Unified Theory of Vapor–Wall Mass Transport in Teflon-Walled Environmental Chambers

Huang, Yuanlong; Zhao, Rongqin; Charan, Sophia M.; Kenseth, Christopher M.; Zhang, Xuan; Seinfeld, John H.

doi:10.1021/acs.est.7b05575

Cited by 70 publications

(109 citation statements)

References 50 publications

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“…A number of studies have demonstrated that absorptive partitioning of volatile organic compounds (VOCs) into the Teflon walls of environmental chambers can affect the results of the experiments conducted within. This partitioning has been shown to be reversible and relatively fast, on a timescale 30 of minutes (Matsunaga and Ziemann, 2010;Yeh and Ziemann, 2015;Krechmer et al, 2016;Ye et al, 2016;Huang et al, 2018). Furthermore, a recent study showed analogous absorptive partitioning of VOCs when transported through PFA (perfluoroalkoxy alkanes) Teflon tubing, with similar interaction parameters as for FEP (fluorinated ethylene propylene) Teflon chamber walls (Pagonis et al, 2017).…”

Section: Introductionmentioning

confidence: 92%

Measurements of Delays of Gas-Phase Compounds in a Wide Variety of Tubing Materials due to Gas-Wall Interactions

Deming¹,

Pagonis²,

Liu³

et al. 2019

Preprint

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Losses of gas-phase compounds or delays on their transfer through tubing are important for atmospheric measurements and also provide a method to characterize and quantify gas-surface interactions. Here we expand recent results by comparing different types of Teflon and other polymer tubing, as well as glass, uncoated and coated stainless steel and aluminium, and other tubing materials by measuring the 15 response to step increases and decreases in organic compound concentrations. All polymeric tubings showed absorptive partitioning behaviour with no dependence on humidity or concentration, with PFA Teflon tubing performing best in our tests. Glass and uncoated and coated metal tubing showed very different phenomenology due to adsorptive partitioning to a finite number of surface sites. Strong dependencies on compound concentration, mixture composition, functional groups, humidity, and 20 memory effects were observed for glass and uncoated and coated metals, which (except for Silonitecoated stainless steel) also always caused longer delays than Teflon for the compounds and concentrations tested. Delays for glass and uncoated and coated metal tubing were exacerbated at low relative humidity but reduced for RH > 20%. We find that conductive PFA and Silonite tubing perform best among the materials tested for gas plus particle sampling lines, combining reduced gas-phase 25 delays with good particle transmission.

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Section: Introductionmentioning

confidence: 92%

Measurements of Delays of Gas-Phase Compounds in a Wide Variety of Tubing Materials due to Gas-Wall Interactions

Deming¹,

Pagonis²,

Liu³

et al. 2019

Preprint

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“…RH-induced oligomer suppression has been reported for toluene and α-pinene SOA formation (Hinks et al, 2018;Huang et al, 2018a). The oligomer decrease under high RH could also be due to RH-volatility dependent organic vapor wall loss (Huang et al, 2018b). A clear m/z dependence of signal reduction under humid conditions as compared to the dry conditions is shown in Fig.…”

Section: Two-dimensional Thermogrammentioning

confidence: 92%

“…ACSM data were analyzed in Igor Pro V6.37 (Wavemetrics, Inc.) using ACSM local v1603 (Aerodyne) and other custom routines. Aerosol concentrations were corrected for depositional particle wall loss (Pathak et al, 2007) but not for organic vapor loss (Huang et al, 2018b;Krechmer et al, 2017;Nah et al, 2017).…”

Section: Environmental Chamber Experiments and Instrumentationmentioning

confidence: 99%

“…The first filter was collected at 3 SLPM for 45 mins, followed by the second filter at 3 SLPM for 30 mins, and afterwards the third filter at 3 SLPM for 15 mins. The ratios of the unit-mass integrated ion signals during the desorption period for the first two filters relative to that of the third filter are shown in Fig Between the first (high-loading) filter collection and the third (low-loading) filter collection, volatilitydependent vapor wall loss may lead to a disproportionate decrease in high molecular weight, low volatility compounds (Huang et al, 2018b;Krechmer et al, 2016), resulting in increasingly greater enhancement towards the high m/z region shown in Fig. 10 S7a.…”

