrate
to
the
waste
(
to
precipitate
the
sulfide)
before
distillation.
Samples
that
contain
hydrogen
sulfide,
metal
sulfides,
or
other
compounds
that
may
produce
hydrogen
sulfide
during
the
distillation
should
be
treated
by
the
addition
of
bismuth
nitrate.

3.4
High
results
may
be
obtained
for
samples
that
contain
nitrate
and/
or
nitrite.
During
the
distillation,
nitrate
and
nitrite
will
form
nitrous
acid,
which
will
react
with
some
organic
compounds
to
form
oximes.
These
compounds
once
formed
will
decompose
under
test
conditions
to
generate
HCN.
The
possibility
of
interference
of
nitrate
and
nitrite
is
eliminated
by
pretreatment
with
sulfamic
acid
just
before
distillation.
Nitrate
and
nitrite
are
interferences
when
present
at
levels
higher
than
10
mg/
L
and
in
conjunction
with
certain
organic
compounds.

3.5
Thiocyanate
is
reported
to
be
an
interference
when
present
at
very
high
levels.
Levels
of
10
mg/
L
were
not
found
to
interfere
in
Method
9010.
9012B­
2
Revision
2
August
2002
3.6
Fatty
acids,
detergents,
surfactants,
and
other
compounds
may
cause
foaming
during
the
distillation
when
they
are
present
in
large
concentrations
and
will
make
the
endpoint
of
the
titration
difficult
to
detect.
They
may
be
extracted
at
pH
6­
7.

4.0
APPARATUS
AND
MATERIALS
4.1
Reflux
distillation
apparatus
such
as
shown
in
Figure
1
or
Figure
2.
The
boiling
flask
should
be
of
one
liter
size
with
inlet
tube
and
provision
for
condenser.
The
gas
scrubber
may
be
a
270­
mL
Fisher­
Milligan
scrubber
(
Fisher,
Part
No.
07­
513
or
equivalent).
The
reflux
apparatus
may
be
a
Wheaton
377160
distillation
unit
or
equivalent.

4.2
Automated
continuous­
flow
analytical
instrument
with:

4.2.1
Sampler.

4.2.2
Manifold.

4.2.3
Proportioning
pump.

4.2.4
Heating
bath
with
distillation
coil.

4.2.5
Distillation
head.

4.2.6
Colorimeter
equipped
with
a
15­
mm
flowcell
and
570
nm
filter.

4.2.7
Recorder.

4.3
Hot
plate
stirrer/
heating
mantle.

4.4
pH
meter.

4.5
Amber
light.

4.6
Vacuum
source.

4.7
Refrigerator.

4.8
5
mL
microburette.

4.9
7
Class
A
volumetric
flasks
­
100
and
250
mL.

4.10
Erlenmeyer
flask
­
500
mL.

5.0
REAGENTS
5.1
Reagent
grade
chemicals
shall
be
used
in
all
tests.
Unless
otherwise
indicated,
it
is
intended
that
all
reagents
shall
conform
to
the
specifications
of
the
Committee
on
Analytical
Reagents
of
the
American
Chemical
Society,
where
such
specifications
are
available.
Other
grades
may
be
used,
provided
it
is
first
ascertained
that
the
reagent
is
of
sufficiently
high
purity
to
permit
its
use
without
lessening
the
accuracy
of
the
determination.
9012B­
3
Revision
2
August
2002
5.2
Reagent
water.
All
references
to
water
in
this
method
refer
to
reagent
water,
as
defined
in
Chapter
One.

5.3
Reagents
for
sample
collection,
preservation,
and
handling
5.3.1
Sodium
arsenite
(
0.1N),
NaAsO
2.
Dissolve
3.2
g
NaAsO
2
in
250
mL
water.

5.3.2
Ascorbic
acid,
C
6
H
8
O
6.

5.3.3
Sodium
hydroxide
solution
(
50%),
NaOH.
Commercially
available.

5.3.4
Acetic
acid
(
1.6M)
CH
3
COOH.
Dilute
one
part
of
concentrated
acetic
acid
with
9
parts
of
water.

5.3.5
2,2,4­
Trimethylpentane,
C
8
H
18.

