Hach DR2400 - Page 64

Procedures Explained
Procedures Explained
Page 64
5940022ProceduresExplained.fm
Sulfide
Sulfide
Sulfide_Procedures Explained_Page 3.fm Page 3 of 4
Interferences
Accuracy Check
Sulfide Standard solutions are very unstable and should be prepared from
sodium sulfate and standardized as described in Standard Methods for the
Examination of Water and Wastewater.
Sample Collection, Storage and Preservation
Collect samples in clean plastic or g lass bottles. Fill completely and cap tightly. Avoid
excessive agitation or prolonged exposure to air. Analyze samples immediately.
Method Performance
Precision
Standard: 275 µg/L S
2–
See Section 3.4.3 Precision for more information, or if the standard concentr ation
did not fall within the specified range.
Sensitivity
See Section 3.4.5 Sensitivity for more information.
Summary of Method
Hydrogen sulfide and acid-soluble metal sulfides react with
N,N-dimethyl-p-phenylen ediamine sulfate to form methylene blue.
The intensity of the blue color is proportion
al to the sulfide concentration.High
sulfide levels in oil field waters may be determined after proper dilution.Test
results are measured at 665 nm.
Required Reagents
Description Qty. required per test Unit Cat. No.
Sulfide Reagent Set (100 tests) .......................................................................................................................22445-00
Includes:
(2) Sulfide 1 Reagent..........................................................................2 mL ................ 100 mL MDB.......1816-32
(2) Sulfide 2 Reagent..........................................................................2 mL ................ 100 mL MDB.......1817-32
Water, deionized .......................................................................................25 mL .............. 4 liters ....................272-56
Required Apparatus
Pipet, volumetric, Class A, 25 mL ..........................................................1 ....................... each ................... 14515-40
Pipet Filler, safety bulb ............................................................................1 ....................... each....................14651-00
Sample Cells, 10-20-25 mL, w/cap.........................................................2 .......................6/pkg.................24019-06
Interfering Substance Interference Levels and Treatments
Strong reducing substances
(sulfite, thiosulfate and hydrosulfite)
Interfere by reducing the blue color or preventing its development
Sulfide, high levels
High concentrations of sulfide may inhibit full color development and require sample
dilution. Some sulfide loss may occur when the sample is diluted.
Program 95% Confidence Limits of Distribution
690 256–294 µg/L S
2–
Portion of Curve ∆Abs ∆Concentration
Entire range 0.010 5 µg/L S
2–
Expected
repeatability
of the
procedure
Amount of
reagents
and
apparatus
needed to
perform the
procedure
Levels of common
sample substances
or conditions that will
cause inaccurate
results
Specific
sampling and
storage
information
for this test
Concise
explanation
of method
Lists all
reagents and
standards
required
for the
procedure
Items
needed to
perform the
procedure
that are not
included
with the
instrument
Confirm
accuracy with
these steps
(in addition,
may also be
used to
troubleshoot a
test, improve
technique,
check
reagents and
to assure
cleanliness of
glassware)