New measurements of resonance ionization detection limits are presented for seven species, of high thermal stability, which are potentially useful surrogates for continuous emission monitoring of incinerator effluent. Resonance ionization detection limit data are now available for 20 aliphatic and aromatic compounds; eight of these compounds have sub part-per-billion detection limits. These eight also exhibit selectivities exceeding 10 3 when detected in the presence of a "soup" of chemically similar interferant species likely to be present in stack gas samples. Preliminary measurements indicate that detection limits, obtained under ideal conditions in a helium carrier gas, are also approached under adverse sampling conditions tested with synthetic "soups". The implications of these measurements on the selection of surrogates and the prospects for repetitive on-line hazardous emissions monitoring are discussed
Continuous monitoring techniques are needed for assurance that the stack gases of hazardous and municipal waste incinerators do not emit unacceptable levels of dangerous compounds. The development of suitable on‐line “real‐time” monitors may help answer current public concerns regarding the safety of thermal processing methods and may simplify the permitting process for new facilities. Recent research is reviewed which suggests that resonance ionization mass spectrometry is capable of real‐time monitoring of wide classes of toxic molecules at the part‐per‐billion level against complex backgrounds of interferant species. Recent advances in laser technology promise to make on‐line repetitive multispecies monitoring of hazardous emissions a practical reality.
WITH the recognition of the important part played by the soil colloidal frqction in determining various physical and chemical properties of a soil, more and more attention has been devoted to finding relationships between these properties and the composition of the soil colloidal fracl tion. The early investigations were restricted almost entirely to a study of the ultimate chemical composition of the soil colloids; but with the application of X-ra diffraction methods to soil investigation (Hendricks leading to a knowledge of the proximate composition of soil colloids was o ened to the soil investigator. With the use of X-ray technique, c R emical analysis, thermal methods, and optical methods, it has become possible not only to identify each mineral species present but also to determine quantitatively its amount in a sample.Because of the large range in rainfall, the small variations in temperature from one section to another, and the relatively small differences in the chemical composition of parent materials, soils formed in the Hawaiian Islands are ideal to use in a study of the role of rainfall in soil enesis. In this investigation an attempt is made to identif the minerakgical constituents present in soil colloids formed un J er Hawaiian weathering conditions. Two soils from Tahiti are included in this study. Until recently most of the investigations dealing with Hawaiian soil colloids have been confined to a study of their chemical com osition. fraction of several Hawaian soils. Hough and Byers (1937) have shown that extensive differences exist between the soil colloids developed under weathering conditions in Hawaii and those developed under conditions normally present in continental United States. In a recent publication Hough et al. 1941) have devoted considerable attention to the chemical In one of the first attempts at characterization of the mineral constituents present in Hawaiian soils, Kerr (1928), from equilibrium studies, has expressed the opinion that the alumino-silicate with cationexchange properties found in a Hawaiian soil is identical with that found in bentonite. KeMey and Pa e (1942) have claimed that a colloidal sample amorphous material ; while those obtained from Naalehu and South Point, Hawaii, contain a large amount of amor hous-appearing material. Their views are based on results obtained P rom X-ray analyses and * Published with the approval of the Director of the Hawaii Agricultural Experiment Station, Honolulu, T.H., as Technical Paper No. rgo. t The author wishes to express his appreciation to L. A. Dean and A. S. Ayres for some of the soil samples and for their helpful suggestions. The author is indebted to W. M. Eller for the ceramic clay sample. and Fry, 1930; Ke P ley et al., 1931), an entirely new avenue of approach McGeorge (1917) has reported on the chemical composition o P the clay analysis of co I loids from fourteen Hawaiian soils.from Aiea, Oahu, is mainly a aolinitic with some gibbsite or limonite and
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