Trace determination of mercury in rice using microwave digestion coupling with atomic fluorescence spectrometry

Objective:To establish a rapid,precise and sensitive method for the trace determination of mercury in rice by microwave digestion coupling with atomic fluorescence spectrometer approach.Methods:After a pretreatment with nitric acid/hydrogen peroxide microwave digestion system,we used atomic fluorescence spectrometer methodology to determine trace mercury in rice.Results:Under the optimized digestion and detection conditions: nitric acid/water/hydrogen peroxide ratio,4:4:2;KBH4 concentraton,0.3%(w/w);lamp current,20 mA;flow rate of carrying gas,300 ml/min;carrying flow,5% HCl,wide linear relationship was achieved in the range of 0.1~50.0 μg/L with relative coefficient of 0.9999 and the detection limit was estimated to be 0.0114 μg/L.We got satisfied recovery rates of spiked samples of 98.9% to 105.9% with RSD of four replicate experiments less than 6.6%.Conclusion:The present method is precise,rapid and sensitive enough for determination of trace mercury in rice.The detection results indicate that rice in Ningbo market is mostly safe.