ABSTRACT
After a long ageing time, the method allowed to detect the ultimate degradation products of nat-PMLA. In Fig. 10b three peaks can be observed. After spiking the aged solution with fumaric, maleic and malic acids, peaks 1, 2 and 3 were assigned to fumarate, maleate and malate anions, respectively. Since only dicarboxylic acids without any oligoelectrolyte remained in the final solution, the DAP method with UV detection allowed estimating the composition, which was 96% malate and 4% fumarate + maleate (the last diacids were not totally separated). Although they were only present in small amounts, fumarate and maleate were easily detected due their strong UV absorption at 200 nm, and their appearance can be explained by a /^-elimination mechanism (Scheme 6) as in the case of PHB.
