Square-wave cathodic adsorptive stripping
voltammetry based on adsorptive accumulation is a
very sensitive technique for the trace determination of
xanthosine 5
0
-monophosphate (5
0
-XMP) and xantho-sine 5
0
-diphosphate (5
0
-XDP). The determination is
based on the strong interaction of the adsorption of
xanthosine phosphate compounds on a mercury elec-trode surface, forming Hg(II)-xanthate. The cathodic
reduction of the accumulated Hg(II)-xanthate complex
provides the basis for direct stripping measurements
of the investigated biological compounds at sub-nanomolar concentration levels. Moreover, controlled
adsorptive accumulation of the Cu(II) complex of
xanthosine phosphate is also reported to assay trace
amounts of xanthosine phosphate. The height of the
sharp chelate peak of adsorbed Cu(II)-xanthate,
coupled with the flat baseline, facilitates measurements
at nanomolar and submicromolar concentration levels.
The adsorption and the redox behaviour of the in-vestigated complexes are indicated by cyclic voltam-metry. Experimental and instrumental parameters for
the quantitative determination were optimized. Statis-tical analysis of the calibration curve data is also included