The GC analysis was carried outin a Hewlett-Packard GC (Model 5890-II) equipped with an electronic integrator. Methyl siliconecolumn (50 m × 0.2 mm, 0.17 m) was used for the analysis. Theconditions used were as follows: temperature programming from 80 to 200 ◦C at the rate of 5◦C/min, held at 200 ◦C for 15 min,F.I.D. temperature 300 ◦C, injection temperature 250 ◦C, carrier
gas: nitrogen at a flow rate of 1 mL min−1 at a split ratio of1:75.