Determination of major-to-trace elements in hot chilli and tomato varieties economically grown in the Northeast of Thailand by ICP-OES following microwave assisted digestion

Multi-element species in hot chilli and tomato fruits at a red-ripe stage were determined using microwave assisted digestion (MAD) followed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The ground sample (0.5 g) was digested with 5 mL of concentrate nitric acid by MAD programmed at 900 W for 35 min, and diluted to 25-mL with 10%(v/v) HCl prior to measurement by the validated method under the optimum conditions of ICP-OES. In this study, major elements (Ca, K, Mg, Na), minor elements (Fe, Zn, Mn, Cu, Si) and trace elements (Cr, Mo, Al, Ni, Pb, Ba) were comparatively classified among each group between hot chilli and tomato samples. It was found that the amounts of Ca (177.2-395.3 mg/kg) were predominant among the major ones for both kinds of the fruit samples. While those of Fe (20.7-43.3 mg/kg) and Zn (11.6-46.9 mg/kg) was comparable among the minor ones. For trace elements, Cr was also predominant for both fruit samples, while those of Mo and Al were considerably distributed among their varieties. From these minerals patterns, some of them available in these economic plants would be a useful database for daily mark of their consumption.