An adsorbent layer (stationary phase) for a pressurized layer chromatographic apparatus, for the development of linear chromatogram, is sealed at the edges by impregnation. For the purpose of solvent control some of the adsorbent material is removed in one or several zones of the adsorbent layer near the place of solvent admission, or one or several baffle plates or wires are arranged behind the place(s) of sample application, or if necessary, the adsorbent layer is provided with a conventionally formed concentration zone in the area of the solvent admission. As a result of the impregnation, the migrating solvent composite does not escape at the edges of the adsorbent layer according to the invention in case of overpressure. As a result of the removal of adsorbent material, or the arrangement of baffles or wires, or the application of a concentration zone, the solvent migrates with a straight-line front.

A chromatographic plate comprising a support having a plurality of linear grooves engraved on the rear is disclosed. Each of said grooves have a uniform depth of a half or less as large as the thickness of the support and serves to guide a cutter. After the chromatographic development, the support may easily be cloven along the grooves into strips together with an adsorbent layer carried by the front of the support to give a sample holder for mass spectrometry.

The method of transfer of macromolecules such as nucleic acid and proteins from a chromatographic substrate to an immobilizing matrix uses as the immobilizing matrix, a charge modified microporous membrane comprising an organic microporous membrane having a charge modifying amount of a cationic charge modifying agent bonded to substantially all of the wetted surfaces of said membrane. The charge modified microporous membrane can also be a reinforced microporous membrane, preferably a porous reinforcing web impregnated with a polymeric microporous membrane. A nucleic acid or protein blotting product comprising a chromatographic matrix having the charge modified microporous membrane on a surface thereof is also provided.

The method of transfer of macromolecules such as nucleic acid and proteins from a chromatographic substrate to an immobilizing matrix uses as the immobilizing matrix, a charge modified microporous membrane comprising an organic microporous membrane having a charge modifying amount of a cationic charge modifying agent bonded to substantially all of the wetted surfaces of said membrane. The charge modified microporous membrane can also be a reinforced microporous membrane, preferably a porous reinforcing web impregnated with a polymeric microporous membrane. A nucleic acid or protein blotting product comprising a chromatographic matrix having the charge modified microporous membrane on a surface thereof is also provided.

The present invention involves a method for separating biological molecules by subjection of said molecules to a separation system in a gel medium. The method most particularly involves the use of a gel slab suitable for such separations which is readily equilibrated with an appropriate solvent for the chosen separation system. An important aspect of the present invention involves the initial preparation of a gel slab comprising between about 0.5% and about 2.0% agarose and between about 1% and about 3.0% linear water-soluble and substantially nonionic polyacrylamide. A preferred gel slab of the present invention contains between about 1% and 3% agarose and about 3% linear, water-soluble, substantially nonionic polyacrylamide. The gel slabs of the present invention are preferably between about 1 mm and 0.5 mm in thickness. Said aged gel slab is then dried to produce a gel precursor sheet. A preferred drying procedure is to subject the gel slab to a stream of warm air to maintain a preferable gel surface temperature of about 45.degree.-50.degree. C., a 0.5 mm gel slab taking about 6-8 min to dry under these conditions. The dried gel precursor sheet, preferably maintained in a dried state for less than about 24 hr, is immersed for at least about 30 min, preferably at about 20.degree. C., in an aqueous separation solvent compatible with the separation system to be utilized. Aqueous separation solvents usable for gel rehydration include those comprising one or more of detergents (preferably nonionic), urea (up to about 10M), ampholytes and pH buffers, for example, depending upon the particular separation system to be used for separation of the biological molecules. Usable separation systems include electrophoresis, immunodiffusion and isoelectric focusing, for example.