Hey!
Instead of calculating PCA go with SVD. Take under the under root of sigmas 's' and now you have eigenvalues. Check for kaiser rule and select the column with eigenvalue less than 1
X = [1 2 3 4 5 ; -1 -3 -1 2 4 ; -2 1.5 3 2 -9 ; 1 -1 0.25 2.3 2.2];
[u,s,v] = svd(X)
Please refer to this link for further information