A simple standard addition method was developedfor determination of the anionic inhibitor p-toluenesulfonicacid in n-butyl-2-cyanoacrylate monomer.Aqueous extraction (pH 10) of the monomer samplesdiluted in chloroform was performed, and the analytewas estimated by means of UV absorption in the rangeof 0.15 to 1.50 g/l. The method developed providesacceptable precision and linearity and is suitable foruse in the routine quality control analysis