Abstract: This method of preventing polymerization of methacrylic acid inn the process of its production is characterized by comprising using, in a refining column, a combination of N-nitrosophenylhydroxylamine or salt thereof with an N-oxyl compound, an N-hydroxy-,2,2,6,6-tetramethylpiperidine compound and a 2,2,6,6-tetramethylpiperidine compound. In this method, N-nitrosophenylhydroxylamine or a salt thereof rises inside a refining column under splitting part thereof to effectively inhibit polymerization of (meth)acrylic acid or the like. The above polymerization in both vapor and liquid phases can be inhibited more effectively by the combined use of the compounds mentioned above.

Abstract: A method is disclosed for preventing the polymerization of (meth)acrylic acid and esters thereof, which method is characterized by using an N-nitrosophenyl hydroxyl amine or a salt thereof, an N-oxyl compound, an N-hydroxy-2,2,6,6-tetramethylpiperidine compound, and a 2,2,6,6-tetramethylpiperidine compound in combination in a purifying column. The N-nitrosophenylhydroxylamine or the salt thereof is partly decomposed in the purifying column and is allowed to ascend the interior of the column and effectively inhibit the polymerization of (meth)acrylic acid. Since the method does not need to use any metal compound, it permits the disposal of the waste liquid to be effected easily. Further, the combined use of the relevant components ensures effective prevention of the polymerization in the gas and the liquid phase.

Abstract: A method for immunological blood testing carried out by the use of a coil column, composed of a transparent tube helically wound on a support rod. To carry out the test, the coil column filled with a liquid solution of a polymer compound is, after a droplet of blood to be tested has been introduced into the liquid solution within the tube, centrifuged while undergoing a planetary motion to allow erythrocytes to sediment.