Static Filtration

The BJP concentrates urine through the absorption of water by absorbent pads located on the underside of an ultrafiltration membrane. Bence Jones protein will be retained on the membrane surface in the front compartment of the BJP unit because it has a 7.5 kDa MWCO membrane, a molecular weight cut-off far from the molecular weight of Bence Jones protein itself. BJP concentrators offer a fast, gentle and convenient method to concentrate multiple clinical samples for analyses by electrophoresis and immunofixation.

No pressure lines, vacuum pumps or centrifuges are required. The procedure is simple and straightforward. The operator loads the sample into the bench-top concentrator, waits for the sample to concentrate and recovers the protein concentrate with confidence. A BJP 5 unit filled with 5 ml urine typically takes about 30-40 min for a 100 fold concentration with recoveries of at least 95-98 % BJP. The BJP 20 static concentrator performs a 100 fold concentration of 10 ml urine in 50 min. The hands-off operation allows the operator time to continue with other analyses in a busy laboratory environment while the device is left unattended to concentrate the urine samples. The impermeable dead stop pocket prevents the urine sample from concentrating to dryness.

BJP concentrators enable rapid and easy concentration of samples:

  • Up to 50% faster than the leading device
  • 20% less expensive than the leading device
  • Up to 98% recovery rate
  • Never over concentrates
  • Easy to fill
  • Easy to read
  • Easy sample removal
  • Choice of formats

Urine Concentrators

Centrifugal Filtration

Centrifugation allows for clear solvent and micro molecules to pass through the ultrafiltration membrane and into a filtrate container positioned below. This is a gentle process that is characterized by quick set up and fast filtration speeds with most solutions.


Vivaproducts has been supplying the highest quality products to the clinical diagnostic marketplace for over 20 years. In 2008 they began offering new products for the purification of DNA in the forensic laboratory market. Vivaproducts are the widest supplier of concentrators to commercial and hospital labs. Their products are consistent, efficient and of the highest quality.

 When testing for the detection of Bence Jones Proteins in Urine Protein Electrophoresis (UPE) or Urine Immunofixation (UIF) there are several important factors to consider when selecting a concentrator used to optimize recovery of these proteins.

Molecular Weight Cut Off:

The Molecular Weight Cut Off (MWCO) is an important consideration when selecting a concentrator. Bence Jones protein is typically around 20,000 – 24,000 Kilodaltons (kDa). The MWCO quoted on various concentrators will have up to a 20% variation in the membrane pores.  You want to ensure that the pore size of the membrane is small enough to capture the protein you wish to retain. An optimum pore size for the capture of a Bence Jones protein will be around 7,500 – 10,000 kDa (depending on type used) to ensure no loss of protein. If the concentrator has a pore size of 15,000 kDa, then the actual size of the pores within the membrane may vary between 12,000 to 18,000 kDa.

Membrane Type:

The membrane used should be highly hydrophilic, if attempting to isolate proteins that are below 50,000 kDa molecular weight. This minimizes protein loss and ensures good recovery.

Static vs. Centrifugal:

The pore size is an important consideration in a static concentrator and is equally important when selecting a centrifugal concentrator. For example, a pore size of 7,500 MWCO will have a significantly different recovery with a static concentrator vs. a centrifugal concentrator due to the force involved. The ideal pore size for the recovery of a Bence Jones protein in a centrifugal concentrator should be around 10,000 kDa.

Other Considerations:

Concentrators that allow for the use of a plastic transfer pipet for added safety in addition to easy-read graduations should be considered.

Somagen now offers the Vivaproducts range of static and centrifugal concentrators for concentrating urines.

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