Determination of Na, K, Ca and Mg in xanthan gum: Sample treatment by acid digestion

A simple alternative decomposition procedure for the determination of Na, K, Ca, and Mg in xanthan gum was proposed. The samples were treated in the presence of HNO3 and HClO4, ensuring complete digestion. After decomposition, Na and K content were determined by flame atomic emission spectrometry and Ca and Mg content by flame atomic absorption spectrometry. The accuracy of the method was verified by comparing the results with those obtained from the conventional decomposition by calcination method, and there were no significant differences between the results at the 95% confidence level. The limits of detection in the sample were 0.011, 0.004, 0.45 and 0.001 mg g−1 for Na, K, Ca and Mg, respectively. The relative standard deviations were lower than 10%. The method proposed is simple, fast, reproducible, and requires less sample than calcinations method.