Microanalysis
Encyclopedia
Microanalysis is the chemical
identification and quantitative analysis
of very small amounts of chemical substance
s (generally less than 10 mg or 1 ml) or very small surfaces of material
(generally less than 1 cm2). One of the pioneers in the microanalysis of chemical element
s was the Austrian Nobel Prize
winner Fritz Pregl
.
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
identification and quantitative analysis
Quantitative analysis (chemistry)
In chemistry, quantitative analysis is the determination of the absolute or relative abundance of one, several or all particular substance present in a sample....
of very small amounts of chemical substance
Chemical substance
In chemistry, a chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e. without breaking chemical bonds. They can be solids, liquids or gases.Chemical substances are...
s (generally less than 10 mg or 1 ml) or very small surfaces of material
Material
Material is anything made of matter, constituted of one or more substances. Wood, cement, hydrogen, air and water are all examples of materials. Sometimes the term "material" is used more narrowly to refer to substances or components with certain physical properties that are used as inputs to...
(generally less than 1 cm2). One of the pioneers in the microanalysis of chemical element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
s was the Austrian Nobel Prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...
winner Fritz Pregl
Fritz Pregl
Fritz Pregl , was an Austrian chemist and physician from a mixed Slovene-German-speaking background...
.
Methods
The most known methods used in microanalysis are:- Most of the spectroscopySpectroscopySpectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
methods: ultraviolet–visible spectroscopy, infrared spectroscopyInfrared spectroscopyInfrared spectroscopy is the spectroscopy that deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light. It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic...
, nuclear magnetic resonanceNuclear magnetic resonanceNuclear magnetic resonance is a physical phenomenon in which magnetic nuclei in a magnetic field absorb and re-emit electromagnetic radiation...
, X-ray fluorescenceX-ray fluorescenceX-ray fluorescence is the emission of characteristic "secondary" X-rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays...
also mass spectrometryMass spectrometryMass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and... - Most of the chromatographyChromatographyChromatography is the collective term for a set of laboratory techniques for the separation of mixtures....
methods : high-performance liquid chromatographyHigh-performance liquid chromatographyHigh-performance liquid chromatography , HPLC, is a chromatographic technique that can separate a mixture of compounds and is used in biochemistry and analytical chemistry to identify, quantify and purify the individual components of the mixture.HPLC typically utilizes different types of stationary...
, Gel permeation chromatographyGel Permeation ChromatographyGel permeation chromatography is a type of size exclusion chromatography , that separates analytes on the basis of size. The technique is often used for the analysis of polymers. As a technique, SEC was first developed in 1955 by Lathe and Ruthven. The term gel permeation chromatography can be...
; - Some thermal analysisThermal analysisThermal analysis is a branch of materials science where the properties of materials are studied as they change with temperature. Several methods are commonly used - these are distinguished from one another by the property which is measured:...
methods: differential scanning calorimetryDifferential scanning calorimetryDifferential scanning calorimetry or DSC is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. Both the sample and reference are maintained at nearly the same temperature...
, Thermogravimetric analysisThermogravimetric analysisThermogravimetric analysis or thermal gravimetric analysis is a type of testing performed on samples that determines changes in weight in relation to change in temperature. Such analysis relies on a high degree of precision in three measurements: weight, temperature, and temperature change...
; - ElectrophoresisElectrophoresisElectrophoresis, also called cataphoresis, is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss , who noticed that the application of a constant electric...
; - Field flow fractionationField Flow FractionationField-flow fractionation, abbreviated FFF, is a separation technique where a field is applied to a fluid suspension or solution pumped through a long and narrow channel, perpendicular to the direction of flow, in order to cause separation of the particles present in the fluid, dependent on their...
; - X-ray diffraction.
Advantages
Compared to normal analyses methods, microanalysis:- Requires less time for preparation
- Requires less sample and solventSolventA solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
and thus produces less waste and is more cost effective.
Disadvantages
- Handling of small quantities is not always simple.
- Higher accuracy of weighing is necessary (e.g. use of accurate balance).