Lead
Lead
Page 6 of 8
Lead_None_Other_LTK_Eng_Ody.fm
4. Open a container of 10-mg/L (10,000 µg/L) Lead Standard Solution.
5. Prepare three sample spikes. Fill three beakers 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 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
Using Class A glassware, prepare a 100-µg/L lead working standard solution by
pipetting 1.0 mL of Lead Standard Solution, 1000-mg/L, into a 100-mL
volumetric flask. Use a TenSette
®
Pipet to add 0.2 mL of concentrated nitric acid
to the flask. Dilute to the mark with lead-free deionized water. This makes a
10-mg/L working standard.
Pipet 10.00 mL of this working solution into a 1-liter plastic volumetric flask.
Add 2.0 mL of concentrated nitric acid to the flask. Dilute to the mark with
lead-free water. This 100-µg/L standard solution should be prepared
immediately before use. Perform the LeadTrak
®
procedure as described above.
Alternatively, prepare a 100-µg/L lead standard solution by using a TenSette
®
Pipet to pipet 0.2 mL from a Lead Voluette
®
Ampule Standard Solution,
50-mg/L as Pb, into a 100-mL plastic volumetric flask. Add 0.2 mL of
concentrated nitric acid, and dilute to volume with deionized water. Prepare
this solution immediately before use.
To adjust the calibration curve using the reading obtained with the 100-µg/L
standard solution:
1. Touch
Options on the current program menu. Touch Standard Adjust.
2. 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.
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