Analytical Chemistry Instruments

Analytical chemistry is the branch of science that uses several analysis techniques or methods and analytical instruments to identify an unknown chemical substance or matter quantitatively as well as qualitatively. Therefore, identification of a substance, elucidation of its structure, and quantitative analysis of its composition are covered in modern analytical chemistry. A large number of journals use analytical techniques, methods, and instruments during the analysis of inorganic, organic, biochemistry, and forensic science samples.

The most difficult task for analytical chemists is to explain the exact branch of analytical work. Generally, we can say it is the branch of science where a large number of research workers work for its development.

For example, all chromatographic or electrophoresis techniques were developed by biochemists or biological scientists but mass spectrophotometry was discovered by physicists. Therefore, we do not call them analysts or analytical chemists for various reasons.

Analytical Techniques

The techniques used in the field of analytical chemistry for the determination of analytes or samples are generally two types: classical techniques and instrumental techniques.

Classical Techniques

In the classical technique, we generally check the presence or absence of a particular component in a given analyte in the laboratory. For example, the Kastle-Meyer test is used to identify the presence of hemoglobin in the given analyte.

Flame Tests

Flame tests are examples of classical techniques that are used to check the presence of specific elements in an analyte. When we expose the sample to a flame, the colour of the flame is changed.

Flame Tests Experiment

1. Chemically pure hydrochloric acid (HCl) is taken in a watch beaker.
2. The top end of a clean platinum wire moistened with HCl is held over a non-Luminus Bunsen flame.
3. The process is repeated until the flame becomes colurless. The platinum wire is again moist with concentrated HCl.
4. A trace of the solid sample is taken at the tip of the wire and held on the base of the non-luminous flame.

The colour change of the flame to the naked eye and the double cobalt blue glass of a particular sample is given below the table.

Instrumental Techniques

Different types of spectroscopic and electronic instruments are used in analytical chemistry during quantitative or qualitative analysis of samples.

• Electrophoresis or gel electrophoresis instruments are used mostly in analytical chemistry for the purification or separation of proteins, amino acids, enzymes, DNA, and RNA in biochemistry.
• Spectroscopy generally involves the measurement and analysis of electromagnetic radiation of given atoms or molecules present in the sample.
• A common instrument that we also use in analytical chemistry is the electrochemical cell. It is used mostly for the purification and analysis of metals.

Quantitative Analysis

Quantitative analysis in analytical chemistry is important because it helps to analyse the amount of sample and the range of relative amounts of constituents. It can be divided into three categories such as macro, semi-micro, and micro.

• In macro methods, we can analyze the sample whose weight is greater than 0.100 g.
• In semi-micro, we can analyze the sample whose weight is between 0.100 and 0.10 g.
• In micro, we can analyze the sample whose weight is less than 0.10 g.
• A sample whose weight is less than 0.002 g is called a submicro or ultramicro sample.

The important steps for quantitative analysis are,

Sampling

It should represent the mass of the material. It can provide the martial in a reasonable pure form.

Separation

The separation technique is used mostly for the conversion of desired constituents of the sample to a measurable form. The selection of the separation technique for a specific situation depends on a number of factors. Such selection is required mostly for accuracy and precision.

Measurement of Desired Constituent

Any physical or chemical property can be used for qualitative identification and quantitative measurement of the sample. If the property is specific and selective for measurement, then separation and pretreatment of the sample can be minimized.

Calculation and Interpretation of Analytical Data

An analysis is not complete until the results are expressed in such a manner that can be understood by all. In recent years, greater attention has been given to statistical data on analytical chemistry. Therefore, it can establish a new branch of science which is termed Chemometrics.

Applications of Analytical Chemistry

Analytical chemistry has numerous applications in various fields of science, including inorganic, organic, physical, biochemistry, forensic science, etc. However, no other branch of science finds such extensive applications.

It also has wide applications in other fields of science such as environmental science, agricultural science, biomedical or drug research, forensic science, and space research.

• In environmental science, analytical chemistry techniques are mostly used for monitoring sulfur dioxide and carbon dioxide.
• Analysis of dissolved oxygen and chlorine from water can be carried out by potentiometry and colorimetry.
• During the analysis of pesticides and insecticides from crops, we used gas and high-performance liquid chromatography techniques in analytical chemistry.
• Spectrophotometry is another instrument used for the analysis of micronutrients such as iron, copper, zinc, molybdenum, boron, and manganese in the soil sample.
• In the field of electronics, analytical chemistry is used for the analysis of traces of elements such as silicon or germanium in semiconductors and transistors.
• In the field of oceanography, earth science, planetary science, and analytical chemistry are extensively used during the analysis of seawater, basaltic rocks, and lunar samples.

Analytical Chemistry Topics