Thermo Scientific TVA2020, Инструкция по эксплуатации

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Calibration
Defining the Response Factor
Thermo Fisher Scientific TVA2020 Instruction Manual 4-11
Response Factor
Actual Concentration
Measured Concentration
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A response factor multiplier is defined as follows:
Example : If 100 ppm of a compound produces an FID response of 50 ppm
on an analyzer calibrated with Methane, then the FID response factor
would be 2.00 (100/50).
When using a response factor multiplier to correct a TVA2020 reading, the
analyzer multiplies the reading by the response factor and displays the
corrected reading. As in the example give above, if a 50 ppm reading is
obtained by the TVA2020, the analyzer would automatically multiply 50
times 2.00 to get the actual concentration of 100 ppm.
Response factors can change as concentration changes. The response factor
for a compound determined at 500 ppm may not be the same as the
response factor determined at 10,000 ppm. By using a response curve, you
can characterize a compounds response over a broader range of
concentrations. If the actual concentration is plotted as Y vs. X (measured
concentration), the resulting curve can be represented by the rational
equation
When using the RF Calc Mode “curve”, the terms A and B are entered into
the TVA2020. A represents the response factor multiplier at very low
concentrations and B represents a change to the response for every percent
concentration increase.
The curve can only be defined by collecting response data at several
different concentrations and using a xy math spreadsheet to calculate the
“best-fit” polynomial expression.
Note Once the response curve has been fit, the calibration gas
concentrations and number of span points should not be changed without
readjusting the curve fit.
▲
Response Factor
Multiplier
Response Curve
Y
AX
1
BX
10000ppm
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