RIZATRIPTAN BENZOATE (RIZ) BELONGS TO A GROUP OF MEDICINES KNOWN AS SEROTONIN AGONISTS [1]. IT IS DESCRIBED CHEMICALLY AS: N, N DIMETHYL-5-(1H-1, 2, 4-TRIAZOL-1-YLMETHYL)-1H-INDOLE-3-ETHANAMINE MONO BENZOATE. IT IS USED IN THE TREATMENT OF MIGRAINES. THE LITERATURE REVEALS THAT VARIOUS METHODS FOR THE DETERMINATION OF RIZATRIPTAN BENZOATE ARE SPECTROPHOTOMETRY, GAS CHOROMATOGRAPHY, HIGH-PERFORMANCE LIQUID CHOROMATOGRAPHY, LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY, MICROEMULSION ELECTROKINETIC CAPILLARY CHROMATOGRAPHY AND REVERSED-PHASE LIQUID CHROMATOGRAPHIC [2]. THE ELECTROCHEMICAL biosensorS ARE INEXPENSIVE AND POSSESS MANY ADVANTAGES SUCH AS LOW BACKGROUND CURRENT, WIDE RANGE OF POTENTIAL WINDOWS, RAPID SURFACE RENEWAL AND EASY FABRICATION [3]. THERE IS NO VOLTAMMETRIC REPORT USING BOVINE SERUM ALBUMIN (BSA) FOR CONSTRUCTION OF RIZATRIPTAN biosensor IN THE ACCESSIBLE LITERATURE. IN THIS WORK, A CHEMICALLY MODIFIED ELECTRODE USING BOVINE SERUM ALBUMIN (BSA) FOR THE VOLTAMMETRIC DETERMINATION OF RIZ IN SOLUTION WAS INTRODUCED. THE RESULTS SHOWED THAT THE MODIFIED ELECTRODE EXHIBITED EXCELLENT ELECTROCATALYTIC ACTIVITY TO RIZ AND SHOWED GREAT PROMISE FOR SIMPLE, SENSITIVE AND QUANTITATIVE DETECTION AND SCREENING OF RIZ. THE OXIDATION PROCESS WAS SHOWN TO BE IRREVERSIBLE OVER THE ENTIRE PH RANGE STUDIED (1.0 - 10.0). THE STUDY OF EXPERIMENTAL PARAMETERS SHOWED THAT THE OXIDATION REACTION IS TOTALLY IRREVERSIBLE AND MAXIMUM CURRENT RESPONSE WAS OBTAINED AT PH=10 IN PHOSPHATE BUFFER. RIZ WAS DETERMINED BY DIFFERENTIAL PULSE VOLTAMMETRY AND THE PEAK CURRENT WAS FOUND LINEARLY WITH ITS CONCENTRATION IN THE RANGE OF 8.0´10-3- 1.0´10-3 MOL L-1. THE OBTAINED MODIFIED ELECTRODE WAS SUCCESSFULLY APPLIED FOR SIMPLE AND RAPID DETERMINATION OF RIZ IN STANDARD SOLUTIONS AND PHARMACEUTICAL TABLETS USING DIFFERENTIAL PULSE VOLTAMMETRY.

UREA IS AN IMPORTANT MARKER FOR STUDIES OF RENAL FUNCTION. THE NORMAL LEVEL OF UREA IN SERUM IS FROM 15 TO 40 MG/DL (1.7–8.3 MM) IN BLOOD SERUM AND LEVEL INCREASES UP TO 100 MM UNDER PATHOPHYSIOLOGICAL CONDITIONS [1]. AN INCREASE IN UREA LEVEL IN BLOOD AND URINE CAN BE CAUSED BY URINARY TRACT OBSTRUCTION, RENAL FAILURE, BURNS, DEHYDRATION AND SHOCK. MOREOVER, REDUCED UREA LEVEL MAY BE SEEN IN HEPATIC FAILURE, NEPHRITIC SYNDROME, AND CACHEXIA WHICH MADE UREA ANALYSIS AS A CONSIDERABLE AREA IN CLINICAL AND AGRICULTURAL CHEMISTRY. ELECTRODEPOSITED ZINC OXIDE (ZNO) WAS DESIGNED TO ACHIEVE NANOSTRUCTURED PLATFORM FOR UREASE ENZYME IMMOBILIZATION VIA COVALENT ATTACHMENT. ELECTROCHEMICAL DEPOSITION AS A RELIABLE, COST-EFFECTIVE, MILD PHYSICOCHEMICAL METHOD AND EASILY CONTROLLABLE ELECTROLYTE FORMULA BY ADDING ORGANIC ADDITIVES, PRODUCE NANOSTRUCTURED METAL OXIDES FILMS WITH CONTROLLED MORPHOLOGY AND THICKNESS. IN THIS STUDY, PVA SELECTION CRITERIA AS AN ORGANIC ADDITIVE IN ELECTROCHEMICAL DEPOSITION WAS BASED ON ITS WATER SOLUBILITY, CONTROLLING THE GROWTH AND CRYSTALLIZATION OF ZNO BY TUNING POLYMER CONTENT IN ELECTRODEPOSITION BATH AND ITS REMOVAL BY A SUBSEQUENT POST-ANNEALING TREATMENT OF THE LAYER IN 400OC. SURFACE CHARACTERIZATION OF THE NANOSTRUCTURED ZNO FILM BY FIELD EMISSION-SCANNING ELECTRON MICROSCOPY (FE-SEM) EXHIBITS FILM SURFACE AREA AS AN EXCELLENT PLATFORM FOR ENZYME IMMOBILIZATION. MONITORING OF biosensor FABRICATION WAS PERFORMED USING CYCLIC VOLTAMMETRY (CV) AND ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS) TECHNIQUES. THE IMPEDIMETRIC RESULTS WERE EXPLAINED FOR UREA DETECTION.

