Hach DR/850 - Page 122

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beaker.
e) Analyze the spiked and unspiked sample as described in
the procedure.
f) Calculate the concentration of mg/L chlorine added to the
sample:
g) The spiked sample result should reflect the analyzed
sample result + the calculated mg/L Cl
2
added (step f).
h) If this increase does not occur, see Standard Additions in
Section 1 for more information.
Method Performance
Precision
In a single laboratory using a standard solution of 1.00 mg/L
chlorine and two representative lots of reagents with the
instrument, a single operator obtained a standard deviation of
±0.01 mg/L chlorine.
In a single laboratory using a standard solution of 1.00 mg/L
chlorine and two representative lots of AccuVac Ampuls with the
instrument, a single operator obtained a standard deviation of
±0.01 mg/L chlorine.
Estimated Detection Limit (EDL)
The estimated detection limit for programs 9 and 11 is 0.02 mg/L
Cl
2
. For more information on derivation and use of Hach’s
estimated detection limit, see Section 1.
Pollution Prevention and Waste Management
Samples treated with sodium arsenite for manganese or
chromium interferences will be hazardous wastes as regulated by
Federal RCRA for arsenic (D004). See Section 3 for more
information on proper disposal of these materials.
mg/L Chlorine added
0.2 vol. standard added()Label value (mg/L Cl
2
)×
25.2 sample( standard volume)+
-----------------------------------------------------------------------------------------------------------------------------=
CHLORINE, FREE continued