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Fully Automated, Trace-Level Determination of
Parent and Alkylated PAHs in Environmental
Waters by Online SPE-LC-APPI-MS/MS
Cesar E. Ramirez
1
, Chengtao Wang
1
, Piero R. Gardinali
1
, Jennifer Massi
2
, Jonathan Beck
2
1
Florida International University, Department of Chemistry and Biochemistry, North Miami Beach, FL
2
Thermo Fisher Scientific, San Jose, CA
Application Note 598
Key Words
Online SPE, dopant-assisted APPI, seawater, reclaimed water, rainwater
runoff, PAH, alkylated PAHs, EQuan, TSQ Quantum Access, mass
spectrometry
Goal
To develop a fast, fully automated protocol for determining a large number
of parent PAHs and alkylated PAHs in environmental waters, using online
solid–phase extraction coupled with liquid chromatography and tandem
mass spectrometry.
Introduction
Polycyclic aromatic hydrocarbons (PAHs) are persistent
organic pollutants produced by both human activities and
natural phenomena. PAHs enter surface waters mainly by
atmospheric fallout, urban runoff, municipal and
industrial effluents, and the spill or leakage of petroleum
and its derivates.
1,2
Petroleum-derived mixtures contain
large amounts of PAHs
3
and these compounds are often
used as markers to determine the source, fate, and
potential effects on natural resources after such substances
are released to the environment.
4,5
Many PAHs have been
found to have toxic, carcinogenic, and mutagenic
properties,
6,7
which have prompted the imposition of
strict regulations on their releases in industrial and
municipal effluents and their concentrations in
environmental waters and drinking water supplies.
Both the United States Environmental Protection Agency
(US EPA) and the European Union have considered at
least 16 parent PAHs as priority pollutants for
environmental monitoring purposes.
8
Well-established methodologies are available for the
analysis of PAHs in waste and surface waters, usually
involving liquid–liquid extraction (LLE) with n-hexane,
toluene, benzene, methylene chloride, or cyclohexane,
1
followed by cleanup steps and detection by gas
chromatography and mass spectrometry (GC-MS).
9-12
However, LLE requires a high volume of sample, is labor
intensive, and time consuming, which severely limits
sample throughput. In addition, large amounts of organic
solvents are evaporated to concentrate the analytes.
Release of the solvent vapor into the atmosphere causes
environmental concerns.
1,13,14
Solid-phase extraction (SPE) provides an alternative to
LLE for sample preparation for PAH analysis. The
well-established approach of injecting the sample into a
large-volume sample loop connected between the SPE
pump and the SPE column allows for sample handling by
automated autosamplers.
15-17
In this application note, a
fast, fully automated protocol for the determination of
parent and alkylated PAHs in environmental waters is
presented on the basis of work using online SPE coupled
with liquid chromatography (LC) and tandem mass
spectrometry (MS/MS) detection with the Thermo Scientific
™
EQuan
™
online SPE LC-MS system.
18
Optimized
conditions for SPE extraction, carryover control,
LC separation, and APPI-MS/MS detection are also
presented. A comparison between the developed method
and LLE-GC-MS in terms of chromatographic resolution
and sensitivity was performed, and examples of
environmental applications are shown.