Copper
Copper
Copper_UniCell_Other_BATH_Eng_Ody.fm Page 3 of 4
Accuracy Check
Standard Additions Method (Sample Spike)
1. After reading test results, leave the sample cell (unspiked sample) in the
instrument.
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. Prepare three sample spikes. Fill three mixing cylinders with 100 mL of
sample. Pipet 0.1 mL, 0.2 mL, and 0.3 mL of 1000-mg/L Cu standard,
respectively, to each sample and mix each thoroughly.
5. Transfer 4 mL of each solution to three sample vials and analyze as described
in the procedure. Accept each standard additions reading by touching
Read.
Each addition should reflect approximately 100% recovery.
6. 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 Solutions Method
Prepare a 2.00-mg/L Standard as follows:
1. Pipet 0.2 mL of 1000-mg/L Cu into a 100-mL volumetric flask. Dilute to the
mark with deionized water. Stopper and invert to mix. Prepare this solution
daily. Perform the copper procedure as described.
2. To adjust the calibration curve using the reading obtained with the
2.00-mg/L standard solution, touch
Options on the current program menu.
Touch
Standard Adjust.
3. Touch
On. Touch Adjust to accept the displayed concentration. 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.
Method Performance
Precision
Standard: 2.00 mg/L Free Cu
See Section 3.4.3 Precision on page 44 for more information, or if the standard
concentration did not fall within the specified range.
Program 95% Confidence Limits of Distribution
146 1.76–2.24 mg/L Free Cu
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