Simple spectrofluorometry methods for estimating petroleum hydrocarbons levels in various sea benthic organisms

Abstract

An analytical evaluation of three modifications of simple spectrofluorometry method applied on nummerous benthic biota samples collected from the North Adriatic Sea was described. The concentrations of petroleum hydrocarbons were measured and calculated after extraction of biota samples. drying extract and concentrated to appropriate volume. Such calculated concentrations of petroleum hydrocarbons in samples in equivalents of Kuwait oil are called “before cleaning”. After fluorescence measuring, the extract is applied to column holding alumina; elution was performed with benzene in n-pentane. Fluorescence and concentrations of petroleum hydrocarbons calculated after alumina cleaning of extract arc called “after alumina cleaning” modifications. To evaluate and accordingly correct the quenching is possible by using the standard addition method and it is “standard addition” modifications. Known volume of alumina cleaned extract is diluted by the addition of n-hexane until the fluorescence of the sample extract is similar to the fluorescence of Kuwait crude oil concentration between I and 4 μg cm −3 in n-Hexane. Fluorescence and concentrations of petroleum hydrocarbons in biota samples calculated after the alumina cleaning of the extract and appropriate dilution are called “after dilution” modifications. There are no statistically significant differences between the concentrations of the petroleum hydrocarbons in the investigated samples obtained with “before cleaning” method and all three modifications in the sample concentrations lower than 6.6, PPM. But in higher concentration ranges, “after cleaning”, and especially “dilution” and “standard addition” modifications, show statistically significantly higher results in comparison with the simple “before cleaning” procedure.