Abstract

A novel and selective method for the fast determination of trace amounts of Pb(II) ions in water samples has been developed. The first organic solution-processable functionalized-nano graphene (SPFGraphene) hybrid material with porphyrin–graphene nanohybrid, 5-4 (aminophenyl)-10, 15, 20-triphenyl porphyrin and its photophysical properties including optical triphenyl porphyrin (TPP) and grapheme oxide molecules covalently bonded together through an amide bond (TPP-NHCO-SPFGraphene) were used as absorbent for extraction of Pb(II) ions by solid phase extraction method. The complexes were eluted with HNO₃ (2M)10% V.V^-1 methanol in acetone and determined the analyte by flame atomic absorption spectrometry. The procedure is based on the selective formation of Pb(II) at optimum pH by elution with organic eluents and determination by flame atomic absorption spectrometry. The method is based on complex formation on the surface of the ENVI-18 DISK^TM disks modified porphyrin–graphene nanohybrid, 5-4 (aminophenyl)-10, 15, 20-TPP and grapheme oxide molecules covalently bonded together through an amide bond (TPP-NHCO-SPFGraphene) followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution is efficient and quantitative. The effect of potential interfering ions, pH, TPP-NHCO-SPFGraphene, amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about 1000 ml providing a preconcentration factor of 600. The maximum capacity of the disks was found to be 398 ± 3 µg for Pb²⁺. The limit of detection of the proposed method is 5 ng per 1000 ml. The method was applied to the extraction and recovery of Pb in different water samples.

Key words: Pb(II), Solid phase extraction (SPE), Octadecyl slica disks, flame atomic absorbtion spectrometry(FAAS), porphyrin–graphene nanohybrid, 5-4 (aminophenyl)-10, 15, 20-triphenyl porphyrin (TPP), grapheme oxide molecules covalently bonded together through an amide bond (TPP-NHCO-SPFGraphene).