BACKGROUND: THE IMPORTANCE OF THE PALLADIUM METAL HAS GROWN MANY FOLDS IN RECENT YEARS DUE TO THE INCREASING APPLICATIONS FOR THE PRODUCTION OF MEDICINAL DEVICES, AND CATALYTIC CONVERTERS ALTHOUGH THE BENEFITS OF CAR CATALYSTS ARE INDISPUTABLE, THE EMISSION OF PD INTO THE ENVIRONMENTAL IS LARGELY ASSOCIATED WITH THE PRODUCTION AND RECYCLING OF CATALYTIC CONVERTERS IN THE METAL FINISHING INDUSTRY AS WELL AS THE OPERATION OF VEHICLE CATALYSTS. SOME OF PD COMPOUNDS HAVE BEEN REPORTED AS POTENTIAL HEALTH RISKS TO HUMANS, ALLERGY, AND OTHER SERIOUS HEALTH PROBLEMS. THE DEVELOPMENT OF ANALYTICAL METHODS FOR THE DETERMINATION OF PD IS IMPORTANT FOR THE EFFECTIVE MONITORING OF POLLUTION LEVELS OF THIS METAL IN THE ENVIRONMENT [1]. IN THIS RESEARCH, A SIMPLE METHOD OF LIQUID-LIQUID MICROEXTRACTION (DLLME) WAS USED FOR THE PRECONCENTRATION OF TRACE AMOUNTS OF PALLADIUM PRIOR TO ITS DETERMINATION BY FLAME ATOMIC ABSORPTION SPECTROMETRY (FAAS).METHODS: IN THIS METHOD, AN APPROPRIATE MIXTURE OF ETHANOL AND CARBON TETRACHLORIDE WAS INJECTED INTO THE WATER SAMPLE CONTAINING PALLADIUM AFTER COMPLEX FORMATION USING 2-MERCAPTOBENZOTHIAZOLE REAGENT. AFTER PHASE SEPARATION, SEDIMENTED PHASE CONTAINING ENRICHED ANALYTES WAS DETERMINED BY FAAS. SOME FACTORS INFLUENCING THE EXTRACTION EFFICIENCY OF PALLADIUM AND ITS SUBSEQUENT DETERMINATION, INCLUDING EXTRACTION AND DISPERSIVE SOLVENT TYPE AND VOLUME, PH OF SAMPLE SOLUTION, CONCENTRATION OF CHELATING AGENT AND EXTRACTION TIME, WERE STUDIED AND OPTIMIZED.RESULTS: UNDER THE OPTIMUM CONDITION FOR 10 ML WATER SAMPLE, THE CALIBRATION GRAPH WAS LINEAR IN THE RANGE OF 0.02-1.2 MG L-1. THE ENRICHMENT FACTOR OBTAINED 40. THE DETECTION LIMIT WAS 0.0024 MG L-1, AND THE RELATIVE STANDARD DEVIATION (RSD) FOR 0.10 MG L-1 WAS 1.66% (N=6).CONCLUSION: THE NEW METHOD OF DLLME COMBINED WITH FAAS WAS PROPOSED FOR THE DETERMINATION OF PD IN WATER SAMPLES. THE ADVANTAGES OF THIS METHOD ARE ITS SIMPLICITY, RAPIDITY AND ITS MINIMIZATION OF WASTE GENERATION. THIS METHOD POSSESSES LOWER LIMIT OF DETECTION THAN OTHER REPORTED PRECONCENTRATION METHODS FOR PD [2], WHICH MAKES IT SUITABLE FOR THE DETERMINATION OF TRACE AMOUNT OF PD IN VARIOUS REAL SAMPLES SUCH AS WATER, SOIL AND GARLIC SAMPLES.

GOLD BELONGS TO THE GROUP OF ELEMENTS WHICH OCCUR ON THE EARTH IN VERY LOW NATURAL CONTENTS. THE CONCENTRATION OF GOLD IN NATURAL WATER IS EXTREMELY LOW [1], IN THE RANGE FROM 0.01 TO 10 NG L-1. IT IS WELL KNOWN THAT GOLD IS ONE OF THE MOST INTERESTING MICRO AMOUNT ELEMENTS DUE TO ITS SIGNIFICANT ROLE ON BIOLOGY, ENVIRONMENT AND INDUSTRY. IT COULD BE ALSO VERY TOXIC FOR HUMAN AND ANIMAL ORGANISM AND PLANTS AND ACCOUNT AS THE POLLUTANTBECAUSE OF ITS INHIBITING EFFECT UPON THE ACTIVITY OF MANY ENZYMES AND ITS PREVENTING EFFECT UPON THE DNA SEPARATION. [1].NUMEROUS METHODS FOR GOLD DETERMINATION ARE KNOWN: UV-VIS SPECTROPHOTOMETRY, ELECTROTHERMAL ATOMIC ABSORPTION SPECTROMETRY, INDUCTIVELY COUPLED PLASMA COMBINED WITH OPTICAL EMISSION SPECTROMETRY OR MASS SPECTROMETRY WAS APPLIED FOR A VARIETY OF SAMPLES IN THE ANALYSIS OF GOLD. FLAME ATOMIC ABSORPTION SPECTROMETRY (FAAS) IS ONE OF THE MOST WIDESPREAD TRADITIONAL ANALYTICAL TECHNIQUES FOR THE DETERMINATION OF TRACE ELEMENTS, BUT IT OFTEN SUFFERS FROM ITS LOW SENSITIVITY. THE DETERMINATION OF TRACE QUANTITY OF HEAVY METALS IN ENVIRONMENTAL SAMPLES