Test Procedures
APPLICATION:
Drinking, surface, and saline waters; domestic and industrial
wastes.
RANGE:
0.00–1.00 ppm Sulfi de
MDL:
0.02 ppm
METHOD:
Under suitable conditions the sulfi de ion reacts with
p-aminodimethylaniline and ferric chloride to produce
methylene blue in proportion to the sulfi de concentration.
Ammonium phosphate is added to remove the color due to
the ferric iron.
SAMPLE HANDLING &
PRESERVATION:
Samples must be taken with a minimum of aeration since
sulfi de is volatilized by aeration and any oxygen which is taken
up will destroy sulfi des by chemical action. Samples that
are used for total sulfi de concentrations may be preserved
by adding 2M zinc acetate solution at a dosage of 2 mL per
liter of sample. This precipitates sulfi de as inert zinc sulfi de.
Determination of dissolved sulfi des in samples not preserved
with zinc acetate must be started within 3 minutes of
sampling.
INTERFERENCES:
Strong reducing agents such as sulfi te, thiosulfate, and
hydrosulfi te prevent the formation of the color or diminish
its intensity. High concentrations of sulfi de will inhibit
the reaction, but dilution of the sample prior to analysis
eliminates this problem.
SULFIDE
SMART Spectro 2 Test Procedures 05.02.16
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