Liquid electrode plasma optical emission spectrometry and its applicability to analysis of radioactive samples

This paper introduces liquid electrode plasma optical emission spectrometry (LEP-OES), which has recently been applied to analysis of radioactive samples. Figure 1 illustrates the principle of LEP-OES. Accordingly, the LEP is generated by an electrical discharge in a microchannel. When a short-pulsed DC voltage (800-1500V) is applied to a narrow channel of the cell containing an electro-conductive solution sample, the electric field concentrates and the sample solution is subjected to localized Joule heating.
Subsequently, water is evaporated and forms a vapor bubble, then plasma appears. This plasma is exploited as an excitation source for optical emission of elements in the sample solution [1]. It requires no plasma gas, high-power supply, or cooling water system. Thus, LEP-OES apparatuses are more compact than the other plasma excitation device such as inductively coupled plasma spectrometry optical emission spectrometry (ICP-OES). This advantage is very important in radioactive elemental analysis because samples have to be treated in a confined space such as a hot cell or a glove-box.