Molybdenum, Molybdate
Molybdenum, Molybdate
Page 4 of 6
Molybdenum_PP_Low_TER_Eng_Ody.fm
Sample Collection, Storage and Preservation
Collect samples in glass or plastic bottles. Analyze samples immediately.
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 Molybdenum Voluette
®
Ampule Standard,
500-mg/L Mo
6+
.
5. Prepare three sample spikes. Fill three mixing cylinders (Cat. No. 1896-42)
with 100 mL of sample. Use the TenSette
®
Pipet to add 0.1 mL, 0.2 mL, and
0.3 mL of standard, respectively, to each sample and mix thoroughly.
6. Analyze 20 mL of each standard addition sample 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, a graph of the best-fit line through the
standard additions data points will appear, accounting for matrix
interferences. Touch
Ideal Line 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 Solutions Method
1. Using Class A glassware, prepare a 2.00-mg/L molybdenum standard
solution by pipetting 10.00 mL of Molybdenum Standard Solution,
10.00-mg/L, into a 50-mL volumetric flask. Dilute to the mark with
deionized water. Prepare this solution daily. Perform the molybdenum
procedure as described above.
2. To adjust the calibration curve using the reading obtained with the
2.00-mg/L Mo 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.
See Section 3.2.4 Adjusting the Standard Curve on page 40 for more information.
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