Fluorometric hydrocarbons

Hiltabrand [29] has investigated the fluorometric determination of polyaromatic aromatic hydrocarbons in seawater. 

Lin, E.L.C., S.M. Cornier, and R.N. Racine. 1994. Synchronous fluorometric measurement of metabolites of polycyclic aromatic hydrocarbons in the bile of brown bullhead. Environ. Toxicol. Chem. 13 707-715. 

When an analyte is fluorescent, direct fluorometric detection is possible by means of a spectrofluorometer operating at appropriate excitation and observation wavelengths. This is the case for aromatic hydrocarbons (e.g. in crude oils), proteins (e.g. in blood serum, in cow milk), some drugs (e.g. morphine), chlorophylls, etc. Numerous fields of applications have been reported analysis of air and water pollutants, oils, foods, drugs monitoring of industrial processes monitoring of species of clinical relevance criminology etc. 

Saxena et al. [512] used polyurethane foams to concentrate trace quantities of six representatives of polynuclear aromatic hydrocarbons (fluoranthene, benzo(k)fluoranthene, benzo(j)fluoranthene, benzo(a) pyrene, benzo(ghi) perylene, and indeno(l,2,3-cd)pyrene) prior to regular screening of these compounds in US raw and potable waters. Final purification and resolution of samples was by gas chromatography and two-dimensional thin layer chromatography, followed by fluorometric analysis and quantification. 

Molecular fluorescence spectrometry has long been regarded as a useful technique for the determination of polycyclic aromatic hydrocarbons (PAHs) and related materials, due to the very high sensitivities which can be achieved. However, molecular fluorescence spectra measured in liquid solution usually are broad and relatively featureless hence, spectral interferences are common in the liquid-solution fluorometric analysis of multicomponent samples. Moreover, the fluorescence of a particular component of a complex sample may be partially quenched by other sample constituents if quenching occurs to a significant extent, the fluorescence signal observed for a particular compound present at a particular concentration will also depend upon the identities and concentrations of other substances present in the sample. Under these conditions, it is virtually impossible to obtain accurate quantitative results. Therefore, it is generally observed that molecular fluorescence spectrometry in liquid solution media is useful for quantitative determination of individual components in complex samples only if the fluorescence measurement is preceded by extensive separation steps (ideally to produce individual pure compounds or, at worst, simple two- or three-component mixtures). 

Ci-Cs hydrocarbons and chlorophyll a analyses were performed on approximately 400 near-surface water samples 2m below the surface) during a one and half month cruise to the Equatorial Pacific Ocean. The hydrocarbons were determined by a flame ionization gas chromatograph. Chlorophyll a was determined fluorometrically. The objective was to determine if a correlation existed between the C2-C3 hydrocarbons and chlorophyll a in open ocean environments. A slight correlation was found between chlorophyll a and ethylene and propylene (R = 0.56). No correlation xjoas found between chlorophyll a and methane, ethane, or propane. 

A number of hydrocarbons were photolysed in a reaction vessel according to the system described by Prof. Wameck, MPI Mainz. Measurements were made with fluorometric and polarographic detection. The photolysis experiment were reproducible with a standard deviation of 3-6 %. Several hydroperoxides could be identifred by "cross"-identifications by comparing the retention times of different photolysed hydrocarbons, aldehydes, ketones and alcohol s with the unknown peaks. 

Abbreviations NADPH-cytochrome c reductase activity (P-450R), radiometric BPH assay (BPH-R), fluorometric BPH assay (BPH-F), 3-methylcholanthrene (3MC), benzo[a]pyrene (BaP), phenobarbital (PB), 3,4,3 4 -tetrachlorobiphenyl (3MC-type inducer) (3,4,3 4 -TCBP), 2,4,5,2 4 5 -hexachlorobiphenyl (non-coplanar PB-type inducer) (HCBP), j8-naphthoflavone (BNF), polyaromatic hydrocarbons (PAH), — (not determined). 

R. Tomingas, G. Voltmer, and R. Bednarik, Direct fluorometric analysis of aromatic polycyclic hydrocarbons on thin layer chromatograms, Set. Total Environ. 1, 261-267 (1977). 

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