Abstract: A device which can be used for filtering samples is described. The device is comprised of a plurality of filter wells, each having a wide region and a narrow region. The device is fitted with a filter element and then filled with a gel filtration matrix which is selected so that molecules of a particular molecular size will diffuse into the matrix. The device is centrifuged to remove water from the interstitial regions of the gel filtration matrix, and a sample is then added to the device containing the dried gel filtration matrix. The device is again centrifuged, causing smaller molecules to diffuse into the matrix and allowing larger molecules to exit the device, wherein they are collected and analyzed. The device is capable of filtering sample sizes as low as 1 &mgr;L and can be used in a variety of existing laboratory equipment, including bench-top centrifuges and microcentrifuges. A process for using the device is also disclosed.

Abstract: A method and a kit for testing a plant for a suspected antigen. A sample of the plant is taken and rubbed between first and second pads to extract sap from the sample and to collect the sap on the first pad. The sap is transferred to a liquid solution, and that solution is tested for the suspected antigen. This may be done by contacting the solution with a tag antibody and with a carrier having a capture antibody so that a tag antibody-antigen-capture antibody complex forms on the carrier if the suspected antigen is in the liquid solution. The carrier is then tested for the tag antibody. The kit preferably includes the first and second pads, the carrier, containers to hold the liquid solution and the tag antibody, and a device or reagent to test the carrier for the tag antibody.

Abstract: A method and a kit for testing a plant for a suspected antigen. A sample of the plant is taken and rubbed between first and second pads to extract sap from the sample and to collect the sap on the first pad. The sap is transferred to a liquid solution, and that solution is tested for the suspected antigen. This may be done by contacting the solution with a tag antibody and with a carrier having a capture antibody so that a tag antibody-antigen-capture antibody complex forms on the carrier if the suspected antigen is in the liquid solution. The carrier is then tested for the tag antibody. The kit preferably includes the first and second pads, the carrier, containers to hold the liquid solution and the tag antibody, and a device or reagent to test the carrier for the tag antibody.