Applications of permanganate chemiluminescence to the analysis of food components

Chemiluminescent oxidations with manganese reagents have been
investigated using flow and spectroscopic techniques.

An assay has been developed for ascorbic acid using the chemiluminescent
oxidation of ascorbic acid with permanganate in acid medium. The assay has
a linear range of 5xl 0-7 to 1 X, 0-3 mol dM-3 and has been applied to a range of
food supplements and fruit juices.

The addition of a manganese (11) catalyst extends the applicability of acid
permanganate to the determination of sugars and polyhydric alcohols. The
reaction has been optimised for the determination of mono and disaccharides
in a flow injection system.

Development of a reagent based on manganese (111)i,n a methanol and
sulphuric acid solution, has further extended the scope of the reaction
enabling the determination of fructose in the range 1 X1 0-7 to 1 X1 0-3 mol d M-3.
The reagent has successfully been used in post column detection with HPLC.

It has been established that the light emission occurs after manganese (VII)
has been reduced and appears to be connected with the production and
disappearance of Mn (111). Chemiluminescence spectroscopy has shown that
the spectra are the same for a large number of aliphatic and aromatic
polyhydroxy compounds. The spectrum remains the same whether the
oxidising reagent is Mn (VII), Mn (IV) or Mn (111)i,n dicating that the same
emitting species is involved in all these reactions and that it involves Mn(III)
and/or Mn(II).