LACTOYL-LACTIC ACID DETERMINATION OF DL-LACTIDE AS STARTING MATERIAL IN THE SYNTHESIS OF POLYLACTIC ACID

This paper reports the determination of lactoyl-lactic acid in dl-lact ide using a kinetic interpretation of their peak heigths ratio obtaine d by HPLC. Lactoyl-lactic acid was the only acid compound identified b y H-1-MNR as impurity in dl-lactide stored in tigthy closed recipients as well as the only compound that appears during the hydrolysis of dl -lactide in mobile phase when process was studied along five hours. We ll resolved and highly symetrical chromatograms showed that the hydrol isis do not take place inside the chromatography column and therefore a simple catenary model was used to relate the peak ratio to the mole fraction of lactoyl-lactic acid in the sample.