Table 1.

Different Types of In-Line Sensors Used in Biotechnology Process Technology^a, ^b

Type of measurement	Sensor technique	Segment of installation	Mode of measurement
Physical parameters
Temperature	Thermometer	USP and DSP	In-line
Pressure	Thermocouple	USP and DSP	In-line
Redox potential	Membrane pressure sensors, redox (Pt) electrode	USP and DSP	In-line
Chemical parameters
pH	pH electrodes	USP and DSP	In-line
Dissolved gas	Amperometry electrodes, CO2 electrodes	Mostly USP	In-line
Gas phase	Paramagnetic CO2 sensors	Mostly USP	In-line
Dissolved compounds	Spectroscopic sensors (glucose, lactate)	USP and DSP	In-line (mostly in research)
Biological parameters
Biomass	Spectroscopic sensors	USP and DSP
	Impedance sensors	Mostly USP
Cell morphology	Fluorescence sensors	USP	In-line (mostly in research)
	Impedance sensors	USP
Viability	In situ microscopy	USP
DNA/RNA/content	Spectroscopic sensors	USP and/or DSP

^aAbbreviations: DSP, downstream Processing; USP,upstream processing.

^bAdapted, with permission, from [28,29].