ISONIAZID IS CONSIDERED AS THE FIRST CHOICE FOR TREATMENT AND RECOVERY OF PHTHISIS DISEASES. THE PHTHISIS DISEASES ARE CONTAGIOUS AND KNOWN AS THE MAIN REASON OF HUMAN DEATH IN ALL OVER THE WORLD. THEREFORE, DETERMINATION OF ISONIAZID, THE ANTI-T B DRUG, AS FIRST-LINE TB DRUGS AND THE MAIN TREATMENT REGIMEN FOR TUBERCULOSIS IN ALL OVER THE WORLD CAN BE VERY VALUABLE [1-2].THEREFORE, DESIGN AND DEVELOPMENT OF A SENSOR WITH THE AIM OF ISONIAZID DETERMINATION CAN BE VALUABLE IN ORDER TO DETERMINATION OF THIS IMPORTANT MATERIAL.HOWEVER, ELECTRO OXIDATION OF ISONIAZIDON BARE ELECTRODES NEEDS HIGH OVER POTENTIALS AND IS KINETICALLY SLOW. THEREFORE, VARIOUS MODIFIED ELECTRODES WITH THE AIM OF IMPROVEMENT OF THE RATE OF ELECTRON TRANSFER AND OVER POTENTIAL REDUCING WERE INTRODUCED. IN MODIFIED ELECTRODES, THE SURFACE OF CONVENTIONAL ELECTRODES WERE COVERED WITH THIN LAYER OF A CHEMICAL COMPOUNDS, WHICH CAUSE IN CHANGE IN PROPERTIES OF ELECTRODE SURFACE AND ELECTROCHEMICAL BEHAVIOR OF ELECTRO-ACTIVE COMPOUNDS [3].RECENTLY CARBON NANOTUBES HAVE ATTRACTED MORE ATTENTION IN CHEMISTRY SPECIALLY IN ELECTROANALYTICAL CHEMISTRY. CARBON NANOTUBES ARE UNIQUE TUBULAR STRUCTURES WITH DIAMETER ON NANOMETER AND HIGH RATIO OF LENGTH TO WIDTH [4]. BECAUSE OF HIGH CHEMICAL STABILITY, HIGH SURFACE AREA, UNIQUE ELECTRONIC AND MECHANICAL PROPERTIES, CARBON NANOTUBES HAVE ATTRACTED MUCH ATTENTION.CARBON NANOTUBES COULD BE ACT AS ELECTRON TRANSFER MEDIATOR BETWEEN ELECTRO-ACTIVE SPECIES AND ELECTRODE SURFACE AND THEREFORE CREATED A NEW APPROACH FOR CONSTRUCTION OF SENSORS AND BIOSENSORS [5].

