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A modified Grob closed‐loop‐stripping device is currently being used to concentrate organic contaminants from drinking water. The identification and quantification of organic contaminants at the nanogran per litre (part‐per‐trillion) level are accomplished by a computerized glass capillary gas chromatography–mass spectrometry system. Applications of closed‐loop‐stripping analysis (CLSA) for monitoring water by water utilities, for studying the use and effects of alternative disinfectants in drinking water, and for providing data on the removal of organic contaminants from water by granular activated carbon (GAC) treatment are discussed. An attempt to validate the method using statistical computations is also included.

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very slow induced decomposition of cumene hydroperoxide was reported to occur with AIBN.19 Competitive Reactions.-Competitive autoxidations were carried out with an equimolar mixture of two substituted isopropylbenzenes (each ca. 1.2-0.6 M ) in chlorobenzene at 60' in the presence of AIBN (0.26-0.09 M ) . Aliquots (each 1 ml) were taken out at appropriate intervals of time and reduced with 15% KSH in aqueous methanol. After completion of reduction, the solution was washed with water, extracted with two 4-ml portions of chloroform, and analyzed by means of glpc. The products were analyzed by a Yanagimoto gas chromatograph with a flame ionization detector, Model GCG-%OF, employing (19) J. A. Howard and K. U. Ingold, Can. J . Chem., 46, 2655 (1968). a 1.0 m X 2.5 mm column packed with Apiezon Grease (5%) on Chamelite CS of 80-100 mesh using NS as a carrier gas at 160-220'. The internal standards for glpc were nitrobenzene for cumene and m-diisopropylbenzene for isopropylcumyl hydroperoxide End isopropylcumyl alcohol. The relative rate constants of competitive oxidation were calculated from the equation k = km/k, = log [ ( b -y)/b]/log[(a -%)/a]. Here, a and b are initial concentrations of substrates and 5 and y are corresponding concentrations a t time t.Acknowledgment. -The authors wish to thank Dr. RII. Yamashita for his helpful advice in performing these experiments.