SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF TOTAL TOBACCO ALKALOIDS AND NICOTINE

A spectrophotometric method for the determination of total tobacco alk aloids and nicotine is described. The method is based on the brominati on of nicotine to form; dibromonicotine which reacts with potassium io dide in the presence of starch to form a water-soluble blue complex. T he complex shows maximum absorbance at 580 mn. Beer's law. is obeyed o ver the concentration range 3.7-29.6 mu g of total tobacco alkaloids i n a final solution volume of 25 ml. The molar absorptivity of the colo ur system is 9.4 x 10(4) l mol(-1) cm(-1). The reproducibility was ass essed by carrying out seven replicate analyses of a solution containin g 14.8 mu g of total alkaloids in a final solution volume of 25 ml. Th e standard deviation and relative standard deviation for the absorbanc e values were found to be 0.01 mu g ml(-1) and 2.7%, respectively. The method is free from the interference of other major toxicants. The an alytical parameters were optimized and the method was applied to the d etermination of total alkaloids and nicotine in tobacco leaves, cigare tte smoke and biological samples. The method is highly sensitive and w as compared with other reported methods.