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Zinc
Digestion
Method Performance
Zinc
Page 4 of 6
7. After completing the sequence, touch
the standard additions data points, accounting for matrix interferences. Touch
, 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 1.00-mg/L zinc standard solution as follows:
1. Using Class A glassware, pipet 10.00 mL of Zinc Standard Solution,
100-mg/L, into a 1000-mL volumetric flask. Dilute to the mark with
deionized water. Prepare this solution daily. Perform the Zincon procedure
as described above.
2. To adjust the calibration curve using the reading obtained with the
1.00-mg/L Zinc standard solution, touch
menu. Touch
Standard Adjust
See Section 3.2.4 Adjusting the Standard Curve on page 40 for more information.
Digestion is required if total zinc is being determined. The following is not the
USEPA digestion (see Section 2.3 Digestion for more information).
a. If nitric acid has not been added to the sample previously, add 5 mL of
Concentrated Nitric Acid (Cat. No. 152-49) to one liter of sample (use a
glass serological pipet and pipet filler). If the sample was acidified at
collection, add 3 mL of nitric acid to one liter of sample.
b. Transfer 100 mL of acidified sample to a 250-mL Erlenmeyer flask.
c. Add 5 mL of 1:1 Hydrochloric Acid (Cat. No. 884-49).
d. Heat sample on a Hot Plate (Cat. No. 12067-01, -02) for 15 minutes at
95 °C (203 °F). Make sure the sample does not boil.
e. Filter cooled sample through a membrane filter and adjust the volume to
100 mL with Deionized Water (Cat. No. 272-56).
f. Adjust the pH to 4–5 with 5.0 N Sodium Hydroxide (Cat. No. 2450-26)
before analysis (see Sample Collection, Preservation and Storage for
instructions).
Precision
Standard 1.00 mg/L Zn
Program
780
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.
Graph
and touch
Ideal Line
OK
Options
.
95% Confidence Limits of Distribution
0.95–1.05 mg/L Zn
∆Abs
0.010
to view the best-fit line through
to view the relationship between
on the current program
∆Concentration
0.01 mg/L Zn
Zinc_PP_Other_ZNC_Eng_Ody.fm
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