METHOD FOR PREPARING SCREEN-PRINTED ELECTRODES MODIFIED WITH OXIDATED SINGLE-WALLED CARBON NANOTUBES DECORATED WITH GRAPHENE QUANTUM DOTS FOR APPLICATIONS IN ELECTROCHEMICAL SENSOR FIELD

The invention relates to a process for preparing screen-printed electrodes (SPCE) modified with oxidated single-walled carbon nanotubes (SWNT) decorated with graphene quantum dots (GQD) for applications in the electrochemical sensor field. According to the invention, the process consists of the following stages: I. synthesis of SWNT functionalized with carboxyl groups, II. GQD preparation by thermal treatment of SWNT-COOH, in the air, at 100°C, III. GQD-COOH interaction with cysteamine to result in GQD comprising thiol groups (GQD-SH), IV. SWNT oxidation to result in oxidated SWNT, which show epoxy, hydroxyl and carboxyl groups, V. deposition of oxidated SWNT, by drop casting method, onto the SPCE surface and successive deposition of GQD-SH, VI. interaction of the so-modified SPCE with dicyclohexyl carbodiimide followed by addition of Ag nanoparticles with an average size of 10 nm, to result in electrodes of the SPCE/oxidated SWNT/GQD-SH/Ag nanoparticles type, which are tested by analytical techniques for electrochemical activity. Invenţia se referă la un procedeu de obţinere unor electrozi serigrafiaţi (SPCE) modificaţi cu nanotuburi de carbon cu un singur perete (SWNT) oxidate şi decorate cu puncte cuantice de grafenă (GQD) pentru aplicaţii în domeniul senzorilor electrochimici. Procedeul, conform invenţiei, constă în etapele:I) sinteza SWNT funcţionalizate cu grupări carboxil,II) preparare GQD prin tratament termic în aer la 100°C a SWNT-COOH,III) interacţia GQD-COOH cu cisteamină rezultând GQD conţinând grupări tiol (GQD-SH),IV) oxidare SWNT, rezultând SWNToxidate, care prezintă grupări epoxi, hidroxil, respectiv, carboxil,V) depunere prin metoda drop casting pe suprafaţa SPCE a SWNT oxidate şi succesiv GQD-SH,VI) interacţia SPCE astfel modificat, cu diciclohexil carbodiimidă urmată de adăugare de nanoparticule de Ag cu dimensiune medie de 10 nm, rezultând electrozi de tip SPCE/SWNT oxidate/GQD-SH/nanoparticule de Ag care sunt testaţi prin tehnici analitice pentru activitatea electrochimică.