Use of a mixed argon–hydrogen–tetrafluoromethane carrier gas for the analysis of nickel materials by electrothermal vaporization coupled to inductively coupled plasma optical emission spectrometry
Electrothermal vaporization (ETV) coupled to inductively coupled plasma optical emission spectrometry (ICPOES) was used to directly determine minor and trace elements in nickel (Ni) foam samples. In addition to 9 mL min−1 CF4 reaction gas, 20 mL min−1 H2 was added to the carrier gas to further enhance the volatility of analytes. Moreover, 45 mL min−1 N2 was introduced into the central channel of the plasma via a sheathing device to improve plasma robustness, sensitivity and detection limit. The ETV program included a pyrolysis step (400 °C, 20 s), a cooling step (21 °C, 15 s), a vaporization step (2300 °C, 30 s), and a cooling step (21 °C, 20 s). The Ar 415.859 nm emission line was systematically used for point-by-point internal standardization, to compensate for sample loading effects on the plasma, before computing the peak area of the transient signal observed for each analyte during the vaporization and final cooling steps (between 45–90 s). External calibration was carried out using increasing amounts of NIST 2710 (Montana soil) standard reference material. The measured concentrations of Cd, Cr, Mn, Mo, Pb, V, and Zn agree with those obtained by pneumatic nebulization ICPOES after digestion with HNO3. This method offers a fast and accurate determination of minor and trace elements in Ni foam without sample preparation.