Study of the effect of nitric acid and metal-based chemical modifiers on graphite platform surfaces by raman spectrometry

Graphite platforms containing metal-based chemical modifiers and nitric acid solutions, individually and in combination, were heated using a typical temperature program for ETAAS; for some measurements, aluminium nitrate was also present as a matrix component. Changes in the graphite surface structure that occurred after heating the platform to various temperatures were evaluated using Raman spectrometry. The presence of thorium, zirconium, palladium or nitric acid resulted in an increase in the content of sp(3)-bonded carbon clusters on the platform surface. In addition, nitric acid affected the chemical modifier phases present, particularly for palladium. The surface alterations observed help explain the effect of the chemical modifiers on platform lifetime and the stabilization mechanism of the modifiers on analyte elements.