Function and design
multi N/C pharma HT
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Method variation coefficient
The variation coefficient of the method (relative standard deviation of the method) is
used for the comparison of different calibrations with different calibration ranges.
Correlation coefficient
The correlation coefficient compares the dispersion of the calibration measuring points
of the regression function with the total dispersion of the calibration. If all calibration
measuring points are on the calculated regression function, the correlation coefficient is
+1 or -1. With a positive correlation coefficient, the regression function is increasing,
with a negative coefficient it is decreasing.
Coefficient of determination
The square of the correlation coefficient is called the coefficient of determination.
Limit of verification
The verification limit of the calibration specifies the lowest concentration that can be
differentiated qualitatively from the zero point with a given probability. The verification
limit should always be smaller than the lowest calibration measuring point.
Limit of detection
The detection limit of the calibration specifies the lowest concentration for which a veri-
fication is possible with a given probability.
Limit of determination
The determination limit of the calibration specifies the lowest concentration that can be
differentiated quantitatively from the zero point with a given probability.
3.6.5
Other calculations
For all measurements where multiple injections are carried out, the average value (AV),
the standard deviation (SD) and the variation coefficient (VC) are calculated and dis-
played. For each sample, a tenfold determination can be carried out as a maximum.
Outlier selection
The control and analysis software can automatically select outliers. The user can specify
a maximum limit for the variation coefficient or even for the standard deviation for this.
The analyzer performs the minimum number of measurements specified in the method.
If the distribution of the measured values is then above the specified maximum value
(SD or VC), additional injections are carried out from the same sample until the specified
maximum number of measurements has been reached.
After each measurement, the software determines the variation coefficient and standard
deviation for all combinations of the measured values. If the variation coefficient or the
standard deviation of at least one combination is smaller than the specified maximum
value, no further measurements are carried out.
The software determines the analysis result from the combination of measured values
with the smallest variation coefficient or the smallest standard deviation. The unused
measurements are considered outliers and deleted.
If carbon and nitrogen are detected in parallel, the outlier selection takes place sepa-
rately for each parameter.
Average value
The average value of the final result is calculated from the concentrations determined
for the individual detections after eliminating the outliers.
