The detection limits for metal analysis by ICP-OES were 0.11,
0.060, 0.013, 0.080, 0.064, 0.341 and 0.028 mg/kg DW, for As, Cd,
Cr, Cu, Ni, Pb and Zn respectively. The analytical precision was
checked by measuring in triplicate about 20% of the samples. The rel-
ative standard deviation routinely was between 1 and 8%, and never
higherthan10%.Forthequalityassuranceofplantanalysis,thecertified
referenceCTA-OTL-1 (OrientalTobacco Leaves fromthe BulgarianInsti-
tute for Plant Protection) was employed. Average recoveries (n = 6)
were 91, 87, 66, 98, 85, 58, and 79% for As, Cd, Cr, Cu, Ni, Pb and Zn,
respectively.