Analysis of Aliphatic Hydrocarbons from Street Dust in Monmouth, IL Abstract Due to the carcinogenic nature and mutagenic potential of some polyaromatic hydrocarbons, such as Triphenylphosphine oxide (PPh3O or TPPO), street dust was collected from four separate locations around the city of Monmouth, Illinois, to be analyzed for these compounds. Each sample collection was washed to extract hydrocarbons for analysis qualitatively and quantitatively via Ultraviolet/Visible Spectroscopy (UV/Vis) and Gas
Chromatography/Mass Spectrometry (GC/MS), respectively. Data collected from UV/Vis showed absorbance peaks in the 200­400 nm range which is indicative of the presence of polyaromatic hydrocarbon compounds. GC/MS data indicated the presence of Icosane
(Eicosane), which is a petroleum derived fuel and TPPO, a polyaromatic compound commonly found in fertilizers. Introduction Street dust contains toxic hydrocarbons generated from the exhaust particles of automobiles.1 Unburnt fuel is released as aliphatic compounds which generally consist of low molecular weight hydrocarbons containing carbon and hydrogen joined together as straight chains, branched chains, or non­aromatic rings. Leaked crankcase oil from automobiles and tire wear on the road surface are common sources of the hydrocarbons in street dust.2 The urban atmospheric environment also contains many organic trace pollutants.3 Urban surfaces receive deposits issued from one or more remote sources such as vehicle emissions, industrial discharges, domestic heating, waste incineration and other anthropogenic activities. Deposits are also known to come from atmospheric transport as well as local human activities such as farming.4 The accumulation of polyaromatic hydrocarbons (PAHs) and aliphatic hydrocarbons in dust and soil may lead to the contamination of vegetation and food chains, resulting in direct or indirect exposure to humans.5 Some polycyclic aromatic hydrocarbons possess a carcinogenic nature as well as exhibit a mutagenic potential.8,6
The relative distribution of homologous n­alkanes provides insight into the potential origin of a sample. Alkanes of higher molecular weights originate from processes which produce homologues that range from approximately C12 to C40 carbons long.6 Four main factors which are affected include: high­temperature combustion fuels, fugitive emissions from oil residues, biogenic sources, and unburned fuels.7 Research shows that high molecular weight alkanes are in fact persistent in the environment; and due to this, alkanes may pose acute toxicity to different organisms that are exposed to them.6 However, due to the volatility and biodegradability of low molecular weight alkanes, they are less toxic. By analyzing street dust through GC/MS, one may

get an approximate idea of the distributions of aliphatic and aromatic hydrocarbons in city streets. This research specifically investigated the distribution of the various classes of hydrocarbons present in street dust collected from different locations around Monmouth, Illinois.
The viable source of samples are found in automobile exhaust, lubricating oils, and tire particles.8 The analysis and extraction of aliphatic and aromatic hydrocarbons was the primary focus. Samples were extracted using a modified version of a previously published extraction procedure.7 The extracted samples were then analyzed with Ultraviolet­Visible Spectroscopy
(UV/Vis) to detect any aromatic hydrocarbons within the wavelength region of 200­400 nm. An increased absorbance in the region of 200­400 nm is evidence towards the presence of aromatic hydrocarbons. Gas Chromatography­Mass Spectrometry (GC/MS), a technique known to prove useful for the analysis of aliphatic hydrocarbons, was used to identify the presence of aliphatic hydrocarbons within the sample extractions.9, 10
Herein, UV/Vis and GC/MS were used to determine the presence of aliphatic and
aromatic