The physical and chemical analysis using a range of methods, each of which is, in fact, a set of different operations and techniques.With their help, the study carried out qualitative and quantitative characteristics of substances and materials.Physical and chemical research methods used in laboratories in various fields in the form of methods, that is, documents that the method specified and brought to the algorithm or instructions.In addition, to obtain results with a given accuracy, set conditions (including the requirements for measuring equipment), under which the procedure is attributed to error (uncertainty), its systematic and random components.
Physico-chemical methods - an important component of Analytical Chemistry.They include chemical transformation or dissolution of the test sample (aliquot), concentration of the desired component, excluding the influence of interfering substances and so on.Analytical methods can be divided into classical and instrumental.Classical methods (known as 'wet analysis') use high-quality (smell, color, precipitation, gas evolution or melting) and quantitative analysis (measurement of weight or volume).Many of them have arisen in the period from the 17th to the 19th century and is still used in cases where their response threshold is sufficient.
is more accurate physical-chemical methods of analysis, based on the instrumental studies.In this case carried out by means of devices for measuring physical quantities such as light absorption, fluorescence, current, potential difference, electrical conductivity, radiation intensity, and others.In some cases it is assumed pretreatment of the sample (the sample) by fractional distillation, separation into components hromatografichekoy column by electrophoresis and so on.
Physico-chemical methods of analysis are applied everywhere.The health, environmental, medical, pharmaceutical and food laboratories.Supervisory authorities and forensic studies.In the scientific and industrial purposes.They founded assessment of the quality of raw materials, intermediate samples of the finished products and commodity chemicals, petrochemicals and oil refining.If analysis using classical analytical techniques could staff with low qualifications (from 2 to 4 digits for ETCS), and in many cases it was quite average or average special education, instrumental studies by specialists with higher qualifications (5-6 digits)with higher education.
in classical studies as a means of measurement commonly used analytical balances and volumetric glassware (cylinders, flasks, pipettes, burettes).Physico-chemical analysis methods involve the use of Photocolorimeters, refractometers, spectrophotometers, chromatographs, mass spectrometers, and so on.Most of them are equipped with personal computers, thereby reducing the total and active time for analysis, consumables (chart paper, etc.), reduced the role of the human factor, thus minimizes the risk of getting inaccurate test results.
Physico-chemical methods of analysis based on the use of the latest models, despite their high cost, can reduce further the cost of analytical control that is due to a significant reduction in the time for analysis.This can be considered for example chromatographic methods.Analysis on older models required after fixation of the detector signals on the chart to do the following:
- remove the instrument chart;
- each signal (appears as a peak, which resembles a triangle), the specific component, identified by the time release of the compound from the column;
- calculate the area of each peak, as the area of the triangle (a ruler to measure the height and width at mid-height magnifying glass);
- calculate the amount of constituents;
- draw result of the test protocol or other records.
In the case of modern chromatographs, the detector signal which is output directly to a computer, all of the above operations are excluded, since they are carried out in automatic mode almost instantly.But it's not the only benefit when using modern physical and chemical methods of analysis.The results thus obtained can be automatically transferred quickly not only in the database of laboratory information management system (LIMS), but also in the database of the organization and on the central control process.