A new approach to mineralization of flaxseed (Linum usitatissimum L.) for trace element analysis by flame atomic absorption spectrometry

- The IR system is a fast and inexpensive alternative for food sample preparation.
- Conditions of the element extractions are studied in details using chemometric tools.
- A potential sample preparation approach for trace element analysis is proposed.

A new approach to the analysis of Cu, Fe, Mn and Zn in flaxseed was developed based on infrared-assisted acid digestion. Quantitation by flame atomic absorption spectrometry yields results in agreement with those arising from aggressive total decomposition using conventional microwave-assisted (MW) digestions. A full factorial design in two levels was applied to evaluate the impact of significant variables for all elements to determine optimal experimental conditions. A desirability function revealed these to be: 2.0 g sample mass, 8 mL of HNO3 and 8 min of heating time in the IR system. Precision better than 10% (RSD) was obtained, superior to that of a combined IR-MW approach. Sample preparation based on IR-assisted digestion provides a rapid and inexpensive alternative to other conventional techniques for the analysis of complex samples and is able to accommodate relatively large masses of sample, alleviating potential homogeneity issues as well as enhancing detection power.