The primary purpose of the Concentrating Pipette Select system is for the concentration of particles. the CPT has the ability to remove all of the liquid from the sample, capturing the particles of interest, then delivering the captured particles into volumes of clean buffer as small as 150 microliters.

Common methods for sample concentration include serial filtration steps by manual methods and centrifugation. Both are time, labor, and material intensive. 

The Concentrating Pipette has the ability to deliver those particles into an extremely small final volume to match the input volume of detection methods such as immunoassay, PCR etc., thus enabling detection at previously undetectable levels.  The automated one-pass system rapidly reduces sample volume while removing matrix-associated inhibitors - providing more efficient and streamlined laboratory processes. The process is very rapid and allows large sample volumes to be concentrated into a standard analysis volume in minutes.

The concentration process uses microfiltration to capture particles onto the surface of a porous membrane filter within the Concentrating Pipette’s single-use tip. After the sample has been processed and the particles have been trapped, InnovaPrep’s patented Wet Foam Elution™ process is employed to wash the particles off of the membrane surface into a very small liquid volume, to match the input sample volume required for the chosen rapid detection methods.


The overall efficiency is the percent of target microparticles that are concentrated and eluted (recovered) from the CPT.  Several factors can affect efficiency, including the nature of the liquid matrix itself, the shape and nature of the microparticles, charges native to the particles, stickiness of the particles and combinations of other nebulous factors.  Efficiency for any type of sample generally has to be determined experimentally, due to these interactions.  While efficiency will vary between sample types, efficiency is generally consistent for samples of the same type.  Efficiency can also vary based on the analytical method and the variability inherent in either the sample or the analytical method.  Efficiencies from 50% to over 90% are common for many types of samples. 

Concentration Factor  

The Concentration Factor is the actual mathematical advantage that the CPT provides to you.  Concentration factor is calculated as follows: 

1. Calculate the liquid to liquid concentration factor 

2. Multiply that figure by the efficiency for the sample that was run. 

3. The result is the “CF” or concentration factor for that sample.

Technical Tip

Note that the higher the initial volume, and the lower the final volume, the higher the CF will be. Efficiency is not the most important factor; it is important, but the CF being high is what gives the most target particles to the analytical device, kit, strip, instrument, or whatever analysis method that is used.

Your samples are special. These examples and a work space will help you determine your options and potential concentration factor. 

Your Samples:1. ___ mL concentrated to _.__ mL  =

   ___/_.__ = ______X Liquid : Liquid

2. ______X x ___% recovery = 

   _____ x 0.___ = ______X Concentration

Processing a larger sample to start with gives a much larger concentration factor.

Example 1:100 mL concentrated to 0.25 mL =

100/0.25 = 400X

400X x 80% recovery =  

400 x 0.80 = 320X CF

Example 2:

1000 mL concentrated to 0.25 mL =    

1000/0.25 = 4000X  Liquid : Liquid  

4000X x 80% recovery  =  

4000 x 0.80 = 3200X Concentration

Example 3: 500 mL concentrated to 0.15 mL (150     

microliters, “small” setting)  =  500/0.15 = 3333X Liquid : Liquid  

3333  x 61% recovery  =  

3333 x 0.61 = 2033X Concentration

Example 4:

50 mL concentrated to 0.25 mL (250

microliters, “medium” setting) =   50/0.25 = 200X Liquid : Liquid

200X x 95% recovery  =  

200 x 0.95 = 190X Concentration