LaMotte CHLORINE - DPD LIQUID - Manual (Page 4)

DPD CHLORINE
TEST METHOD SPECIFICATIONS
Drinking water supplies and distribution systems, swimming pool and spas, sewage
and chlorinated waste waters, process waters and sanitizing solutions.
RANGE
0 to 4.0 ppm Chlorine (may be extended by dilution)
METHOD
In the absence of Iodide, Free Available Chlorine reacts instantly with the buffered
diethyl-p-phenylenediamine indicator (DPD) to produce a red color in proportion to
the amount of chlorine present. Subsequent addition of potassium iodide produces a
rapid color response from the combined forms of chlorine (chloramines).
HANDLING & PRESERVATION
Chlorine in aqueous solutions, particularly weak solutions, is not stable. Exposure to
sunlight or agitation will accelerate the reduction of chlorine. Fill sample containers to
the top and cap tightly. Analyze samples as soon as possible after collection.
INTERFERENCES
The only interfering substance likely to be encountered is oxidized manganese. The
extent of this interference can be determined by treating a sample with sodium arsenite
to destroy the chlorine present, so that the amount of interference can be measured.
CALIBRATION
The single test colorimeter is precalibrated. In order to comply with NPDWR or
NPDES reporting regulations, the calibration should be checked periodically by using
a set of reference standards including a 0 mg/L blank and 0.3, 1.0, and 4.0 mg/L
chlorine. To prepare these standards, a LaMotte 250 ppm standard chlorine equivalent
solution (Code 6973) is available. Consult with your local regulatory agency to
determine standardization frequency.
LaMOTTE COMPANY
Helping People Solve Analytical Challenges ®
PO Box 329 • Chestertown • Maryland • 21620 • USA
800-344-3100 • 410-778-3100 (Outside USA) • Fax 410-778-6394
Visit us on the web at www.lamotte.com
63670-01-LI 02/13