Spectrophotometric and High Performance Liquid Chromatographic Determination of Copper, Nickel, Iron, Cobalt, Vanadium, Cadmium, Lead and Mercury using new Semicarbazones as Complexing Reagents

Abstract

During this report period following complexing reagents were prepared: 1. 2-pyrrolcarboxaldehyde-4-phenyl-3-thiosemicarbazone (PAPT). 2. 2-pyrrolcarboxaldehyde- thiosemicarbazone (PATS). 3. 2-pyrrolcarboxaldehyde- phenylsemicarbazone (PAPS). 4. 2-Hydroxyacetophenone-4-phenyl-3-thiosemicarbazone. 5. 2-Pyrideinecarboxaldehyde-4-phenyl-3-thiosemicarbazone. 6. 2-Thiophenecarboxaldehyde-4-phenyl-3-thiosemicarbazone 7. 6-Methyl-2-pyridinecarboxaldehyde-4-phenyl-3-thiosemicarbazone 8. 6-Methyl-2-pyridinecarboxaldehyde-4-phenylsemicarbazone.

The reagents were characterized by element micro-analysis, infrared, UV and visible spectroscopy. The reagents react with metal ions to form coloured complexes. The effect of pH, reagent concentration, solvent and solution stability were examined. The optimized conditions were used to examine the effect of concentration on the absorbances. Beer’s law was obeyed by each of the element at the wave length of its maximum absorbance. The result of spectrophotometric studies is tabulated. The reagents 2-pyrrolcarboxaldehyde-4-phenyl-3-thiosemicarbazone, 6-Methyl-2-pyridinecarboxaldehyde-4-phenylsemicarbazone, 2-pyrrolcarboxaldehyde-4-phenylsemicarbazone, 2-Pyrideinecarboxaldehyde-4-phenyl-3-thiosemicarbazone and 2-Thiophenecarboxaldehyde-4-phenyl-3-thiosemicarbazone were examined for the HPLC determination of metal ions. The reagents 2-pyrrolcarboxaldehyde-4-phenyl-3-thiosemicarbazone was used for solvent extraction and HPLC determination of copper (2), iron (2), nickel (2) and mercury (2). The complexes were eluding from Microsorb C-18, sum (150x4.8 mm id) column with methanol: acetonitrile: water: sodium acetate (1mM): tetra butyl ammonium bromide (1mM) (60:28:10:1:1 v/v/vv/v) using a flow rate of 1ml/min. Detection UV was at 254 nm. The method was applied for the determination of the metal in a canal water and amount found were within 27-250 μg/L with coefficient of variation (C.V) within 2.7 to 5.1%. the method was also applied for the determination of copper (2), nickel (2), iron (2) and mercury (2) in the surface water fishes in the range of 0.021-1.2 μg/g with C.V 1.1-6.4%. Nickel (2)., lead (2) and mercury(2) complexes of 6-Methyl-2-pyridinecarboxaldehyde-4-phenylsemicarbazone separated for column Microsorb C18, u (150x4.6 mm id), when eluted with methanol-water-chloroform using the flow rate 1.0ml/min. the copper(2), nickel(2), palladium(2) and sliver (1) complexes of 2-pyrrolcarboxaldehyde- phenylsemicarbazonesprate from the Microsorb C-18 (150x4.6 mm id) when eluted with methanol : water : acetonitrile: sodium acetate (1mM) (68:6.5:0.5 v/v/v/v/v) using flow rate of 1 ml/min . the detection UV was at 280nm. The copper (2), iron (2) and mercury (2) complexes of 2-Thiophenecarboxaldehyde-4-phenyl-3-thiosemicarbazone were separated from Microsorb C-18, 5 μm (150x4.6 mm id) column, when eluted with ethanol: acetonitrile: water : aqueous sodium acetate(1mM) (68:25:6.5:0. v/v/v/v) using flow rate of 1ml/min the detection of UV was at 280 nm. The separation of copper (2), iron (2) and mercury (2) complexes of 2-Pyrideinecarboxaldehyde-4-phenylthiosemicarbazone was carried out from Phenomenex Sil C-18, 5um column (150x4.6 mm id), when eluted with a mixture methanol: water: acetonitrile: sodium acetate(1mM): tetra butyl ammonium bromide (0.16%) (68:4:27:0.5:0.5 v/v/v/v/v) using flow rate of 0.8 ml/min. the detection at 390 nm. The linear calibration range and detection limit for each of the metal ion at optimized conditions was determined. The methods were applied for the determination of metals from nickel-ammonium alloy, synthetic mixtures of metal ions, palladium charcoal, ghee samples and fresh water fishes. The result obtained were compared it atomic absorption spectrophotometer.