1265 in “edge computing” mode that is directly connected to the control subsystems based on microcontroller platforms. The master controller logs the different variables read by the sensors, which are processed by the control algorithms to trigger the actuators of each module. Along with the above, the variables logged in a database in “cloud computing” mode are reported to be used as input for the “back-end” system of a web service monitoring the process in progress (“front-end”). The MABIOMET device that quantifies bioaccessibility is a combination of parts, pieces, sensors and controllers in a specific, orderly, logical and sequential manner, where the procedure for its application and use is only for metals and metalloids of the soil matrix. Additionally, it provides social benefits by registering the environmental variable (bioaccessible concentration) in mining soils adjacent to populated areas, allowing us to evaluate the degree of habitability of the sector and quantify the impact on people’s health. 3.1.2 Gastric stage and gastrointestinal stage extraction tests by MABIOMET in UTEM´s laboratory For validation and effectiveness, it is verified that the averages of the repetitions are within the confidence limits established by the BGS 102 reference material (Hamilton, E. M. et al, 2015) . The method includes performing 15 repetitions for both tests and applying a statistical method of reliability by standard deviation and comparison of confidence limits of the BGS102 reference material certificate, thus incorporating the recommendations by the British Geological Survey, Nottingham, United Kingdom, to validate reference soils (Wragg, J., Cave, 2012). In Table Nº1, a summary is presented with the statistical data of the validation, and the confidence interval is calculated using Student’s T distribution with a confidence level of 95 %. Table N°2 records the results ranges obtained for the integral functional and operational validation of the MABIOMET device in the laboratory regarding its speed and temperature operation. Table N° 1: Statistical values obtained for determining Pb and As bioaccessible in the gastric and gastrointestinal stages for the BGS 102 reference utilising MABIOMET. Statistical Parameter Bioaccessible Pb (gastric stage) Bioaccessible As (gastrointestinal stage) Average [mg/kg] 11.48 5.81 Standard Deviation (SD) 1.89 0.40 Relative standard deviation (RSD%) 17 7 Confidence interval obtained using Student’s T distribution [mg/kg] [1.6 – 2.3] [5.63- 5.99] Certified concentration BGS-102 [mg/kg] 13 5.4 Certified confidence interval [7-19] [3-7.8] Table N°2 Summary of operational validation results of the MABIOMET device in the Laboratory of Soil and Environment, UTEM. Study Variables Original UBM method expected values Experimentally obtained values Rotation speed device 30 RPM Maximum 30-28.5 RPM Bioreactor thermal control 37 ± 2 °C 37 ± 0.5 °C RSD% removal of the device (%relative standard deviation) 10-20% 7-17%
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