Section: Tmax Shiftmentioning

confidence: 99%

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Chlorine-initiated oxidation of n-alkanes under high NOx conditions: Insights into secondary organic aerosol composition and volatility using a FIGAERO-CIMS

Wang¹,

Ruiz²

2018

Preprint

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Abstract. Chlorine-initiated oxidation of n-alkanes (C8-12) under high nitrogen oxides conditions was investigated. Observed secondary organic aerosol yields (0.16 to 1.65) are higher than those for OH-initiated oxidation of C8-12 alkanes (0.04 to 0.35).A High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer coupled to a Filter Inlet for Gases and AEROsols (FIGAERO-CIMS) was used to characterize the gas-and particle-phase molecular composition. Chlorinated organics were 10 observed, which likely originated from chlorine addition to the double bond present on the heterogeneously produced dihydrofurans. A two-dimensional thermogram representation was developed to visualize composition and relative volatility of organic aerosol components using unit-mass resolution data. Evidence of oligomer formation, thermal fragmentation and thermal decomposition was observed. Aerosol yield and oligomer formation were suppressed under humid conditions (35 to 67 % RH) relative to dry conditions (under 5 % RH). The temperature at peak desorption signal, Tmax, a proxy for aerosol 15 volatility, was shown to change with aerosol filter loading, which should be constrained when evaluating aerosol volatilities using the FIGAERO-CIMS. Results suggest that long-chain anthropogenic alkanes could contribute significantly to ambient aerosol loading over their atmospheric lifetime.

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“…One impediment to the measurement of lower-volatility gases is the influence of inlet tubing and other experimental apparatus surfaces. Several recent experiments have probed the effects of Teflon chamber walls on experimental processes (Matsunaga and Ziemann, 2010;Krechmer et al, 2016bKrechmer et al, , 2017Huang et al, 2018). A variety of organic and inorganic gases have been shown to reversibly absorb into Teflon (and other polymer) tubing or reversibly adsorb onto the surface of a variety of solid materials including stainless steel (Pagonis et al, 2017;Deming et al, 2019;.…”

Section: Introductionmentioning

confidence: 99%

Performance of a new coaxial ion–molecule reaction region for low-pressure chemical ionization mass spectrometry with reduced instrument wall interactions

2019

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Abstract. Chemical ionization mass spectrometry (CIMS) techniques have become prominent methods for sampling trace gases of relatively low volatility. Such gases are often referred to as being “sticky”, i.e., having measurement artifacts due to interactions between analyte molecules and instrument walls, given their tendency to interact with wall surfaces via absorption or adsorption processes. These surface interactions can impact the precision, accuracy, and detection limits of the measurements. We introduce a low-pressure ion–molecule reaction (IMR) region primarily built for performing iodide-adduct ionization, though other adduct ionization schemes could be employed. The design goals were to improve upon previous low-pressure IMR versions by reducing impacts of wall interactions at low pressure while maintaining sufficient ion–molecule reaction times. Chamber measurements demonstrate that the IMR delay times (i.e., magnitude of wall interactions) for a range of organic molecules spanning 5 orders of magnitude in volatility are 3 to 10 times lower in the new IMR compared to previous versions. Despite these improvements, wall interactions are still present and need to be understood. To that end, we also introduce a conceptual framework for considering instrument wall interactions and a measurement protocol to accurately capture the time dependence of analyte concentrations. This protocol uses short-duration, high-frequency measurements of the total background (i.e., fast zeros) during ambient measurements as well as during calibration factor determinations. This framework and associated terminology applies to any instrument and ionization technique that samples compounds susceptible to wall interactions.

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Unified Theory of Vapor–Wall Mass Transport in Teflon-Walled Environmental Chambers

Cited by 70 publications

References 50 publications

Measurements of Delays of Gas-Phase Compounds in a Wide Variety of Tubing Materials due to Gas-Wall Interactions

Measurements of Delays of Gas-Phase Compounds in a Wide Variety of Tubing Materials due to Gas-Wall Interactions

Chlorine-initiated oxidation of n-alkanes under high NOx conditions: Insights into secondary organic aerosol composition and volatility using a FIGAERO-CIMS

Performance of a new coaxial ion–molecule reaction region for low-pressure chemical ionization mass spectrometry with reduced instrument wall interactions

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