PLASMON RESONANCE SCATTERING (PRS) IS A NEW, SENSITIVE AND SIMPLE SPECTRAL ANALYTICAL TECHNIQUE, AND APPLIES TO DETERMINATION OF TRACE SUBSTANCES WITH SATISFACTORY RESULTS. IT HAS BEEN REPORTED THAT SOME METAL NANOPARTICLES (NPS) SUCH AS NANOSILVER EXHIBITED A PARTICULAR OPTICAL AND ELECTRONIC PROPERTIES, AND WERE UTILIZED TO NANO-ANALYTICAL CHEMISTRY [1, 2]...

THE MAIN RESTRICTIONS IN DETERMINATION OF THE INNER TRANSITION ELEMENTS IN ENVIRONMENTAL SAMPLES COME FROM THE HIGH CONTENT OF THE MATRIX AND THE EXTREMELY LOW CONCENTRATION LEVELS OF THE ELEMENTS IN THOSE SAMPLES, WHICH ARE BELOW THE DETECTION LIMITS OF THE CONVENTIONAL INSTRUMENTAL TECHNIQUES [1]. THEREFORE, AN EFFICIENT SEPARATION AND PRECONCENTRATION TECHNIQUE IS FREQUENTLY REQUIRED FOR DETERMINATION OF THESE ELEMENTS IN COMPLEX MATRICES. IN THIS PROJECT, A NEW FACILE, RAPID, INEXPENSIVE, AND SENSITIVE METHOD BASED ON MAGNETIC SOLID PHASE MICROEXTRACTION WAS DEVELOPED FOR DETERMINATION OF LANTHANUM IN ENVIRONMENTAL WATER SAMPLES. IN SPME TECHNIQUE, SELECTION OF AN APPROPRIATE SORBENT IS AN IMPORTANT STRATEGY IN THE ELABORATION OF ANALYTICAL PROCEDURE, AND NANOMETER SORBENTS HAVE PROVED TO BE ESPECIALLY EFFECTIVE AS A RESULT OF ITS HIGH SPECIFIC SURFACE AREAS, HIGHLY ACTIVE SURFACE SITES AND THE ABSENCE OF INTERNAL DIFFUSION RESISTANCE IN THE SEPARATION PROCESS. MAGNETIC NANOPARTICLES (MNPS), AS A NEW KIND OF NANOMETER MATERIAL, HAVE GAINED MORE ATTENTION, EASY CONTROL AND FAST MAGNETIC SEPARATION UNDER AN EXTRA MAGNETIC FIELD MAKES THEM EXCELLENT CANDIDATES FOR MANY IMPORTANT APPLICATIONS [2].

BACKGROUND: METHYLENE BLUE IS A HETEROCYCLIC AROMATIC CHEMICAL COMPOUND WITH THE MOLECULAR FORMULA C16H18N3SCL. IT IS A CATIONIC DYE, REDOX INDICATOR, AND PHOTOSENSITIZER AND HAS MANY USES IN A RANGE OF DIFFERENT FIELDS. IN AQUACULTURE, IT SERVES AS AN ANTI-FUNGAL AND ANTI-PARASITC. RECENTLY IT HAS BEEN TESTED AS A POSSIBLE TREATMENT FOR SOME CANCERS. CLINICAL STUDIES ARE ALSO UNDERWAY THAT INDICATE METHYLENE BLUE SIGNIFICANTLY SLOWS DOWN THE PROGRESSION OF ALZHEIMER'S DISEASE...

MOLYBDENUM (MO) IS A BIOLOGICALLY IMPORTANT TRACE ELEMENT WHICH OCCURS IN VARIOUS OXIDATION STATES. HOWEVER, AS WITH OTHER TRACE METALS, WHAT IS ESSENTIAL IN TINY AMOUNTS CAN BE HIGHLY TOXIC AT LARGER DOSES [1]. PROLONGED EXPOSURE TO MO IN THE ENVIRONMENT CAN CAUSE TOXICITY TO HUMANS, ANIMALS, AND PLANTS [2]. ...

