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Anionic Surfactant Detection

Anionic Surfactant Detection. In Aqueous Environments. John Raia Chem 4101 December 9 th , 2011. The Problem.

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Anionic Surfactant Detection

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  1. Anionic Surfactant Detection In Aqueous Environments John Raia Chem 4101 December 9th, 2011

  2. The Problem • In the Deep Water Horizon catastrophe that occurred Spring of 2010, over 1 million gallons of an undisclosed mixture of sulfonated anionic surfactants (Corexit®) were sprayed across the oil spill site to act as an oil dispersant agent. • Some specific anionic surfactants have known toxicities for various marine species (especially green algae, sea turtles, and dolphins). They are also known to havesevere respiratory and digestive issues in humans are suspected causers of human endocrine disruption. • Over time the migration of the surfactants could effect ecological systems many miles away from where they were originally introduced. § §Kerr, R. A. A Lot of Oil on the Loose, Not So Much to Be Found. Science 2010, 329, 734-735.

  3. Hypothesis • It is crucial to be able to identify specific anionic surfactants that are still present in aqueous environments. • Since migration of surfactants throughout aqueous sources is an issue, quick and effective methods of sampling, detection and characterizing surfactants is essential. • By monitoring the deaths of migrating aquatic species (i.e. dolphins and sea turtles) found around coastal shores, a direct correlation to the presence of anionic surfactants in water in that area hopefully can be made, and the contents can be analyzed both quantitatively and qualitatively. º ºNelson, Karen. One year later, Gulf oil disaster claims, questions unsettled http://www.duluthnewstribune.com/event/article/id/196672/ (accessed October 16th, 2011)

  4. Classification of Anionic Surfactant Species Classifications1 • Soaps : CnH2n+1COO-X • Alkyl Sulfates (AS) • Linear Alkylbenzene Sulfonates (LAS) and Secondary Alkyl Sulfonates (SAS) : Cn Hn+1SO3-X • Alkylether Sulfates (AES): CnH2+l-(OCH2CH2)n-OSO3X • Fluorinated: CnH2n-1OPO(OH)O-X • Dioctyl Sodium Sulfosuccinate (DOSS)* • 444.216 Da • CAS #: 577-11-7 • Molecular Formula: C20H37NaO7S • MP: 153–157 °C Approx. 1 million gallons of sulfonated surfactant mixture dispersedin 6.43 E 17 gallons of marine water. (detection limit from 1ppt to 3ppm) º Other standards for comparison can be purchased accordingly *Sigma-Aldrich. <http://www.sigmaaldrich.com/catalog/ProductDetail.do?D7=0&N5=SEARCH_CONCAT_PNO%7CBRAND_KEY&N4=D201170%7CALDRICH&N25=0&QS=ON&F=SPEC >(accessed Oct 26, 2011).

  5. Sampling and Extraction • Sampling • Costal regions • Beached migrating aquatic species with known toxicities • Sampled radially, with constant distance • Positive sampling for anionic surfactants should be resampled at varying depths • Solid Phase Extraction (C18 cartridge)2 Condition w/ MeOH and H2O 100 mL sample of seawater Frozen with 4% formaldehyde until analysis

  6. Possible Separation Methods

  7. Possible Detection Methods † YuxiuA. et al. Soft Matter. 2011, 7, 6873.

  8. Method of Choice: HPLC-MS • Reversed Phase Column (C18) • Gradient elution for lowering time of detection • Ion Trap Mass Spec • Atmospheric Ionization Source with ESI • Full scan mode • Fragmentations from 75 to 800 m/z • LOD – 0.00021 ug/L (1ppt = 1 ug/L)1 http://www.forumsci.co.il/HPLC/system.gif

  9. Equipment • Column: LiChristopher 100 RP-18 (Merck)(9) • 250mm x 2mm and 3um particle diameter • HPLC- Ion Trap MS (5) • Atmospheric pressure Chemical Ionization • Negative Ion Quadrupole Mode LCQ Fleet Ion Trap Mass Spectrometer from ThermoScientific

  10. Example Data(4)

  11. Conclusion • The methods that were proposed allow not only for the detection and presence anionic surfactants at low limits of detection that are needed for the study of anionic surfactants in the gulf, but also allow for differentiation of homologues as long as a standard comparison is present.

  12. References • (1) Olkowska, E.; Polkowska, Ż.; Namieśnik, J. Analytics of surfactants in the environment: problems and challenges. Chem. Rev. 2011, 111, 5667-5700.( • (2) Riu, J.; Eichhorn, P.; Guerrero, J. A.; Knepper, T. P.; Barceló, D. Determination of linear alkylbenzenesulfonates in wastewater treatment plants and coastal waters by automated solid-phase extraction followed by capillary electrophoresis–UV detection and confirmation by capillary electrophoresis–mass spectrometry. Journal of Chromatography A 2000, 889, 221-229. • (3) Alzaga, R.; Peña, A.; Ortiz, L.; Marı́a Bayona, J. Determination of linear alkylbenzensulfonates in aqueous matrices by ion-pair solid-phase microextraction–in-port derivatization–gas chromatography–mass spectrometry. Journal of Chromatography A 2003, 999, 51-60. • (4) Lara-Martín, P. A.; Gómez-Parra, A.; González-Mazo, E. Simultaneous extraction and determination of anionic surfactants in waters and sediments. Journal of Chromatography A 2006, 1114, 205-210. • (5) Petrovic, M. Determination of anionic and nonionic surfactants, their degradation products, and endocrine-disrupting compounds in sewage sludge by liquid chromatography/mass spectrometry. Anal. Chem. 2000, 72, 4560. • (6) Poppe, A. Negative-ion mass spectrometry. X. A spurious [CH5]- ion: problems with negative chemical-ionization quadrupole instrument. Org. Mass Spectrom. 1986, 21, 59. • (7) Boiani, J. Spectator ion indirect photometric detection of aliphatic anionic surfactants separated by reverse-phase high-performance liquid chromatography. Anal. Chem. 1987, 59, 2583. • (8) An, Y.; An, Y. Disassembly-driven colorimetric and fluorescent sensor for anionic surfactants in water based on a conjugated polyelectrolyte/dye complex. Soft matter 2011, 7, 6873. • (9) LiChrospher® 100 RP-18 and RP-18 Endcapped | Merck Chemicals International http://www.merck-chemicals.com/lichrospher-100-rp-18-and-rp-18-endcapped/c_DMOb.s1LSAoAAAEWsOAfVhTl (accessed 11/11/2011, 2011).

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