Determination of K and Na in Melamine By Flame Atomic Absorption Spectrometry with Bi-Capillary Nebulizer

A method of microwave-assisted digestion combined with flame atomic absorption spectrometry (FAAS) was proposed for the determination of K and Na in melamine.Study was focused on the ionization interferences of K and Na in FAAS,resulting in reduction of absorbances and deviation from linear ity of calibration curve,thus leading to erroneous analytical results.In the present method,dual-capillary nebulizers were used to introduce the sample solution and the ionization suppressor separately so that ionization interferences were effectively eliminated and K and Na in melamine were accurately determined.Values of detection limit for K and Na were found to be 0.74 g·L-1 and 1.8 g·L-1 respectively.Values of recovery of 86.0%-102.0% were achiered.