Improvement of analytical performance in inductively coupled plasma optical emission spectrometry without compromising robustness using an infrared-heated sample introduction system with a pneumatic nebulizer

Abstract

A simple enhanced sample introduction system, using pneumatic nebulization (PN), was developed for inductively coupled plasma optical emission spectrometry (ICP OES). The aerosol generated by a Burgener parallel-flow nebulizer, coupled to a single-pass flip chamber (FC), was heated to 230 °C using a ceramic infrared (IR) heater. Multivariate optimizations were conducted to find operating conditions that maximized analyte sensitivity while maintaining plasma robustness, as measured by the Mg II/Mg I intensity ratio. Other spray chamber designs, such as a single-pass (SP) and a custom Scott-type double-pass (DPE), were also tested in order to find the ideal combination with the Burgener nebulizer. Under optimum conditions and compared to conventional pneumatic nebulization at room temperature, a 6 fold improvement in sensitivity and a 4–7 fold improvement in detection limit was obtained for 38 elements using FC(IR), SP(IR) and DPE(IR). The improvement was more significant for ionic rather than atomic emission lines. Plasma robustness also increased significantly over room temperature PN. Moreover, the improvements in analytical performance are observed for FC(IR), SP(IR) and DPE(IR), despite using a sample introduction rate over 10 times lower than room temperature PN.