Some analytical properties of low pressure flames

An investigation has been made into the analytical behaviour of low pressure nitrous oxide-acetylene and oxy-acetylene names, between pressures of ca. 15–300 and 10–100 torr, respectively, for the purposes of atomic emission spectroscopy. Samples were introduced into the flame on a loop of tungsten wire, and the resulting emission pulses measured in the space immediately beyond the edge of the primary reaction zone. Attention was largely concentrated on metals which are difficult to determine in conventional atmospheric flames. Absolute detection limits for Sr, Al, Cr, Cu, Ti and V lie in the range 10⁻⁹–10⁻¹⁰ g. The relative atomisation efficiences of the flames used were also measured, and were found to increase with decreasing pressure; an effect attributed to the highly reducing properties of a low pressure flame, and one which was felt to account for the high analytical sensitivity obtained in these studies.