Theory Of Measurement - Thermo Scientific Orion 2230XP User Manual

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Calibration of the Instrument for Measurement Analysis Section 6
ABS HIGH LIMIT = 5 AU or by de-selecting the dilution event
DILUTION EVENT = NOT ASSIGNED
During the analysis of high concentration samples, the system checks the final absorbance
value of the reacted solution and if it exceeds the set limit (ABS HIGH LIMIT) it will execute the
dilution steps and use the calibrated dilution factor to calculate the final concentration.

Theory of Measurement

Measurement in the Orion 2230XP Silica Analyzer is done by measuring the absorbance of a
single wavelength of light through the sample, and comparing the result with the absorbance of
the same wavelength of light through a standard solution of known concentration. If the two
absorbencies match, then the sample concentration is equal to the standard solution.
To facilitate the comparison, the analyzer is first calibrated with standards to determine the
slope and intercept of the range of concentration it can analyze, and then the measurement of
the unknown sample is interpolated along the calibration curve to calculate the unknown
concentration.
i.e., Concentration = (Slope x Absorbance) + intercept. Where Slope and Intercept - Determined
from Calibration. Absorbance - Calculated through measurement.
The two variables (Slope and Intercept) are available for editing in the calibration parameters
menu screen
2230XP Silica Analyzer Thermo Scientific Orion  41