Woods Hole Oceanographic Institution
Technical Report WHOI-84-09
A procedure is described for the collection of remote marine aerosol samples by high-volume filtration, cascade impaction, dry fallout collection and rain. Samples were analyzed quantitatively for five classes of naturally occurring lipids (n-alkanes, wax esters, fatty alcohols, sterols and fatty acids) and polycyclic aromatic hydrocarbons (PAHs). Air samples (4,000 to 10,000 m³) were collected on glass fiber filters under automatic control. Rain samples of 1-5 L were collected on an event basis. Filters and rain samples were extracted with methylene chloride. The extracts were fractionated into discrete chemical classes by silica-gel adsorption chromatography. The fractions were derivatized if necessary and analyzed by HRGC and HRGC / MS. A second filter extraction was required for fatty acid salt analysis. Internal standards were used to quantify recoveries and concentrations. Mean recoveries relative to the internal standards were 96.5 ± 2.8% for C18-C36 n-alkanes, 96.4 ± 5.3% for C20-C30 n-fatty acids, 92.5 ± 4.5% for C14-C30 n-fatty alcohols and 93.3 ± 1.4% for cholesterol. Typical blanks and concentrations for remote marine aerosol and rain samples are described and compared with other methods used in coastal marine, rural and suburban sampling locations.
The authors would like to acknowledge the contributions by the many people who assisted us in the development of this method and the preparation of the manuscript. We would like to thank Dr. Oliver Zafiriou for helping us to formulate the method and his special insight concerning the analysis of the fatty acid salts; Ms. Gale Nigrelli and Dr. Stuart Wakeham for their comments and direction during the development of the silica-gel chromatogrphy procedure; and Drs. Paul Comita and Jurg Schneider and Mr. Steven O. Smith for testing the method by applying it to new and different sample types. Dr. Stuart Wakeham graciously provided the HRGC analysis of the wax esters, and Dr. Nelson Frew assisted with the HRGC / MS analyses. We are grateful to Mr. C. Snipes at Holmes and Narver, Inc., the staff of the University of Hawaii's Mid-Pacific Marine Laboratory at Enewetak, the Department of Energy, Mr. Don Nelson and the staff at the National Oceanic and Atmospheric Administration (NOAA) Global Monitoring for CLimatic Change (GMCC) Observatory in American Samoa for major logistical support during the field work at these sites. We would also like to thank Mr. John Jasper for proof-reading the manuscript and Ms. Peggy Chandler for typing it.
This work was supported by the National Science Foundation, Ocean Science Division under NSF grants OCE 77-12914 and OCE 81-11947 as part of the SEAREX program.