Identification of photocatalytic degradation products of diazinon in TiO2 aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

  • Vasilis N. Kouloumbos
  • Despina F. TsipiEmail author
  • Anastasia E. Hiskia
  • Dejan Nikolic
  • Richard B. van Breemen


The photocatalytic degradation of the organophosphorus insecticide diazinon in aqueous suspensions has been studied by using titanium dioxide as a photocatalyst. The degradation of the insecticide was a fast process and included the formation of several intermediates that were identified using GC/ion-trap mass spectrometry with EI or CI in positive and negative ionization mode and HPLC/electrospray-QqTOF mass spectrometry. Since primarily hydroxy derivatives were identified in these aqueous suspensions, the mechanism of degradation was probably based on hydroxyl radical attack. The initial oxidative pathways of the degradation of diazinon involved the substitution of sulfur by oxygen on the P=S bond, cleavage of the pyrimidine ester bond, and oxidation of the isopropyl group. Exact mass measurements of the derivatives allowed the elemental formula of the molecules to be determined confidently. Similarities to the metabolic pathways occurring in living organisms were observed.


Diazinon Isopropyl Group Diazi Exact Mass Measurement Pyrimidine Moiety 
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  1. 1.
    Dubus, I.; Hollis, J.; Brown, C. Pesticides in Rainfall in Europe. Env. Pollut. 2000, 110, 331–344.CrossRefGoogle Scholar
  2. 2.
    Garcia, S.; Ake, C.; Clement, B.; Huebuer, H.; Donnelly, K.; Shalat, S. Initial Results of Environmental Monitoring in the Texas Rio Grande Valley. Environ. Int. 2001, 26, 465–474.CrossRefGoogle Scholar
  3. 3.
    Albanis, T.; Hela, D.; Sakellarides, T.; Konstantinou, I. Monitoring of Pesticide Residues and Their Metabolites in Surface and Underground Waters of Imathia (N. Greece) by Means of Solid-Phase Extraction Disks and Gas Chromatography. J. Chrom. A 1998, 823, 59–71.CrossRefGoogle Scholar
  4. 4.
    Bailey, H.; Deanovic, L.; Reyes, E.; Kimball, T.; Larson, K.; Cortright, K.; Connor, V.; Hinton, D. Diazinon and Chlorpyrifos in Urban Waterways in Northern California, USA. Environ. Toxicol. Chem. 2000, 19, 82–87.CrossRefGoogle Scholar
  5. 5.
    Bailey, H.; Kraddoi, R.; Elphick, J.; Mulhall, A.; Hunt, P.; Tedmanson, L.; Lovell, A. Whole Effluent Toxicity of Sewage Treatment Plants in the Hawkesbury-Nepean Watershed, New South Wales, Australia, to Ceriodaphnia dubis and Selenastrum capricornutum. Environ. Toxicol. Chem. 2000, 19, 72–81.Google Scholar
  6. 6.
    Roberts, T.; Hutson, D., Eds. in Chief.; Metabolic Pathways of Agrochemicals—Part 2: Insecticides and Fungicides; RSC: UK, 1999, pp 258–263.Google Scholar
  7. 7.
    Diazinon cancellation order 4/01, EPA2001Google Scholar
  8. 8.
    Ku, Y.; Chang, J. Effect of Solution pH on the Hydrolysis and Photolysis of Diazinon in Aqueous Solution. Water Air Soil Pollut. 1998, 108, 445–456.CrossRefGoogle Scholar
  9. 9.
    Mansour, M.; Feicht, E.; Behechti, A.; Schramm, K.-W.; Kettrup, A. Determination Photostability of Selected Agrochemicals in Water and Soil. Chemosphere 1999, 39, 575–585.CrossRefGoogle Scholar
