OLIVE PITS-BASED CARBON BLACK AGGLOMERATE AS AN ADSORBENT FOR PIPETTE-TIP SOLID-PHASE EXTRACTION FOR THE DETERMINATION OF CAFFEINE IN ENERGY DRINKS
Authors:   Departamento de Control Químico, Facultad de Ciencias Químicas y Farmacia, Universidad Nacional Autónoma de Honduras, Ciudad Universitaria, Tegucigalpa, Honduras, ROSALES GÓMES ASHLY A. , RAMOS DOBLADO AXEL M. ,   Departamento de Química, Facultad de Ciencias Químicas y Farmacia, Universidad Nacional Autónoma de Honduras, Ciudad Universitaria, Tegucigalpa, Honduras, CALLEJAS TABORA MARÍA F. ,   Departamento de Control Químico, Facultad de Ciencias Químicas y Farmacia, Universidad Nacional Autónoma de Honduras, Ciudad Universitaria, Tegucigalpa, Honduras, ZELAYA NASSER SUANY Y. ,   Departamento de Química, Facultad de Ciencias Químicas y Farmacia, Universidad Nacional Autónoma de Honduras, Ciudad Universitaria, Tegucigalpa, Honduras, RODRÍGUEZ-RIVAS FREDY A. ,   Departamento de Química, Facultad de Ciencias Químicas y Farmacia, Universidad Nacional Autónoma de Honduras, Ciudad Universitaria, Tegucigalpa, Honduras, PONCE-RODRIGUEZ HENRY DANIEL ,   Departamento de Control Químico, Facultad de Ciencias Químicas y Farmacia, Universidad Nacional Autónoma de Honduras, Ciudad Universitaria, Tegucigalpa, Honduras, CABALLERO ÁLVARO ,   Departamento de Química Inorgánica e Ingeniería Química, Instituto Químico para la Energía y el Medioambiente (IQUEMA), Universidad de Córdoba, 14014 Córdoba, Spain, DOMÍNGUEZ-ROBLES JUAN ,   Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain
Published: August 2024

Vegetal wastes are an interesting source for the synthesis of nanostructured carbon materials, which are potentially useful in various applications. Carbon black agglomerates (CBA) obtained from olive pits, synthesized in our previous research, had a low crystalline structure typical of this type of materials, with a pore size of 2.27 nm, confirming their micro/mesoporous structure, and with a high surface value of around 587 m2/g. These materials were used for the extraction of caffeine in energy drinks using a green-approach micro-sample technique called pipette-tip solid-phase extraction. This microextraction technique features reduced consumption of organic solvents, of the amount of sorbent and extraction time, thus making the whole sample pretreatment process faster and greener. In this work, we proposed an analytical method for the analysis of caffeine in commercial energy drinks, using CBA with a great extraction capacity due to its high porous surface area. The developed methodology has proven to be useful from a green chemistry point of view, using only one milligram of nanostructured sorbent, minimal solvent consumption, a reduced volume of sample, as well as easy and rapid automatization for the analysis of commercial energy drinks. For the quantification of the analyte in the energy drinks, a one-point standard addition calibration was applied to correct the matrix effect. Similar caffeine concentrations per milliliter were found in the three analyzed samples, likewise, the amounts of caffeine close to those reported by the manufacturers were established for two of the samples analyzed.