Advantages and effects of nitrogen doping into the central channel of plasma in axially viewed-inductively coupled plasma optical emission spectrometry.pdfVIP

Analytica Chimica Acta 789 (2013) 33–40 Contents lists available at SciVerse ScienceDirect Analytica Chimica Acta journal homepage: /locate/aca Advantages and effects of nitrogen doping into the central channel of plasma in axially viewed-inductively coupled plasma optical emission spectrometry Guilherme Luiz Schef?er, Dirce Pozebon ? Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonc? alves, 9500, 91509-900 Porto Alegre, RS, Brazil highlights ? Addition of N2 to the nebulizer gas used in axially viewed-ICP OES is investigated. ? A small ?ow of N2 (20 mL min?1) increases plasma robustness. ? Addition of N2 through the nebulizer gas affects energy transfer in the ICP. ? Matrix effects are mitigated by adding N2 and the ICP performance is maintained. graphical abstract article info Article history: Received 7 March 2013 Received in revised form 17 June 2013 Accepted 22 June 2013 Available online 26 June 2013 Keywords: Axially viewed plasma Robustness N2 doping Matrix effects abstract The effects and bene?ts of N2 addition to the central channel of the ICP through the nebulizer gas used in ICP OES with axial view con?guration were investigated in the present study. The N2 ?ow rate, nebulizer gas ?ow rate, RF power and sample uptake rate were evaluated and compared for two sample introduc- tion systems (pneumatic nebulization/aerosol desolvation and conventional pneumatic nebulization). It was observed that N2 did not affect solution nebulization and aerosol transport but affects the ICP characteristics. The higher thermal conductivity of N2 (in comparison with Ar) changes energy distribution in the ICP, observed by monitoring the signals of Ar emission lines and sodium emission. The ratio Mg(II)- 280.270 nm/Mg(I)-285.213 nm was utilized as a diagnostic tool for plasma robustness. The addition of N2 (20 mL min?1) increased plasma robustness signi?cantly and mitigated effects caused by Na, K and Ca. For 40 spectral lines evaluated, it was obs