What is analytical chemistry?
Analytical chemistry is a branch of applied chemistry that studies the composition of matter in depth. Analytical chemistry separates, identifies, measures, and studies the components of a substance; it also studies, develops, and improves the tools and methods for analyzing samples.
In a chemical analysis, a sample is separated into the analyte and the matrix. The analyte is a component of the sample that is of interest; this can be an element, a compound, or an ion. The matrix is all of the other components that are not of interest for the analysis.
What is the matrix effect?
The type of matrix is important to determine the manner in which the analysis should be carried out, as well as the quality of the results obtained. The effects that the other components of the sample have on the analyte and their ability to react to applied analytical methods is known as a matrix effect.
To eliminate or mitigate the matrix effect, different calibration methods may be used, such as preparing the samples before taking them to analysis.
What types of analyses are carried out in analytical chemistry?
Qualitative: identifying the elements of a sample.
Quantitative: determining the concentration of each element in a sample.
What methods are applied in analytical chemistry?
The methods of chemical analysis are divided into two main groups:
- Chemical methods (classical).
- Instrumental methods (modern).
Today, professional chemical analysis uses only instrumental methods; classical chemical methods have been relegated to the academic world as part of the teaching of the discipline.
Qualitative chemical methods include, for example:
- The flame test, which is used to detect metal ions based on the spectrum of the flame, which will vary for each element.
- Chemical tests, such as the Kastler-Meyer test, which is used in forensic medicine to detect the presence of blood.
Two of the chemical methods for quantitative analysis are:
- Gravimetric analysis: determines the amount of substance present in a sample based on its mass. The substance is separated from the rest of the sample through a chemical reaction or by precipitation, and then its mass is measured on a high-precision analytical balance.
- Volumetric analysis: the amount of substance is determined based on the volume of substances interacting with each other in a known reaction. This type of reaction is known as a stoichiometric reaction; in it, the reactants and products are equalized in a balanced equation that provides the molar numbers (or proportions) of each element.
Some of the various modern instrumental methods are:
- Thermal analysis, which measures the interaction of a material with heat. The most common procedures are calorimetry and thermogravimetric analysis.
- Microscopy, which observes molecules at microscopic levels; this may be optic, electronic, or with a scanning probe.
- Electrochemical analysis, which measures the volts (the potential) and amps (the current) of the analyte in an electrochemical cell. This type of analysis may be:
- Potentiometry: measures the potential difference of the electrodes.
- Coulometry: measures the transferred charge over time.
- Amperometry: measures the cell current over time.
- Voltammetry: measures the cell current while the cell potential is being modified.
What applications does analytical chemistry have?
Analytical chemistry has numerous applications in the fields of industry and trade. In medicine, this branch of chemistry is fundamental, especially for diagnosis.