SURFACES WITH DESIRED FUNCTIONALITY ARE ATTRACTIVE IN MANY RESEARCH AREAS AND HAVE BEEN ACTIVELY DEVELOPED BOTH IN ACADEMIA AND INDUSTRY [1]. THE DESIRED FUNCTIONALITY OF THESE SURFACES IS MOSTLY ACHIEVED BY COATING WITH CHEMICAL/BIOLOGICAL MOLECULES. AMONG THE WIDE RANGE OF APPLICATIONS INVOLVING MODIFIED SURFACES, MODIFICATION OF VOLTAMMETRIC ELECTRODES AND THEIR APPLICATIONS IN ELECTROANALYSIS HOLDS A PROMINENT PLACE. AMONG THE VARIOUS TYPES OF ELECTRODE MODIFICATION METHODS, ACTIVE ATTENTION IS CURRENTLY BEING PAID TO SELFASSEMBLED MONOLAYERS (SAMS) AND COVALENTLY MODIFIED ELECTRODES. THESE PROCEDURES MAKE IT POSSIBLE TO MODIFY ELECTRODE SURFACES WITH VARIOUS FUNCTIONALITIES WHICH ARE PARTICULARLY ATTRACTIVE FOR THE FABRICATION OF SENSING AND BIOSENSING INTERFACES WHERE A SPECIFIC INTERACTION WITH A SPECIES IN SOLUTION IS REQUIRED [2]. THE POPULARITY OF SAMS ARISES FROM THEIR EASE OF PREPARATION, THE WELL-DEFINED MONOLAYER THAT RESULTS AND THE POSSIBILITY OF INTRODUCING A VAST NUMBER OF FUNCTIONAL GROUPS AT THE MONOLAYER SURFACES [3]. HOWEVER THE LIMITED POTENTIAL WINDOW AND THE POOR LONG-TERM STABILITY OF THE SAMS OFFSET THIS POPULARITY [4]. TO SOLVE THESE LIMITATIONS, COVALENT MODIFICATION OF THE ELECTRODE SURFACES HAS BEEN EXPLORED. COVALENT MODIFICATION OF THE ELECTRODE HAVE IMPORTANT ADVANTAGES SUCH AS THERMAL STABILITY, ELECTROCHEMICAL STABILITY OVER A WIDE POTENTIAL RANGE AND POSSIBILITY OF INTRODUCING DIFFERENT FUNCTIONAL GROUPS AT THE MONOLAYER SURFACE [5].THE AIM OF THIS SEMINAR IS TO PROVIDE AN UP-TO-DATE VIEW OF RECENT ADVANCES MADE IN THE ELECTROANALYTICAL APPLICATIONS OF COVALENTLY MODIFIED ELECTRODES, BY FOCUSING ESPECIALLY ON THE WORKS PERFORMED IN THE PAST DECADE, AND TO HIGHLIGHT THE ANALYTICAL POTENTIAL OF THESE STRATEGY FOR CONSTRUCTION OF CHEMICAL AND BIOCHEMICAL SENSORS.

A NEW CU2+CARBON PASTE ELECTRODE (CPE) USING 2, 2' - (1E, 1' E) -1, 1' - (2, 2' -AZANEDIYLBIS (ETHANE-2, 1-DIYL) BIS (AZAN-1-YL-1-YLIDENE)) BIS (ETHAN-1-YLIDENE) DIPHENOL (ADEZEDP) HAS BEEN PREPARED. THE INFLUENCE OF VARIABLES INCLUDING SODIUM TETRAPHENYLBORATE (NATPB), IONOPHORE, AND AMOUNT OF MULTIWALLED CARBON NANOTUBES (MWCNT), CDO NANOWIRES, CDS NANOPARTICLES AND PALLADIUM NANOPARTICLES LOADED ON ADEZEDP AND NUJOL ON THE ELECTRODES RESPONSE WAS STUDIED AND OPTIMIZED. AT OPTIMUM VALUES OF ALL VARIABLES, FOR EACH NANOMATERIALS THE ELECTRODES RESPONSE WAS LINEAR IN CONCENTRATION RANGE OF 1.0 × 10-8 TO 1.0 × 10-1 MOL L-1 FOR ADEZEDP WITH NERNSTIAN SLOPE. THE GOOD PERFORMANCE OF ELECTRODE VIZ. WIDE APPLICABLE PH RANGE (2.0-5.0), FAST RESPONSE TIME (»6 S), AND ADEQUATE LIFE TIME (3 MONTHS) INDICATE THE UTILITY OF THE PROPOSED ELECTRODES FOR EVALUATION OF CU2+ION CONTENT IN VARIOUS SITUATIONS. FINALLY, THESE ELECTRODES HAVE BEEN SUCCESSFULLY APPLIED FOR THE DETERMINATION OF CU2+IONS CONTENT IN VARIOUS REAL SAMPLES. THE SELECTIVITY OF PROPOSED ELECTRODE WAS EVALUATED BY SEPARATION SOLUTION METHOD AND FIXED INTERFERENCE METHOD.

