Hach DR2400 - Page 737

Sulfate
Sulfate
Sulfate_AVPP_Other_SV4_Eng_Ody.fm Page 5 of 6
Calibration Standard Preparation
To perform a sulfate calibration using the SulfaVer method, use Class A
glassware to prepare calibration standards containing 10, 20, 30, 40, 50, 60 and
70 mg/L SO
4
2–
as follows:
1. Into seven different 100-mL Class A volumetric flasks, pipet 1, 2, 3, 4, 5, 6,
and 7 mL of the 1000-mg/L Sulfate Standard Solution.
2. Dilute to the mark with deionized water. Mix thoroughly.
3. Using the SulfaVer method and the calibration procedure described in the
User-Entered Programs section of the spectrophotometer Instrument Manual,
generate a calibration curve from the calibration standards prepared above.
Method Performance
Precision
Standard: 30 mg/L SO
4
2–
See Section 3.4.3 Precision on page 44 for more information, or if the standard
concentration did not fall within the specified range.
Sensitivity
See Section 3.4.5 Sensitivity on page 44 for more information.
Summary of Method
Sulfate ions in the sample react with barium in the SulfaVer 4 and form a
precipitate of barium sulfate. The amount of turbidity formed is proportional to
the sulfate concentration. The SulfaVer 4 also contains a stabilizing agent to hold
the precipitate in suspension. Test results are measured at 450 nm.
Required Reagents
Quantity Required
Description per test Unit Cat. No.
SulfaVer
®
4 Reagent Powder Pillows ....................................................1 ....................... 100/pkg.............21067-69
or
SulfaVer
®
4 Sulfate Reagent AccuVac Ampuls ....................................1 ....................... 25/pkg...............25090-25
Required Apparatus
Beaker, 50-mL............................................................................................1 ....................... each........................500-41
Sample cells, 10-mL, w/cap....................................................................2 ....................... 6/pkg.................24276-06
Required Standards
Sulfate Standard Solution, 1000-mg/L............................................................................ 500 mL...............21757-49
Sulfate Standard Solution, 1000-mg/L, 2-mL Ampules ............................................... 20/pkg...............21757-20
Water, deionized ................................................................................................................. 4 liters ....................272-56
Program 95% Confidence Limits of Distribution
680 27–33 mg/L SO
4
2–
685 18–43 mg/L SO
4
2–
Program ∆Abs ∆Concentration
680 0.010 1 mg/L SO
4
2–
685 0.010 2 mg/L SO
4
2–