Pulsed radio-frequency discharge inductively coupled plasma mass spectrometry for oxide analysis

• Solid sampling method was developed via pulsed RF discharge at atmospheric pressure.
• Crater on oxide sample surface suggests feasibility of sampling nonconductive solid.
• Combined with ICPMS, LODs of 10− 8–0− 9 g/g were achieved for most elements.

A direct solid sampling technique has been developed based on a pulsed radio-frequency discharge (RFD) in mixture of N2 and Ar environment at atmospheric pressure. With an averaged input power of 65 W, a crater with the diameter of 80 μm and depth of 50 μm can be formed on sample surface after discharge for 1 min, suggesting the feasibility of the pulsed RFD for sampling nonconductive solids. Combined with inductively coupled plasma mass spectrometry (ICPMS), this technique allows to measure elemental composition of solids directly with relative standard deviation (RSD) of ~ 20%. Capability of quantitative analysis was demonstrated by the use of soil standards and artificial standards. Good calibration linearity and limits of detection (LODs) in range of 10− 8–10− 9 g/g were achieved for most elements.