Intercept and Centring

In many situations it is appropriate to include extra terms in the calibration model. Most commonly an intercept (or baseline) term is included to give an inverse model of the form 

Concentration (mgC1) Absorbance at 335 nm Predicted concentration (mgr1) 

Best fit straight lines for classical and inverse calibration data for pyrene at 335 nm, no intercept 

Exactly the same principles can be employed for calculating the coefficients as in Section 2.1.2, but in this case b is a vector rather than scalar, and AT is a matrix radier than a vector, so that 

The predicted concentrations are fairly easy to obtain, the easiest approach involving file use of matrix based methods, so that 

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