The spectrophotometric determination of trace N-nitrosamines in solution was investigated in order to enhance its recovery and sensitivity. Based on the investigation on the recovery below 10% in this method, the reason was found relating to formation of spectrophotometric invisible NO_x (x < 2) species such as NO. Consequently an oxidation tube was added in the instrument to convert these NO_x species into the detectable NO_2, therefore the recovery for N-nitrosamine with concentration of 2 * 10~(-5) ～ 2 * 10~(-8) mol/L could be increased to 80% ～ 98%, close to that of thermal energy analyzer (76% ～ 96%). On the other hand, resulting from the discovery that many N-nitrosamines could be evaporated under microwave radiation, a new method combining microwave radiation with the improved spectrophotometric method was thus reported for determining both N-nitrosamines and nitrogen oxides in tobacco and tobacco products. Within 3 minutes both N-nitrosamines and nitrogen oxides in tobacco or tobacco products could be collected for detection.

Key words: MICROWAVE RADIATION, SPECTROPHOTOMETRY, NITROSAMINE, NITROGEN OXIDE, tobacco