Residue of butralin in tobacco and its transfer rate into tobacco smoke
In order to determine the residue of butralin in tobacco and its transfer rate into smoke, a method for determining butralin with GC-MS/MS is developed. The butralin in sample was extracted with acetonitrile saturated by n-hexane, purified by graphite-amidocyanogen solid phase extraction cartridge, eluted with a mixture of 3:1 (v/v) acetonitrile-toluene, and determined by GC-MS/MS. Twelve flue-cured tobacco samples applied at different butralin rates during growing and their smoke samples were analyzed. The results showed that: 1) The average recoveries of butralin in tobacco and smoke samples were 101.02% and 96.59% with the relative standard deviation of 6.11 % and 6.79% at the limit of detection of 0.87 ng/mL, respectively. 2) For the leaves of the same stalk position, the contents of butralin in tobacco and smoke samples increased with the increase of butralin application. 3) For the same application rate, the stalk positions in the order of butralin content in tobacco leaf were lower > middle > upper. 4) The transfer rates of butralin from tobacco into mainstream smoke ranged from 10.49% to 14.28% with the average of 12.76%. This method is suitable to determining the residues of butralin in tobacco and its transfer rate into smoke.