Spectroscopic analysis

Abstract

Spectroscopic apparatus for sequentially detecting the presence of a plurality of elements in a sample. The apparatus includes a plurality of lamps (,) each of which is for detecting the presence of a respective at least one predetermined element in a plurality of elements. A beam selector (,) which may be a mirror, is operative to direct a beam of light (,) from any one of lamps (,) to an analysis zone (,). The apparatus includes a monochromator (,), the drive (,) of which is under the control of a controller (,) with a memory device (,) linked thereto. Predetermined settings for the monochromator corresponding to the peak settings for each wavelength of interest can be stored in memory (,) for subsequently driving the monochromator to those settings without the need to undertake a peaking routine for each elemental analysis, thereby saving analyses time. The lamp and beam selector arrangement of the apparatus substantially reduces the time required to change from one lamp to another thereby facilitating sequential spectroscopic multi-element analyses of samples. Apparatus which uses a flame for atomising a sample includes valves (,and,) for controlling the flow of oxidant (,) and fuel (,) gases to a spray chamber (,) and then analysis zone (,), the oxidant (,) being supplied via a nebuliser (,). The valves (,and,) are preferably high speed oscillating valves having an adjustable on to off time ration under the control of a microprocessor (,). The oscillating valves (,and,) allow rapid changes to be made to the oxidant and fuel gas flows, thereby also saving analysis time.