LIKE NATURAL WATER AND OTHER REAL SAMPLES OF ENVIRONMENTAL INTEREST IN WHICH THEY ARE FOUND AT VERY LOW CONCENTRATIONS, REQUIRES THE USE OF PRECONCENTRATION METHODS COUPLED TO SPECTROSCOPIC METHODS, SUCH AS FAAS. TO OVERCOME THESE LIMITATIONS ON THE DETERMINATION OF GOLD BY FAAS, SEPARATION-ENRICHMENT IS NECESSARY. IN THE PRESENT WORK, WE REPORT AN IN SITU SOLID PHASE FORMATION EXTRACTION (ISSPFE). ISSPFE IS A NEW EXTRACTION METHOD THAT IS BASED ON USE OF SURFACTANTS [2]. IN THIS METHOD A CATIONIC SURFACTANT WITH A PROPER ALKYL GROUP CHAIN IS DISSOLVED IN THE AQUEOUS SAMPLE AND THEN A PROPERION-PAIRING AGENT IS ADDED. DUE TO INTERACTION BETWEEN SURFACTANT AND ION-PAIRING AGENT, VERY FINE SOLID PARTICLESARE FORMED. IN THIS RESEARCH, AU (III) IONS WERE COMPLEXED WITH 2-NITROSO-1-NAPHTHOLAND EXTRACTED WITH FINE SOLID PARTICLES THAT WERE FORMED INTO THE SOLUTION. AFTER EXTRACTION, THE CONCENTRATION OF GOLD WAS DETERMINED BY FLAME ATOMIC ABSORPTION SPECTROMETER. SEVERAL VARIABLES THAT AFFECT THE EXTRACTION EFFICIENCIES, INCLUDING PH, CONCENTRATION OF CHELATING AGENT, TYPE AND CONCENTRATION OF SURFACTANT, KCLO4 CONCENTRATION, EXTRACTION TIME AND SALT ADDITION, WERE INVESTIGATED AND OPTIMIZED. UNDER THE BEST EXPERIMENTAL CONDITIONS, THE CALIBRATION CURVE EXHIBITED LINEARITY OVER THE RANGE OF 5.0-800.0 NG ML-1 WITH A CORRELATION COEFFICIENT OF 0.998 AND DETECTION LIMIT BASED ON THREE TIMES THE STANDARD DEVIATION OF THE BLANK SIGNAL WAS 1.5 NG ML-1. EIGHT REPLICATE DETERMINATION OF 200.0 NG ML-1 GOLD GAVE A RSD OF ±2.1%. FINALLY, THE PROPOSED METHOD HAS BEEN SUCCESSFULLY APPLIED FOR THE DETERMINATION OF GOLD IN THE REAL WATER SAMPLES.

CADMIUM IS A TOXIC HEAVY METAL THAT APPEARS IN THE ENVIRONMENT MAINLY DUE TO INDUSTRIAL PROCESSES. THE EFFECT OF CADMIUM POISONING IS MANIFESTED IN A VARIETY OF SYMPTOMS, INCLUDING HIGH BLOOD PRESSURE, KIDNEY DAMAGE AND DESTRUCTION OF RED BLOOD CELLS. THEREFORE, THE DETERMINATION OF TRACE LEVELS OF CADMIUM IN ENVIRONMENTAL SAMPLES IS NECESSARY [1]. AMINO ACIDS ARE GOOD METAL-BINDERS BECAUSE THEY CAN COORDINATE WITH METALS THROUGH OXYGEN, NITROGEN AND SOMETIMES SULFUR ATOMS. CYSTINE IS AN AMINO ACID RESULTS FROM CYSTEINE OXIDATION WITH THE FORMATION OF A DISULFIDE BRIDGE [2]. BASED ON THE COMPLEXING POWER OF L-CYSTINE TOWARD METAL IONS AND IT’S LOW SOLUBILITY IN NEUTRAL AQUEOUS SOLUTION, IT WAS APPLIED FOR THE MODIFICATION OF ZEOLITE Y TO PRECONCENTRATE TRACE LEVEL OF CADMIUM ION.USING THE MODIFIED ZEOLITE, A SOLID PHASE EXTRACTION COLUMN AND PRECONCENTRATION METHOD WAS DEVELOPED FOR THE DETERMINATION OF CADMIUM (II) ION IN AQUEOUS SAMPLES BY FLAME ATOMIC ABSORPTION SPECTROMETRY. THE METHOD IS BASED ON SORPTION OF CADMIUM (II) ION ON THE MODIFIED ZEOLITE. THE SORBENT EXHIBITED GOOD SORPTION ABILITY FOR CADMIUM (II) AT PH=5.CADMIUM ION WAS ELUTED FROM THE COLUMN BY NITRIC ACID. THE CALIBRATION GRAPH WAS LINEAR IN THE RANGE 0.75-80 NG ML-1 CADMIUM IN THE INITIAL SOLUTION. THE DETECTION LIMIT AND PRECONCENTRATION FACTOR OF THIS METHOD WERE FOUND 0.31 NG.ML-1 AND 100 RESPECTIVELY. THE VARIOUS PARAMETERS SUCH AS PH, SAMPLE AND ELUENT FLOW RATE, VOLUME OF THE SAMPLE, VOLUME AND CONCENTRATION OF THE ELUENT SOLUTION WERE OPTIMIZED. THE DEVELOPED METHOD WAS APPLIED FOR THE DETERMINATION OF TRACE AMOUNT OF CADMIUM ION IN DRINKING WATER, RIVER WATER AND WASTEWATER SAMPLES.