Analytical Chemistry August 1955 [antikvár]

ANALYTICAL CHEMISTRY WALTER J. MURPHY, Editor Trace Analysis "IT/HERE very small quantities of materials are determined or detected, we soon ' ' find that we are faced with unique problems. The samples used are generally quite large relative to the amount of material being determined, and this presents problems of separating the wanted from the unwanted. There can be, of course, definite difficulties in sampling if uniformity is absent. Furthermore, the elements or compounds sampled are most often in concentrations of parts per million or parts per billion, and they may be of known composition, or the traces may have to be identified before a method can be developed for their quantitative determination. Trace materials and analytical methods for their study are rather taken for granted in catalytic, nutrition, and biochemical research. Air pollution studies until recently have been largely educated guesses as to what materials and concentrations were causing the pollution. Stream pollution studies are about at the same stage of development. The programs for air pollution research have been centered largely around analytical research to perfect methods for rapid surveys to better define the problems and so determine what measures can be taken to correct conditions. Air pollution has been the subject of much discussion in the lay press and in scientific circles, and because the air we breathe is the concern of everyone of us, the laws passed and the money spent can be subject to much unscientific bias. Air pollution can be caused by liquids, gases, and solids as such, or in various combinations, so that the problem is exceedingly complex. Odor may be present and may be from a harmful or harmle.ss compound. Lack of odor is not a sign of healthful air. It is to the credit of the various groups concerned with these studies that analytical tools are recognized to be of prime importance in collecting data from which scientific conclusions can be drawn and later legislation enacted. It will be the responsibility of the analyst to monitor conditions to see that laws are not broken. It is also encouraging to see that many instruments are of the recording type so that 24-hour records of contaminants can be carried out. Here infrared, ultraviolet, mass spectrometry, and the automatic counting of dust particles are all used in the analytical program. In both stream and air pollution the biochemist and biologist play a leading role in their studies of the effect of trace materials on life. The public naturally clamors for action, but it is better to spend the millions which will be spent on control by industry for those conditions which are actually causing health hazards.