Laser-based detection of PAHs and BTXE-aromatics in oil polluted soil samples

Abstract

Time-resolved laser-induced fluorescence spectroscopy and fiber optics are applied for the detection of aromatic hydrocarbons in oil contaminated water and soil samples. Time-integrated data accumulation of fluorescence intensities in an "early" and in a "late" time window with respect to the exciting laser pulse simplifies the method in such a way that it becomes very attractive for practical applications. For ultraviolet laser excitation at 337 nm and recording fluorescence signals at 400 nm, typical detection limits of the present set-up are 0.5 mg engine oil/L in water and 5 mg engine oil/kg in soil. A discrimination between BTXE-aromatics and PAHs in oil polluted soil or water samples is possible, when more than one laser wavelength in the ultraviolet is used for the excitation. The possibilities for a thermal discrimination between different aromatics are also discussed.

Applications and New Developments in Fluorescence Spectroscopic Techniques for the Analysis of Polycyclic Aromatic Hydrocarbons

“…Recently, in most of the fluorescence-based instrumentation, conventional lamps e.g., Xe/Hg lamps, are being replaced by a laser source because of the availability of a desired/required excitation wavelength laser source at a reasonable cost. LIF detection has been successfully applied for PAHs and BTXE-aromatics analysis in oil polluted soil samples [20] and for vapor detection of PAHs. [21] Recently, the technique has been successfully connected to other fluorescence techniques like excitation emission matrix fluorescence, synchronous fluorescence scan, chemometric techniques, etc.…”

“…EEMF has been successfully used for characterization of PAHs in polluted samples. [29,30] The photo-physical effects, which cannot be always ruled out in some field samples, make quantitative analysis of individual PAHs difficult. In this regards more researchers are focusing on combining EEMF with chemometric techniques for individual PAHs analysis in their mixtures.…”

Total synchronous fluorescence scan spectra of petroleum products

“…need tedious separation procedures for characterization of multicomponent/complex mixture systems. However fluorescence techniques have higher selectivity for such systems [1,2].…”

“…Therefore, the fluorescence properties of petroleum products have been studied intensively for devising fluorescence-based analytical methods [1,2,3,4,5,6]. For multifluorophoric samples at higher concentrations, despite the presence of factors such as light attenuation (LA), self-absorption, energy transfer (ET) and collisional quenching (CQ), it has been observed earlier that the use of right-angle sample geometry is capable of providing better analytical utility, as compared to front-face or 45°-angle sample geometry [6,7].…”

Spectral signatures of fluorescence and light absorption to identify crude oils found in the marine environment

“…To expand the knowledge of petroleum products, various techniques based on UVvisible, Infrared, Raman spectroscopy or chromatography have been used [4]- [8]. However, from among the various techniques, the most efficient method for highly complex structures seems to be fluorescence [9,10] due to its high sensitivity.…”