1264 3. MANUSCRIPT 3.1 METHODOLOGY The ISO 17924 standard describes the method to simulate the release of metals from soil and soil materials after passing through three compartments of the human gastrointestinal tract: mouth, stomach and small intestine. The amount of fluid mixture to be used in bioaccessibility tests is made under the specifications of the original method published as a full free-to-use technical report of inter-laboratory tests (Wragg, J. et al, 2009). The original UBM method implemented by BARGE was used to determine the bioaccessibility of metals and metalloids present in samples of abandoned tailings from Chile by MABIOMET. For this purpose, the first step was to implement the original UBM method at the laboratory level according to ISO 17924 (ISO, 2018), considering the specifications established in the original method. Subsequently, the MABIOMET device was implemented in the Laboratory of Soil and Environment of the Department of Industry, Faculty of Engineering of the Universidad Tecnológica Metropolitana , following the experimental design summarised in Figure N°1. Finally, the statistical analysis, which included the calculation of confidence intervals, hypothesis tests and Tukey graphs. Fig. 1: Scheme of the MABIOMET device experimental design. Prepared by the authors. 3.1.1 Design and description of the MABIOMET prototype: The device is designed and protected by the patent application (PCT/CL2020/050198,WO2022/140868 in favour of the Universidad Tecnológica Metropolitana. It has a patent granted by INAPI in Chile in April 2024, registration 68865, trademark registration No. 1388792, and applications pending in Europe, Canada, Australia, and China. To quantify bioaccessible concentrations of the elements under study: As, Pb, Cu, Fe, Zn; after the extraction process in the MABIOMET device that simulates an artificial stomach based on the UBM method, an ICP-MS is performed according to the “Standard Methods for the examination of water and wastewater 23rd Edition Method 3030 K - 3125 B”, or by AAS with flame. For the Pb analysis of MR102 by AAS, an external calibration curve was prepared in the range suggested by the equipment manufacturer (0.2-20 mg L-1). The device is comprised of three stages or modules. It is designed as a system of boxes or cubes assembled between them. The control system of the operational variables is composed of a microprocessor-based platform, which functions as a master system
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