Chemical sensors, technological evolution

In recent years, the evolution of the technological components required for IR sensor systems has been denoted by a significant miniaturisation of light sources, optics and detectors. Essentially, an IR sensor consists of (i) a polychromatic or monochromatic radiation source, (ii) a sensor head and (iii) a spectral analyser with a detector. As sensors where all optical elements can be included in the sensor head are the exception rather than the rule, also various optics, waveguides and filters may form essential parts of IR-optical chemical sensors. Another important building block, in particular when aiming at sensors capable of detecting trace levels, are modifications of the sensor element itself. 

In the last decade, a rapid technological evolution took place in the field of chemical sensors in general, and enzyme based sensors in particular (7). This progress has been at least partly due to the commercial interest in sensor technology for diagnostic medicine, both for real-time analysis of metabolites in metabolically unstable patients and rapid bed-side monitoring (2-J). 

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