LaMotte SMART Spectro Spectrophotometer - Manual (Page 74)

CHLORINE
LIQUID DPD METHOD • CODE 4859
QUANTITY CONTENTS CODE
30 mL DPD 1A Free Chlorine Reagent P-6740-G
30 mL *DPD 1B Free Chlorine Reagent *P-6741-G
30 mL *DPD 3 Total Chlorine Reagent *P-6743-G
*WARNING: Reagents marked with a * are considered to be potential health hazards. To view
or print a Material Safety Data Sheet (MSDS) for these reagents see MSDS CD or
www.lamotte.com. To obtain a printed copy, contact LaMotte by e-mail, phone or fax.
All water for cities and communities must be sanitized; even waters that come
from clean sources, protected watersheds, reservoirs, and deep wells, are
commonly sanitized to assure safety. Chlorine is the most commonly used
sanitizer for several reasons: it is effective against a wide range of
microorganisms, the cost is low, and the methods of applying it have been well
developed. If an adequate concentration of chlorine is present in the water for
a few minutes, disease producing bacteria will be destroyed. A number of
conditions affect the sanitizing action of chlorine. In municipal systems these
can be controlled so that if chlorine is detectable, it can be assumed that
bacteria have been killed. The factors that influence the rate of kill are
temperature, pH, presence of other materials that react with chlorine, time,
and the concentrations of the various chlorine combinations that are formed in
the water with ammonia and other substances that react with chlorine.
The fact that chlorine can be easily detected and measured makes chlorine a
favorite water sanitizer of those concerned with the public safety of water
supplies. Chlorine concentrations in the range of 0.1 to 0.4 parts per million
are usually maintained in municipal supplies.
Chlorine can be added in the form of chlorine gas, liquid sodium hypochlorite
(bleach), granular calcium hypochlorite or as organic chlorine compounds.
Chlorine is not present in natural water supplies; if it is present it is the result
of chlorination of a water supply or of chlorinated compounds being discharged
as waste from industrial operations. The presence of chlorine in concentrations
above 0.5 parts per million should be considered evidence of pollution from
chlorine treated effluents or from a process in which high concentrations of
chlorine are used.
APPLICATION: Drinking, surface, and saline waters; swimming pool water;
domestic and industrial wastes.
RANGE: 0.00–4.00 ppm Chlorine
METHOD: In the absence of iodide, free available chlorine reacts
instantly with DPD to produce a red color. Subsequent
addition of potassium iodide evokes a rapid color response
from the combined forms of chlorine (chloramines).
SMART SPECTRO TEST PROCEDURES 05.04 Chlorine - Liquid DPD 1/3