5.3.6
Hexane,
C
6
H
14.

5.3.7
Chloroform,
CHCl
3.

5.4
Reagents
for
cyanides
amenable
to
chlorination
5.4.1
Calcium
hypochlorite
solution
(
0.35M),
Ca(
OCl)
2.
Combine
5
g
of
calcium
hypochlorite
and
100
mL
of
water.
Shake
before
using.

5.4.2
Sodium
hydroxide
solution
(
1.25N),
NaOH.
Dissolve
50
g
of
NaOH
in
1
liter
of
water.

5.4.3
Sodium
arsenite
(
O.
1N).
See
Sec.
5.3.1.

5.4.4
Potassium
iodide
starch
paper.

5.5
Reagents
for
distillation
5.5.1
Sodium
hydroxide
(
1.25N).
See
Sec.
5.4.2.

5.5.2
Bismuth
nitrate
(
0.062M),
Bi(
NO)
3
C
5H
2
O.
Dissolve
30
g
Bi(
NO)
3
C
5H
2
O
in
100
mL
of
water.
While
stirring,
add
250
mL
of
glacial
acetic
acid,
CH
3
COOH.
Stir
until
dissolved
and
dilute
to
1
liter
with
water.

5.5.3
Sulfamic
acid
(
0.4N),
H
2
NSO
3
H.
Dissolve
40
g
H
2
NSO
3
H
in
1
liter
of
water.

5.5.4
Sulfuric
acid
(
18N),
H
2
SO
4.
Slowly
and
carefully
add
500
mL
of
concentrated
H
2
SO
4
to
500
mL
of
water.

5.5.5
Magnesium
chloride
solution
(
2.5M),
MgCl
2
C
6H
2
O.
Dissolve
510
g
of
MgCl
2
C
6H
2
O
in
1
liter
of
water.

5.5.6
Lead
acetate
paper.

5.6
Reagents
for
automated
colorimetric
determination
9012B­
4
Revision
2
August
2002
5.6.1
Pyridine­
barbituric
acid
reagent:
Place
15
g
of
barbituric
acid
in
a
250­
mL
volumetric
flask,
add
just
enough
reagent
water
to
wash
the
sides
of
the
flask,
and
wet
the
barbituric
acid.
Add
75
mL
of
pyridine
and
mix.
Add
15
mL
of
concentrated
HCl,
mix,
and
cool
to
room
temperature.
Dilute
to
250
mL
with
reagent
water
and
mix.
This
reagent
is
stable
for
approximately
six
months
if
stored
in
a
cool,
dark
place.

5.6.2
Chloramine­
T
solution:
Dissolve
2.0
g
of
white,
water
soluble
chloramine­
T
in
500
mL
of
reagent
water
and
refrigerate
until
ready
to
use.

5.6.3
Sodium
hydroxide,
1
N:
Dissolve
40
g
of
NaOH
in
reagent
water,
and
dilute
to
1
liter.

5.6.4
All
working
standards
should
contain
2
mL
of
1
N
NaOH
(
Sec.
5.6.3)
per
100
mL.

5.6.5
Dilution
water
and
receptacle
wash
water
(
NaOH,
0.25
N):
Dissolve
10.0
g
NaOH
in
500
mL
of
reagent
water.
Dilute
to
1
liter.

6.0
SAMPLE
COLLECTION,
PRESERVATION,
AND
HANDLING
6.1
Samples
should
be
collected
in
plastic
or
glass
containers.
All
containers
must
be
thoroughly
cleaned
and
rinsed.

6.2
Oxidizing
agents
such
as
chlorine
decompose
most
cyanides.
To
determine
whether
oxidizing
agents
are
present,
test
a
drop
of
the
sample
with
potassium
iodide­
starch
test
paper.
A
blue
color
indicates
the
need
for
treatment.
Add
0.1N
sodium
arsenite
solution
a
few
mL
at
a
time
until
a
drop
of
sample
produces
no
color
on
the
indicator
paper.
Add
an
additional
5
mL
of
sodium
arsenite
solution
for
each
liter
of
sample.
Ascorbic
acid
can
be
used
as
an
alternative
although
it
is
not
as
effective
as
arsenite.
Add
a
few
crystals
of
ascorbic
acid
at
a
time
until
a
drop
of
sample
produces
no
color
on
the
indicator
paper.
Then
add
an
additional
0.6
g
of
ascorbic
acid
for
each
liter
of
sample
volume.

