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Selenium
Method Performance
Summary of Method
Selenium
Page 6 of 8
, then select
View: Fit
the sample spikes and the "Ideal Line" of 100% recovery.
See Section 3.2.2 Standard Additions on page 32 for more information.
Standard Solution Method
Prepare a 0.5-mg/L Se standard solution as follows:
1. Pipet 1.00 mL of a Selenium Standard Solution, 100-mg/L, into a 200-mL
volumetric flask. Dilute to volume with deionized water. Transfer 100 mL of
the standard into a 500-mL Erlenmeyer flask. Perform the test as described
above.
2. To adjust the calibration curve using the reading obtained with the 0.5-mg/L
standard solution, touch
.
Standard Adjust
3. Touch
. Touch
On
Adjust
concentration is used, touch the number in the box to enter the actual
concentration, then touch
See Section 3.2.4 Adjusting the Standard Curve on page 40 for more information.
Precision
Standard: 0.500 mg/L Se
Program
640
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
Portion of Curve
Entire range
See Section 3.4.5 Sensitivity on page 44 for more information.
An EDTA masking agent is added to the sample to remove interferences such as
iron prior to the test. The addition of a sulfate buffer adjusts the sample to the
optimum pH of 1 to 2. Under these conditions, diaminobenzidine reacts with all
selenium present as selenite (Se
which is extracted and the color intensity measured colorimetrically. Selenium
2+
6+
present as Se
and Se
are measured at 420 nm.
and touch
Ideal Line
OK
on the current program menu. Touch
Options
to accept the displayed concentration. If an alternate
. Touch
.
OK
Adjust
95% Confidence Limits of Distribution
0.486–0.514 mg/L Se
∆Abs
0.010
4+
) to give a yellow-colored piazselenol complex
is not detected unless the sample is distilled. Test results
to view the relationship between
∆Concentration
0.01 mg/L Se
Selenium_None_Other_DAB_Eng_Ody.fm
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