A multi-analyte sensor system based on hollow core photonic bandgap fiber and Raman anti-Stokes spectroscopy. The system includes: i) an inlet to introduce an analyte sample into an analyzer chamber which analyzer includes; ii) a measurement system to derive the anti-Stokes spectral peaks and/or spectra of the sample; iii) a set of reference calibrants corresponding to the analytes of which the sample is primarily comprised; iv) a second inlet to introduce said calibrants into the analyzer chamber; v) a second measurement system to derive the anti-Stokes spectral peaks and/or spectra of the calibrants vi) an outlet through which the sample and calibrants are expelled from the analyzer chamber.