Simple, economical and highly sensitive electrodes for the detection of caffeine by using activated carbon from peach stones have been developed. The activated carbons were synthesized by chemical activation using ZnCl 2 and ZnCl 2 :FeCl 3 (1:1) as chemical agents, producing carbons with different textural properties and morphologies, which led to differences in the electroactive area of the materials that affected the electrochemical response to caffeine. The electrodes presented a linear response in the concentration range from 3.98 × 10 −5 to 4.58 × 10 −4 and 6.37 × 10 −4 M for the carbon activated with ZnCl 2 and ZnCl 2 :FeCl 3 (1:1), respectively. The detection limits were estimated in 2.85 × 10 −5 and 1.60 × 10 −5 M. The electrodes were tested to measure caffeine in real life samples, giving caffeine concentrations close to the reported values. Despite presenting the lowest surface area and the lowest thermal stability, the activated carbon obtained with ZnCl 2 :FeCl 3 (1:1) was more sensitive to caffeine, measuring caffeine concentrations very close to the reported values for the tested beverages. These results show that these electrodes may be an alternative to develop new and reliable analytical tools at low cost with high efficiency.

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In this work, the influence of degassing temperature and urea functionalization were investigated as ways to improve the CO2 adsorption performance of CPO-27-Mg. Through post-synthesis modification treatments, four samples with different degrees of urea functionalization were obtained, incorporating 10, 25, 50, and 100% of urea concerning the metal sites of the MOF. Alternatively, the influence of the degassing temperature of the non-functionalized MOF between 70 and 340 °C was also evaluated. The resulting compounds were characterized by N2 adsorption–desorption isotherms at −196 °C using TGA-MS, FTIR, and PXRD. Finally, the thermally treated and functionalized CPO-27-Mg was evaluated for CO2 capture.