Univariate optimization of segmented-flow injection for inductively coupled plasma mass spectrometry

Abstract

Through optimization of the operating conditions for the segmented air–water carrier, the peak height sensitivity was found to be dependent on the nebulizer gas flow rate and the r.f. power but largely independent of the sample injection volume, the carrier flow rate, and the ratio of air to water in the carrier. Under-optimized operating conditions, performing flow injection (Fl) into the air bubbles of a segmented air–water carrier resulted in similar or improved detection limits for all analytes, except Se, when compared with those obtained using continuous nebulization. This was true even if only 0.1 cm³ injections were made. Changing the segmenting gas from air to Ar, N₂ or H₂, did not result in appreciable changes in analyte signals or positions of maximum ionization with in the plasma, nor did it improve the tolerance of inductively coupled plasma mass spectrometry to the effect caused by 0.01 and 0.1 mol dm^–3 Na compared with that experienced using Fl into an all-water carrier.