Building Consensus on PTR-MS Methods for Sampling of Indoor Environments

Crafting Consensus Methods
Oral Presentation

Prepared by M. Link
NIST, 100 Bureau Drive, MS 8633, Gaithersburg, Maryland, 20899, United States


Contact Information: [email protected]; 970-556-3133

ABSTRACT

Over the past 15 years real-time mass spectrometers using H3O+ proton-transfer reaction ionization (PTR-MS) have become more ubiquitous in laboratories that measure indoor air because of their promise of fast measurements with low sensitivities compared to other measurement methods. Many peer-reviewed studies exist describing methods and procedures for sampling indoor air with PTR-MS, but there is a paucity of comprehensive general guidance, in part, due to instrument-specific technologies that create unique instrument operating conditions and associated data treatment methods. To solve this problem NIST convened a 40+ person ASTM working group comprised of representatives from all known instrument manufacturers, academics, analytical lab contractors, and local, state, and federal government representatives to develop a standard practice for PTR-MS measurements of indoor air. The working group developed general guidance for PTR-MS measurements, including workflows and diagrams. The guidance is applicable for measurements of indoor air but likely has guidance that extends to outdoor air measurements and other reagent ions used in real-time mass spectrometers. Lessons learned from the development of the standard practice will be used to develop future test methods and reference material standards for chemical ionization mass spectrometers.