6.3
Aqueous
samples
must
be
preserved
by
adding
50%
sodium
hydroxide
until
the
pH
is
greater
than
or
equal
to
12
at
the
time
of
collection.

6.4
Samples
should
be
chilled
to
4
E
C.

6.5
When
properly
preserved,
cyanide
samples
can
be
stored
for
up
to
14
days
prior
to
sample
preparation
steps.

6.6
Solid
and
oily
wastes
may
be
extracted
prior
to
analysis
by
Method
9013
(
Cyanide
Extraction
Procedure
for
Solids
and
Oils).
It
uses
a
dilute
NaOH
solution
(
pH
=
12)
as
the
extractant.
This
yields
extractable
cyanide.

6.7
If
fatty
acids,
detergents,
and
surfactants
are
a
problem,
they
may
be
extracted
using
the
following
procedure.
Acidify
the
sample
with
acetic
acid
(
1.6M)
to
pH
6.0
to
7.0.

CAUTION:
This
procedure
can
produce
lethal
HCN
gas.

Extract
with
isooctane,
hexane,
or
chloroform
(
preference
in
order
named)
with
solvent
volume
equal
to
20%
of
the
sample
volume.
One
extraction
is
usually
adequate
to
reduce
the
compounds
below
the
interference
level.
Avoid
multiple
extractions
or
a
long
contact
time
at
low
pH
in
order
to
9012B­
5
Revision
2
August
2002
keep
the
loss
of
HCN
at
a
minimum.
When
the
extraction
is
completed,
immediately
raise
the
pH
of
the
sample
to
above
12
with
50%
NaOH
solution.

7.0
PROCEDURE
7.1
Pretreatment
for
cyanides
amenable
to
chlorination
7.1.1
This
test
must
be
performed
under
amber
light.
K
3[
Fe­(
CN)
6]
may
decompose
under
UV
light
and
hence
will
test
positive
for
cyanide
amenable
to
chlorination
if
exposed
to
fluorescent
lighting
or
sunlight.
Two
identical
sample
aliquots
are
required
to
determine
cyanides
amenable
to
chlorination.

7.1.2
To
one
500
mL
sample
or
to
a
sample
diluted
to
500
mL,
add
calcium
hypochlorite
solution
dropwise
while
agitating
and
maintaining
the
pH
between
11
and
12
with
1.25N
sodium
hydroxide
until
an
excess
of
chlorine
is
present
as
indicated
by
KI­
starch
paper
turning
blue.
The
sample
will
be
subjected
to
alkaline
chlorination
by
this
step.

CAUTION:
The
initial
reaction
product
of
alkaline
chlorination
is
the
very
toxic
gas
cyanogen
chloride;
therefore,
it
is
necessary
that
this
reaction
be
performed
in
a
hood.

7.1.3
Test
for
excess
chlorine
with
KI­
starch
paper
and
maintain
this
excess
for
one
hour
with
continuous
agitation.
A
distinct
blue
color
on
the
test
paper
indicates
a
sufficient
chlorine
level.
If
necessary,
add
additional
calcium
hypochlorite
solution.

7.1.4
After
one
hour,
add
1
mL
portions
of
0.1N
sodium
arsenite
until
KI­
starch
paper
shows
no
residual
chlorine.
Add
5
mL
of
excess
sodium
arsenite
to
ensure
the
presence
of
excess
reducing
agent.

7.1.5
Test
for
total
cyanide
as
described
below
in
both
the
chlorinated
and
the
unchlorinated
samples.
The
difference
of
total
cyanide
in
the
chlorinated
and
unchlorinated
samples
is
the
cyanide
amenable
to
chlorination.

7.1.6
If
samples
are
known
or
suspected
to
contain
sulfide,
add
50
mL
of
0.062M
bismuth
nitrate
solution
through
the
air
inlet
tube.
Mix
for
three
minutes.
Use
lead
acetate
paper
to
check
the
sample
for
the
presence
of
sulfide.
A
positive
test
is
indicated
by
a
black
color
on
the
paper.

