Flow
injection (FI) in combination with inductively coupled plasma
mass spectrometry (ICPMS) is advantageous for the analysis of volume-limited
samples and is invaluable for the analysis of corrosive samples that
would prematurely degrade ICPMS components. However, the dispersion
process with 50-μL injections in FI degrades ICPMS sensitivity.
Monosegmented flow analysis (MSFA), where the sample plug is in the
middle of 1 mL of air, eliminates dispersion while preserving the
rinsing effect of the carrier. More reproducible as well as sharper,
narrower, and more symmetrical peaks result with MSFA than FI, leading
to a 2-fold improvement in detection limit and a 5-fold increase in
sample throughput versus FI. Furthermore, by facilitating the formation
of small droplets during nebulization, the air surrounding the sample
even enhances sensitivity by 20–40%, depending on the element,
compared to that obtained with direct sample aspiration. Coupling
MSFA to ICPMS, which does not degrade analytical performance, is advantageous
for the determination of Pt in 0.50 M H2SO4 electrolyte
from a simulated fuel cell. It also enables the multielement analysis
of a 150-μL buffer sample containing as little as 60 μg
of plant protein, thus further extending the range of applications
of ICPMS.