Frequently Asked Questions

We have a Chemical Compatibility Chart that you can use for reference.

Ideally, nitrocellulose (NC) membranes would be made entirely of nitrocellulose polymer. However, almost all commercially available filtration grade membrane filters labeled as “nitrocellulose” are actually composed of membranes made with a mixture of nitrocellulose and cellulose acetate polymers. This is because pure nitrocellulose membrane filters are very difficult to manufacture with acceptable characteristics. 

In an effort to provide clarity to consumers, some manufactures refer to membranes containing a mixture of nitrocellulose and cellulose acetate polymers as mixed cellulose esters (MCE) membranes. In almost all filtration applications, mixed cellulose esters (MCE) membrane filters are equivalent to nitrocellulose (NC) membrane filters.

Yes, the MCE membrane filters do have a limited shelf life. The MCE membranes necessarily contain wetting agents that improve performance by ensuring good wettability with water and aqueous solutions. Prolonged storage of the MCE membrane filters, especially after the packaging has been opened, may allow the wetting agents to degrade. For optimal filter performance, it is recommended that the MCE filters be consumed within one year from being received.

The grid dimensions are 3mm x 3mm. The average number of squares for a 47 mm disc filter is 185.

Sterile mixed cellulose esters (MCE) membrane filters are used in vast quantities for microbiological studies across many industries and are manufactured in very high volumes to accommodate this demand.  Economies of scale and process automation allow the sterile MCE membrane filters to be offered at lower pack costs compared to non-sterile MCE membrane filters.  Non-sterile MCE filters are used much less frequently, necessitating less efficient, smaller volume manufacturing runs and packaging methods.  Consequently, the non-sterile MCE membrane filters have intrinsically greater manufacturing costs and must be offered at higher prices.

Unfortunately, in most instances, we are unable to supply the MCE membrane filters with custom diameters. Please inquire with your Sterlitech sales representative about alternatives.

MCE membranes feature fast flow rates, a high protein binding capacity, and great thermal stability, making them a staple for many environmental and biological laboratories. Furthermore, they are available as presterilized, individually wrapped membranes, and can include a gridded pattern for quantifying microbial growth.