What are some common techniques used in analytical chemistry?

Learning Centre > What are some common techniques used in analytical chemistry?

The most commonly-used tests are colourimetric, spectrophotometric, chromatographic, and electrochemical.

The most commonly-used tests are colourimetric, spectrophotometric, chromatographic, and electrochemical. The most commonly-used tests are colourimetric, spectrophotometric, chromatographic, and electrochemical.

The most commonly-used techniques in analytical chemistry are listed below:

Qualitative analysis

Qualitative analysis is used to determine if a compound is present or not. It doesn't measure how much of the compound is there, just whether it is there or not.

Chemical test

There are many chemical tests that can help you determine the quality of something. For example, there is the acid test for gold and the Kastle-Meyer test for blood.

Flame test

Inorganic qualitative analysis is a way to find out if certain ions or elements are in a liquid. You do a series of tests to figure out what's in the liquid. If you think you see something, you do a confirming test. Sometimes small carbon-containing ions are included in such schemes. Today, these tests are rarely used, but they can be useful for educational purposes or in fieldwork or other situations where access to high-quality instruments is not available.

For example, the flame test for Sodium (Na) is when you add a few drops of sodium metal to a hot, non-luminous flame. The colour produced is orange.

Quantitative analysis

Quantitative analysis is the measurement of the quantities of particular chemical constituents present in a substance. Quantities can be measured by mass (gravimetric analysis) or volume (volumetric analysis).

Gravimetric analysis

Gravimetry is the determination of the weight of a sample. A common example is determining the amount of water in a soil sample. Gravimetric analysis involves heating the sample to remove any moisture, then weighing it before and after drying for an accurate measure of water content. The difference in weight before and after the experiment will determine the amount of water present in the sample.

Volumetric analysis

Volumetric analysis uses the change in volume of a substance to determine concentration. An example of this is titration, which involves adding a reactant to a solution being analyzed until some equivalence point is reached. Often the amount of material in the solution being analyzed may be determined. People who have taken chemistry during secondary education would be familiar with acid-base titration. This process involves a colour-changing indicator. Many other titrations exist, including potentiometric titrations. These titrations may utilize a variety of indicators to achieve some degree of equivalence.

Instrumental Methods

Spectroscopy

Spectroscopy is a way of measuring how molecules interact with electromagnetic radiation. Spectroscopy consists of many different applications such as atomic absorption spectroscopy, atomic emission spectroscopy, ultraviolet-visible spectroscopy, x-ray spectroscopy, fluorescence spectroscopy, infrared spectroscopy, Raman spectroscopy, dual-polarization interferometry, nuclear magnetic resonance spectroscopy, photoemission spectroscopy, Mössbauer spectroscopy and so on.

Mass spectrometry

Mass spectrometry is a way to measure the mass-to-charge ratio of molecules using electric and magnetic fields. Electron ionization, chemical ionization, electrospray ionization, fast atom bombardment, matrix-assisted laser desorption/ionization, and other ionization approaches are available. Mass spectrometry is also classified by mass analyzers: magnetic-sector, quadrupole mass analyzer, quadrupole ion trap, time-of-flight, Fourier transform ion cyclotron resonance, and so on.

Electrochemical analysis

Electroanalytical methods use an electrochemical cell to determine the potential (volts) and/or current (amps) of the analyte. The techniques for altering and tracking cell characteristics are typically classified according to which aspects of the cell are controlled and which are observed. Potentiometry (the difference in electrode potentials is measured), coulometry (the transferred charge is measured over time), amperometry (the cell's current is measured over time), and voltammetry (the cell's current is measured while actively changing the cell's potential) are the four primary types.

Thermal analysis

The interaction of a substance and heat is measured by calorimetry and thermogravimetric analysis.

Separation

Separation techniques are used to simplify the complexity of materials mixtures. This area is represented by chromatography, electrophoresis, and field flow fractionation.

Hybrid techniques

A "hybrid" or "hyphenated" technique can be created by combining several approaches. Today, several examples are in frequent use, and new hybrid processes are being developed. Gas chromatography-mass spectrometry, gas chromatography-infrared spectroscopy, liquid chromatography-mass spectrometry, and liquid chromatography-NMR spectroscopy are some examples.

A hyphenated separation approach involves combining two (or more) approaches to identify and separate chemicals from solutions. The alternative method is most often chromatography. In chemistry and biochemistry, hyphenated approaches are quite popular. A slash may be used instead of a hyphen if the name of one of the techniques includes one.

Microscopy

Single molecules, single cells, biological tissues, and nanomaterials are all visible in this visualization technique. It is an essential and appealing approach in analytical science.

Analytical techniques are also being revolutionized by hybridization with older analytical approaches. Optical microscopy, electron microscopy, and scanning probe microscopy are three types of microscopic study. This area is presently developing rapidly as a result of the rapid growth of the computer and camera industries.

Lab-on-a-chip

Devices that combine (multiple) laboratory operations on a single chip of only millimeters to several square centimetres in size and can manage extremely small fluid volumes down to picoliters, which are able to be stored.

Key Takeways

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