FOR THE PAST SEVERAL YEARS, NANOMATERIALS HAVE BEEN ATTRACTED CONSIDERABLE ATTENTION IN DIFFERENT AREAS OF THE SCIENCE SUCH AS ELECTRONICS, CATALYSTS, AND SENSORS. ACCORDING TO THE RECENT ADVANCES IN SYNTHESIS AND ENGINEERING OF NANOSTRUCTURES ALSO BECAUSE OF THE UNIQUE PHYSICOCHEMICAL PROPERTIES OF THESE NANOMATERIALS, THEY HAVE BEEN USED AS AN EXCELLENT CHOICE TO PRODUCE MORE SENSITIVE AND EFFECTIVE SENSING DEVICES. ...

DICHLORODIPHENYLTRICHLOROETHANE (DDT) IS AN ORGANOCHLORINE PESTICIDE THAT HAS BEEN USED THROUGHOUT THE WORLD FOR THE CONTROL OF SOIL-DWELLING INSECTS AND AS A TREATMENT AGAINST DISEASES SUCH AS MALARIA AND TYPHUS. IN THE ENVIRONMENT, DDT PRODUCES TWO DEGRADATION PRODUCTS, 1, 1-DICHLORO-2, 2-BIS- (P-CHLOROPHENYL) -ETHANE (DDD) AND 1, 1-DICHLORO-2, 2-BIS- (PCHLOROPHENYL) -ETHYLENE (DDE) THROUGH TWO DEGRADATION PATHWAYS [1]. DDT AND ITS DEGRADATION PRODUCTS CAUSE SEVERAL HARMFUL EFFECTS ON HUMANS AND WILDLIFE BECAUSE OF THEIR ACTION AS ENDOCRINE DISRUPTERS BY INTERFERING WITH HORMONAL ACTIVITY [2]. THIS STUDY IS FOCUSED ON USING ION MOBILITY SPECTROMETRY (IMS) TECHNIQUE WITH CORONA DISCHARGE IONIZATION SOURCE AS A RAPID, SIMPLE AND SENSITIVE METHOD FOR DETERMINATION OF DDT AND ITS MAIN METABOLITES IN ENVIRONMENTAL WATER. THIS TECHNIQUE IS BASED ON ION MOBILITY WHICH IS PROPORTIONAL TO THE MOLECULAR WEIGHT AND CHARGE [3]. PARAMETERS INFLUENCING DETECTION AND DETERMINATION EFFICIENCY SUCH AS, INJECTION AND OVEN TEMPERATURE, FLOW RATE OF GASES AND ALSO CORONA AND DRIFT VOLTAGES, WERE THOROUGHLY OPTIMIZED. THIS DEVELOPED METHOD SHOWED GOOD RESULT FOR DETERMINATION OF DDT AND ITS METABOLITES IN LOW LEVELS (UNDERMG/L). THE PROPOSED METHOD WAS VALIDATED WITH ENVIRONMENTAL WATER SAMPLES. THE SPIKED RECOVERY WAS BETWEEN 93-98 % FOR AGRICULTURAL-FIELD WATER. THE ESTABLISHED METHOD HAS BEEN PROVED TO BE A SIMPLE, RAPID, SENSITIVE, INEXPENSIVE AND ECO-FRIENDLY PROCEDURE FOR THE DETERMINATION OF DDT AND ITS MAIN METABOLITES IN ENVIRONMENTAL WATER SAMPLES.

