NWT has supplied ion exchange membrane (soluble metal ions) and filter (solid metal oxide) standards to numerous clients including instrument manufacturers and power generation facilities. The ion exchange membranes are prepared by passing a solution containing soluble metals through the membranes. The filters are manufactured by passing a water suspension of solid metal oxides through the filters. Using this approach, a distribution comparable to actual samples is developed on both the membranes and the filters. The metal oxides are slightly radioactive. The total activity per filter is usually less than one µCi.
NWT has successfully prepared membranes and filters loaded with chromium, cobalt, copper, iron, manganese, nickel and zinc. Loadings range from approximately 0.01 to 10 mg/filter. Due to the nature of the production technique used for the filters, NWT employs two different approaches. In the first approach, NWT prepares multiple standards at one time and provides a listing of available filter loadings to clients. Clients can then choose filters to meet their calibration requirements. The second approach is to have clients specify the filter loadings for the filters. However, there are limitations to the specifications which must be discussed with NWT. More flexibility is available relative to ion exchange membrane loadings. However, the loading is limited to the capacity of the membrane. Either Nanodex CX|200© or Toray RX-1© membranes can be supplied. Customers can specify the loadings they require on ion exchange membranes.
Additional information on other types of custom filters can be found on the Custom Filter Page.
For more information, including pricing, contact Mike Miller at NWT at (408) 281-1100 or firstname.lastname@example.org.