Use of microwave induced plasma spectrometry as detector for the determination of O, N and H traces after carrier gas hot extraction

Abstract

The determination of O, N and H using a microwave induced plasma coupled to carrier gas hot extraction was exploratory investigated. The signal intensities versus time of blanks and calibration materials were recorded. To check for interferences the signal intensities versus wavelength were recorded at the times just before increase and at the maximum of the time dependent analytical signal. O, N and H were investigated at their prominent wavelengths of 777 nm, 174 nm and 486 nm, respectively. Calibration was performed for O, N and H in the ranges of 0–27 μg, 35–1000 μg and 3–43 μg respectively. For concentration values in the middle of the linear part of the investigated calibration interval, a relative precision of 5% at 13 μg, 2% at 74 μg and 0.6% at 23 μg for O, N and H respectively was found. The maximum matrix load to the plasma used was found to be 150 μg min⁻¹. From the signal to noise ratio and the sensitivity obtained, instrumental limits of detection (3s) of 0.01 μg for O, 1 μg for N and 0.1 μg for H were found. Assuming a typical sample mass of 1 g this corresponds to relative LODs of 0.01 μg g⁻¹, 1 μg g⁻¹ and 0.1 μg g⁻¹ for O, N and H respectively.