SOL GEL PROCEDURE IS HIGHLY EFFICIENT DUE TO THE LOW TEMPERATURE OF THE CHEMICAL PROCESS, HIGH HOMOGENEITYAND PRODUCT PURITY, WHICH ENABLES INSERTING SOME BIOLOGICAL ACTIVE SUBSTANCES INTO THE PREPARATION. SOL GEL DERIVED SILICA XEROGELS ARE NONTOXIC AND BIOCOMPATIBLE.THE AIM OF PRESENT STUDY WAS TO UTILIZE SOLGEL METHOD TO SYNTHESIZE TWO TYPES OF XEROGELS AND INVESTIGATE HOW CHANGING THE CATALIYST INFLUENCES STRUCTURE OF MATRICES. TETRAETHYL ORTHOSILICATE (TEOS) AS AN SIO2 PRECURSOR, HCL (0.01M) AND NH4OH (1M) AS CATALYIST WERE USED. SILICA XEROGELS WERE PREPARED BY TWO PROCEDURES: 1.TEOS, ETHANOL, WATER, HCL MIXAD FOR 1H AND THEN LEFT FOR GELATION.2. TEOS, ETHANOL, WATER, HCL WERE MIXED AND THE SOL HYDROLYEZED FOR ONE DAY AND THEN AMMONIA WAS ADDED THEN IT IS LEFT TO GELATION. AFTER GELATION, THEY WERE DRIED AT ROOM TEMPERATURE. CHARACTERIZATION ASSAYS COMPRISED ANALYSIS OF THE MATRIX BY SCANNING ELECTRON MICROSCOPE (SEM) TECHNIQUES, DETERMINING THE SPECIFIC SURFACE AREA OF SOLIDS (BET) AND AVERAGE PORE SIZE MEASURMNET (BJH). SEM IMAGES SHOW ACID CATAYIZED SILICA XEROGELS HAVE DENSE AND TRANSPARENT TRUCTURE AND ACID/BASE CATALYZED XEROGELS ARE OPAQUE AND THEY HAVE LARGER PORES. ALSO ACID CATAYIZED PARTICLES HAVE SHOWN PLATE LIKE STRUCTURE WHERASE ACID/BASE CATALYZED PARTICLES HAVE SHOWN SPHERICAL STRUCTURE (FIG1, 2). THE EFFECT OF CATALYSTS ON THE SURFACE AREA AND GELATION TIME ARE SHOWN IN TABLE1. FOR ACID CATALYZED XEROGELS THE POROSITY ANALYSIS WAS NOT APPLICABLE BECAUSE THE SURFACE AREA AND PORE SIZE WERE TOO SMALL TO BE MEASURED WITH THIS TECHNIQUE.

ACETYLSALICYLIC ACID (ASA), COMMONLY KNOWN AS ASPIRIN, IS ONE OF THE MOST IMPORTANT NONSTEROIDAL ANTI-INFLAMMATORY, ANALGESIC AND ANTIPYRETIC DRUGS IN THE WORLD. IT IS WIDELY USED TO RELIEVE MINOR ACHES, PAINS AND REDUCE FEVER AND IS ALSO GREAT EFFECTIVE IN TREATING THE ANTITHROMBOTIC, CORONARY HEART DISEASE, PREVENTING COLON CANCER AND PREGNANCY INDUCED PRE-ECLAMPSY [1, 2]. SUCH WIDESPREAD USE OF ASPIRIN HAS RESULTED IN PROBLEMS OF OVERDOSE ESPECIALLY IN PERSONS SUFFERING FROM CHRONIC INFLAMMATORY DISEASES, WHO TAKE THIS DRUG HABITUALLY [3]. ...

TIO2 NANOPARTICLES WERE PREPARED BY THE P-25 MODIFIED SOL-GEL METHOD UNDER DIFFERENT TTIP CONCENTRATIONS, P-25 LOADING AND THE GELATION PHS. STRUCTURAL PROPERTIES OF NANOPARTICLES WERE CHARACTERIZED BY XRD, FESEM AND BET ANALYSIS. RESULTS SHOW THAT CRYSTALLINITY LEVEL, PARTICLES SIZE AND THE SURFACE AREA ARE A FUNCTION OF P-25 LOADING AND GELATION PH, WHEREAS TTIP CONCENTRATION AFFECTS ONLY ON THE CRYSTALLINE COMPOSITION. ACID RED 73 WAS USED AS A MODEL ORGANIC CONTAMINANT TO EVALUATE THE PHOTOCATALYTIC ACTIVITY OF THE TIO2 NANOPARTICLES PREPARED BY THE P-25 MODIFIED SOL-GEL METHOD UNDER OPTIMAL SYNTHESIS PARAMETERS. THE AS-PREPARED TIO2 NANOPARTICLES EXHIBIT HIGHER PHOTOCATALYTIC PERFORMANCE AS COMPARED TO THE COMMERCIAL TIO2 POWDER. THIS RESULT CAN BE ATTRIBUTED TO THE OPTIMAL STRUCTURAL PROPERTIES OF THE TIO2 NANOPARTICLES SYNTHESIZED UNDER OPTIMAL CONDITIONS.

