Extending the Linear Dynamic Range of Single Particle ICP-MS for
the Quantification of Microplastics
George C. Caceres, Monique E. Johnson, John L. Molloy, Sang Bok Lee,
and Antonio R. Montoro Bustos*
Cite This: https://doi.org/10.1021/acs.analchem.5c03552
Read Online
ACCESS
Metrics & More Article Recommendations
*
sı
Supporting Information
ABSTRACT: In response to the growing concern of microplastics (1 μm to 5 mm) accumulation aecting human health, the
development of analytical methods continues to be critical for the detection and characterization of microplastic particles. In this
context, pursuing exceptional particle detection capability down to practical low levels and rapid analyses with high sample
throughput makes single particle inductively coupled plasma mass spectrometry (spICP-MS) very attractive for microplastics
analysis. Existing spICP-MS-based studies have routinely shown limitations in the accurate sizing and quantification of particle
number concentration through targeting carbon content, with reported size limits of detection in the range of 0.62 to 1.8 μm and a
substantial reduction in the transport of particles larger than 3 μm. In this work, the linear dynamic range of spICP-MS for the
accurate quantification of polystyrene microparticles (PS MPs) via the monitoring of their carbon content (
13
C
+
) is extended to
larger particle sizes (5 μm) through using a high eciency sample introduction system with rigorous optimization of the
13
C signal
and operating at a lowered nebulizer gas flow to improve sample transport of larger particles to the plasma. Reliable quantification of
particle number concentration (PNC), accepted as falling within 20% of expected particle stock concentrations, was achieved
through a 20% lowered nebulizer gas flow for a full suite of commercial PS MPs ranging from 2 to 5 μm as well as a 2.2 and 4.8 μm
PS MP contained within mixtures of the two materials, regardless of PNC ratio.
M
icroplastics are defined as plastic particles of nominal
sizes between 1 μm and 5 mm.
1
Interest in their study
has grown exponentially over the past two decades, which
comes as a response to their considerable ubiquity. The
widespread nature of microplastics has raised great concern
over their potential impact on human health and has led to
greater eorts to improve our understanding of these impacts.
The analytical techniques used to further our understanding of
microplastics provide the core tools required to advance such
research. Techniques such as scanning electron microscopy,
transmission electron microscopy, dynamic light scattering,
nanoparticle tracking analysis, pyrolysis gas chromatography−
mass spectrometry, X-ray photoelectron spectroscopy, Raman
spectroscopy, and Fourier transform infrared spectroscopy are
all popular methods for the analysis of microplastics.
2,3
While
each analytical technique oers great advantages regarding key
measurement aspects such as size determination and
resolution, particle counting capabilities, polymer identification
capabilities, sample integrity, ease of use, and cost, each also
possesses shortfalls that can be addressed through supple-
mentary techniques.
2,4
Single particle inductively coupled plasma mass spectrom-
etry (spICP-MS) is one such technique that has shown
promise for use in the analysis of microplastics and is capable
of oering specific benefits over those previously listed. The
primary advantage of spICP-MS is particle number concen-
Received: June 13, 2025
Revised: August 29, 2025
Accepted: September 3, 2025
Articlepubs.acs.org/ac
© XXXX The Authors. Published by
American Chemical Society
A
https://doi.org/10.1021/acs.analchem.5c03552
Anal. Chem. XXXX, XXX, XXX−XXX