7.2
Distillation
procedure
7.2.1
Place
500
mL
of
sample,
or
sample
diluted
to
500
mL
in
the
one
liter
boiling
flask.
Pipet
50
mL
of
1.25N
sodium
hydroxide
into
the
gas
scrubber.
If
the
apparatus
in
Figure
1
is
used,
add
water
until
the
spiral
is
covered.
Connect
the
boiling
flask,
condenser,
gas
scrubber
and
vacuum
trap.

7.2.2
Start
a
slow
stream
of
air
entering
the
boiling
flask
by
adjusting
the
vacuum
source.
Adjust
the
vacuum
so
that
approximately
two
bubbles
of
air
per
second
enter
the
boiling
flask
through
the
air
inlet
tube.

7.2.3
If
samples
are
known
or
suspected
to
contain
nitrate
or
nitrite,
or
if
bismuth
nitrate
was
added
to
the
sample,
add
50
mL
of
0.4N
sulfamic
acid
solution
through
the
air
inlet
tube.
Mix
for
three
minutes.
9012B­
6
Revision
2
August
2002
NOTE:
Excessive
use
of
sulfamic
acid
could
create
method
bias.

7.2.4
Slowly
add
50
mL
of
18N
sulfuric
acid
through
the
air
inlet
tube.
Rinse
the
tube
with
water
and
allow
the
airflow
to
mix
the
flask
contents
for
three
minutes.
Add
20
mL
of
2.5M
magnesium
chloride
through
the
air
inlet
and
wash
the
inlet
tube
with
a
stream
of
water.

7.2.5
Heat
the
solution
to
boiling.
Reflux
for
one
hour.
Turn
off
heat
and
continue
the
airflow
for
at
least
15
minutes.
After
cooling
the
boiling
flask,
and
closing
the
vacuum
source,
disconnect
the
gas
scrubber.

7.2.6
Transfer
the
solution
from
the
scrubber
into
a
250­
mL
volumetric
flask.
Rinse
the
scrubber
into
the
volumetric
flask.
Dilute
to
volume
with
water.

7.3
Automated
colorimetric
determination
7.3.1
Set
up
the
manifold
in
a
hood
or
a
well­
ventilated
area
as
shown
in
Figure
3.

7.3.2
Allow
colorimeter
and
recorder
to
warm
up
for
30
min.
Run
a
baseline
with
all
reagents,
feeding
reagent
water
through
the
sample
line.

7.3.3
Place
appropriate
standards
in
the
sampler
in
order
of
increasing
concentration.
Complete
loading
of
the
sampler
tray
with
unknown
samples.

7.3.4
When
the
baseline
becomes
steady,
begin
the
analysis.

7.4
Standard
curve
for
samples
without
sulfide
7.4.1
Prepare
a
series
of
standards
by
pipetting
suitable
volumes
of
working
standard
potassium
cyanide
solution
into
250­
mL
volumetric
flasks.
To
each
flask,
add
50
mL
of
1.25N
sodium
hydroxide
and
dilute
to
250
mL
with
water.
Prepare
using
the
following
table.
The
sodium
hydroxide
concentration
will
be
0.25N.

mL
of
Working
Standard
Solution
(
1
mL
=
10
µ
g
CN­)
Concentration
(
µ
g
CN­/
L)

0.0
1.0
2.0
5.0
10.0
15.0
20.0
Blank
40
80
200
400
600
800
7.4.2
After
the
standard
solutions
have
been
prepared
according
to
the
table
above,
pipet
50
mL
of
each
standard
solution
into
a
100­
mL
volumetric
flask
and
proceed
to
Secs
7.3.2
and
7.3.3
to
obtain
absorbance
values
for
the
standard
curve.
The
final
concentrations
for
the
standard
curve
will
be
one
half
of
the
amounts
in
the
above
table
(
final
concentrations
ranging
from
20
to
400
µ
g/
L).
9012B­
7
Revision
2
August
2002
7.4.3
It
is
recommended
that
at
least
two
standards
(
a
high
and
a
low)
be
distilled
and
compared
to
similar
values
on
the
curve
to
ensure
that
the
distillation
technique
is
reliable.
If
distilled
standards
do
not
agree
within
+
10%
of
the
undistilled
standards,
the
analyst
should
find
the
cause
of
the
apparent
error
before
proceeding.