AMINO ACIDS ARE ESSENTIAL BUILDING BLOCKS OF BIOLOGICAL MOLECULES, AND THE DEVELOPMENT OF NEW TECHNOLOGIES FOR THEIR SENSITIVE AND UNIVERSAL QUANTITATIVE DETERMINATIONS IS OF GREAT INTEREST 1. HOWEVER, THE DETERMINATION OF AMINO ACIDS IS NOT ALWAYS SIMPLE GIVEN THAT THESE COMPOUNDS LACK NATURAL CHROMOPHORE OR FLUOROPHORE FOR PHOTOMETRIC AND FLUOROMETRIC DETECTION. OVER THE PAST TWO DECADES, THE SIGNIFICANT ANALYSIS METHODS OF AMINO ACIDS HAVE FOCUSED ON UV-VISIBLE ABSORPTION, FLUORESCENCE, MASS SPECTROMETRY, AND THE LIKE, IN WHICH THE INVESTIGATED DERIVATIVES ARE FORMED MAINLY VIA THE REACTIONS BETWEEN THE PRIMARY AMINO GROUP AND O-PHTHALALDEHYDE IN THE PRESENCE OF AN ALKYL THIOL BY PRE- OR POSTCOLUMN DERIVATIZATION. BUT THE DERIVATIZATION PRODUCTS ARE USUALLY UNSTABLE, AND THE ABOVE DETECTION TECHNIQUES HAVE MORE OR LESS SUFFERED FROM DIVERSE DISADVANTAGES WITH REGARD TO THE EXPENSIVE EQUIPMENT, INSUFFICIENT SELECTIVITY, AND TIME-CONSUMING PROCESS OF SAMPLE PREPARATION. DURING THIS PERIOD, DUE TO ITS OBVIOUS ADVANTAGES OF FREE DERIVATIZATION, LOWER COST, BETTER SELECTIVITY, AND HIGHER SENSITIVITY, ELECTROCHEMICAL DETECTION HAS BEEN WIDELY EMPLOYED TO MONITOR A GREAT VARIETY OF ANALYTES OF INTEREST 2.SOL-GEL TECHNOLOGY AND USING OF SILICATED MATRIX THAT FINALLY WAS CRYSTALLIZED AS GLASSICAL CRYSTALS, HAS BEEN USED FOR ANALYTICAL INVESTIGATION SINCE LAST CENTURY. SOL-GEL ELECTROCHEMISTRY HAS PROVIDED EXTENSIVE RESEARCH RANGE IN ANALYTICAL CHEMISTRY IN LAST FIFTY YEARS. SOL-GEL PROCESS HAS BEEN DONE ON THE BASIS OF HYDROLYSIS AND CONDENSATION OF ORGANOMETALLIC ALKOXIDES FOLLOWING THE GEL FORMATION PROCESS BY FORMING POLYMERIC BONDS WITH M (OR) X. IN THIS RESEARCH, CARBON-CERAMIC ELECTRODE OF TYROSINE HAS BEEN USED FOR INVESTIGATION OF ELECTROCHEMICAL BEHAVIOR OF TYROSINE 3.EFFECTIVE PARAMETERS SUCH AS SOLUTION PH, SUPPORTING ELECTROLYTE CONCENTRATION, OPTIMIZING PERCENTAGE OF TIO2, MODIFYING WITH POLYPYROLE, SCAN RATE, WERE INVESTIGATED IN THIS RESEARCH. AMOUNT OF ADSORBED TYROSINE ON CARBON-CERAMIC ELECTRODE WAS DETERMINED USING CYCLIC VOLTAMMETRY.

BACKGROUND AND OBJECTIVE(S): IN THIS PAPER, A NEW ADSORBENT, MWCNTCARBON CERAMIC COMPOSITES (MWCNT/CCC), WAS PREPARED BY THE FACILE SOLGEL METHOD. THE STUDY AIMED TO OPTIMIZE THE OPERATION PARAMETERS FOR THE ADSORPTION OF BASIC YELLOW 28 (BY28) DYE ON MWCNT/CCC USING RESPONSE SURFACE METHODOLOGY. ...