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9
Sulfide
Testing
Procedure
1. Using the table below, determine the sample volume and type of Dräger
tube required for your test.
Sulfide Range
(mg/L)
Sample Volume
(mL)
Dräger Tube
Identification
Tube Factor (Used
in Equation)
1.2 to 24
10.0
H
2
S 100/a
.12
2.4 to 48
5.0
H
2
S 100/a
.12
4.8 to 96
2.5
H
2
S 100/a
.12
60 to 1,020
10.0
H
2
S 0.2%/A
1500
120 to 2,040
5.0
H
2
S 0.2%/A
1500
240 to 4,080
2.5
H
2
S 0.2%/A
1500
2. Break the tip from each end of the Dräger tube and place it in the desig
-
nated hole next to chamber 3. Make sure the arrow on the tube is pointing
downward and that the o-ring seals around the tube.
3. Connect the rubber hose from chamber 3 to the Dräger tube.
4. With a filter press, collect a sufficient volume of solids free filtrate for
analysis. If a low concentration of soluble sulfides is to be detected, a
large volume of filtrate will be required. Use the table above as a guide.
During the sampling, filtration, and preparation process, the sample
should not be exposed to air for an extended period of time. Sulfides
can be lost rapidly due to air oxidation.
5. Fill the syringe with the measured amount of solid-free filtrate. Place a
rubber septum over the sample entry point above chamber 1. Force the
needle through the septum and inject the filtrate into chamber 1.
6. Slowly inject 10 mL of 5N sulfuric acid solution into chamber 1 through the
rubber septum using the syringe and needle.
7. Immediately start the CO
2
gas flow. Adjust the rate such that the ball in
the flowmeter stays between the two lines. One CO
2
bulb should provide
about 15 to 20 minutes of flow at this rate.
