391 / 670
(e)
Repeat in triplicate.
170
(f)
Calculate concentration of the silver nitrate solution according to section
I
a. The difference
171
between the calculated concentration and the certified value should be within 0.5%. If outside the
172
acceptance value, check the experimental procedures and titration system. If issue is not
173
resolved, then use fresh standardized silver nitrate. If fresh standardized silver nitrate does not
174
provide an acceptable result, replace the electrolyte of the electrode and check the operating
175
condition of the dosing unit.
176
177
178
I. Calculations
179
(a)
Calculate silver nitrate concentration (SNC) in mol/L for system suitability verification and
180
report to 4 decimal places:
181
182
If using
[
D
b
]
183
10 V
5.844
) /
(
1
1
u u
m
L mol
SNC
184
185
Where
186
݉
1
= weight of sodium chloride in 5 mL or 1 mL of [Db] standard solution (mg);
187
ܸ
1
= Volume of 0.1 M or 0.02 M AgNO
3
consumed at titration endpoint (mL);
188
5.844 = sodium chloride weight in μg corresponding to 1 mL of 0.1 mol/L
AgNO
3
;
189
10 = mass conversion from titer to the concentration of titrant.
190
191
Or if using purchased standard grade 0.10 M NaCl
[
C
h]
192
1
3
V
1.0 ) /
(
V
L mol
SNC
u
193
194
Where
195
͵
= volume of purchased standard grade 0.10 M sodium chloride added (mL);
196
ܸ
1
= Volume of 0.1 M or 0.02 M AgNO
3
consumed at titration endpoint (mL);
197
198
199
200
201
(b
)
Calculate chloride content in sample (CL) and report to 3 significant digits:
202
203
m
100
)
( c 45.35 ) 100 /
(
0 -2
uu
uu
f
VV
g mg CL
204
W
here:
205
2015.07/2015.08 (February 2016)
Chlor-02/Chlor-04
FOR ERP USE ONLY
DO NOT DISTRIBUTE