Selection Guide for Spectrum Dialysis Membranes
Selecting "the Right Membrane"
The key to a successful dialysis separation is using the RIGHT MEMBRANE under the right conditions. There are 6 steps to follow when selecting a membrane:

Select grade (Biotech or Standard) based on application.
Select type based on chemistry: CE or RC.
Select membrane configuration based on application (tubing, disposable device or flat-sheet system).
Select from among 18 MWCO's based on solute size.
Select from among 5 sizes (disposable device) or from among 16 flat widths (tubing) based on volume.
Select the membrane treatment preferred for your application.
Use Spectrum's Dialysis Parameter Search to help select a product: 

Spectra/Por Biotech Grade Membranes
Biotech membranes are specifically engineered for more critical separation constraints in which an ultrapure membrane with a precise MWCO is required. Since these synthetic membranes are manufactured using a process without metal salts, no pre-treatment or cleaning is required. Biotech membranes are available in 2 membrane types:
Biotech Cellulose Ester (CE)    wide range of selectivity & purity
Biotech Regenerated Cellulose (RC)    combined selectivity, purity & resistance
For ultimate convenience and ease-of-use, Spectrum offers:
Biotech Ready-to-Use Dialysis Devices    small volumes, in-process sampling & rapid dialysis
Spectra/Por Standard Grade Membranes
Ideal for basic, multi-purpose dialysis, this low cost membrane can be used for a wide variety of dialysis applications in which only general separations are required and low level membrane impurities are of little concern. The standard RC type is composed of natural cellulose regenerated from cotton linters for strength and durability.
Standard Regenerated Cellulose (RC)    broad range, low cost lab applications
Membrane Grade:    Biotech    Standard
Membrane Type:    CE    RC    RC
MWCO (Daltons):    100-500, 500-1000, 3.5-5K, 8-10K, 20K, 50K, 100K, 300K, 1000K    3.5k, 8k, 10k, 15k, 25k    1k, 2k, 3.5k, 5k, 6-8k, 10k, 12-14k, 15k, 25k, 50k
Physical Properties:    Opaque, Rigid, Hydrophilic    Opaque, Flexible, Hydrophilic    Clear Flexible, Hydrophilic
Organic Resistance:    Fair    Good    Good
pH Range:    2 - 9    2 - 12    2 - 12
Temperature Limit:    37°C    60°C    121°C
(Autoclavable)
Flat Sheet:    NO    NO    YES
Recommended
Closures:    Universal Only    Universal Only    Universal or Spectra/Por®
Ready-to-Use
Dialysis Devices:    Float-A-Lyzer G2
Tube-A-Lyzer    NO    Dialysis Sacks