Use of signal-to-root background ratio as the optimization parameter for inductively coupled plasma atomic emission spectroscopy with charged-coupled device detection

Abstract

The use of the signal-to-root background ratio (SRBR) of a spectral line as the measurable parameter chosen as the criterion for single-element optimization of an inductively coupled plasma with charge-coupled device detection is described. The theoretical background to the choice of the SRBR, rather than the more usual signal-to-background ratio (SBR), is given. Single-element optimization of the carrier gas flow rate and viewing height using both atomic and ionic lines from ten elements is described. The improvement in the detection limit by using the SRBR over the SBR varies by a factor of 1.0–4.8. For example, the detection limit for the Mn II emission line at 257.610 nm is improved from 13.4 ng ml^–1 by SBR optimization to 2.8 ng ml^–1 by maximizing the SRBR.