Evaluation with Various Standard MethodsTheory of Calibration
Evaluation with Various Standard Methods
Below please find a description of how Chromeleon calculates calibration points, which form the basis for any calibration function F. Note that the formula used for the calculation depends on the selected 
Standard Methods (External, Internal/External (with/without var. ISTD), Internal (with/without var. ISTD)).
For evaluating unknown samples, i.e., calculating the Amount values, the inverted form of the corresponding Calibration Function F is used (=inverted function A). This means that the c0, c1, c2, and c3 calibration coefficients form function A that is inverted for amount calculation. The result is F(x).
Tip:
For the formulas for the Standard Addition method, refer to Evaluation with the Standard Addition Method.
'External' Evaluation:
Calibration:
Y(i,k) = RESPONSE(i,k)
X(i,k) = AMOUNT_NOMINAL(i,k) * WEIGHT(k)/DILFAC(k) * INJECTVOL(k)/REFINJECT
Evaluation: Calculation of the Amount peak variable for peak i in the sample x
AMOUNT(i,x) = DILFAC(x)/WEIGHT(x) * RSP-FACTOR(i) * F[RESPONSE(i,x)]
Description: see below.
'Internal' Evaluation:
Calibration:
Y(i,k) = 100 * RESPONSE(i,k)/RESPONSE(ISTD,k)
X(i,k) = AMOUNT_NOMINAL(i,k) * WEIGHT(k)/DILFAC(k)
Evaluation: Calculation of the Amount peak variable for peak i in the sample x
AMOUNT(i,x) = DILFAC(x)/WEIGHT(x) * RSP-FACTOR(i) * F[100 * (RESPONSE(i,x)/RESPONSE(ISTD,x)]
The ISTD peak itself will not be evaluated!
Description: see below.
'Internal' Evaluation (with variable ISTD):
Calibration:
Y(i,k) = AMOUNT_NOMINAL(ISTD) * RESPONSE(i,k)/RESPONSE(ISTD,k)
X(i,k) = AMOUNT_NOMINAL(i,k) * WEIGHT(k)/ DILFAC(k) * INJECTVOL(k)/REFINJECT
Evaluation: Calculation of the Amount peak variable for peak i in sample x
AMOUNT(i,x) = DILFAC(x)/WEIGHT(x) * RSP-FACTOR(i) * F[AMOUNT_SOLL(ISTD) * (RESPONSE(i,x)/RESPONSE(ISTD,x)]
The Internal Standard ("ISTD") peak itself is not evaluated!
Description: see below.
'Internal/External' Evaluation:
Calibration:
'External' calibration, including the ISTD peak! (Also, refer to 'External')
Evaluation: Calculation of the Amount peak variable for peak i in the sample x
The ISTD peak itself is evaluated 'Externally'!
FACTOR_IS(x) = AMOUNT_NOMINAL(ISTD)/AMOUNT(ISTD,x)
AMOUNT(i,x) = DILFAC(x)/WEIGHT(x) * RSP-FACTOR(i) * FACTOR_IS(x) * F[RESPONSE(i,x)]
Description: see below.
'Internal/External' Evaluation (with variable ISTD):
Calibration:
Calibration is 'External', including the ISTD peak! However, the nominal amount for the ISTD peak from the sample list (ISTD Amount) is used. The sample weight of the ISTD peak is not considered.
Y(i,k) = RESPONSE(i,k)
X(i,k) = AMOUNT_NOMINAL(i,k) * WEIGHT(k)/DILFAC(k) * INJECTVOL(k)/REFINJECT
X(ISTD,k) = AMOUNT_NOMINAL(ISTD,k) * 1/DILFAC(k) * INJECTVOL(k)/REFINJECT
Evaluation: Calculation of the Amount peak variable for peak i in the sample x
The ISTD peak itself is evaluated 'Externally', but without Weight correction.
AMOUNT(ISTD,x) = DILFAC(x) * RSP-FACTOR(ISTD) F[RESPONSE(ISTD,x)]
FACTOR_IS(x) = AMOUNT_NOMINAL(ISTD,x)/AMOUNT(ISTD,x)
AMOUNT(i,x) = DILFAC(x)/WEIGHT(x) * RSP-FACTOR(i) * FACTOR_IS(x) * F[RESPONSE(i,x)]
Description:
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F: |
Calibration function |
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X(i,k): |
X-coordinate of a calibration point for peak i for the standard sample k |
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Y(i,k): |
Y-coordinate of a calibration point for peak i for the standard sample k |
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k: |
Calibration sample (standard) |
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x: |
Unknown sample (analysis sample) |
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RESPONSE(i): |
Reference variable (Int.Type; that is, Area, Height, CE-Area) of peak i in a sample |
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RESPONSE(ISTD): |
Reference variable (Int.Type; that is, Area, Height, CE-Area) of the corresponding ISTD peak of a sample |
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AMOUNT_NOMINAL(i): |
Amount of peak i from the amount table for the standard sample k |
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AMOUNT_NOMINAL(ISTD): |
ISTD Amount for the sample k from the sample list |
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AMOUNT(ik): |
Calculated amount of the peak i for the sample k |
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WEIGHT: |
Weight (Sample Weight Factor) for a sample |
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DILFAC: |
Dil. Factor (Dilution Factor) for a sample |
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INJECTVOL: |
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REFINJECT: |
Injection volume of the first sample in a calibration series |
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RSP-FACTOR(i): |
Response Factor of the peak i from the QNT amount table |