Spot test analysis

6 SPOT TEST ANALYSIS The term spot reaction is applied to micro and semimicro tests for compounds or for ions. In these chemical tests manipulation with drops (macro, semimicro, and micro) play an important part. Spot reactions may be carried out by any of the following processes  

The actual spotting is the fundamental operation in spot test analysis, but it is not always the only manipulation involved. Preliminary preparation is usually necessary to produce the correct reaction conditions. The preparation may involve some of the operations of macro analysis on a diminished scale (compare Section II.5), but it may also utilize certain operations and apparatus peculiar to spot test analysis. An account of the latter forms the subject matter of the present section. 

Throughout this text the term sensitivity will be employed synonymously with limit of identification. The concentration limit is the greatest dilution in which the test gives positive results it is expressed as a ratio of substance to solvent or solution. For these two terms to be comparable, a standard size drop must be used in performing the test. Throughout this book, unless otherwise stated, sensitivity will be expressed in terms of a standard drop of 0 05 ml. 

Very small and even-sized drops can be obtained by means of platinum wire loops the size of the loop can be varied and by calibrating the various loops (by weighing the drops delivered), the amount of liquid delivered from each loop is known fairly accurately. A number of loops are made by bending platinum wire of suitable thickness the wires should be attached in the usual manner to lengths of glass rod or tubing to act as handles. They are kept in 

Pyrex test-tubes fitted with corks or rubber stoppers and labelled with particulars of the size of drop delivered. It must be pointed out that new smooth platinum wire allows liquids to drop off too readily, and hence it is essential to roughen it by dipping into chloroplatinic acid solution, followed by heating to glowing in a flame this should be repeated several times. Micro burettes sometimes find application for the delivery of drops. 

Confirmatory tests for ions may be carried out either on drop reaction paper or upon a spot plate. The technique of spot tests is fully described in Section 2.6. 

The following micro apparatus will be found useful micro porcelain, silica, and platinum crucibles of 0.5 to 2 ml capacity micro beakers (5 ml) and micro conical flasks (5 ml) micro centrifuge tubes (0.5, 1.0 and 2.0 ml) micro test-tubes (40-50 x 8 mm) micro volumetric flasks (1, 2, and 5 ml) 

The actual spotting is the fundamental operation in spot test analysis, but it is not always the only manipulation involved. Preliminary preparation 

Before dealing with the apparatus required for spot test reactions, it is necessary to define clearly the various terms which are employed to express the sensitivity of a test. The limit of identification is the smallest amount recognizable, and is usually expressed in micrograms (pg), one microgram being one-thousandth part of a milligram or one-millionth part of a gram  

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Jungreis, E. Spot Test Analysis, 2nd ed. Wiley New York, 1997. 

Spot Test Analysis Clinical, Environmental, Forensic and Geochemical Applications. By Ervin Jungreis... 

The problem of separating solid and liquid phases either before or after taking a sample drop or two of the test solution frequently arises in spot test analysis. When there is a comparatively large volume of liquid and the solid matter is required, centrifugation in a micro centrifuge tube (Fig. 11.34) may be employed. Alternatively, a micro sintered glass filter tube (Fig. 11.49), placed in a test-tube... 

Various other chemical and technical subjects, not directly discussing the products of their publishing company, are reviewed in house organs. Lvbricationy a publication devoted to discussions of the selection and use of lubricants, in the May-June issues of 1950 presented a general review of the concepts and measurements of viscosity. Inco Corrosion Reporter in each issue discusses the chemistry and manufacture of some corrosive material, such as fluorine, chlorine, phosphorus, or hydrofluoric acid. Interchemical Review has published reviews of spot test analysis, the organic chemistry of dyes, and other chemical subjects. 

Modern Techinques in Electroanalysis. Edited by Petr Vanysek Total Reflection X-Ray Fluorescence Analysis. By Reinhold Klockenkamper Spot Test Analysis Clinical, Enviromental, Forensic, and Geochemical Applications, Second Edition. By Ervin Jungreis... 

Rathore HS, Sharma R, Mital S. 1997. Spot test analysis of pesticides Detection of carbaryl and mancozeb in water. Water Air Soil Pollut 97 431-441. 

Inorganic species were characterised by means of atomic absorption, ion chromatography. X-ray fluorescence. X-ray diffraction as well as spot-test analysis [15] and mass balance. The catalyst was also characterised by means of BET surface area and pore volume. 

Hardcastle WA and Ellison E (2002) Expression of uncertainty in qualitative analysis. Approaches to the problem. EURACHEM/CITAC Conference Discussion Paper. Jungreis E (1997) Spot test analysis. In Winefordner JD (ed.) Chemical Analysis, vol. 141. New York John Wiley. Rios A, Barcelo D, Buydens L, Cardenas S, Heydorn K, Karlberg B, Klemm K, Lendl B, Milman B, Neidhart B, Rios A, Stephany R, Townshend A, Zschunke, and Valcarcel M (2002) Quality assurance of qualitative analysis in the framework of the European project ME-QUALAN . Accreditation and Quality Assurance 8 68-77. 

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