Development of a photochemical source for the production and calibration of acyl peroxynitrate compounds

Abstract

Abstract.A dynamic system for the calibration of acyl peroxynitrate compounds (APNs) has been developed in the laboratory to reduce the difficulty, required time, and instability of laboratory-produced standards for difficult-to-synthesize APN species. In this work we present a photochemical source for the generation of APN standards: acetyl peroxynitrate (PAN), propionyl peroxynitrate (PPN), acryloyl peroxynitrate (APAN), methacryloyl peroxynitrate (MPAN), and crotonyl peroxynitrate (CPAN). APNs are generated via photolysis of a mixture of acyl chloride (RC(O)Cl) and ketone (RC( =O)R) precursor compounds in the presence of O 2 and NO 2 . Subsequent separation by a prep-scale gas chromatograph and detection with a total NO y instrument serve to quantify the output of the APN source. Validation of the APN products was performed using iodide ion chemical ionization mass spectroscopy (I − CIMS). This method of standard production is an efficient and accurate technique for the calibration of instrumentation used to measure PAN, PPN, APAN, MPAN, and CPAN.

Observations of Isocyanate, Amide, Nitrate, and Nitro Compounds From an Anthropogenic Biomass Burning Event Using a ToF‐CIMS

“…A literature survey (Brophy & Farmer, ; Iyer et al, ; Lee et al, ; Veres & Roberts, ) of formic acid calibration factors (normalized to 1 × 10 6 Hz reagent ion) provides a range between 2.9 and 13 Hz ppt −1 (with reported errors of 0.6–5.0 Hz ppt −1 ) highlighting the variation in sensitivity that is associated with the instruments' condition and circumstance for this particular compound. Our formic acid calibration factor of 6.20 ± 1.28 Hz ppt −1 (4.13 ± 0.85 Hz ppt −1 normalized to 1 × 10 6 Hz reagent ion) is well within this range.…”

“…They are a reservoir of NO 2 , thus enabling the transport of NO x and subsequent ozone formation at remote locations, and are typically semivolatile, contributing to secondary organic aerosol formation and thus particulate matter (PM) with further associated air quality issues. Other nitrates such as peroxynitric acid have previously been detected by iodide CIMS (Veres et al, ) and peroxyacetyl nitrate (PAN), which has previously been detected by PAN iodide CIMS (Veres & Roberts, ). Nitro‐organic compounds such as nitrophenol and its degradation products, which have been shown to be genotoxic (Sekler et al, ), have many sources including vehicular emission, degradation of pesticides (Lüttke et al, , and references therein), secondary gas phase reactions (Berndt & Böge, ), and aqueous aerosol phase reactions (Yuan et al, ) and have vapor pressures low enough to readily partition into the condensed phase (Bannan et al, ).…”

Photochemical processing of diesel fuel emissions as a large secondary source of isocyanic acid (HNCO)

“…We calibrated the NI‐PT‐CIMS for HNCO with a stable source of HNCO that was produced by passing a stream of zero air at 50 cm 3 min −1 STP over the outlet of a diffusion cell containing heated cyanuric acid (250°C) [ Roberts et al ., ]. HNCO concentrations were determined with a custom‐built analyzer that converts HNCO to NO on a heated platinum catalyst (750°C) followed by a molybdenum catalyst (450°C) and detects NO via chemiluminescence [ Veres and Roberts , ]. The NI‐PT‐CIMS had a sensitivity to HNCO of 47.5 normalized counts per second/parts per trillion by volume (pptv) and a detection limit (S/N = 3) for HNCO of 5 pptv at 1 s acquisition (supporting information for additional calibration details).…”

Instrumentation and measurement strategy for the NOAA SENEX aircraft campaign as part of the Southeast Atmosphere Study 2013

“…PAN was produced with an efficiency of 93 ± 5 % from a nitric oxide standard as determined from measurements of NO x and NO y using the CRDS instrument. The other PAN compounds were calibrated relative to this photosource before and after the project with the methods described by Veres and Roberts (2015). Nitryl chloride was calibrated using a portable source that uses the reaction of molecular chlorine (Cl 2 ) with sodium nitrite (NaNO 2 ) as described by Thaler et al (2011) with a the output of the source calibrated by thermal decomposition at 350 • C and detection by NO 2 using CRDS as described by Wild et al (2014).…”