Polycyclic Aromatic Hydrocarbon Analysis with the Mars Organic Analyzer Microchip Capillary Electrophoresis System

Abstract

The Mars Organic Analyzer (MOA), a portable microchip capillary electrophoresis (CE) instrument developed for sensitive amino acid analysis on Mars, is used to analyze laboratory standards and real-world samples for polycyclic aromatic hydrocarbons (PAHs). The microfabricated CE separation and analysis method for these hydrophobic analytes is optimized, resulting in a separation buffer consisting of 10 mM sulfobutylether-beta-cyclodextrin, 40 mM methyl-beta-cyclodextrin, 5 mM carbonate buffer at pH 10, 5 degrees C. A PAH standard consisting of seven PAHs found in extraterrestrial matter and two terrestrial PAHs is successfully baseline separated. Limits of detection for the components of the standard ranged from 2000 ppm to 6 ppb. Analysis of an environmental contamination standard from Lake Erie and of a hydrothermal vent chimney sample from the Guaymas Basin agreed with published composition. A Martian analogue sample from the Yungay Hills region of the Atacama Desert was analyzed and found to contain 9,10-diphenylanthracene, anthracene, anthanthrene, fluoranthene, perylene, and benzo[ghi]fluoranthene at ppm levels. This work establishes the viability of the MOA for detecting and analyzing PAHs in in situ planetary exploration.

Toxicogenomic Studies in Human Populations

“…The program supports the development of environmental sensors that measure the exposome (Wild, 2005) and "fingerprints" (markers) that measure the responsome, which together in the context of genetic risk comprise the emerging field of exposure biology. Improvements in the resolution and throughput of existing toxicogenomic assays and the development of newer technologies such as lab-on-a-chip systems (Stockton et al, 2009) are ongoing, and their increased application to exposed human populations should help elucidate the contribution of exposure to chronic disease.…”

Capillary Electrophoresis Analysis of Organic Amines and Amino Acids in Saline and Acidic Samples Using the Mars Organic Analyzer

“…The microdevices were prepared as previously described (Skelley and Mathies, 2003;Skelley et al, 2005Skelley et al, , 2006Stockton et al, 2009). In summary, a sacrificial layer of polysilicon was deposited via chemical vapor deposition on a 10 cm borofloat glass wafer.…”

“…A 3 mm deep polydimethylsiloxane gasket with 4 mm diameter wells was placed over the reservoir holes to allow for larger volume. A schematic of the microdevice has been published and is presented in Supplemental Data Stockton et al, 2009).…”

“…The Mars Organic Analyzer (Skelley et al, 2005) was used with minor modifications to the optical subsystem that allow for more sensitive analysis of amino acids Stockton et al, 2009). The 404 nm laser was passed through a dichroic and focused to a 10-20 mm spot in the channel approximately 0.6 cm from the cathode reservoir.…”

Implementation of microchip electrophoresis instrumentation for future spaceflight missions

“…ME-LIF is an extremely powerful tool to search for these nonstatistical distributions of molecular properties present in a sample, by separating a mixture into its components, identifying them, and quantifying their levels. ME-LIF has been used to investigate a variety of organics that can serve as biomarkers, including amines [31,32], amino acids [32,33], organic acids [34], aldehydes and ketones [35], nucleobases [36], polyaromatic hydrocarbons [37], fatty acids [38], and thiols [39]. Depending on the geochemical context of the sample analyzed, these molecular classes can inform us of the potential for biological processes in the location under study.…”