Verification of aluminium with alizarin

Chemicals needed

aluminium sulphate

acetic acid 25% GSATZEND.gif (935 Byte) C     R 10-35    S (1/2)-23-26-45

ethanolic alizarin solution GSLEICHT.gif (932 Byte) F    R 11    S (2)-7-16

Equipment needed

test tube

Test procedure



Alizarin forms with aluminium(III) a colored complex. Alizarin (derived from madder root) + alum (potassium aluminum sulfate) was in the past very important for the dyeing of fabrics.

alizarin.gif (1892 Byte)

Structural formula of alizarin


  alizarin.gif (1892 Byte)

Alizarin aluminium complex (left), alizarin solution (right)


Inspired by VII.3, "Aluminiumnachweis als Alizarin-S-Farblack", p. 76, [3]
see under: Al-Nachweis mit Alizarinsulfonsäure, Natriumsalz