Determinação da composição inorgânica e orgânica do lúpulo (humulus lupulus) por ICP-MS e PS-MS

Abstract

In this work, analytical procedures were developed using paper spray mass spectrometry (PS-MS) to identify the organic compounds found in hops and inductively coupled plasma mass spectrometry (ICP-MS) to determine the elemental composition of hops. For the analyzes performed by ICP-MS, the samples were digested in closed flasks assisted by microwave radiation using dilute nitric acid and hydrogen peroxide. The elements Ag, As, Cd, Co, Cr, Cu, Ni, Pb, Sb and V were determined in 12 hop samples from four different countries. From the determined concentrations, the samples were broken down into groups resulting from the geographic indicators using chemometric tools by hierarchical cluster analysis (HCA) and principal component analysis (PCA). Satisfactory recoveries in the range of 80 to 119% were obtained for all analytes, considering the two samples used in the addition and recovery experiments. For PS-MS, sample preparation was performed by grinding the hop samples in an agate crucible with a 1% v v-¹ formic acid solution. Then, this solution was centrifuged and the liquid was collected without the precipitate to be used for analysis. The PS-MS analyzes allowed the visualization of ions in the mass spectrum for the samples analyzed in both negative and positive modes, allowing these data to be analyzed by the fragments found in the spectrum and identified according to the mass charge ratio and the studies in the literature on compounds present in hop samples.