Abstract: Devices are provided with enhanced rates of sampling in applications such as monitoring of environmental chemical exposure levels. Preferred embodiments include a small motor and power supply, such as a battery, to move an intake surface with respect to the environment, which embodiments may be used as personal monitors. Chemical species collected through the intake surface diffuse to a collector and the collector may be analyzed for concentration of chemical species.

Abstract: A diagnostic device is provided where the preferred embodiment is useful for sorting seric or plasmatic lipoproteins into four cholesterol fractions. The device comprises a plurality of gel matrixes, preferably agarose-based, defining a liquid pathway upon which a directioinal electrophoretic gradient can be imposed. The gel matrixes are in a serial relationship and preferably are of a successively decreasing pore size from a most upstream matrix to a most downstream matrix. In a preferred embodiment the three more downstream gel matrixes are in a noncontiguous relationship and are separated by interfaces containing buffer. These interfaces are adapted to receive a separate lipoprotein fraction upon reversal of the electrophoretic gradient direction.