Development of a Compound-Specific Carbon Isotope Analysis Method for 2-Methyltetrols, Biomarkers for Secondary Organic Aerosols from Atmospheric Isoprene

Abstract

The stable carbon isotope compositions of 2-methyltetrols, biomarker compounds for secondary organic aerosols formed from isoprene in the atmosphere, have been determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). In this work, isoprene with various delta(13)C values was used to produce 2-methyltetrols via an oxidation reaction with hydrogen peroxide in sulfuric acid under direct sunlight. The target compounds with different stable carbon isotope compositions were then derivatized by methylboronic acid with a known delta(13)C value and measured by GC/C/IRMS. With delta(13)C values of 2-methyltetrols and methylboronic acid predetermined, isotopic fractionation is evaluated for the derivatization process. Through reduplicate delta(13)C measurements, the carbon isotope analysis achieved excellent reproducibility and high accuracy with an average error of <0.3 per thousand. The differences between the predicted and measured delta(13)C values range from -0.10 to 0.29 per thousand, indicating that the derivatization process does not introduce isotopic fractionation. The delta(13)C values of 2-methyltetrols could be calculated on the basis of the stoichiometric mass balance equation among 2-methyltetrols, methylboronic acid, and methylboronate derivatives. Preliminary tests of 2-methyltetrols in PM(2.5) aerosols at two forested sites were conducted and revealed significant differences in their isotope compositions, implying possible application of the method in helping us understand the primary emission, photochemical reaction, or removal processes of isoprene in the atmosphere.

Quantification of the carbonaceous matter origin in submicron marine aerosol by &lt;sup&gt;13&lt;/sup&gt;C and &lt;sup&gt;14&lt;/sup&gt;C isotope analysis

“…A number of studies have even attempted compound specific stable carbon analysis: Turekian et al (2003) were able to derive isotope ratio of oxalate attributing it to mostly marine precursors; Li et al (2010) developed a method for isoprene biomarkers; Fisseha et al (2006) and Wang and Kawamura (2006) were able to perform stable carbon analysis of organic acids; Kim et al (2005) and Zhang et al (2009) developed an isotope analysis of polycyclic aromatic hydrocarbons. However, stable carbon isotope analysis is somewhat inconclusive due to inability to separate continental non-fossil and fossil fuel sources which can only be reliably done by radiocarbon analysis (Szidat et al, 2009).…”

A method for stable carbon isotope ratio and concentration measurements of ambient aromatic hydrocarbons

“…Within several years different research groups published results of stable carbon isotope measurements for a variety of atmospheric VOCs (Anderson et al, 2004;Czapiewski et al, 2002;Iannone et al, 2003Iannone et al, , 2005Irei et al, 2006;Norman et al, 1999;Rogers and Savard, 1999;Rudolph et al, , 2003Smallwood et al, 2002;Thompson et al, 2003). Nevertheless, the number of publications on isotopic composition measurements and their application is still quite limited due to the need for elaborate and expensive experimental techniques and challenging data interpretation (Eckstaedt et al, 2011;Fisseha et al, 2009;Giebel et al, 2010;Iannone et al, 2005Iannone et al, , 2009Iannone et al, , 2010Irei et al, 2006;Li et al, 2010;Moukhtar et al, 2011). An overview of existing techniques to measure stable carbon isotope ratios of VOCs is given in a recent paper (Gensch et al, 2014).…”

“…While their atmospheric mixing ratios are mostly in the ranges of pptV to ppbV, these compounds play an important role in tropospheric chemical processes (Atkinson, 2000;Jordan, 2009;Kleinman et al, 2003). Aromatic VOCs are important constituents of urban and rural air masses (Forstener et al, 1997;Lurmann and Main, 1992). These compounds, mostly originating from fossil fuel use, are found in evaporated gasoline, fuels and solvents, vehicle exhaust and many other anthropogenic-related emissions (Hurley et al, 2001;Jang and Kamens, 2001;Reimann and Lewis, 2007).…”

Bioconversion of Lignocellulose: Inhibitors and Detoxifi cation

“…Although ME is produced in the leaves and flowers of some plants [49], and abiotically through the atmospheric oxidation of isoprene [50][51][52], discovery efforts in the MEP pathway necessitated access to multi-milligram quantities of the sugar. these efforts, no dedicated chemical syntheses of the sugar existed, although some syntheses of derivatives of ME had been reported [53].…”