SOLID-PHASE MICROEXTRACTION WITH TEMPERATURE-PROGRAMMED DESORPTION FOR THE ANALYSIS OF IODINATION DISINFECTION BY-PRODUCTS

An analytical approach for the determination of chlorination and iodin ation disinfection byproducts based on solid-phase microextraction (SP ME) was developed, Solid-phase microextraction presents a simple, rapi d, sensitive, and solvent-free approach to sample preparation in which analytes in either air or water matrixes are extracted into the polym eric coating of an optical fiber. Analytes are subsequently thermally desorbed in the injection port of a gas chromatograph for separation, detection, and quantitation, Thermal degradation of iodoform was obser ved during desorption from a polyacrylate fiber in initial GC/MS and G C/ECD experiments, Experiments were designed to determine SPME conditi ons that would allow quantification without significant degradation of analytes. Isothermal and temperature-programmed thermal desorptions w ere evaluated for efficacy in transferring analytes with wide-ranging volatilities and thermal stabilities into chromatographic analysis col umns, A temperature-programmed desorption (TPD) (120-200 degrees C at 5 degrees C/min with an on-column injection port or 150-200 degrees C at 25 degrees C/min with a split/splitless injection port) was able to efficiently remove analytes with wide-ranging volatilities without ca using thermal degradation, The SPME-TPD method was linear over 2-3 ord ers of magnitude with an electron capture detector and detection limit s were in the submicrogram per liter range, Precision and detection li mits for selected trihalomethanes were comparable to those of EPA meth od 551. Extraction efficiencies were not affected by the presence of 1 0 mg/L soap, 15 mg/L sodium iodide, and 6000 mg/L sodium thiosulfate, The SPME-TPD technique was applied to the determination of iodination disinfection byproducts from individual precursor compounds using GC/M S and to the quantitation of iodoform at trace levels in a water recyc le system using GC/ECD.