Constant current chronopotentiometric stripping of sulphated polysaccharides

We show that electrochemically inactive molecules of polysaccharide (PS), if carrying sulphated groups (e.g. ι-carrageenan and dextran sulphate) produce in buffered solutions two well-developed chronopotentiometric peaks H_PS and H′_PS (due to catalytic hydrogen evolution) at hanging mercury drop electrode. Peak H_PS of ι-carrageenan displayed a striking increase at negative accumulation potentials, which was tentatively explained by uncoiling the PS double-helical structure at these potentials. Nanomolar concentrations of ι-carrageenan can be determined at moderate accumulation times.