PHENAZOPYRIDINE (PAP) [2, 6-DIAMINO-3- (PHENYLAZO) PYRIDINE], IS A HETEROCYCLIC AROMATIC AZO COMPOUND THAT HAS BEEN USED IN THE TREATMENT OF URINARY TRACT INFECTIONS SINCE 1930S AND IS UTILIZED TO ALLEVIATE THE PAIN IN CONDITIONS SUCH AS CYSTITIS AND URETHRITIS [1]. THE INTERACTION OF PHENAZOPYRIDINE HYDROCHLORIDE WITH DS-DNA BASED ON THE DECREASING OF THE OXIDATION SIGNAL OF GUANINE AND ADENINE WAS STUDIED ELECTROCHEMICALLY AT A PENCIL GRAPHITE ELECTRODE (PGE) USING DIFFERENTIAL PULSE VOLTAMMETRY. THE DECREASE IN THE INTENSITY OF THE GUANINE AND ADENINE OXIDATION SIGNALS AFTER THEIR INTERACTION WITH PHENAZOPYRIDINE HYDROCHLORIDE WERE USED AS INDICATOR SIGNALS FOR THE SENSITIVE DETERMINATION OF PHENAZOPYRIDINE HYDROCHLORIDE. THIS biosensor MADE OF PRETREATED PENCIL GRAPHITE ELECTRODE (PGE) MODIFIED WITH MULTIWALL CARBON NANOTUBES (MWCNTS) AND CHITOSAN (CHIT) DECORATED WITH THE DS-DNA [2]. THE DIFFERENCE BETWEEN ADENINE AND GUANINE SIGNALS OF THE DS-DNA AFTER AND BEFORE INTERACTION WITH PHENAZOPYRIDINE HYDROCHLORIDE WAS DIRECTLY PROPORTIONAL TO PHENAZOPYRIDINE HYDROCHLORIDE CONCENTRATION, WHICH USED FOR QUANTITATIVE INSPECTIONS. UNDER THE OPTIMUM CONDITIONS, A LINEAR DEPENDENCE OF THE GUANINE AND ADENINE OXIDATION SIGNALS WAS OBSERVED FOR THE PHENAZOPYRIDINE HYDROCHLORIDE CONCENTRATION IN THE RANGE OF 0.05-30 G ML-1 WITH A DETECTION LIMIT OF 0.025 GML-1. THIS METHOD IS SUCCESSFULLY APPLIED FOR THE DETERMINATION OF PHENAZOPYRIDINE HYDROCHLORIDE IN HUMAN PLASMA, URINE SAMPLES, AND PHARMACEUTICAL.

OXYTETRACYCLINE (OTC) IS A COMMON TETRACYCLINE ANTIBIOTIC WITH A BROAD RANGE OF ACTIVITY AND A LOW COST. IT WIDELY USED IN SWINE AND ANIMAL FARMING. ITS LOW ABSORPTION ON ORAL ADMINISTRATION CAUSES THE CONTAMINATION OF SWINE MANURE BY UNMETABOLIZED MATERIAL [1] AND MAKES IT AS MOST FREQUENTLY DETECTED TETRACYCLINES IN WATER BODIES AND SEDIMENTS AROUND THE WORLD [2]. IT IS REPORTED OTC CAN PREVENT THE BIOACTIVITY OF VARIOUS MICROORGANISMS [3]. ...

THE PRESENT WORK DESCRIBES THE PERFORMANCE OF AN ENZYME biosensor BASED ON IMMOBILIZED POLYPHENOL OXIDASE OF SINGLE WALLED CARBON NANOTUBES (SWCNTS). THIS ELECTRODE WAS PREPARED BY FIRST MODIFICATION OF ELECTRODE SURFACE BY 10ML ACETONE SOLUTION OF 1 MG/ML SWCNTS AND THEN ENZYME IMMOBILIZATION WAS APPLIED ON THE SURFACE OF MODIFIED ELECTRODE.

OLEUROPEIN, A NATURAL PRODUCT OF THE SECOIRIDOID GROUP, IS THE MAJOR BIOACTIVE COMPOUND IN OLIVE LEAVES. FOR ITS WIDE RANGE OF PHARMACOLOGICAL PROPERTIES SUCH AS ANTIOXIDANT AND ANTICANCER, OLEUROPEIN IS COMMERCIALLY AVAILABLE AS FOOD SUPPLEMENT IN MEDITERRANEAN COUNTRIES.WE HAVE DEVELOPED AN ELECTROCHEMICAL DNA biosensor BASED ON THE IMMOBILIZATION OF DOUBLESTRANDED DEOXYRIBONUCLEIC ACID (DSDNA) ON THE SURFACE OF A CHITOSANE-MODIFIED CARBON PASTE ELECTRODE FOR THE RAPID, SENSITIVE AND SELECTIVE DETERMINATION OF OLEUROPEIN. A CONSIDERABLE INCREASE WAS OBSERVED IN THE OXIDATION SIGNAL OF OLE AT THE DNA-COATED ELECTRODE COMPARED WITH THE DNA-FREE ELECTRODE, INDICATING THE PRE-CONCENTRATION OF OLE DUE TO THE INTERACTION WITH THE SURFACE-CONFINED DNA LAYER. AFTER OPTIMIZING DIFFERENT EXPERIMENTAL CONDITIONS, A LINEAR CONCENTRATION RANGE OF 0.30-12.0 MM WITH A DETECTION LIMIT OF 0.090 MM WAS OBTAINED. THE PROPOSED biosensor WAS SUCCESSFULLY APPLIED TO THE DETERMINATION OF OLE IN OLIVE LEAF EXTRACT AND HUMAN SERUM SAMPLES.