Dried sample of 0.500 g of herb that was not
previously washed was placed in PTFE vessel for
digestion. Acid was added gradually into content of
PTFE vessel. At the beginning, 8 ml of concentrated
HNO3 was poured into PTFE vessel. The vessel was
closed, placed on the rotating turntable of the microwave
oven and then digestion was started at defrost
for 3 min (see Table 3). When the time finished, the
vessel was removed from the oven and cooled to room
temperature. Four milliliters of concentrated HClO4
was added to previous content of the vessels and
digestion was allowed to continue at 400 W for 4
min. After re-cooling, 3 ml of concentrated HCl was
added into the vessel and then the power was gradually
increased at 400 W for 2 min, at 550 W for 2 min
and 700 W for 4 min. Finally 1 ml of concentrated
HClO4 was added into cooled PTFE vessel for digestion
at 700 W for 3 min. After digestion in microwave,
the digest was transferred into a volumetric
flask and made up to 50 ml with deionized water.
To prepare the infusion of the herbs, 0.500 g dried
sample was placed in a beaker, then 25 ml of deionized
water at 95 8C was poured into the same beaker
and it was kept in water bath at 95 8C for 30 min.
After cooling, the extract was filtered through the