CERIUM IS A MEMBER OF LANTHANIDE GROUP OF ELEMENTS. IT HAS MANY INDUSTRIAL APPLICATIONS IN THE AREAS OF LIGHTING, METALLURGY, GLASS AND CERAMICS. DUE TO ITS USAGE IN MANY FIELDS OF HUMAN ENDEAVOR, THERE IS GROWING NEED TO STUDY THE ENVIRONMENTAL, MEDICAL AND BIOLOGICAL EFFECTS OF CERIUM. HENCE, THE AVAILABILITY OF RAPID, SENSITIVE AND SELECTIVE METHODS FOR CERIUM DETERMINATION IS OF IMPORTANCE [1]. AMONG DIFFERENT TECHNIQUES THAT ARE USED FOR MEASURING METAL CATIONS, POTENTIOMETRIC TECHNIQUE USING ION SELECTIVE ELECTRODES IS A SIMPLE, RAPID, INEXPENSIVE AND SELECTIVE METHOD [2, 3]. IN THIS PROJECT, A CERIUM (III) SELECTIVE ELECTRODE WAS PREPARED BY INCORPORATING DIBENZO-18-CROWN-6 AS A NEUTRAL IONOPHORE. THE BEST RESPONSE CHARACTERISTIC WAS OBTAINED USING THE COMPOSITION (W/W%) OF NITROBENZENE (AS PLASTICIZER): PVC: SODIUM TETRAPHENYLBORATE (AS AN ANION EXCLUDER): DIBENZO-18-CROWN-6 IN THE PERCENTAGE RATIO OF 63.0: 30.0: 2.0: 5.1. THE ELECTRODE EXHIBITS SIGNIFICANTLY ENHANCED RESPONSE TOWARD CERIUM IONS OVER A WIDE CONCENTRATION RANGE WITH A GOOD NERNSTIAN SLOPE. THE DETECTION LIMIT OF THE ELECTRODE WAS 9.7×10-7 M. THE EFFECTS OF THE PH AND POSSIBLE INTERFERING IONS WERE INVESTIGATED. THE PROPOSED ELECTRODE WAS SUITABLE FOR USE IN AQUEOUS SOLUTIONS IN A WIDE PH RANGE OF 1.0-10.0 AND REVEALED A GOOD SELECTIVITY TOWARDS CE3+ION OVER A WIDE RANGE OF METAL CATIONS. IN ADDITION, THIS ELECTRODE WAS SUCCESSFULLY USED FOR THE DETERMINATION OF CE3+ IN REAL SAMPLES.

THE OBJECTIVE OF THIS WORK IS STUDY THE POTENTIOMETRIC BEHAVIOR OF AMOXICILLIN (AMX) AT NANO ZEOLITE-MODIFIED ION SELECTIVE ELECTRODE DOPPED WITH COPPER (II) IONS (CU2+). ZEOLITE THAT USED IS CLINOPTILOLITE THAT MADE IT INTO NANO PARTICALES WITH BALL-MILL METHOD. ONE OF THE PROPERTIES OF ZEOLITES IS ABILITY TO ION EXCHANGE AND APPLIED HERE FOR MAKING MODIFIER [1]. CU2+ WORK AS CATALYST TO OXIDIZE AMX WITH NANO CLINOPTILOLITE THIS AIM INCREASE BECAUSE NANO PARTICLES HAVE BETTER RATIO SURFACE TO VOLUME. MODIFIER THAT APPLIED IN ELECTRODE IDENTIFY BY XRD METHOD AND SEM. IN THIS WORK FOR PREPARATION ION SELECTIVE ELECTRODE AND MIXED DIOCTYL PHTHALATE AND CU(II)-NC AND POLY VINYL CHLORIDE AND TETRAHYDROFURAN. THEN GLASSY PIPES WITH A DIAMETER OF 2 MM INSERTED IN MIXTURE AND DRYING IN ROOM TEMPERATURE REVIEWED THE ELECTRODES RESPONSE IN ABSENT AND PRESENT OF AMX BY POTENTIOMETRIC METHOD. BY USING THIS ELECTRODES EXPERIMENTAL PARAMETERS AFFECTING ON THE EFFICIENCY INCLUDING SOLUTION PH, TEMPERATURE AND MODIFIER PERCENT WERE EXAMINED AND OPTIMIZED. Β-LACTAMIC ANTIBIOTICS (INCLUDING HERE AMX) ARE THE OLDEST AND IMPORTANT ANTIMICROBIAL AGENT THAT ARE STILL WIDELY USED TO TREAT HUMAN AND ANIMAL DISEASES. VARIOUS ANALYTICAL METHODS HAVE BEEN REPORTED FOR THE SEPARATION AND DETERMINATION OF AMX BASED ON SPECTROPHOTOMETRIC [2], [3] AND [4], FLUORIMETRIC [5] CAPILLARY ELECTROPHORESIS [6] AND [7], HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY [8] AND [9] AND ELECTROCHEMICAL METHODS [10-12].

THE DEVELOPMENT OF ION SELECTIVE SENSORS ARE THE WELL ESTABLISHED IN MOST FREQUENT APPLICATIONS IN THE FIELDS OF ENVIRONMENTAL, AGRICULTURAL, INDUSTRIAL AND CLINICAL ANALYSIS [1].THIS IS DUE TO THEIR SEVERAL ADVANTAGES, SUCH AS HIGH SPEED, EASE OF PREPARATION, SIMPLE INSTRUMENTATION, RELATIVELY FAST RESPONSE, WIDE WORKING CONCENTRATION RANGE, ADEQUATE SELECTIVITY AND LOW COST [2-4].IN THIS STUDY, A NEW POLYVINYL CHLORIDE (PVC) MEMBRANE SENSOR FOR LA3+ION BASED ON KRYPTOFIX 22DD AS AN ION CARRIER WAS PREPARED. EFFECTS OF EXPERIMENTAL PARAMETERS SUCH AS MEMBRANE COMPOSITION, AMOUNT OF PLASTICIZER AND AMOUNT OF ADDITIVE ON THE POTENTIAL RESPONSE OF LA3+SENSOR WERE INVESTIGATED. THE BEST OPERATION OBTAINED IN THE MEMBRANE INCLUDING: 4.0 MG KRYPTOFIX 22DD, 1.0 MG SODIUM TETRAPHENYL BORATE (NATPB), 65.0 MG NITROBENZENE (NB) AND 30.0 MG PVC. THE SENSOR EXHIBITED A NERNSTIAN SLOPE OF 17.9 MV/DECADE IN LA3+ ACTIVITY. THE STATIC RESPONSE TIME WAS 5 S OVER THE ENTIRE CONCENTRATION RANGE AND POTENTIALS STAYED CONSTANT FOR 4 MIN. THE PRACTICAL UTILITY OF THE SENSOR HAS BEEN DEMONSTRATED BY USING IT AS AN INDICATOR ELECTRODE IN THE POTENTIOMETRIC TITRATION OF LA3+WITH EDTA. THE PROPOSED SENSOR WAS SUCCESSFULLY USED FOR DETERMINATION OF LANTHANUM (III) IN REAL WATER SAMPLES.