The two optical isomers
of LA were determined with an L/D ratio of 41:59 by GCMS. The
purified LA was further confirmed by 1H (3.92 ppm for CH and
0.95 ppm for CH3) and 13C signal (177.6 ppm for C@O, 65.5 ppm
for CH and 18.4 ppm for CH3) NMR spectroscopy (Fig. 4), respectively
(Brown, 2008).