An argon-nitrogen-hydrogen mixed-gas plasma as a robust ionization source for inductively coupled plasma mass spectrometry

作者：Makonnen Yoseif; Beauchemin Diane^*

来源：Spectrochimica Acta Part B: Atomic Spectroscopy , 2014, 99: 87-93.

DOI：10.1016/j.sab.2014.06.015

• Inductively coupled plasma mass spectrometry
• Mixed-gas plasma
• Robustness
• Matrix effect

Multivariate optimization of an argon-nitrogen-hydrogen mixed-gas plasma for minimum matrix effects, while maintaining analyte sensitivity as much as possible, was carried out in inductively coupled plasma mass spectrometry. In the presence of 0.1 M Na, the 33.9 +/- 3.9% (n = 13 elements) analyte signal suppression on average observed in an all-argon plasma was alleviated with the optimized mixed-gas plasma, the average being - 4.0 +/- 8.8%, with enhancement in several cases. An addition of 23% v/v N-2 in the outer plasma gas, and 0.50% v/v H-2 to the central channel, as a sheath around the nebulizer gas flow, was sufficient for this drastic increase in robustness. It also reduced the background from ArO+ and Ail as well as oxide levels by over an order of magnitude. On the other hand, the background from NO and ArN+ increased by up to an order of magnitude while the levels of doubly-charged ions increased to 7% (versus 2.7% in an argon plasma optimized for sensitivity). Furthermore, detection limits were generally degraded by 5 to 15 fold when using the mixed-gas plasma versus the argon plasma for matrix-free solution (although they were better for several elements in 0.1 M Na). Nonetheless, the drastically increased robustness allowed the direct quantitative multielement analysis of certified ore reference materials, as well as the determination of Mo and Cd in seawater, without using any Matrix-matching or internal standardization.

• 出版日期2014-9-1