POLAROGRAPHIC STUDY OF ACROLEIN AND ITS DETERMINATION BY FLOW-INJECTION WITH AMPEROMETRIC DETECTION AT A MERCURY-ELECTRODE

A study of the electrochemical behavior of acrolein at a dropping merc ury electrode using different polarographic techniques is described. T heoretical studies of the reversibility of the wave of acrolein were c arried out using two different polarographic techniques: direct curren t tast and differential pulse. Differential pulse polarography may be used to determine acrolein concentration in a Britton-Robinson buffer solution of pH 10 in the ranges 2 x 10(-7)-10(-8) and 5 x 10(-8)-10(-4 ) mol dm(-3) and a coefficient of variation of 1.7% for a concentratio n of 10(-)5 mol dm(-3). A flow injection method with amperometric dete ction at a potential of -1.4 V using a mercury electrode is also descr ibed. Before each injection, any drop hanging from the tip of the capi llary needs to be dislodged and a new electrode drop dispensed; three different drop sizes were tested. A linear relationship between peak i ntensity and acrolein concentration was obtained in the range 10(-5)-1 0(-7) mol dm(-3), with a detection limit of 9.8 x 10(-8) mol dm(-3) an d a coefficient of variation of 2.9% for a 2 x 10(-7) mol dm(-3) conce ntration. Several organic and inorganic species were tested in order t o ascertain whether they interfered with the signal for acrolein. The proposed methods were applied to the determination of acrolein in seaw ater samples.