  10. 10.
    Scheunert, I.; Mansour, M.; Dorfler, U.; Schroll, R. Fate of Pendimethalin, Carbofuran, and Diazinon under Abiotic and Biotic Conditions. Science Total Environ. 1993, 132, 361–369.CrossRefGoogle Scholar
  11. 11.
    Lacorte, S.; Lartiges, S.; Garrigues, P.; Barcelo, D. Degradation of Organophosphorus Pesticides and Their Transformation Products in Estuarine Waters. Environ. Sci. Technol. 1995, 29, 431–438.CrossRefGoogle Scholar
  12. 12.
    Mills, A. Le; Hunte, S. An Overview of Semiconductor Photocatalysis. J. Photochem. Photobiol. A. Chem. 1997, 108, 1–35.CrossRefGoogle Scholar
  13. 13.
    Fujishima, A.; Rao, T.; Tryk, D. Titanium Dioxide Photocatalysis. J. Photochem. Photobiol. A. Chem. 2000, 1, 1–21.CrossRefGoogle Scholar
  14. 14.
    Muszkat, L.; Bir, L.; Feigelson, L. Solar Photocatalytic Mineralization of Pesticides in Polluted Waters. J. Photochem. Photobiol. A. Chem. 1995, 87, 85–88.CrossRefGoogle Scholar
  15. 15.
    Guillard, C.; Pichat, P.; Huber, G.; Hoang-Van, C. The GC-MS Analysis of Organic Intermediates from the TiO2 Photocatalytic Treatment of Water Contaminated by Lindane (1α,2α,3β,4α,5α,6β-hexachlorocyclohexane). J. Adv. Oxid. Technol. 1996, 1, 53–60.Google Scholar
  16. 16.
    Topalov, A.; Molnar-Gabor, D.; Kosanic, M.; Abramovic, B. Photomineralization of the Herbicide Mecoprop Dissolved in Water Sensitized by TiO2. Water Res. 2000, 34, 1473–1478.CrossRefGoogle Scholar
  17. 17.
    Herrmann, J. -M.; Guillard, C.; Arguello, M.; Aguera, A.; Tejedor, A.; Piedra, L.; Fernandez-Alba, A. Photocatalytic Degradation of Pesticide Pirimiphos-Methyl. Determination of the Reaction Pathway and Identification of Intermediate Products by Various Analytical Methods. Catal. Today 1999, 54, 353–367.CrossRefGoogle Scholar
  18. 18.
    Hiskia, A.; Mylonas, A.; Papaconstantinou, E. Comparison of the Photoredox Properties of Polyoxometallates and Semiconducting Particles. Chem. Soc. Rev. 2001, 30, 62–69.CrossRefGoogle Scholar
  19. 19.
    Mak, M.; Hung, S. Degradation of Neat and Commercial Samples of Organophosphate Pesticides in Illuminated TiO2 Suspensions. Toxicol. Environ. Chem. 1992, 36, 155–168.CrossRefGoogle Scholar
  20. 20.
    Mas, D.; Hisanaga, T.; Pichat, P. Photoatalytic Degradation of the Pesticides Asulam and Diazinon in TiO2 Aqueous Suspensions. Trends Photochem. Photobiol. 1994, 3, 467–479.Google Scholar
  21. 21.
    Meijers, R.; Oderwaldmuller, E.; Nuhn, P.; Kruithof, J. Degradation of Pesticides by Ozonation and Advanced Oxidation. Ozone-Sci. Eng. 1995, 17, 673–686.Google Scholar
  22. 22.
    Doong, R.; Chang, W. Photoassisted Titanium Dioxide Mediated Degradation of Organophosphorus Pesticides by Hydrogen Peroxide. J. Photochem. Photobiol. A. Chem. 1997, 107, 239–244.CrossRefGoogle Scholar
  23. 23.
    Hasegawa, K.; Kanbara, T.; Kagaya, S. Photocatalyzed Degradation of Agrochemicals in TiO2 Aqueous Suspensions. Denki Kagaku 1998, 66, 625–634.Google Scholar
  24. 24.
