ISFET probe type

In FIA, chemical-sensing field-effect transistors (Chem. FETs) and ion-selective field-effect transistors (ISFETs) (see sections 2.1.3 and 2.1.4) can be used with notable advantages over the more familiar membrane electrodes - namely miniaturization capability, high signal-to-noise ratio, faster response, decreased contribution of the detector to the creation of sample dispersion, etc. [346]. These types of potentiometric detectors can be reduced in size, enabling their incorporation into a hypodermic needle or other suitable probe, for making in vivo measurements [347]. 

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