Membranes
	Membranes enable a very convenient, fast and economical separation. Often they are also used as a neutral sample support for further analysis.

Overview of available membrane filters
Material	Properties and pore sizes	Type
Cellulose mixed esters	- suitable for aqueous solutions - also available sterile and/or   with grid - recommended for gravimetric    analysis - autoclaving possible at 121 °C - economical - pore sizes 0.2 - 0.45 - 0.65 -   0.8 - 1.2 µm	PORAFIL® CM
Cellulose mixed esters, fabric-reinforced	- suitable for aqueous solutions - higher mechanical stability than   PORAFIL® CM - pore sizes 0.2 - 0.45 - 0.8 -   3.0 µm	PORAFIL® MV
Cellulose nitrate	- thermally stable up to 125 °C - autoclaving possible at 121 °C - pore sizes 0.2 - 0.45 µm	PORAFIL® NC
Polycarbonate	- very low halogen blank values - suitable for quantitative AOX   determination - thermally stable up to 140 °C - pore sizes 0.4 µm	PORAFIL® PC
Cellulose acetate	- suitable for aqueous and many   alcoholic media - low protein binding capacity - thermally stable up to 180 °C - pore sizes 0.2 - 0.45 - 0.8 -   1.2 µm	PORAFIL® CA
Polytetrafluoroethylen (PTFE)	- hydrophobic membrane - suitable for almost all solvents,   chemical resistance towards   acids and bases - for filtration of aggressive   media - thermally stable up to 145 °C - pore sizes 0.2 - 0.45 - 1.0 -   3.0 µm	PORAFIL® TE
Polyester	- chemically very resistant   membrane ( not as stable as   PFTE) - suitable for TOC/DOC    determination - thermally stable up to 150 °C - pore sizes 0.05 - 0.2 - 0.4 - 1.0 -   5.0 µm	PORAFIL® PE
Regenerated cellulose	- suitable for all media except   strong acids and bases - thermally stable up to 180 °C - pore sizes 0.2 - 0.45 µm	PORAFIL® RC