Determination of vanadium, manganese, silver and lead by graphite furnace atomic absorption spectrometry after preconcentration on silica-gel modified with 3-aminopropyltriethoxysilane

3-aminopropyltriethoxysilane modified silica-gel was used for the separatio n and preconcentration of vanadium, silver, manganese, and lead prior to th eir determination by graphite furnace atomic absorption spectrometry. Surfa ce characteristics and surface area of the silica-gel before and after chem ical modification were determined by elemental and surface area analysis. T he retention and recovery of the analyte elements were studied by applying batch and column techniques. The experimental parameters, such as the effec t of pH of the sample, shaking time in batch technique, flow rate of the el uent and the amount of silica, on retention and elution have been investiga ted. Vanadium, manganese, silver and lead were quantitatively (greater than or equal to 90%) recovered in the batch technique with R.S.D. values of 2. 2, 1.9, 3.8 and 1.4%, respectively. The same recoveries were obtained in th e column technique except for manganese, for which it was only 70%. Detecti on limits of the method for vanadium, manganese, silver and lead are 0.006, 0.002 0.0004 and 0.004 mu g, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.