**Appendix**

### **A. Chemometrics books**

Here is below a selection of the most interesting books dealing with chemometrics. This list will be convenient as well for the beginner as for the specialist.


 Jackson, J. E., *A user's guide to principal components*. Wiley-Interscience: Hoboken, N.J., 2003; p xvii, 569 p.

PCA: The Basic Building Block of Chemometrics 37

Pourcentages = {};

% components space

% components space

Contrib =[];

**B.2 PCA by SVD** 

[n,p]=size(X);

% Scores T

% Column centering meanX = mean(X);

T = U \* SingularValues;

**C. Chemometrics software list** 

 Minitab (http://www.minitab.com/) Statcon (http://www.statcon.de/)

experimental design.

Coord = X\_Cent\*V\_scores;

Contrib = X\_Cent'\*V\_loadings;

% Size of the data matrix X

X\_Centred = X - ones(n,1) \* meanX;

% Compute scores and loadings simultaneously [U SingularValues Loadings] = svd(X\_Centred);

modelling, prediction, classification, and experimental design.

Eigenvector Research (http://www.eigenvector.com/) sells a PLS\_Toolbox

Chemometry Consultancy (http://www.chemometry.com/)

Coord =[];

end;

on

for i=1:size(D\_scores,1)

Perrcentages{i,1} = strcat('PC',num2str(i));

Perrcentages{i,2} = num2str(D\_scores(i,i)/TotalVP\*100);

% Compute factorial coordinates (scores) for each sample point on

% Compute factorial contributions (loadings) for each sample point

CAMO (http://www.camo.no/) maker of Unscrambler software, for multivariate

Stat-Ease (http://www.statease.com/) maker of Design-Expert DOE software for


## **B. Matlab codes**

TotalVP = trace(D\_scores);