DYES ARE WIDELY USED IN INDUSTRIES SUCH AS THE TEXTILE, PULP MILL, PAPER PRODUCTION, FOOD TECHNOLOGY, PRINTING, LEATHER TANNING, AND PLASTICS INDUSTRIES. MANY DYES ARE TOXIC TO SOME ORGANISMS, CARCINOGENIC AND MUTAGENIC TO HUMANS. METHYL ORANGE (MO) IS AN INTENSELY COLORED AZO DYE COMPOUND WHICH IS WIDELY USED FOR DYEING AND PRINTING OF TEXTILES, PHARMACEUTICAL, FOOD INDUSTRIES AND AS INDICATOR. THE PRESENCE OF AZO GROUP (N=N) ON MO AND ITS LOW BIODEGRADABILITY MAKES IT AN ISSUE OF CONCERN FOR ENVIRONMENTAL SCIENCE. MO IS REGARDED AS ALLERGY MATERIALS AFTER CONTACTING BY SKIN, WHICH CAUSES SHIN ECZEMA AND EVEN BE POISONOUS IF SWALLOWED [1]. THEREFORE, THE DEVELOPMENT OF SIMPLE AND SENSITIVE ANALYTICAL METHODS FOR ACCURATE DETERMINATION OF TRACE AMOUNT OF METHYL ORANGE IS IMPORTANT FOR ITS ENVIRONMENTAL MONITORING. DISPERSIVE LIQUID-LIQUID MICROEXTRACTION (DLLME) IS AN ATTRACTIVE MODE OF LIQUID MICROEXTRACTION WHICH HAS RECEIVED MUCH ATTENTION FOR SAMPLE PRETREATMENT. THIS METHOD HAS BEEN APPLIED FOR THE SEPARATION AND PRECONCENTRATION OF TRACE METAL IONS AND ORGANIC POLLUTANTS IN THE DIFFERENT MATRICES [2, 3]. IN THE PRESENT STUDY A DISPERSIVE LIQUID-LIQUID MICROEXTRACTION (DLLME) METHOD COUPLED TO UV-vis spectrophotometry IS DEVELOPED FOR THE SENSITIVE DETERMINATION OFMETHYL ORANGE. THE METHOD IS BASED ON EXTRACTION OF METHYL ORANGE WITH DLLME PROCEDURE USING CARBON TETRACHLORIDE (EXTRACTION SOLVENT) CONTAINING METHYLTRIOCTYL AMMONIUM CHLORIDE WHICH PROVIDES COUNTER ION AND ALSO ACTS AS AN DISPERSER. AFTER EXTRACTION, THE PHASE SEPARATION IS PERFORMED WITH A RAPID CENTRIFUGATION, AND METHYL ORANGE IS DETERMINED IN THE ENRICHED PHASE BY UV-vis spectrophotometry. UNDERTHE OPTIMUM EXTRACTION CONDITION, THE METHOD YIELDS A LINEAR CALIBRATION CURVE IN THE CONCENTRATION RANGE OF 5 TO 400 NG ML-1, AND THE LIMITS OF DETECTION WAS 1.53 NG ML-1 FOR TARGET ANALYTES. THE RELATIVE STANDARD DEVIATION FOR TEN REPLICATE MEASUREMENTS OF 50 AND 300 NG ML-1 OF METHYL ORANGE WAS 3.61 AND 1.43%, RESPECTIVELY. THE PROPOSED METHOD WAS SUCCESSFULLY APPLIED TO DETERMINATION OF TRACE AMOUNTS OF METHYL ORANGE IN REAL SAMPLES WITH SATISFACTORY RESULTS.

