2.3.6. Metals and Microelements (Cu, Fe, Na, Mn, Zn, K)

The EPA 6010b [32] and EPA 3052 [33] were used for the metals and microelements. The Perkin Elmer Optima 8000 ICP-OES spectrometer was used with a Milestone Strt D microwave mineralizer. Standard solutions of the individual elements were used.

The samples were mineralized in an acid medium in the microwave digester; then after suitable dilution with double distilled water it was injected into ICP to directly measure the concentration in mg/L. ICP memorized the calibration curves of each element and then processed the final result.