Metrohm MARS Aerosol Sampler

Overview

The Metrohm MARS (Mobile Aerosol Reference Sampler) is a real-time, continuous aerosol sampling system engineered for high-fidelity pre-concentration and transfer of atmospheric particulate matter into aqueous solution for subsequent ion chromatographic or elemental analysis. Unlike conventional filter-based collection methods—which yield only time-integrated bulk concentrations—the MARS operates on the principle of steam-jet impaction coupled with thermophoretic deposition, enabling dynamic, near-real-time capture of water-soluble ionic species (e.g., SO₄²⁻, NO₃⁻, NH₄⁺, Cl⁻, Na⁺) and selected metal ions (including Cr(VI), As, Pb, Cd) directly from ambient or process air streams. Designed for integration into continuous monitoring networks, the MARS eliminates offline extraction steps, reduces analytical uncertainty associated with filter handling and leaching efficiency, and supports second-to-minute temporal resolution—critical for source apportionment, exposure assessment, and regulatory compliance tracking in complex urban, industrial, or indoor environments.

Key Features

• Continuous, unattended aerosol sampling at adjustable flow rates (typically 16.7 L/min standard, configurable up to 30 L/min)
• Steam-jet impaction combined with thermophoretic enhancement ensures >95% collection efficiency for particles <10 µm aerodynamic diameter (PM₁₀), including submicron fractions down to ~0.03 µm
• No filter media required—sample is directly deposited into deionized water within a cooled collection vessel, minimizing artifact formation and preserving redox-sensitive species such as Cr(VI)
• Integrated temperature, pressure, and flow monitoring with digital PID control for stable operation across variable environmental conditions (−20 °C to +40 °C ambient range)
• Modular design compatible with Metrohm MARGA 2060 (Monitor for AeRosols and Gases in Ambient air) for synchronized gas–aerosol speciation
• Corrosion-resistant wetted path constructed from PFA, quartz, and electropolished stainless steel—compliant with ISO 14644-1 Class 5 cleanroom requirements when deployed in controlled environments

Sample Compatibility & Compliance

The MARS is validated for use with ambient air, tunnel exhaust, cleanroom supply air, HVAC ducts, and industrial stack effluents. It complies with key international method frameworks including EN 16450 (ambient air quality—measurement of PM mass concentration), ISO/TS 21385 (aerosol measurement—requirements for online monitors), and ASTM D6216 (standard practice for ambient air monitoring of inorganic anions). When paired with Metrohm IC systems, full traceability aligns with ISO/IEC 17025:2017 laboratory accreditation criteria. Data integrity meets FDA 21 CFR Part 11 requirements when operated with Metrohm’s MagIC Net™ software under configured audit-trail and electronic-signature protocols.

Software & Data Management

MARS operation is fully integrated into Metrohm’s MagIC Net™ platform, supporting automated calibration verification, remote diagnostics, and event-triggered sampling (e.g., exceeding preset ion thresholds). Raw flow, temperature, and collection volume data are timestamped and stored with ≥1 Hz resolution. Export formats include CSV, XML, and netCDF for interoperability with third-party air quality modeling tools (e.g., CAMx, CMAQ). All configuration changes, user logins, and instrument state transitions are recorded in a tamper-evident audit trail—enabling GLP/GMP-compliant reporting and regulatory submission readiness.

Applications

• Long-term trend analysis of secondary inorganic aerosols (SIA) in urban background monitoring stations
• Real-time detection of hexavalent chromium (Cr(VI)) emissions from electroplating or stainless-steel fabrication facilities
• Indoor air quality (IAQ) assessment in hospitals, pharmaceutical cleanrooms, and semiconductor fabrication fabs
• Source characterization in road tunnels and underground parking structures
• Validation of low-cost sensor networks through co-location studies with reference-grade instrumentation
• Supporting health impact studies requiring time-resolved exposure metrics aligned with epidemiological time windows

FAQ

How does MARS differ from traditional filter-based aerosol samplers?
MARS provides continuous, liquid-phase collection without filter handling, enabling higher temporal resolution, improved recovery of volatile and redox-labile species, and elimination of post-collection extraction variability.
Can MARS be used for metallic aerosol speciation beyond Cr(VI)?
Yes—when coupled with ICP-MS or hyphenated IC-ICP-MS, MARS supports quantification of As(III)/As(V), Sb(III)/Sb(V), and other oxidation-state-specific metals, provided sample stabilization protocols are applied during collection.
Is MARS suitable for field deployment in harsh outdoor environments?
Yes—its IP54-rated enclosure, wide operating temperature range, and internal desiccant management allow year-round unattended operation in temperate and Mediterranean climates; optional heating/cooling modules extend viability to arctic or desert deployments.
Does MARS require routine maintenance beyond consumable replacement?
Routine tasks include weekly cleaning of the steam nozzle and collection vessel, quarterly calibration of mass flow controllers against NIST-traceable standards, and annual verification of thermophoretic alignment per Metrohm Service Bulletin SB-MARS-03.