The nitrous oxide-hydrogen flame in spectroscopic analysis

Abstract

A high temperature flame, burning hydrogen supported by nitrous oxide, is described as an atom reservoir for thermal emission spectroscopy of elements such as aluminium. The flame has a low burning velocity and can be supported on most conventional burners supplied for use with air-acetylene in emission or absorption studies. Emission from aluminium at 3962 and 3944 Å shows a 2:1 intensity ratio and extends throughout the entire length of the flame. A detection limit of 4 p.p.m. at 3962 Å was obtained with a 1·5 × 10^–2-mm slit and a linear calibration graph between 20 and 200 p.p.m. Zinc, cadmium and lead, which show negligible emission in the air-hydrogen flame, emit strongly in nitrous oxide supported hydrogen. Calcium shows strong emission, even in the ionic doublet at 3934 and 3968 Å, particularly at low concentrations.