Investigation of the role of hollow cathode (vaporization) temperature on the performance of particle beam-hollow cathode atomic emission spectrometry (PB-HC-AES)

An evaluation of the effect of cathode temperature on analyte emission responses for the particle beam-hollow cathode glow discharge atomic emission spectroscopy (PB-HC-AES) system is described. A series of Cu salts were introduced as both nebulized solutions and dry particulates to examine the effect of vaporization temperature on the resulting Cu I emission intensity. For the analysis of aqueous samples, a high-efficiency thermoconcentric nebulizer was used to generate a fine aerosol of the solution flowing at rates of 1.5 mL min^-1. A momentum separator-particle beam interface was employed for desolvation and subsequent introduction of dry analyte particles into a heated hollow cathode glow discharge source for vaporization, atomization and excitation. In the case of dry particle analysis, the particle beam interface was modified to allow introduction of samples by vacuum action through a 1 mm id stainless-steel tube. The effects of both vaporization temperature and analyte particle size were investigated by monitoring Cu emission intensity as well as by examining collected particles by scanning electron microscopy. Results indicate an optimum vaporization temperature of 200-300°C for this group of Cu salts, with increased analyte emission intensities obtained through the introduction of smaller-sized particles.