    San, N.; Hatipoglu, A.; Kocturk, G.; Cinar, Z. Photocatalytic Degradation of 4-Nitrophenol in Aqueous TiO2 Suspensions: Theoritical Prediction of the Intermediates. J. Photochem. Photobiol. A. Chem. 2002, 146, 189–197.CrossRefGoogle Scholar
  25. 25.
    Calza, P.; Pelizzetti, E.; Brussino, M.; Baiocchi, C. Ion Trap Tandem Mass Spectrometry Study of Dexamethasone Transformation Products on Light Activated TiO2 Surface. J. Am. Soc. Mass Spectrom. 2001, 12, 1286–1295.CrossRefGoogle Scholar
  26. 26.
    D’Oliveira, J.; Minero, C.; Pelizzetti, E.; Pichat, P. Photodegradation of Dichlorophenols and Trichlorophenols in TiO2 Aqueous Suspensions: Kinetic Effects of the Positions of the Cl Atoms and Identification of the Intermediates. J. Photochem. Photobiol. A 1993, 72, 261–267.CrossRefGoogle Scholar
  27. 27.
    Stan, H.; Kellner, G. Negative Chemical Ionization Mass Spectrometry of Organophosphorus Pesticides. Biomed. Mass Spectrom. 1982, 9, 483–492.CrossRefGoogle Scholar
  28. 28.
    Lopez-Avila, V. Mass Spectral Fragmentation of Diazinon and Diazinon-d10 under Electron Impact. Org. Mass Spectrom. 1985, 20, 530–532.CrossRefGoogle Scholar
  29. 29.
    Mucke, W.; Alt, K.; Esser, H. Degradation of 14C-Labeled Diazinon in the Rat. J. Agri. Food Chem. 1970, 18, 208–212.CrossRefGoogle Scholar
  30. 30.
    Miyazaki, H.; Tojinbara, I.; Watanabe, Y.; Osaka, T.; Okui, S. Studies on Metabolism of Diazinon [O,O-Diethyl-O-(2-Isopropyl-4-Methyl-6-Pyrimidinyl)Phosphorothioate] in Animals and Plants. Proceedings of the First Symposium on Drug Metabolism Action; Chiba, Japan, 1970; pp 135–138Google Scholar
  31. 31.
    Janes, N.; Machin, A.; Quick, M.; Rogers, H.; Mundy, D.; Cross, A. Toxic Metabolites of Diazinon in Sheep. J. Agri. Food Chem. 1973, 21, 121–124.CrossRefGoogle Scholar
  32. 32.
    Atkinson, R.; Aschmann, S.; Arey, J.; McElroy, P.; Winer, A. Product Formation from the Gas-Phase Reactions of the OH Radical with (CH3O)PS and (CH3O)2P(S)SCH3. Environ. Sci. Technol. 1989, 23, 243–244.CrossRefGoogle Scholar
  33. 33.
    Yang, R.; Hodgson, E.; Dauterman, W. Metabolism in Vitro of Diazinon and Diazoxon in Rat Liver. J. Agri. Food Chem. 1971, 19, 10–13.CrossRefGoogle Scholar
  34. 34.
    Machin, A.; Rogers, H.; Cross, A.; Quick, M.; Howells, L.; Janes, N. Metabolic Aspects of the Toxicology of Diazinon I. Hepatic Metabolism in the Sheep, Cow, Pig, Guinea-Pig, Rat, Turkey, Chicken, and Duck. Pesticide Sci. 1975, 6, 461–473.CrossRefGoogle Scholar
  35. 35.
    Shishido, T.; Fukami, J. Enzymatic Conjugation of Diazinon with Glutathione in Rat and American Cockroach. Pesticide Biochem. Physiol. 1972, 2, 39–50.CrossRefGoogle Scholar

Copyright information

© American Society for Mass Spectrometry 2003

Authors and Affiliations

  • Vasilis N. Kouloumbos
    • 1
  • Despina F. Tsipi
    • 1
    Email author
  • Anastasia E. Hiskia
    • 2
  • Dejan Nikolic
    • 3
  • Richard B. van Breemen
    • 3
  1. 1.Pesticide Residues LaboratoryGeneral Chemical State LaboratoryAthensGreece
  2. 2.Institute of Physical Chemistry NCSR “Demokritos”AthensGreece
  3. 3.Department of Medicinal and PharmacognosyUniversity of Illinois College of PharmacyChicagoUSA

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