Francesco Capecchiacci
University of Florence, Italy
Title: Contamination tests of metal and non-metal elements from packaging materials to food gases
Biography
Biography: Francesco Capecchiacci
Abstract
This study presents the results of different tests carried out to evaluate the possible contamination of food gas due to contact with different materials used for gas storage and distribution, including carbon steel cylinders and tanks, as well as copper pipes. A specific procedure for sampling and analysis of up to 26 metal and non-metal elements, was defined and tested on: (i) CO2 stored in a ~45 m long copper pipe, (ii) CO2, N2 and O2 stored within 36 carbon steel cylinders of different inner volume, and (iii) CO2 stored in 20 tanks constituted of different steel types (e.g. CRYALSIM, SELCO 52 LT FALK). After a storage period, the gases were transferred to a trap, i.e. dewars equipped with gas bubble diffusers and filled with 100 mL of a 1% HNO3 solution in Milli-Q water. The analysis was carried out by ICP-AES and ICP-MS. Although no reference values indicating the concentration limits of metal/metalloid contaminants in food gases are currently promulgated, the effective contamination level of the elements that were systematically detected in the CO2 samples (Al, Cr, Cu, Fe, Ni, and Zn) was estimated by considering the limit concentrations for mineral waters for human consumption (European Directive 98/83/EC). Such a comparison showed that the contaminant concentrations were 3 to 6 orders of magnitude lower than the limit concentrations (LCs). This implies that the amount of contaminants that could be possibly related to the contact of CO2 with the selected packaging materials was negligible.