LaMotte 1200-UDV-CL - Manual (Page 4)

DPD CHLORINE TEST METHOD SPECIFICATIONS
APPLICATION
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 mg/L 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. The 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 3.5 mg/L chlorine. To
prepare these standards, a LaMotte 1000 mg/L standard chlorine equivalent solution
(Code 3858) is available. Consult with your local regulatory agency to determine
standardization frequency.
EPA APPROVED COMPLIANCE MONITORING OF WASTEWATER
Order Total Residual Chlorine, LaMotte Method 7916 (Code 7916-EPA). Follow all
sections except substitute the “Total Residual Chlorine ” section of the 3670-UDV
instructions for “11.0 Procedure.” This will provide a method for the Model
1200-UDV-CL colorimeter which follows an EPA approved method for compliance
monitoring of wastewater.
LaMOTTE COMPANY
Helping People Solve Analytical Challenges SM
PO Box 329 • Chestertown • Maryland • 21620 • USA
800-344-3100 • 410-778-3100 • Fax 410-778-6394
Visit us on the web at www.lamotte.com
3670-UDV · 11/01