Abstract: A free-flow electrophoresis apparatus introduces a pressure-driven flow laterally through the sidewalls of a separation chamber. A neutral solute is hydrodynamically focused by the lateral flow before being collected through an outlet at a bottom of the chamber. Meanwhile, charged solutes are removed from the neutral solute stream by application of an electric field. As a result, the neutral solute is both concentrated and isolated from a complex mixture. This purification technique is also versatile, as a pH of the separation medium may be chosen to match a pI of the desired solute.

Abstract: Spectrophotometric measurements on highly absorbing turbid samples face technical challenges that can be solved by reducing a path length of an optical chamber used during measurement. Reducing the path length requires exceptional control of variables that may be difficult to achieve in unit-use and inexpensive cuvettes. The invention provides a precise inexpensive method for producing an optical cavity useful in making spectrophotometric measurements on high attenuation liquid samples. Two components are shaped such that, when in contact, a central optical chamber and peripheral groove are formed. Liquid adhesive dispensed into the groove wicks around the interface perimeter, sealing the components together when cured. This results in a short precisely controlled path length that reduces chances of mechanical induced distortions (that arise with other bonding methods).