Abstract
A limiting noise in inductively coupled plasma atomic emission spectrometry and relations between slit conditions and detection limits were investigated with an echelle spectrometer using a prism as a cross disperser. A Hamamatsu R-955 multialkali PMT was used as a detector. Since the net background signal was considerably law in the u.v. region, the shot noise contribution in the relative standard deviation (RSD) of the background signal was found to be extremely large (50% under a slit condition, width 100 pm and slit height 1000 μm at 200 nm). In order to obtain a RSD value comparable to that with a conventional grating spectrometer, it was necessary that the slit width was larger than or equal to 200 μm. The use of a slit width of 200 μm, however, provides nearly the same resolving power as that with the conventional spectrometer.
