A system is described for monitoring the effluent water from the purification apparatus of ammunition plants. This system will give warning of any colored species, but is mainly valuable for detecting trinitrotoluene (TNT) at low levels (70 ppb). The heart of the system is a fluorescent-dyed quaternary ammonium ion-exchange resin which darkens in contact with TNT. The resin is irradiated with ultraviolet radiation and the fluorescent output Is monitored by a photomultiplier.T h e detection of T N T (2,4,6-trinitrotoluene) in effluent water from ammunition plants is necessary for controlling this pollutant (1). This paper describes a detection system which is presently usable a t 0.07 p p m and could be made more sensitive. T h e basis of the method is the absorption of T N T on a quaternary ammonium ion-exchange resin. T h e original thought was to absorb a fluorescent molecule on an ionic site and then the T N T on the same site. It was thought that the quenching of the fluorescence could be used to measure the TNT. As i t happened, the fluorescence was quenched, b u t probably only in t h e trivial sense that a colored product formed on the resin and filtered both the ultraviolet exciting light and t h e emitted light. This did turn out to be sensitive at low levels since t h e colored compounds are held on the surface of a resin bead and quickly form a n effective light filter.T h e reactions of TNT to give colored products are well known ( 2 , 3 ) . Reactions of T N T with quaternary amines are not known and indeed we saw no reaction in aqueous solution.However, it appears likely t h a t Meisenheimer anions are formed in the resins to give the dark colored products. Several structures, including dimers of two TNT molecules, have been suggested for Meisenheimer anions. Our major new evidence involves the strong binding of these colored species in the resin.Ammunition plants purify the effluent water with various absorbing columns and need methods to detect breakthrough. T N T is one of t h e more toxic materials as are some of its decomposition products in the so-called "pink water". These colored breakdown products also given a signal on the resins. Colorless organic compounds or inorganic ions will not be detected. EXPERIMENTALApparatus. The essentials of our apparatus (Figure 1) consist of the liquid flow system and an optical system for illuminating and viewing the beads immersed in the liquid system. This portion contains beads of commercial ion-exchange resin dyed with a fluorescent dye. Initially the beads glow brightly under UV irradiation and this glow is detected photometrically and registered on a strip chart recorder. T N T in the water causes the resin beads to darken on the surface and the measured light output immediately decreases.The flow system uses a Cole-Parmer Masterflo pump in which only Viton tubing touches the solution until it reaches the Pyrex ' Present address, Harvey Mudd College, Claremont, Calif. *Present address, California Institute of Technology, Pasadena. Calif.U-tube containi...
THE PSYCHOLOGIST may become involved in the detection and therapy of the child with a minimal brain dysfunction in a wide variety of situations. He performs an important role in the management of this syndrome, which manifests itself in behavioral disorders. Since it is identified through analysis of abnormal behavior, it is important that the psychologist have a general understanding of the detection and treatment of this syndrome. My intent here is to describe the minimal brain dysfunction syndrome and to present drug therapy as a tool in the management of the characteristic behavioral problems. The minimal brain dysfunction child is not uncommon. He causes many behavioral difficulties for his family, school personnel, and the professionals in psychology and medicine. Such a child seems to be in constant, purposeless activity. He is in perpetual motion. He is unable to concentrate. Although he is bright, he does poorly in school. He wants to have friends, but his companions avoid him. Because his behavior is abnormal, he is often unbearable to his parents, teachers, and playmates.A recent HEW study indicated that this syndrome is not restricted to any specific socioeconomic group or nationality but is found worldwide.' Although estimates vary among communities, it seems that moderate and severe disorders are found in approximately 3 out of 100 elementary school children. Another estimate states that this disorder affects 5 percent or more of the children in this country. As is true of a number of childhood disat NANYANG TECH UNIV LIBRARY on June 24, 2015 isc.sagepub.com Downloaded from
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