Significance and Use
5.1 FTOHs are volatile and semivolatile precursors to perfluorinated carboxylic acids and are used in the synthesis of various surfactants and as intermediates in the manufacturing of a variety of consumer products including polymers, paints, adhesives, aqueous film-forming foam, waxes, and cleaning agents (1 and 2).6 The residential indoor air burden of FTOHs from consumer products, building materials, and household dust is not well understood as there are limited emission data available (1-4).
5.2 The indoor environment can be one of the primary pathways for general population exposure to PFAS, including FTOHs, due to direct (that is, skin contact or ingestion) or indirect exposure (that is, inhalation of suspended particles and gases) to chemicals in consumer products and building materials (3-5).
5.3 Validated analytical methods to characterize FTOHs in test chamber air are necessary as the initial step for conducting human exposure assessments using mass-transfer models and other techniques.
5.4 The scope of this test method may expand to other types of air samples, in particular indoor air samples, as data becomes available.
5.5 FTOHs have previously been quantified using liquid chromatography-mass spectrometry (LC-MS) (6-8); however, targeted analysis using gas chromatography-mass spectrometry (GC-MS) is preferred due to sensitivity limitations arising from ionization with LC-MS and from adduct formation when LC-MS chromatographic conditions are optimized for concomitantly quantifying other PFAS (1, 2, 9-17).
5.6 Sampling with TD tubes can be performed passively using diffusion caps or actively using a pump/forced air. This increases the flexibility of the sampling and analytical method because a wide range of air volumes can be collected (~500 mL to ~500 L), which in turn increases the range of concentrations which can be assessed. TD tube sampling also eliminates the variability of solvent extraction recovery. TD tubes are desorbed and preconcentrated with an appropriate TD apparatus, and the sample is then immediately transferred to a GC column for separation and analysis; thus, minimizing the potential for sample loss or contamination and significantly increasing sensitivity to FTOHs (2, 14-19).
5.7 GC-MS/MS is used in this standard to quantify trace levels of FTOHs in test chamber air because of its ability to obtain precursor-to-product mass fragmentation spectra via MRM and because its higher sensitivity and selectivity compared to GC-single quadrupole MS or LC-MS. This analytical approach improves reliability and detectability of measuring FTOHs in air samples, especially for sampling methods that involve large air volumes or complex matrices (12, 18, 19).
Scope
1.1 This test method covers the detection and quantification of fluorotelomer alcohols (FTOHs), a group of volatile and semivolatile per- and polyfluoroalkyl substances (PFAS), in air samples collected on thermal desorption (TD) tubes by thermal desorption-gas chromatography-triple quadrupole tandem mass spectrometry (TD-GC-MS/MS) in multiple reaction monitoring (MRM) mode.
1.2 This test method has been validated in a single lab for 1H, 1H, 2H, 2H-perfluorohexan-1-ol (4:2 FTOH; CAS No. 2043-47-2), 1H, 1H, 2H, 2H-perfluorooctan-1-ol (6:2 FTOH; CAS No. 647-42-7), 1H, 1H, 2H, 2H-perfluorodecan-1-ol (8:2 FTOH; CAS No. 678-39-7), and 1H, 1H, 2H, 2H-perfluorododecan-1-ol (10:2 FTOH; CAS No. 865-86-1) as target analytes.
1.3 This test method is not limited to these target analytes; however, the applicability of this test method to other volatile and semivolatile PFAS shall be demonstrated by meeting or exceeding the performance criteria of this test method.
1.4 This test method has been validated for air samples collected from test chambers. It may be applicable to indoor air samples, including samples of interior vehicle and workplace air, air from associated sampling containers, such as sampling bags or bottles, as well as ambient outdoor air samples; however, the applicability of this test method to other types of air samples shall be demonstrated by meeting or exceeding the performance criteria of this test method.
1.5 This test method is to be used in concert with approved standards for conducting air sampling, such as Practice D6196 (choosing sorbents, sampling parameters, and thermal desorption analytical conditions for monitoring volatile organic chemicals in air), and for conducting chamber tests, such as Practice D7706 (micro-scale chamber), Guide D5116 (small-scale chamber), Practice D6670 (full-scale chamber), or Practice D7143 (emission cells).
1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
