Archaeological Chemistry II Advances in Chemistry Series No. 171 Giles F. Carter, Editor Eastern Michigan University A symposium sponsored by the Division of the History of Chemistry of the American Chemical Society. Beautifully illustrated with 15 color plates and printed on high-quality enameled stock, this book highlights the great strides that have been made in under standing the origin and distribution of archaeological specimens composed of pottery, glass, metal, bone, and pitch, through the unfolding of new and improved analytical techniques. Emphasis is on the historical knowledge derived from the chemical analysis and investigation of various artifacts including South American dyes, Egyptian glass, ancient Near Eastern ivory, Spanish ceramics, Chinese bronzes, prehistoric American copper, and copper-based Roman coins. CONTENTS Perspectives and General Techniques: Chemistry and Archaeology · Conservation of Archaeological Materials · Radiocarbon Dating · Spark Source Mass Spectrometry · Applications of X-Ray Radiography · Organic Materials: Trace Element Analysis in Bone · Amino Acid Analysis in Radiocarbon Dating of Bone Collagen · Amino Acid Racemization Dating of Bone and Shell · Ancient Near Eastern Archaeological Ivory Artifacts · Asphalts from Middle Eastern Sites · The Identification of Dyes in Textiles · Ceramics: Analysis of Early Egyptian Glass · Spanish and SpanishColonial Majolica Ceramics · Soapstone Artifact Characterization · Atomic Absorption Spectroscopy of Archaeological Ceramic Materials «Metals: Lead Isotope Ratios in the Manufacture of Pigments · Lead Isotope Analyses and Sources of Nigerian "Bronzes" · Ancient Chinese Bronze Compositions · Prehistoric Copper Artifacts · Chemical Compositions of Copper-Based Roman Coins
389 pages (1978) Clothbound $46.00 LC 78-26128 ISBN 0-8412-0397-0 No. 138 Archaeological Chemistry I 254 pages (1974) Clothbound $29.00 SIS/American Chemical Society 1155 16th St., N.W./Wash., D.C. 20036 Please send the following: Archaeological Chem. I (ACH 0211 -7) $29.00 ea
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al detectors. Because atomic spec trometry detectors are metal specific, chromatograms should contain only peaks which are readily attributable to the metal compounds of interest. This is true as long as there are no atomic spectral or nonspecific inter ferences. In contrast to emission spec trometry, atomic absorption and fluo rescence spectrometry have relatively simple patterns of atomic spectral in terference. On the basis of this criteri on, the latter techniques are to be pre ferred as detectors for routine metal compound analysis by chromatog raphy. Nonspecific interferences, i.e., light scatter and molecular absorption with atomic absorption and light scatter and molecular fluorescence with atom ic fluorescence, can cause serious error. T h e most likely source of these problems in chromatographic systems is the solvent peak in gas chromatog raphy or the elution of refractory sub stances. With flame atomic absorp tion, nonspecific interferences are minimal. When electrothermal atom izers are used with atomic absorption, continuous background correction must usually be employed. Light scat ter can be a serious source of error in both flame and electrothermal nondispersive atomic fluorescence. Unfortu nately, scatter correction is not as straightforward in atomic fluorescence as in atomic absorption. However, the present author has obtained adequate background compensation by measur ing the scatter of radiation from a lamp such as Au, (i.e., of an element not present in the sample). No pres ently available method of background correction will compensate for molec ular absorption when a component of the fine structure directly overlaps with the analyte line. Fortunately the likelihood of the latter problem is very small; no substantiated cases have yet been reported in chromatographic ap plications. Applications In the following, applications will be presented which illustrate the areas of applicability and the power of metal specific detectors. No a t t e m p t will be made to comprehensively re view all the applications in the litera ture. To date there have been in the neighborhood of 150 publications on the use of metal specific detectors with chromatography. These have been in the fields of occupational health and environmental, biological, clinical, and agricultural sciences. A variety of elements have been studied with the gas chromatographymicrowave emission spectrometry de tector including Hg, Cu, Al, Fe, Be, As, Sb, P, S, Br, CI, I, H, C, and Ν
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(22). Of these P, S, Br, CI, I, H, C, and Ν cannot be done by either atomic ab sorption or fluorescence spectrometry. T h e direct current argon plasma emission detector has been used in the gas chromatographic study of cyclopentadienylmanganese tricarbonyl in nonleaded gasolines (24). T h e limit of detection of the compound was 3 ng and a relative standard deviation of 0.8 to 3.4% was obtained. Determi nation of this compound in ambient air will be very important in future studies of air pollution resulting from the automobile. Biomethylation of arsenic was stud ied by Braman and Foreback (25) using an arc emission technique. T h e detection limit in various environmen tal samples was 0.5 ng for the methylarsenic acids. T h e phenomenon of biomethylation of metals was clearly demonstrated to be a serious hazard in the case of mercury. Recent work with arsenic and other metals suggests the existence of a much more wide spread threat. Only one application of atomic fluo rescence spectrometry as a detector for chromatography has been reported (10). T h e simultaneous detection of Cu, Zn, and Ni glycines, and EDTA's and copper trien was recorded. Atomic fluorescence detection has since been used for the simultaneous determina tion of P b and Cd alkyls in gasoline (26). Of the detectors discussed in this paper, atomic absorption spectrome try is finding more widespread accep tance for metal speciation studies. Some of the more interesting gas chro matographic applications include in vestigations of biomethylation of Hg (6), Se (17), and P b (27). In related work, mercury compounds have been studied in fish (4), alkyllead com pounds in gasoline (28), biological ma terials (2,9) and ambient air (19), and selenium compounds in plant transpi ration gases (16). Arsenic compounds have been analyzed in water (30) and mixtures of arsenicals (31). Typical of the good detection limits obtainable in these studies is a value of 0.5 ng/m ;! for each of the lead alkyls in ambient air (19). Chromium, particularly the carcino genic hexavalent forms, has been de termined in natural waters (1, 32), li quified coal and shale (3.3). Zinc com pounds have been studied in plant tis sue extracts (34). Gasoline has been analyzed for lead compounds (35). Copper chelates of NTA, EDTA, KGTA, and CDTA have been sepa rated and determined (36). Conclusion
Metal specific detectors for chroma tography are indispensible tools in the investigation of metal compounds in
