Identify predetermined marker

Hi,
I'm new to NIR-measurement as wenn as chemometrics. My current project involvs the recognition of determined spectra (of a reference system) among others.
The materials are currentlys not really set. So I try to give a predetermined mixture of substances into another matrix and group the measured NIR-spectra according to a) contains predetermined mixture and b) does not contain mixture (but other mixtures could be possible). This way the mixture could be used as a unique marker. 
What would be the best chemometric way to accomplish this task?
Currently I am trying to use PLS-DA, SMC and PCA combined with a distance quantifier.
Thanks for your thought about this.
seb