LaMotte DPD-FAS TITRIMETRIC OUT FIT DT - Manual (Page 2)

INTRODUCTION
The DPD-FAS (Diethyl-p-phenylene Diamine-Ferrous Ammonium
Sulfate) titrimetric method of A. T. Palin, as described in Standard
Methods
APHA, AWWA, WPCF, 18th edition, provides a simple and
accurate means of differentiating free and combined chlorine fractions,
and while these determinations are of primary interest, an extension of
the basic methods permits the determination of chlorine dioxide,
chlorite, bromine, iodine and ozone.
The Model DT Outfit with special stabilized reagents and common
glassware makes the method suitable for both laboratory and field use.
The instructions are divided into 6 major sections (I-VI). Use the
section that describes the sample being tested.
I.
DPD Method for Free & Combined Chlorine
II. Simplified Procedure for Free, Combined & Total Chlorine and
Nitrogen Trichloride
III. DPD Method for Chlorine Dioxide and Chlorite
IV. DPD Method for Bromine
V. DPD Method for Iodine
VI. DPD Method for Ozone
DILUTED FAS TITRANT PREPARATION
A diluted stock of FAS titrant should be made fresh each day and any
left at the end of the day should be discarded. Use the 1.0 mL pipet
(0354) to measure and transfer 1.0 mL of *Ferrous Ammonium Sulfate
(6815) to the 25 mL graduated cylinder (0417). Fill the graduated
cylinder to the 25 mL line with deionized water (5115PS). Invert
several times to mix. When a titration is made, pour the diluted FAS
into the funnel top of the buret (0426) until it is full to the top. Adjust
to the “0” line.
NOTE:
The quantities given are suitable for concentrations of Total
Chlorine up to 5 mg/L (5 ppm). Where the Total Chlorine exceeds
5 mg/L, use a smaller amount of the sample and dilute to 100 mL with
distilled water, and use the usual amounts of reagents given for a 100
mL sample.
CONCENTRATION RANGE OF DPD PROCEDURES
The quantities of reagents that have been given for all of the tests
described are suitable for concentrations of total available chlorine up to
5 mg/L (ppm). Where the total chlorine exceeds this figure, use a
smaller sample and dilute with distilled water to a total volume of 100
mL.
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