GE Analytical Instruments ©2016
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DLM 68100-09 EN Rev. A
Chapter 5: Calibration and Verification
To use the Auto Range feature (see
) all five of the Analyzer’s measurement ranges
should be calibrated.
6
The five calibrations, one for each range that you select for use in the Auto Range
measurement, are stored as a Calibration Group.
Handling Standards
GE Analytical Instruments recommends special handling of all standards to ensure proper preparation and
analysis. Most standards are provided in 250 mL bottles. Before performing calibration or verification, standards
solutions should be transferred into 40 mL vials for use with the Analyzer’s vial port. Additionally, observe the
following practices:
•
Keep all standards containers refrigerated at all times to help ensure stability; store at approximately
5 °C (±4 °), away from light, in a box or solid-door refrigerator. Warm standards to ambient temperature
prior to starting analysis.
•
Certified reference materials should be stored separate from other chemicals, such as IPA, acetone,
and acetic acid.
•
Avoid storage of standards in uncapped containers.
•
Shake the 250 mL bottle containing reference materials prior to pouring into vials.
•
Remove vial caps only when prepared to pour standards and replace caps immediately after pouring.
•
Avoid handling of vial septa. Also avoid touching the top of the vial to protect against introducing
foreign particles, TOC, and IC.
•
Wear gloves when preparing standards.
•
Pour standards in a clean area to avoid introducing contaminants.
Prepare IC Standard Solution
The IC calibration requires one to six IC standard(s), and the concentration of the standard(s) should equal the
expected concentration of the samples that will be analyzed.
Prepare the IC standard(s) solution using anhydrous sodium carbonate (Na
2
CO
3
) with a purity of 99.9
+
%. The
Na
2
CO
3
should be dried at 250 °C for one hour. Cool the dry Na
2
CO
3
in a desiccator prior to weighing.
For example, a 50-ppm IC solution can be prepared by dissolving 0.221 g of dried Na
2
CO
3
in 500 mL of distilled
water or equivalent. Other concentrations can be prepared by proportioning the weight of Na
2
CO
3
or volume of
water.
6.
The Auto Range feature can be used without calibrating all five ranges; however, it will not be as accurate
as when the ranges are calibrated. When any of the ranges are not calibrated, the default calibration
constants for that range are used. This method is useful for a quick, approximate measurement of an
unknown sample.
