Pyxis SP-900 - Absorbance Measurement; Performing Absorbance Measurement

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6 Absorbance Measurement
The following steps are used to measure the absorbance values of a sample:
1. Press the Absb icon to launch the absorbance measurement page.
2. Place a vial filled with the blank sample in the sample vial compartment. Press
the ZERO button to zero the method.
3. Place a vial filled with the sample in the sample vial compartment. Press the
READ button to read absorbance. The absorbance values of first 6
wavelengths (table 3) will be shown. Press the READ button again to show the
absorbance values of the last three wavelengths.
Figure 16 Absorbance Measurement
Press EXIT to return to the main page. Timing function for absorbance measurement may
not be available for some models.
Table 3 Wavelength of each channel
Channel
Wavelength (nm)
1
560
2
570
3
630, high gain
4
525, high gain
5
455
6
525
7
365
8
630
9
420
Note that the absorbance values measured with Pyxis SP-900 is generally smaller than
those measured with a spectrophotometer equipped with a monochromatic light source or
detector. The Pyxis SP-900 absorbance values should, however, linearly correlate with
the absorbance values measured with the spectrophotometer. Thus for any colorimetric
system, Pyxis SP-900 absorbance follows Lambert-Beer law.