Patricia F. Lynch

Applications of infrared spectroscopy in petroleum analysis and oil spill identification

Abstract Each year an estimated 5 to 10 million tons of oil are discharged into the oceans of the world. Eighty percent of this spilled oil remains in the environment, directly poisoning marine life and indirectly threatening the rest of the plant and animal environment.

Anomalous Bands in Infrared Difference Spectra Due to Frequency Shifts

Artifacts appearing in infrared difference spectra can be caused by the lack of wavelength reproducibility and/or molecular interactions such as solvent effects. These artifacts appear as derivatives in difference spectra. Experimental spectra containing a number of bands with a variety of bandwidths were shifted over a range of frequencies and subtracted from the original spectra to intentionally produce anomalous bands. Models based on both Lorentzian and Gaussian band shapes were used to fit the observed data, and it was found that either band shape could be used to adequately predict the observed results within the experimental error of the measurements. Moreover, the models can be used to determine the values of the frequency shifts from the peak-to-peak differences of artifacts.

Infrared spectra of petroleum weathered naturally and under simulated conditions

The feasibility of weathering petroleum in confined areas and under simulated conditions was explored. Four separate weathering systems were studied with as many as 60 different oils. Infrared spectra of oils weathered in these different systems were compared with each other and with unweathered oils using a computer ratio method. The results on an oil from an actual spill case showed that oils weathered in three of these systems to the same extent as oil taken from the spill.

The Use of Infrared and Raman Spectroscopy to Study Corrosion Inhibitors on Metal Surfaces

Abstract Infrared and Raman spectroscopy have been used to study the effects of three organic inhibitor solutions on iron. Unique infrared and Raman spectra were obtained for each solution. Infrared spectra of surface films in the fingerprint region are different from one inhibitor to the next, and they are also dependent upon the pH of the applied solution. Spectra of films on iron formed from all three inhibitors suggest the presence of polymeric-like materials which are possibly chemically bonded to the iron surface.

TANKER TRAGEDIES: IDENTIFYING THE SOURCE AND DETERMINING THE FATE OF PETROLEUM IN THE MARINE ENVIRONMENT

Three major oil spills this winter in the New England coastal area have forced immediate action on the part of oceanographic, chemical and biological researchers to determine the fate of the oil in the environment and its effects on aquatic life. This paper discusses the infrared and gas chromatographic analyses of air, water, sediment and tarball samples collected at one or more of these spill sites. The chemical partitioning of these petroleum samples in the environment is discussed and the possible source of “mystery” tarballs is conjectured based on infrared analyses.

Chemical Analysis of Dispersed Oil in the Water Column

Water and air samples collected from treated and untreated simulated oil spills have been analyzed for hydrocarbons. In test tanks, 6.2 m tall, the concentration of oil in the water just beneath the surface is initially 27 times greater when a dispersant is used. During a 3-day experiment, however, the amount of oil in the water column decreased significantly in both the treated and untreated cases. When a dispersant was used, the maximum concentration in the water column gradually moved toward the bottom of the tank. Results of laboratory, meso scale, and a real spill are compared.

ON THE BEACH - INFRARED SPECTROSCOPY IN THE REAL WORLD

Organic extracts of sea water, beach sands, clams and ocean sediments have been analyzed by infrared spectroscopy during a three year study. Over 300 water samples, 37 sand and sediment samples and 12 clam samples were analyzed. Infrared spectra of the extracts were measured after removing the solvent. Furthermore, the spectra were re-measured after separation by TLC, and some were re-measured after saponifying the extracts. The spectra, obtained after removing the solvent, have suggested novel uses of infrared spectroscopy in marine pollution studies, e.g., various fractions of petroleum and phthalic acid esters can be monitored. Moreover, infrared spectroscopy can be used very effectively to “screen” samples in order to determine further analysis requirements.