Chapter 4 – Tests for the Elements, their Ions and Compounds
01 Jan 1972-pp 94-524
About: The article was published on 1972-01-01. It has received 6 citations till now.
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TL;DR: 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 as mentioned in this paper, and these techniques are reviewed, and pesticide and fumigant use by early collectors and later collections management staff is documented.
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.
63 citations
TL;DR: In this paper, 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 and some better-known pigments based on carbon are summarized, with an indication of which form or forms of carbon each contains.
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.
48 citations
TL;DR: In this paper, the Freer collection of Japanese paintings of the twelfth to the sixteenth centuries has been determined, and basic lead carbonate (lead white) was found in 12 out of 13 Chinese paintings and in all three Korean 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.
16 citations
TL;DR: The outlook and likely impact of these tests on the expansion of scientific investigation and legacy and technical details of selected spot tests used in solving crime are described.
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.
7 citations
TL;DR: In this article, the corrosion products on a silver dragon suspected to have been treated with cyanide revealed both silver cyanide and chalconatronite, which can be formed on silver objects cleaned or replated using a cyanide solution.
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.
5 citations
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5 citations
TL;DR: In this article, Kupferpulver mit anhaftendem Quecksilber wird nach Filtration in Salpetersaure gelost und die Losung dann direkt colorimetriert.
Abstract: Durch colorimetrische Bestimmung mit p-Dimethylaminobenzylidenrhodanin ist es moglich, 20–150 μg Quecksilber in 100 ml Losung gut reproduzierbar neben den meisten anderen Metallen direkt zu erfassen. Ist der Quecksilbergehalt der zu analysierenden Proben gering, kann Quecksilber durch Zementation mit Kupferpulver angereichert werden. Die Zementation gelingt aus schwach sauren, auch salpetersaurehaltigen Losungen praktisch vollstandig, wenn 3 Std geruhrt wird und etwa in der Losung vorhandene oxydierende Substanzen zuvor mit SO2 reduziert werden. Zur Zementation gut geeignetes Kupferpulver ist durch Ausfallen mit Zinkpulver aus schwach saurer Kupfersulfatlosung zu gewinnen. Das Zementat, Kupferpulver mit anhaftendem Quecksilber, wird nach Filtration in Salpetersaure gelost und die Losung dann direkt colorimetriert. Bei Einwaagen von etwa 10 g Probesubstanz konnen nach der beschriebenen Methode noch Gehalte von 2–5 ppm Hg mit einem Fehler von ±10% bestimmt werden.
5 citations
5 citations
TL;DR: In this article, the mechanism of the topochemical reaction of ammonium salts is discussed, and the application of the test in spot test analysis is described, as well as its application in the detection of organic bases.
Abstract: Hydrogen sulfide is liberated when molten alkali thiocyanate reacts with ammonium salts or with salts of primary, secondary and tertiary aliphatic and aromatic amines. The mechanism of the topochemical reaction of ammonium salts is discussed. The reactivity of molten potassium thiocyanate permits the detection of organic bases. The application of the test in spot test analysis is described.
5 citations
TL;DR: In this article, the authors describe a scenario where a 6.9-6.9～7.4-7.9 ～6.0ppm = 0.023μgB/cm2.
Abstract: カーミン酸は濃硫酸溶媒中でホウ素の光度定量用試薬として用いられていたが,水溶液中でも利用できることがわかった.カーミン酸水溶液は6.9～7.4のpH領域でホウ素の添加により530～600mμの吸収がいちじるしく減少する.この吸収の減少した試料溶液を対比液として,試薬ブランクの吸光度を測定する間接法を用いて光度定量を行なった.最適の定量条件は,カーミン酸濃度8×10-4M,pH範囲6.9～7.4,緩衝溶液濃度10-2M,測定波長554mμである.本法により8.0ppmまでのホウ素の定量ができ,定量感度は0.023μgB/cm2である。呈色の安定性,温度,共存塩類の影響などについても実験した.本法は水溶液中で反応が進行するため操作が簡単で,共存する金属イオンの多くはEDTAを加えてその妨害作用をいんぺいできる長所を持っている.
5 citations