Specifies the detection of thioalcohols. Hydrogen sulphide can also be detected by the test. Inapplicable in the presence of only traces of peroxides. Shaking of a test portion with sodium plumbite solution (Doctor solution) and observation of the mixture. From its appearence, the presence of thioalcohols, hydrogen sulphide, peroxides or elemental sulphur can be deduced. Confirmation by the addition of sulphur, shaking and observation of the appearance of the final mixture.