Beckman Coulter UniCel DxC 600, Инструкция по эксплуатации

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A13914AF
8-15
User Defined Reagents
Wavelength Selection
8
IMPORTANT
The system may accept incorrect calibration data if:
• multipoint span values are not entered during UDR setup,
• span values of 0 are entered, and/or
• the samples are not loaded correctly during the run.
Wavelength Selection
Introduction
The UniCel DxC 600/800 provides a selection of ten wavelengths ranging throughout the UV-visible
spectral region from which to measure the absorbance of a desired analyte. These are 340, 380, 410,
470, 520, 560, 600, 650, 670, and 700 nm. In order to run a user-defined reagent, two wavelengths are
required: the primary or analysis wavelength, and the secondary or reference wavelength.
Primary Wavelength Selection
Knowledge of the spectral curve of the chromophore of interest facilitates proper selection of
wavelengths. The primary wavelength is selected based on the maximum absorbance peak
obtained using the desired chromophore. The secondary wavelength, which will vary depending on
the properties of the chromophore, is used to compensate for variations in the light intensity each
time the xenon lamp is flashed. For a detailed description of the principles of flash correction, refer
to CHAPTER 2,
Theory of Operation in the UniCel DxC Synchron Clinical Systems Reference Manual .
Secondary Wavelength Selection
To select the optimal secondary wavelength for a given analyte, the following criteria are
recommended:
•
The secondary wavelength should be as close to the primary wavelength as possible without
overlapping the spectral curve of the desired chromophore. The secondary reference
wavelength should be near the base of the analytical absorption curve. If the wavelength
selected resides on the spectral curve, a loss of sensitivity may result.
•
In order to minimize any optical interference due to the presence of another absorption curve,
the selection of the secondary wavelength will depend on the location of the other curve in
relation to the primary wavelength of the desired chromophore. If the second curve overlaps
the primary wavelength, there may be an interference; however, proper selection of the
secondary wavelength can function as a "bichromatic" measurement effectively minimizing or
eliminating absorbance due to the interfering substance. In this instance, the secondary
wavelength should be on the interfering curve at or near a point where the absorbance is at the
same level as the crossover absorbance on the primary wavelength. If, however, the second
curve does not interfere at the primary wavelength, the secondary wavelength should not be
selected within the area encompassed by that curve.