First identification: A, B.
Second identification: A, C, D.
A. Melts between 125°C and 128°C.
B. The infrared absorption spectrum is concordant with the reference spectrum of methyl paraben or with the spectrum obtained from methyl paraben CRS.
C. Examine the chromatograms obtained in the test for related substances. The principle spot in the chromatogram obtained with test solution (b) is similar in position and size to the principle spot in the chromatogram obtained with reference solution (b).
D. To about 10 mg in a test tube add 1 ml of sodium carbonate solution R, boil for 30 seconds and cool (solution A). To a further 10 mg in a test tube add 1 ml of sodium carbonate solution R, the substance partly dissolves (solution B). Add at the same time to each of solutions A and B 5 ml of aminopyrazolone solution and 1 ml of potassium ferricyanide solution R and mix. Solution B is yellow to orange brown. Solution A is orange to Red, the colour is clearly more intense than any similar colour that may be obtained with solution B