The electrocapture technology was developed to find more efficient

strategies to perform sample preparation in microfluidic devices.

       The electrocapture device utilizes an electric field to trap or immobilize

charged molecules traveling in a flow stream. The electric field -of appropriate

strength and direction- is applied  on a microfluidic channel where an

electrolyte is continuously flowing into the system.  As the sample flows

into the electrified area, charged molecules attracted towards the upstream

junction are captured by means of the counteracting effects of hydrodynamic

and electrical forces.

                                         Basics of Electrocapture

                             Capture of Negatively Charged Molecules

           After sample treatment, the immobilization is reverted by turning off

the power supply, by which the captured molecules are released into the

flow stream for collection or injection into an analytical system. A schematic

representation of the electrocapture of molecules is illustrated below.

          Meanwhile the sample is captured, another solution can be injected into

system. The solution can contain reagents or a particular chemical composition

by which multistep microreactions [Ref 1] or sample cleanup [Ref 2] can be achieved.

In addition, as in the system the sample is captured into a few nanoliters,

several microliters of sample can be injected and concentrated in a sharp band

of about 30 nL [Ref 3].

          In 2005 the Journal Analytical Biochemistry kindly asked me to write a review

about the applications explained above, please refer to that article if you want to

have a nice introduction to this technology [Ref 4].  

          Furthermore, the very same system can be used to fractionate/separate

polypeptides by using voltage-gradient elution [Ref 5].

         Feel free to contact me for comments, questions or collaborations [email me].