Interpretation techniques, chromatographic

Rasmussen [82] describes a gas chromatographic analysis and a method for data interpretation that he has successfully used to identify crude oil and bunker fuel spills. Samples were analysed using a Dexsil-300 support coated open tube (SCOT) column and a flame ionisation detector. The high-resolution chromatogram was mathematically treated to give GC patterns that were a characteristic of the oil and were relatively unaffected by moderate weathering. He compiled the GC patterns of 20 crude oils. Rasmussen [82] uses metal and sulfur determinations and infrared spectroscopy to complement the capillary gas chromatographic technique. 

Chromatographic techniques represent one of the most significant sources of analytical data found in today s pharmaceutical laboratories. All of the chromatographic techniques produce data that must be acquired, interpreted, quantified, compared, reported, and finally archived (see Chapter 21). Whether the analysis is qualitative or quantitative in nature, the data must somehow be interpreted and reported so that meaningful decisions can be made. It may be as simple as a qualitative decision that indicates whether a reaction has reached completion successfully, or it may be a series of quantitative analyses that help determine if a batch or lot of product meets its specifications and may now be released. This chapter also examines the evolution and perhaps the revolution that has taken place within the chromatography data system (CDS) marketplace. 

This chapter reviews the year s published work on physical and analytical aspects of steroid chemistry. No attempt has been made to survey the enormous number of routine applications of spectroscopic methods to structure determination. Attention has been concentrated mainly upon those developments of a fundamental nature which increase our understanding of the physical techniques and the phenomena which they explore. The major advances reported this year in the area of spectroscopy lie in the interpretation and applications of Cn.m.r. tritium n.m.r. has made its appearance as a method for the analysis of labelled steroids. The short sections on analytical methods give the Reviewer s selection of significant advances in radioimmunoassay and chromatographic methods of interest to chemists. 

The usefulness of an analytical technique is directly related to an understanding of its theory. This part of the book will explain the basic concepts of gas chromatography (GC), the purpose and selection of columns, and the interpretation of the chromatographic record, that is, the chromatogram. The information in this part will give the reader sufficient information to understand what GC is, how the separation occurs, and how to relate data to sample composition. 

The kinetics of the condensation of the Cr(H20)63+ ion and its corresponding deprotonated species have been studied in the pH region 3.5-5.0 [25°C, I = 1.0 M(NaC104)] (201). The study of this reaction is complicated by the formation of higher oligomers. Chromatographic analysis of the products as a function of time established the dinuclear species to be the main product for the first 5% of reaction, and the initial-rate kinetics of condensation were studied by a pH-stat technique. The observed pH dependence of the rate was interpreted in terms of the second-order rate constants defined by Eq. (44), and values for... 

Analysts, however, must exercise caution in interpreting results, since the work-up techniques may cause misleading alterations in the compound ) under study. A case in point involves the gas chromatographic... 

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