A sample sensor (200) for detecting a concentration of a sample in a sample mixture, the sample sensor (200) comprising a light source (101), a detector element, a processing section (106) and parameter measuring means. The light source (101) produces a light beam (113) for exciting molecules of the sample. The detector element detects an 5 amount of excited molecules of the sample and provides a detector current indicating the amount. The processing section (106) is coupled to the detector element (103) for processing the detector current to generate an output signal (109) representing the concentration. The processing section (106) comprises a temperature compensation module (112) being arranged for compensating for a temperature dependent wavelength shift of the light source (101) 10 based on at least one measured value of a temperature dependent parameter of the light source (101), other than an output wavelength. The parameter measuring means obtain the at least one measured value.