Validation of a method for the analysis of iron and manganese in table olives by flame atomic absorption spectrometry

There is no generally accepted method for determination of the amounts of iron and manganese in table olives. Application of flame atomic absorption spectrometry to the analysis of both elements has been examined to validate a method that may be used by the industry's quality control laboratory as well as by the laboratories of regulatory agencies. The method has detection limits of 0.106 and 0.022 mg/L and quantification limits of 0.271 and 0.057 mg/L, for Fe and Mn, respectively, referred to the solution to be measured. There was no significant effect due to the matrix, but a slight bias due to the presence of Ca has been detected. Recoveries were excellent, and the method was robust. Influence of operator, HCl and Mg salt compounds, calcination equipment, or dates on results was not found. Relative errors were, in general, below 4% for both cations, and repeatability was below 3.43 and 0.38 mg/kg of olive paste for Fe and Mn, respectively. The method is proposed for the analysis of Fe and Mn in ripe olives and table olives in general.