X-ray fluorescence analysis of Mexican varieties of dried chili peppers II: Commercial and home-grown specimens

Abstract

Elemental analyses of samples of Mexican varieties of dried chili peppers were carried out using X-ray Fluorescence (XRF). Several specimens of Capsicum annuum L., Capsicum chinense, and Capsicum pubescens were analyzed and the results compared to previous studies of elemental contents in other varieties of Capsicum annuum (ancho, morita, chilpotle, guajillo, pasilla, and árbol). The first set of samples was bought packaged in markets. In the present work, the study focuses on home-grown samples of the árbol and chilpotle varieties, commercial habanero (Capsicum chinense), as well as commercial and home-grown specimens of manzano (Capsicum pubescencs). Samples were freeze dried and pelletized. XRF analyses were carried out using a spectrometer based on an Rh X-ray tube, using a Si-PIN detector. The system detection calibration was performed through the analysis of the NIST certified reference materials 1547 (peach leaves) and 1574 (tomato leaves), while accuracy was checked with the reference material 1571 (orchard leaves). Elemental contents of all elements in the new set of samples were similar to those of the first group. Nevertheless, it was found that commercial samples contain high amounts of Br, while home-grown varieties do not.