Calibration; Equipment Required - Thermo Scientific 410i Instruction Manual

Chapter 4

Calibration

This chapter describes the procedures for performing a standard zero/span
calibration and a multipoint calibration of the Model 410i. The
information described here is more than adequate to perform the
calibration. However, if greater detail is needed, please refer to the Quality
1
Assurance Handbook for Air Pollution Measurement Systems .
The following sections discuss the required apparatus and procedure for
calibrating the instrument.

Equipment Required

The following equipment is required to calibrate the instrument:
CO Concentration
A cylinder of CO in air containing an appropriate concentration of CO
2
2 2
suitable for the selected operating range of the analyzer under calibration is
Standard
necessary. The assay of the cylinder must be traceable either to a National
Institute of Standards and Technology (NIST) CO in Air Standard
2
Reference Material (SRM) or an NIST/EPA approved gas manufacturer's
Certified Reference Material (CRM).
A recommended protocol for certifying CO gas cylinders against a CO ,
2 2
SRM or CRM is given in the Quality Assurance Handbook 1 . The CO gas
2
cylinder should be recertified on a regular basis determined by the local
quality control program.
Zero Air Generator
Calibration requires zero air that is free of contaminants which will cause a
detectable response on the CO analyzer. The zero air should contain <0.5
2
ppm CO .
2
Depending on the grade, zero air as supplied in cylinders from commercial
suppliers typically contains CO concentrations in the 0.1 to 400 ppm
2
range. So cylinder zero air should be scrubbed of the residual CO prior to
2
its use in the instrument as a dilution gas or a zero standard.
It is also possible to use a zero air generator in place of zero air cylinders.
Zero air generation is a three-step process involving:
Thermo Fisher Scientific Model 410i Instruction Manual 4-1