ELECTRO ANALYSIS OF METAL IONS AT THE CONDUCTING POLYMER MODIFIED ELECTRODES HAS OBTAINED GREAT INTEREST, AS THE POLYMER CAN PRECONCENTRATE THE TARGET METALS AND ENHANCE THE ANALYTICAL PERFORMANCE [1, 2]...

SULFONAMIDE DERIVATIVES THAT HAVE SULFUR AND AMINE GROUPS IN THEIR MOLECULAR STRUCTURE ARE APPLIED AS ANTIBACTERIAL AGENTS. THEIR RESIDUE CAN REACH ENVIRONMENT AND MAY CAUSE TOXICITY AND SERIOUS PUBLIC HEALTH HAZARDS. AS THESE MEDICATIONS ARE ELECTRO-ACTIVE, THEIR BEHAVIOR AND CONCENTRATION CAN BE MONITORED BY DESIGNED ELECTRODES [1-3]. RECENTLY, CARBON PASTE ELECTRODES (CPES) ARE CONSIDERED NOTEWORTHY DUE TO THEIR VALUABLE PROPERTIES LIKE LOW COST, NON-TOXICITY, RENEWABLE SURFACE AND BEING ABLE TO BE MODIFIED BY WIDE RANGE OF MATERIALS. ...

BACKGROUND: REACTIVE OXYGEN SPECIES (ROS) ARE PRODUCED AS A CONSEQUENCE OF NORMAL AEROBIC METABOLISM AND ARE ABLE TO INDUCE DNA OXIDATIVE DAMAGE [1-2]. THE STUDY OF THESE REACTIVE SPECIES AND ITS EFFECTS ON THE ORGANISM HAVE BEEN OF PRIMARY INTEREST, SINCE THEY INDUCE SOME DAMAGE TO CELLS BY REACTING WITH BIOMOLECULES SUCH AS PROTEINS, LIPIDS AND CAUSE SERIOUS LESIONS TO DNA. AT THE CELLULAR LEVEL, THE EVALUATION OF THE PROTECTIVE EFFECT OF ANTIOXIDANTS CAN BE ACHIEVED BY EXAMINING THE INTEGRITY OF THE DNA NUCLEOBASES USING ELECTROCHEMICAL TECHNIQUES [3-4].METHODS: IN THIS WORK, AN ELECTROCATALYTIC VOLTAMMETRIC METHOD TO ASSESS TOTAL ANTIOXIDANT CAPACITY (TAC) USING DNA-MODIFIED GRAPHITE ELECTRODE (DNA-GE) WAS DEVELOPED. THE OXIDATIVE LESIONS GENERATED AFTER IMMERSION OF THE DNA-GE IN THE FENTON MIXTURE WERE INDIRECTLY QUANTIFIED AFTER THE ELECTROCHEMICAL OXIDATION OF THE ADENINES AND GUANINES THAT REMAINED UNOXIDIZED ON THE ELECTRODE SURFACE. THE INCREASE OF THIS ELECTROCATALYTIC CURRENT IN THE PRESENCE OF SEVERAL ANTIOXIDANT SPECIES WAS STUDIED.RESULTS: USING ASCORBIC ACID (AA) AS A MODEL ANTIOXIDANT SPECIES, THE DETECTION OF AS LOW AS 10.0 NM OF AA IN AQUEOUS SOLUTION WAS POSSIBLE. THE PROTECTION EFFICIENCY WAS EVALUATED FOR SEVERAL ANTIOXIDANT COMPOUNDS. THE BIOSENSOR WAS APPLIED TO THE DETERMINATION OF THE TOTAL ANTIOXIDANT CAPACITY (TAC) IN BEVERAGES. THE BIOSENSOR DEVELOPED WAS APPLIED TO THE DETERMINATION OF TAC IN SEVERAL BEVERAGES AND THE RESULTS WERE COMPARED WITH THOSE ATTAINED USING OTHER METHODOLOGIES TO OBTAIN AN OVERALL PICTURE OF THE ANTIOXIDANT PROFILE.CONCLUSION: THE BIOSENSOR DEVELOPED WAS DISPOSABLE AND REQUIRED A VERY EASY, RAPID AND REPRODUCIBLE PREPARATION. IN ADDITION TO THIS, THE LOW DETECTABILITY ALLOWED ITS ADVANTAGEOUS USED FOR TAC EVALUATION IN FOODSTUFFS AS IT WAS SUCESSFULLY SHOWN IN SEVERAL BEVERAGES. THE PROPOSED METHOD WAS PROVED TO BE SIMPLE, SENSITIVE, FAST, AND ENVIRONMENTALLY FRIENDLY.