Test A may be omitted if tests B, C &D are carried out. Tests B, C and D may be omitted if tests A are carried out.

A.       The infrared absorption spectrum is concordant with the reference spectrum of methyl paraben or with the spectrum obtained from methyl paraben RS.

B.       The light absorption in the range 230 to 360 nm of a 0.0005% w/v in ethanol (95%) exhibits a maximum at about 258 nm, absorbance at about 258 nm, 0.52 to 0.56.

C.      Boil 10 mg with 10 ml of water, cool and add 0.05 ml of ferric chloride solution; a reddish violet colour is produced.

Dissolve 0.1g in 2 ml of ethanol (95%) boil and add 0.5 ml of mercuric nitrate solution; a precipitate is formed and the supernatant liquid becomes red.

A 10% w/v solution in ethanol (95%) is clear or not more opalescence than Opalescence standard OS1 prepared by 5.0 ml of Opalescence standard & 95 ml of water .and not more intensely coloured than reference solution prepared by mixing 1.5 ml ferric chloride colorimetric solution, 0.8 ml cobaltous chloride colorimetric solution, 0.2 ml cupric sulphate colorimetric solution and 97.5 ml of 1% w/v HCl solution.

Not more than 1.0 %.

Not more than 0.1%

99.0 - 101.0%