In recent years, laser ablation-inductively
coupled plasma mass
spectrometry (LA-ICPMS) has gained increasing importance for biological
analysis, where ultratrace imaging at micrometer resolution is required.
However, while undoubtedly a valuable research tool, the washout times
and sensitivity of current technology have restricted its routine
and clinical application. Long periods between sampling points are
required to maintain adequate spatial resolution. Additionally, temporal
signal dispersion reduces the signal-to-noise ratio, which is a particular
concern when analyzing discrete samples, such as individual particles
or cells. This paper describes a novel, two-volume laser ablation
cell and integrated ICP torch designed to minimize aerosol dispersion
for fast, efficient sample transport. The holistic design utilizes
a short, continuous diameter fused silica conduit, which extends from
the point of ablation, through the ICP torch, and into the base of
the plasma. This arrangement removes the requirement for a dispersive
component for argon addition, and helps to keep the sample on axis
with the ICP cone orifice. Hence, deposition of sample on the cones
is theoretically reduced with a resulting improvement in the absolute
sensitivity (counts per unit mole). The system described here achieved
washouts of 1.5, 3.2, and 4.9 ms for NIST 612 glass, at full width
half, 10%, and 1% maximum, respectively, with an 8–14-fold
improvement in absolute sensitivity, compared to a single volume ablation
cell. To illustrate the benefits of this performance, the system was
applied to a contemporary bioanalytical challenge, specifically the
analysis of individual biological cells, demonstrating similar improvements
in performance
