Abstract
The behavior of surfactants of different natures and chain lengths was studied in flame atomic absorption spectrometry (FAAS) analyses. The variations of absorbance, which arise as a consequence of the surfactant addition to aqueous solutions of Cr(VI) or Cr(III), were measured. Depressions were observed below the critical micelle concentration (CMC), whereas enhancements were observed above the CMC. These depressions are more significant when the surfactant is opposite in charge to the analyte and the longest surfactant chain is used. A mechanism that enables explanation of the effects of a surfactant on FAAS is also suggested. This mechanism is based on the preferential orientation of surfactant molecules to the surface of nebulized droplets.