Cosmochemistry trace analysis

Magnetic sector ion microprobes are becoming increasingly important in isotopic analysis of extratenestrial materials as spot size decreases and the precision and accuracy of the measurements improve. The first of the commercially available ion microprobes used in cosmochemistry were the Cameca ims 3f-7f series machines, which initially became available in the mid-1980s. These multipurpose instruments are able to measure isotopic compositions of most elements of interest in cosmochemistry and can also be used to measure trace element abundances. Their main drawback is that the relatively small mass spectrometer can only be operated at mass-resolving powers below about 9000, and at this mass resolving power, the transmission of the mass spectrometer is very low. 

Twentieth-century chemistry has evolved into numerous subdisciplines closely connected with subdisciplines from the other sciences. Physical chemistry, chemical physics, biochemistry, clinical chemistry, and nuclear chemistry are well known examples. [1] The connections to the earth sciences and the astronomical sciences are much less known and have received relatively little historical attention. Yet these interdisciplinary fields are extremely rich and have histories that are rewarding subjects for the historian of science. The purpose of the present paper is to provide a historical introduction to what is currently known as cosmochemistry, or the chemistry of the universe. In one sense, this is a modern branch of science, established only in the 1950s, but it can be plausibly traced back to the late nineteenth century, if not earlier. It can even be argued that it dates back to about 1800, when meteorites were first subjected to chemical analysis. 

Analysis of extraterrestrial materials, and in particular meteorites, is an important focus of cosmochemical research, as such samples preserve chemical and isotopic records of early solar system conditions and processes. The first studies of meteorites, which recognized that such samples have an extraterrestrial origin, date back to the late eighteenth century [3], but modem research in cosmochemistry has a much more recent origin. This is traced back by many to the founder of contemporary geochemistry, V.M. Goldschmidt, as he produced early, but well-founded, compilations of cosmic element abundances, based on data acquired for meteorites [4, 5]. Goldschmidt s work was later continued and extended by Suess in collaboration with Urey and their study on the abundances of the elements [5] is still an important milestone in cosmochemistry. 

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