Polychlorinated Dibenzo-p-dioxin Analysis from Photodegradation of
Triclosan
Jason BrennanChem 4101, Fall 2010December 10th, 2010
TriclosanCommon antimicrobial agent
used in hand soaps and hygienic products
Estimated release of 22 metric tons per year into US waters[1]
Can become chlorinated from chlorine in wastewater transport or disinfection and photodegrade into polychlorinatedibenzo-p-dioxins (PCDDs)
Photolytic half-lives of approx. 1 day during Summer months[1] http://www.dialsoap.com/
liquid_hand_soap.html
Analytes (PCDDs)
Estimations are 1.06 μg/L in US waterways [1]
Half-lives in humans range from 3-8 years [2]
Concentrations of 2.5 μg/L have been shown to cause developmental defects in aquatic life [3]
1,2,8- and 2,3,7-trichlorodibenzo-p-dioxin (TCDD)1,2,3,8-tetrachlorodibenzo-p-dioxin (TeCDD)
PCDD Detection ProblemProblem:
Polychlorinated dibenzo-p-dioxins are hypothesized to be carcinogenic compounds and the 1,2,8- 2,3,7- and 1,2,3,8-PCDDs are hypothesized to be photodegredation products of triclosan
Hypothesis:Micellar electrokinetic chromatography modified
with γ-cyclodextrin with UV absorbance detection can be used to detect the analytes in river water samples.
Micellar Electrokinetic ChromotographyReasons:
Micelles allow for neutral species detection γ-cyclodextrin modification increases sensitivityRelatively low cost/sampleQuick sample runs
Swiss Laboratory for Doping Analyses [4]
Instrumentation Agilent 7300 CECost: $50,000Instrument Parameters[5]
Fused silica capillary 40 cm effective length 50 μm I.D. 375 μm O.D.
15 kV applied voltageUV photo diode array
detector (225 nm) “Z” cell path length for
increased sensitivity10 °CLOD 0.1 ppm (S/N=3)Dynamic Range
0.3 ppm-500 ppm
Sample PreparationAqueous Sample [1] Buffer solutions [5]5 ml aqueous river
samples extracted into n-hexanes or cyclohexane
Solvent extracted into methanol
Concentrated to minimal volume for instrumental analysis
100 mM Sodioum dodecyl sulfate
50 mM γ-cyclodextrin5 M ureapH buffer
50 mM borate (pH=9.0)50 mM phosphate
(pH=2.5)
Stock solutions of chlorinated dioxins for calibration curves and spiking can be obtained from Sigma-AldrichBuffer solutions can be purchased from Agilent
Acidic SRW-CD-MEKCSRW – stacking using reverse migrating
micelles and a water plugRequires low conductivity matrix with
surfactant concentration slightly higher than critical micelle concentration
Water plug with low pH is injected into the capillary followed by the sample solution
Allows for 200 times lower LOD than CD-MEKC (20 ppm down to 0.1 ppm)
Sample Data[5]
Normal CD-MEKC SRW-CD-MEKC
ConclusionSRW-CD-MEKC allows for decreased
retention time of PCDDs and dynamic range is lowered to levels predicted in river samples
MEKC analysis allows for reasonably priced quantitative analysis of these environmental pollutants
Once these PCDDs have been confirmed in river water samples further analysis could be done to determine degradation pathway using SRW-CD-MEKC method of detection
Other Potential MethodsAdvantage Disadvantage
HPLC [1] Low LODMany column/solvent combinations for maximum resolutionReproducible
Requires flow rate and solvent optimization
GC/MS [1,7] Low LODNon-destructiveReproducibleGives structural information
Results are qualitative not quantitativeRelatively expensive instrumentation
Infrared Spectroscopy [8]
FTIR can be used for quick measurementsGives structural information
Aqueous matrix makes IR difficultResults are qualitative not quantitative
Fluorescence High sensitivity and selectivity
PCDDs do not fluoresce due to heavy atom effect
References [1] Buth, J.M., Grandbois, M., Vikesland, P.J.*, McNeill, K.*, Arnold, W.A. 2009. Aquatic
photochemistry of chlorinated triclosan derivatives: potential source of polychlorodibenzo-p-dioxins. Environ. Toxicol. Chem., 28(12) 2555-2563
[2] Geyer HJ, Schramm KW, Feicht EA, et al (2002). "Half-lives of tetra-, penta-, hexa-, hepta-, and octachlorodibenzo-p-dioxin in rats, monkeys, and humans—a critical review". Chemosphere 48 (6): 631–44.
[3] Tisha C. King Heiden, Jan Spitsbergen, Warren Heideman, and Richard E. PetersonPersistent Adverse Effects on Health and Reproduction Caused by Exposure of Zebrafish to 2,3,7,8-Tetrachlorodibenzo-p-dioxin During Early Development and Gonad DifferentiationToxicol. Sci. (2009) 109(1): 75-87
[4] Swiss Laboratory for Doping Analyses. http://www.doping.chuv.ch/en/lad_home/lad-prestations-laboratoire/lad-prestations-laboratoire-appareils/lad-prestations-laboratoire-appareils-ec.htm . Accesses Dec. 6 2010.
[5] Koji Otsuka, Hirofumi Hayashibara, Sumio Yamauchi, Joselito P. Quirino, Shigeru Terabe, Highly-sensitive micellar electrokinetic chromatographic analysis of dioxin-related compounds using on-line concentration, Journal of Chromatography, Volume 853, Issues 1-2, 20 August 1999, Pages 413-420
[6] http://www.chem.agilent.com/en-US/Products/Instruments/electrophoresis/capillary/system/pages/default.aspx. Accessed December 7th 2010.
[7] {Sommer, S.; Kamps, R.; Schumm, S.; Kleinermanns K. F. GC/FT-IR/MS Spectroscopy of Native Polychlorinated Dibenzo-p-dioxins and Dibenzofurans Extracted from Municipal Fly-Ash. Analytical Chemistry, 69, 6, 1113-1118. 1997.
[8] Charles J. Wurrey, Donald F. Gurka, Billy J. Fairless, Robert D. Kleopfer, Applications of infrared spectroscopy to dioxin analyses of environmental samples, Chemosphere, Volume 18, Issues 1-6, Chlorinated Dioxins and Related Compounds, 1989, Pages 897-902