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An Example of the Application of Analytical Chemistry to Environmental Science Tongwen Wang Virginia State University May 5th, 2016 Analytical Chemistry Chemical Analysis Instrumental Analysis Gas Chromatography (GC) High Performance Liquid Chromatography (HPLC) Mass Spectrometry (MS) Key Ideas in Water Treatment Transformation Processes Biological Abiotic (Oxidative, reductive, hydrolytic, etc) vs. Removal Processes Destructive Partitioning • Solid phase • Liquid phase • Gas phase Typical Oxidants Used in Water Treatment • Free chlorine (FC): ClO¯ • Monochloroamine (MCA): HOCl + NH3 NH2Cl + H2O • Chlorine dioxide (ClO2): produced using a Bench-Scale ClO2 Generator • Ozone (O3): generated using a Model GLS-1 PCI-WEDECO ozone generator from compressed oxygen • Hydrogen peroxide (H2O2) • Permanganate (MnO4¯) • UV: A 254-nm low-pressure mercury-vapor lamp System 1: Diazinon • Commonly used as a pesticide since 1952. • Inhibition of the acetylcholinesterases of most kinds of insects. • Also affect the nervous systems of humans. • Degradation by free chlorine (FC), hydrogen peroxide (H2O2), monochloroamine (MCA), UV, chlorine dioxide (ClO2) and ozone (O3). Extracted ion chromatograms at (a) m/z 289 and (b) m/z 153 Mass Spectrum of (a) Diazoxon (MW: 288) and (b) IPMP (MW: 152) Pathway of oxidation of diazinon System 2: Fonofos • To control lepidopterous insects • Interferes with the nervous system by inhibiting cholinesterase • FC, H2O2 and permanganate oxidation were carried out Total ion chromatograms of free chlorine and H2O2 oxidation of fonofos at pH 7.0 Mass spectra for (a) fonofos (MW: 246) and (b) unknown Pathway of oxidation of fonofos LC/UV and GC/MS Analysis of Hydrolysis Byproducts of Fonofos A. Reaction mixture analyzed with direct injection into HPLC/UV system after spiking of internal standard. B. Reaction mixture extracted into hexane followed by GC/MS analysis. UV spectra of fonofos hydrolysis product and thiophenol standard extracted at the retention time of the corresponding peaks (a) GC/MS TIC of fonofos hydrolysis; (b) Mass spectra of fonofos hydrylate and in the data base Pathway of Fonofos hydrolysis System 3: Aldicarb Structure of Aldicarb Sulfoxide and Aldoxycarb TICs of Aldicarb standard and byproducts under various oxidation systems TICs of Aldoxycarb standard and its oxidation byproduct under FC oxidation system Mass spectrum of the unknown in the oxidation of Aldoxycarb under FC oxidation system Summary for Oxidation of Aldicarb Acknowledgement Dr. Yinfa Ma Dr. Craig D. Adams Dr. Paul Ki-souk Nam Dr. Klaus Woelk Dr. Honglan Shi Financial Support Awwa Research Foundation (project 3170) Thank You!