Formation of secondary ozonides from the reaction of an unsaturated phosphatidylcholine with ozone

Abstract

Phosphatidylcholines are significant components of pulmonary surfactant in the alveolar region of the lung, where they play a major role in lung function due to their surface tension reducing properties. However, separation and the direct identification of many of the primary products of reaction of phosphatidylcholines with inhaled pollutant gases has not been possible until recently due to the lack of suitable analytical techniques, so that compounds such as fatty acid methyl esters generally have been used as analogues for the phospholipids. We report here the first isolation and identification of the products of reaction of ozone with one of the unsaturated components of lung surfactant, beta-oleoyl-gamma-palmitoyl-L-alpha-phosphatidylcholine (OPPC), using a combination of high-performance liquid chromatography, fast atom bombardment mass spectrometry, and Fourier transform infrared, ultraviolet absorption, and nuclear magnetic resonance spectrometry as well as gas chromatography. The products are shown to be the cis and trans secondary ozonides of the parent phosphatidylcholine, analogous to those previously observed by other researchers in the reactions of the simple fatty acid methyl esters with ozone. This also appears to be the first report of fast atom bombardment mass spectra of these phospholipid secondary ozonides. The implications of this work for the inhalation of ozone, formed in photochemical smog, are discussed.

Hydroxyl radical oxidation of phospholipid-coated NaCl particles

“…A second set of masses at m/z 650 and 672 was also used as an internal standard in that region, based on the assumption that they are attributable to the proton and sodium adducts of the phospholipid aldehyde B (Scheme 2) observed previously in the ozone oxidation of POPC 28,41 and its isomer OPPC. 42,43 Table 1 lists the measured m/z of the proton adduct peaks, the formulae and exact masses of the closest matches to the measured m/z that are chemically and mechanistically reasonable, the relative error in ppm, and the assigned structures as shown in the schemes. For some of the peaks, potential additional formulae and structures are listed which may contribute to the peaks.…”

A new mechanism for ozonolysis of unsaturated organics on solids: phosphocholines on NaCl as a model for sea salt particles

“…[27][28][29][30][31] band is formed at B1110 cm À1 that is characteristic of the peroxide C-O bond 32,33 of the secondary ozonide ring (1,2,4-trioxolane, SOZ) known to be formed in ozone-alkene reactions. 14,[34][35][36][37][38][39][40] New bands at B1385 and 1347 cm À1 are also assigned to the SOZ. 31,33 The peak at 1210 cm À1 is assigned to a C-O moiety, although the specific species is not known.…”

Review of Recent Smog Chamber Studies for Secondary Organic Aerosol

“…ROO·와 HO 2 반응으로 organic hydroperoxide wacki et al, 2012;Atkinson and Arey, 2003;Benson, 1965). Alkoxy radical (RO·) 역시 peroxy radical (ROO·) Taatjes et al, 2013;Mauldin Iii et al, 2012;Welz et al, 2012;Neeb et al, 1996;Hatakeyama and Akimoto, 1994;Lai et al, 1990). 두 번째 경로는 peroxide channel (그림 3)인데, isomerization으로 δ 위치에 있는 탄소에 결합해 있는 수소원자 를 빼앗아서 (또는 1,4 hydride shift) organic hydroper-…”