7.4.4
Prepare
a
standard
curve
ranging
from
20
to
400
µ
g/
L
by
plotting
absorbance
of
standard
versus
the
cyanide
concentration
7.5
Standard
curve
for
samples
with
sulfide
7.5.1
It
is
imperative
that
all
standards
be
distilled
in
the
same
manner
as
the
samples
using
the
method
of
standard
additions
(
for
example,
bismuth
nitrate
must
also
be
added
to
the
standards).
Standards
distilled
by
this
method
will
give
a
linear
curve,
at
low
concentrations,
but
as
the
concentration
increases,
the
recovery
decreases.
It
is
recommended
that
at
least
five
standards
be
distilled.

7.5.2
Prepare
a
series
of
standards
similar
in
concentration
to
those
mentioned
in
Sec.
7.4.1
and
analyze
as
in
Sec.
7.3.
Prepare
a
standard
curve
by
plotting
absorbance
of
standard
versus
the
cyanide
concentration.

7.6
Calculation:
Prepare
a
standard
curve
by
plotting
peak
heights
of
standards
against
their
concentration
values.
Compute
concentrations
of
samples
by
comparing
sample
peak
heights
with
the
standard
curve.

8.0
QUALITY
CONTROL
8.1
Refer
to
Chapter
One
for
specific
quality
control
procedures.

8.2
Verify
the
calibration
curve
with
an
independent
calibration
check
standard.
If
the
standards
are
not
within
15%
of
the
expected
value,
a
new
recalibration
curve
is
required.
Verify
the
calibration
curve
with
every
sample
batch
by
analyzing
a
mid­
range
standard.

8.3
Run
one
matrix
spike
sample
for
every
10
samples
to
check
the
efficiency
of
sample
distillation.
A
matrix
spike
should
be
prepared
by
adding
cyanide
from
the
working
standard
or
intermediate
standard
to
500
mL
of
sample
to
ensure
a
concentration
of
approximately
40
µ
g/
L.
Both
the
matrix
duplicate
and
matrix
spike
duplicate
are
brought
through
the
entire
sample
preparation
and
analytical
process.

8.4
The
method
of
standard
additions
shall
be
used
for
the
analysis
of
all
samples
that
suffer
from
matrix
interferences
such
as
samples
which
contain
sulfides.

9.0
METHOD
PERFORMANCE
9.1
Precision
and
accuracy
data
are
not
available
at
this
time.

10.0
REFERENCES
1.
Annual
Book
of
ASTM
Standards,
Part
31,
"
Water,"
Standard
D2036­
75,
Method
B,
p.
505
(
1976).
9012B­
8
Revision
2
August
2002
2.
Goulden,
P.
D.,
B.
K.
Afghan,
and
P.
Brooksbank,
Determination
of
Nanogram
Quantities
of
Simple
and
Complex
Cyanides
in
Water,
Anal.
Chem.,
44(
11),
pp.
1845­
49
(
1972).

3.
Standard
Methods
for
the
Examination
of
Water
and
Wastewater,
14th
ed.,
pp.
376
and
370,
Method
413F
and
D
(
1975).

4.
Technicon
AutoAnalyzer
II
Methodology,
Industrial
Method
No.
315­
74
WCUV
Digestion
and
Distillation,
Technicon
Industrial
Systems,
Tarrytown,
New
York,
10591
(
1974).
9012B­
9
Revision
2
August
2002
Figure
1.
Apparatus
for
Cyanide
Distillation
9012B­
10
Revision
2
August
2002
Figure
2.
Cyanide
Distillation
Apparatus
9012B­
11
Revision
2
August
2002
Figure
3.
Cyanide
Manifold
AA11
9012B­
12
Revision
2
August
2002
METHOD
9012B
TOTAL
AND
AMENABLE
CYANIDE
(
AUTOMATED
COLORIMETRIC
WITH
OFF­
LINE
DISTILLATION
)
9012B­
13
Revision
2
August
2002
METHOD
9012B
(
continued)
