Chapter 4 – Tests for the Elements, their Ions and Compounds

A history of pest control measures in the anthropology collections, national museum of natural history, smithsonian institution

Abstract: Since the mid-19th century, various pest eradication techniques have been employed on the anthropology collections at the National Museum of Natural History, Smithsonian Institution. These techniques are reviewed, and pesticide and fumigant use by early collectors and later collections management staff is documented. Also chronicled are the ways in which the choice of chemicals has changed over the years and the decisions that led to those changes. The effects of pest eradication techniques on the collections are discussed, and the author's findings are offered as the basis for further research.

The characterization of pigments based on carbon

Abstract: A primary classification of carbons is into crystalline and non-crystalline forms. The only crystalline carbon encountered as a pigment is graphite; a secondary classification for non-crystalline forms is into flame carbons (formed in the gas phase), cokes (formed in a liquid or plastic phase), chars (formed entirely in the solid phase) and natural forms such as coal. The main features, molecular structures and physical and chemical properties of these carbon types, so far as they are relevant to pigment studies, are reviewed in outline. Some better-known pigments based on carbon are summarized, with an indication of which form or forms of carbon each contains. X-ray diffraction patterns for graphites, and for examples of the non-crystalline types, are described and discussed. Particle morphology of various carbons and pigments, as elucidated from scanning electron micrographs, is described in some detail, and notes are added on the use of optical microscopy in studying these materials.

‘Lead white’ in Japanese paintings

Abstract: Japanese paintings of the twelfth to the sixteenth centuries in the collection of the Freer Gallery of Art has been determined. In 12 out of 13 Chinese paintings, and in all three Korean paintings, basic lead carbonate (lead white) was found. Of the 29 Japanese paintings, six had basic lead carbonate, 20 had basic lead chloride (which occurred as two different compounds), and two carried both of these species. One Chinese painting had lead sulphate and one Japanese painting lead phosphate. Historical evidence suggests that two forms of 'lead white' were known and distinguished during the eighth century in Japan; the possible connection between this and the present findings on Japanese paintings is discussed.

Narration and Legacy of Important Chemical Spot Tests in Forensic Investigation.

Abstract: Chemical spot tests are one of the oldest and simplest presumptive methods of analytical chemistry. They are an integral part of the schematic analysis of different types of substances in various pure and applied scientific disciplines including forensic science. The role of spot tests has remained eternal utility in different branches of forensic science to analyze various types of physical or trace evidences. Forensic experts need to have an absolute understanding of the foundation and technicality behind complex reactions of customary spot tests. Forensic science literature dwells in the diversity of spot tests but an informative and comprehensive compendium of such prose remains occasional and limited in general. Keeping in view the ample history and legacy of spot test, the current review was constructed from a core of historical literature to recapitulate trending applications, chemistry, and limitations of notable "Griess test", "Luminol test", "Kastle-Meyer test", "Phenolphthalein test", "Ninhydrin test", and "Spy dust" in forensic science. The aim of this review article was to describe the outlook and likely impact of these tests on the expansion of scientific investigation. The anticipated output of this review is supposed to impart compatible knowledge in the attentive readers interested in understanding legacy and technical details of selected spot tests used in solving crime.

Treatment of a Silver Dragon for the Removal of Silver Cyanide and Chalconatronite

Abstract: Analysis of the corrosion products on a silver dragon suspected to have been treated with cyanide revealed both silver cyanide and chalconatronite. It appears that both of these corrosion products can be formed on silver objects cleaned or replated using a cyanide solution. These corrosion products darken with exposure to light; therefore, they may be mistaken for silver sulfide. In order to determine how to remove the highly poisonous cyanide corrosion product, numerous tests were run. Using a carefully timed procedure the silver cyanide was removed with an aqueous solution of 20% sodium thiosulfate. The chalconatronite was removed mechanically.

Ferrozine---a new spectrophotometric reagent for iron

Abstract: -N=C&N-, have been known to react as bidentate ligands with certain metal ions such as ferrous, cuprous, and cobaltous, to give colored complex species (1-6). This effect was first noticed with the ferrous ion ( I ) , and since this complex of a given compound is generally of a more intense color than are those with other ions (7), the atomic configuration in question was given the trivial name of the ferroin group. During the last century, hundreds of compounds containing the ferroin group have been synthesized (7), the majority of which demonstrate the ability to form complexes with the ferrous ion. Most of these complexes are only weakly colored, are unstable under normal physical conditions, or are formed over a very narrow pH range. A few of these compounds, however, form stable, intensely colored species with the ferrous ion and are, therefore, suitable for the quantitative determination of iron (8). Examples of compounds which have found acceptance for such use are 1,lOphenanthroline (9), 4,7-diphenyl-l,lO-phenanthroline (IO), 2,2‘-bipyridine (I]), 2,6-bis(2-pyridyl)-pyridine (11). 2,4,6tris(2-pyridyl)-1,3,5-triazine (12), and phenyl 2-pyridyl ketoxime (13, 14). Many of these reagents are the product of difficult and tedious organic syntheses and, hence, are high in cost (14). Although for even the most expensive of these reagents, the cost of a single manual analysis is fairly low, when one considers automated continuous instrumental analysis, a lowcost yet highly sensitive reagent would be desirable, since the cost of maintaining such an analytical instrument with I

Modified Reagents for Determination of Urea and Ammonia

Abstract: Combinations of reagents are described for the catalyzed indophenol reaction for the determination of ammonia, which produces a stable blue color. The procedure is adapted to the determination of urea after hydrolysis with urease.

Spectrophotometric determination of hydrogen sulfide in natural waters1

Abstract: Winkler method for dissolved oxygen analysis. Limnol. Oceanog., 10: 135-140. CARRITT, D. E., AND J. H. CARPENTER. 1966. Comparison and evaluation of currently employed modifications of the Winkler method for determining dissolved oxygen in seawater; a NASCO report. J. Marine Res., 24: 286318. CLINE, J. D. 1968. Kinetics of the sulfide-oxygen reaction in seawater; An investigation at constant temperature and salinity. M.S. Thesis, Univ. Washington, Seattle. 68 p. CUSTER, J. J., AND S. NATELSO?\T. 1949. Spectrophotometric determination of microquantities of iodine. Anal. Chem., 21: 1005-1009. THOMPSON, T. G., AND R. J. ROBINSON. 1939. Notes on the determination of dissolved oxygen in sea water. J. Marine Res., 2: 1-8. WHEATLAND, A. B., AND L. J. SMITH. 1955. Gasometric determination of dissolved oxygen in pure and saline water as a check of titrimetric methods. J. Appl. Chem. (London), 5: 144-148. WINKLER, L. W. 1888. Die Bestimmung des im Wasser gelosten Sauerstoffes. Chem. Ber., 21: 2843-2855.