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 membrane standards are prepared by passing a solution containing soluble metals through the membranes. The filter standards 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 membrane and the filter standards. The metal oxides on the filter standards are initially slightly radioactive. The total activity per filter standard is usually less than one µCi.
NWT has successfully prepared membrane and filter standards 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 filter standards, 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 filter standards to meet their calibration requirements. The second approach is to have clients specify the filter loadings for the filter standards. However, there are limitations to the specifications which must be discussed with NWT. More flexibility is available relative to ion exchange membrane standard loadings. However, the loading is limited to the capacity of the membrane. Either Nanodex CX|200© or Toray RX-1© membrane standards can be supplied. Customers can specify the loadings they require on ion exchange membrane standards.
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.