微波辐射辅助快速检测微量亚硝胺的研究

Investigation on Fast Determination of Trace N-Nitrosamines Assisted by Microwave Radiation

分析了分光光度法对于溶液中亚硝胺回收率过低的原因 ,发现去亚硝基化反应产物NOBr在吹离溶液过程中分解成为光度法无法检测的NOx (x<2 ) ,鉴于此 ,在装置中增加一个CrO3 氧化管 ,将生成的NOx (x <2 )转化成可被显色检测的NO2 ,使亚硝胺回收率高于 90 % ,接近公认标准方法———热能分析仪 (TEA)法的类似指标 (76 %～96 % ) ;而检测限可达 2× 10 -8mol/L .发现微波辐射能使亚硝胺在低于其沸点的温度下挥发和 /或分解 ,并将其用于辅助光度法检测 ,可以在 3min之内将样品中的亚硝胺收集以供测定 ,形成快速同时检测环境样品 (如烟草 )

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 NOx (x < 2) species such as NO. Consequently an oxidation tube was added in the instrument to convert these NOx species into the detectable NO2, therefore the recovery for N-nitrosamine with concentration of 2 x 10(-5) &SIM; 2 x 10(-8) mol/L could be increased to 80 % &SIM; 98 %, close to that of thermal energy analyzer ( 76 % &SIM; 96 %). On the other hand, resulting from the discovery that many N-nitrosamines could he 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.