A NOVEL, SIMPLE AND EFFICIENT METHOD FOR THE NICKEL (NI) SPECIATION AND DETERMINATION IN DIFFERENT WATER SAMPLES WAS DEVELOPED USING DISPERSIVE LIQUID-LIQUID MICROEXTRACTION (DLLME) TECHNIQUE FOLLOWED BY UV-vis spectrophotometry. IN THIS WORK, A PROCEDURE FOR PRECONCENTRATION OF NICKEL USING DLLME WITH THE REAGENT DITHIZONE AS COMPLEXING REAGENT WAS DEVELOPED. THE PROCEDURE IS BASED ON COMPLEXATION OF NI (II) WITH DITHIZONE, AND THEN EXTRACTION OF THE COMPLEX USING DLLME TECHNIQUE. THE PROCCES IS BASED ON A TERNARY SYSTEM OF SOLVENTS, WHERE APPROPRIATE AMOUNTS OF THE EXTRACTION SOLVENT (CHLOROFORM) , DISPERSERSOLVENT (ACETONE) AND THE CHELATING AGENT. DITHIZONE ARE DIRECTLY INJECTED INTO AN AQUEOUS SOLUTION CONTAINING NI (II).SOME EFFECTIVE PARAMETERS ON EXTRACTION AND COMPLEX FORMATION, SUCH AS EXTRACTION AND DISPERSER SOLVENT TYPE AND THEIR VOLUME, EXTRACTION TIME, SALT EFFECT, PH AND CONCENTRATION OF THE CHELATING AGENT HAVE BEEN OPTIMIZED. UNDER THE OPTIMAL CONDITIONS, THE LIMITS OF DETECTION FOR NICKEL WAS 4 MG/L, AND ENHANCEMENT FACTORS (EFS) OF 70 WAS OBTAINED FROM ONLY 5.00ML OF WATER SAMPLE. THE CALIBRATION GRAPH WAS LINEAR IN THE RANGE OF 10-700 MG L-1. THE RELATIVE STANDARD DEVIATION (R.S.D.S) FOR TEN REPLICATE MEASUREMENTS OF 10MGL-1 OF NICKEL WAS 2.1%. PROPOSED PROCEDURE WAS SUCCESSFULLY APPLIED TO THE DETERMINATION OF NICKEL IN WATER SAMPLES. THE PROPOSED METHOD WAS SIMPLE, RAPID, COST EFFICIENT AND SENSITIVE, ESPECIALLY FOR THE DETECTION OF NICKEL.

CANCER OR CHNGAR IS ASYMMETRIC DIvisION OF CELLS IN THE BODY OR HEAD. CANCER CELLS FALL APART OF NORMAL MECHANISMS OF DIvisION AND GROWTH OF CELL. IN A HEALTHY ORGANISM, ALWAYS BETWEEN THE CELL DIvisION, CELL SENESCENCE AND DIFFERENTIATION, THERE IS A BALANCE [1]. ...

HYDRIDE GENERATION (CHG) IS A WELL-ESTABLISHED TECHNIQUE FOR DETERMINATION OF TOXIC ARSENIC (AS) [1]. ELECTROCHEMICAL HYDRIDE GENERATION (ECHG) HAS BEEN INTRODUCED AS A SUITABLE ALTERNATIVE TO COMMON HYDRIDE GENERATION BY NABH4, AND HAS BEEN SHOWN, TO BE CAPABLE OF CIRCUMVENTING SOME OF THE DISADVANTAGES ASSOCIATED WITH THE NABH4-ACID REDUCING SYSTEM [2]. THIS PAPER DESCRIBES A NOVEL METHOD FOR THE QUANTITATIVE DETERMINATION OF ARSENIC IN FOOD AND ENVIRONMENTAL SAMPLES. THE METHOD IS BASED ON ELECTROCHEMICAL REDUCTION OF AS TO ARSINE (ASH3) IN AN ELECTROCHEMICAL CELL AND SUBSEQUENT REACTION OF ASH3 WITH SILVER DIETHYLDITHIOCARBAMATE TO GIVE AN ABSORBING COMPLEX AT 525 NM. THE ELECTROCHEMICAL GENERATOR CONSISTED OF A CATHODE CELL SEPARATED FROM THE ANODE CELL BY A NAFION ION EXCHANGE MEMBRANE. ARSINE IS GENERATED AT THE CATHODE AND REACTS WITH SILVER DIETHYLDITHIOCARBAMATE IN A HEADSPACE MICROFUNNEL. THE AFFECTING PARAMETERS ON THE EFFICIENCY OF THE ELECTROCHEMICAL HYDRIDE GENERATION AND THE MICROEXTRACTION STEPS HAVE BEEN EXAMINED AND OPTIMIZED. THE ANALYTICAL PERFORMANCE OF THE METHOD HAS BEEN EVALUATED UNDER OPTIMIZED OPERATING CONDITION (GRAPHITE CATHODE, 150 MA CURRENT, 0.3 M H2SO4 AS CATHOLYTE, 10 MIN FOR REACTION DURATION) AND THE ANALYTICAL FIGURES OF MERITS HAS BEEN REPORTED. AS ADVANTAGE, THE SYSTEM IS VERY FAST, EFFICIENT AND ENVIRONMENTALLY FRIENDLY FOR MONITORING TOTAL ARSENIC FOOD AND WATERS.