engleski

The role of analytical methods in industry

The samples interesting to an analytical chemist working in industry usually are not simple and homogeneous. They are in solid, liquid or gaseous state in the amount from traces (μ g) to cubic metres or tones. Analytical methods are important in many industrial processes from the beginning, just for controlling the feedstock, then in control of some intermediates and finally, in controlling and monitoring the quality of final product. Sometimes vendors expect quantitative analysis of traces, but sometimes they need only a degree of compound purity. Even though they are used in industrial application, classical analytical methods like gravimetric and volumetric are very rare today. Instead, modern and sophisticated methods like spectrometric, potentiometric, chromatographic, etc. are quite common in industrial control, analytical or research laboratories. There are several charasteristic steps to be followed in the analysis : recommendation of an appropriate method, sampling, sample preparation for measurements, taking analysis by measuring some of the features connected with the concentration of analyte, calculation of results, validation of the method and results. Easier are measurements of a liquid or gaseous sample, they are more homogeneous compared to solid samples. Common procedure involves a qualitative analysis and after that quantification of the identified compound or group of compounds. Very often a wide spectrum of different analytical and other physical and chemical procedures are involved in the analysis. Starting with a solid sample, first step is usualy grinding to much smaller particles, after that a degradation method follows, then separation by precipitation, extraction, centrifugation or by some chromatographic and electromigration techniques, and finally, determination of the particular compound structure by different spectroscopic (IR, UV, MS, NMR) techniques, taking into account different calibration procedures using the accepted standards. Before sending results it is quite common to validate a method with the results from different laboratories. Separation techniques, specially the chromatographic one has advantage to scale up themself easily. After using a technique as the analytical one, next step is a semipreparative range then a preparative, and finally production range to produce a new product in the commercial amount. Modern sophisticated analytical method usualy offers more pieces of information than needed by the management in industry and analytical chemists have to force the management to obtain additional pieces of information.

analytical measurements; sample preparation; industrial application

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