Manganese
Manganese
Manganese_PP_High_POX_Eng_Ody.fm Page 3 of 4
Sample Collection, Storage and Preservation
Collect samples in acid-washed plastic bottles. Do not use glass containers due
to possible adsorption of Mn to glass. If samples are acidified, adjust the pH to
4–5 with 5.0 N Sodium Hydroxide (Cat. No. 2450-32) before analysis. Do not
exceed pH 5, as manganese may precipitate. Correct the test result for volume
additions; see Section 3.1.3 Correcting for Volume Additions on page 29.
Accuracy Check
Standard Additions Method (Sample Spike)
1. After reading test results, leave the sample cell (unspiked sample) in the
instrument. Verify the chemical form.
2. Touch
Options. Touch Standard Additions. A summary of the standard
additions procedure will appear.
3. Touch
OK to accept the default values for standard concentration, sample
volume, and spike volumes. Touch
Edit to change these values. After values
are accepted, the unspiked sample reading will appear in the top row. See
Standard Additions in the instrument manual for more information.
4. Snap the neck off a Manganese Voluette
®
Ampule Standard, 250-mg/L Mn
(Cat. No. 14258-10).
5. Prepare three sample spikes. Fill three Graduated Mixing Cylinders
(Cat. No. 1896-40) with 10 mL of sample. Use the TenSette
®
Pipet
(Cat. No. 19700-01) to add 0.1 mL, 0.2 mL, and 0.3 mL of standard,
respectively, to each sample and mix thoroughly. This will result in a
2.5 mg/L increase in manganese in each sample spike.
6. Analyze each sample spike as described in the procedure above, starting with
the 0.1 mL sample spike. Accept each standard additions reading by touching
Read. Each addition should reflect approximately 100% recovery.
7. After completing the sequence, touch
Graph to view the best-fit line through
the standard additions data points, accounting for matrix interferences. Touch
View: Fit, then select Ideal Line and touch OK to view the relationship between
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
1. Prepare a 10.0-mg/L manganese standard solution by pipetting 10.0 mL of
Manganese Standard Solution, 1000-mg/L, into a 1000-mL volumetric flask.
Dilute to the mark with deionized water. Prepare this solution daily. Perform
the manganese periodate oxidation procedure as described above.
2. The calibration curve can be adjusted to account for variability in laboratory
technique. To adjust the calibration curve using the reading obtained with the
10.0 mg/L standard solution, touch
Options on the current program menu.
Touch
Standard Adjust.
3. Touch
On. Touch Adjust to accept the displayed concentration (the value
depends on the selected chemical form). If an alternate concentration is used,
touch the number in the box to enter the actual concentration, then touch
OK.
Touch
Adjust.
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