1. Spectrophotometry (19th century)
-Spectrophotometry is considerd as a powerful tool for chemical analysis as it is a scientific technique which can be used to measure the interaction between light and matter.
-It functions by measuring the amount of light which can be absorbed or transmitted by a sample, that can provide valuable information about the sample's composition, concentration, and properties.
-It works on the following Principle:
•Light source: Lamp or laser are used as a light source which emits a beam of light and that beam is directed towards the sample.
•Sample preparation:Dissolving a sample in a solvent or placing it in a specialized container give us a prepared sample for observation.
•Light absorption or transmission: As soon as the light beam interacts with the sample, the amount of light absorbed or transmitted is measured.
•Detector: Photodiode or photomultiplier tube devices are used to detect the measured light.
-Types of Spectrophotometry:
1. UV-Vis Spectrophotometry: The absorption of light in the ultraviolet and visible regions of the electromagnetic spectrum is measured.
2. Infrared (IR) Spectrophotometry: The absorption of light in the infrared region of the electromagnetic spectrum is measured.
3. Nuclear Magnetic Resonance (NMR) Spectrophotometry: The interaction between nuclear spins and a magnetic field is measured.
-Applications:
•Quantitative analysis: The concentration of a substance in a sample can be determined using Spectrophotometry.
•Qualitative analysis: identification of the presence of a substance in a sample.
•Biological research: To study biological molecules, such as proteins and DNA.
•Environmental monitoring: To monitor environmental pollutants, such as heavy metals and pesticides.
•Pharmaceutical analysis: To analyze pharmaceuticals, such as determining the concentration of active ingredients.
-Advantages:
☆High sensitivity:It can detect very small changes in the sample.
☆High specificity:We can distinguish between different substances based on their unique spectral signatures due to Spectrophotometry
☆Non-destructive: The sample is not altered during the analysis hence it is a non destructive technique.
2. Chromatography (1900s):
-Chromatography is considered as a powerful tool for separation and analysis as it is a laboratory technique used for the separation, identification, and quantification of the components in a mixture.
-This term "chromatography" is derived from the two Greek words "chroma" (color) and "graphein" (to write), as the technique was originally used for the separation and identification of colored compounds.
-It works on the following Principle:
•Stationary phase: A solid or liquid,generally called a stationary phase is used for the separation of the components from the mixture.
•Mobile phase:A gas or liquid, generally called a mobile phase is used for carrying the mixture through the stationary phase.
•Separation:The separation of components from the mixture is based on their interactions with the stationary and mobile phases.
•Detection: Various techniques, such as spectroscopy or mass spectrometry are used for detection and identification of separated components.
-Types of Chromatography:
1. Paper Chromatography: The stationary phase is usually a paper and a solvent is the mobile phase.
2. Thin Layer Chromatography (TLC): A thin layer of silica gel or alumina is used as the stationary phase and a solvent as the mobile phase.
3. Gas Chromatography (GC): The mobile phase id a usually a gas and a solid or liquid as the stationary phase.
4. Liquid Chromatography (LC): The mobile phase is usually a liquid and a solid or liquid as the stationary phase.
5. High-Performance Liquid Chromatography (HPLC): High pressure is used for the separation of the components.
-Applications:
•Pharmaceutical analysis: It can be used for analyzing pharmaceuticals, such as identifying impurities and determining potency.
•Environmental monitoring: It can be used to monitor environmental pollutants, such as pesticides and heavy metals.
•Food analysis:It can be used for analyzing food, such as identifying additives and contaminants.
•Biological research:It can be used for thw separation and identification of biological molecules, such as proteins and DNA.
•Forensic analysis: It can be used in forensic science for analysis of evidence, such as identifying substances and determining their origin.
-Advantages:
☆High sensitivity: It can be helpful in detecting very small amounts of a substance.
☆High specificity:It can easily distinguish between very similar substances.
☆Flexibility: It can be used for the analysis of wide range of substances, from small molecules to large biomolecules.
BIOCHEMISTRY INVENTIONS
1. Vitamin Discovery (20th century):
-The essential nutrients that play a crucial role in maintaining our overall health and well-being are known as vitamins.
-Their discovery has been a gradual process which has spanned several centuries and numerous scientists and researchers has contributed to it.
-Early Beginnings:
1.Scurvy and the role of citrus fruits: James Lind,in 18th century discovered that citrus fruits can be used for curing scurvy, a disease which was caused by a lack of vitamin C.
2. Beriberi and the role of whole grains: Christiaan Eijkman,in 19th century discovered that whole grains can be used for curing beriberi, a disease which was caused by a lack of thiamine (vitamin B1).
-The Dawn of Vitamin Research:
1. Casimir Funk and the concept of vitamins:He in 1912 proposed the concept of vitamins, which he defined as "vital amines" essential for life.
2. Elmer McCollum and the discovery of vitamins A and B: He in 1913, discovered vitamins A and B, and depicted their importance in maintaining health.
-The Golden Age of Vitamin Research:
1. Vitamin C discovery: Albert Szent-Györgyi in 1928 discovered vitamin C, and depicted its importance in preventing scurvy.
2. Vitamin D discovery: Edward Mellanby,in 1922 discovered vitamin D, and depicted its importance in maintaining bone health.
3. Vitamin E discovery:Herbert Evans and Katherine Bishop in 1922 discovered vitamin E, and depicted it's importance in maintaining reproductive health.
-Modern Era of Vitamin Research:
1. Vitamin B complex discovery: Various B vitamins, including thiamine, riboflavin, niacin, and folate were discovered be researchers in 1930s and 1940s.
2. Vitamin K discovery:Henrik Dam in 1922 discovered vitamin K, and depicted its importance in maintaining blood clotting.
-Impact of Vitamin Discovery:
1. Improved public health: Significant improvements in public health, particularly in the prevention and treatment of deficiency diseases has been made possible because of the discoveries made regarding vitamins.
2. Advances in medicine: Advancements in medicine, particularly in the treatment of diseases related to vitamin deficiencies is possible because of vitamins.
3. Increased understanding of human nutrition: Research in vitamins has increased our understanding of human nutrition, and has led to the development of nutritional guidelines and recommendations.
2. DNA Structure Elucidation (1953):
- The most significant scientific discoveries of the 20th century was the elucidation of the double helix structure of DNA by James Watson and Francis Crick in 1953 which revolutionized our understanding of genetics and it also paved the way for major advances in fields like molecular biology, genetic engineering, and genomics.
-Historical Background:
•Friedrich Miescher's discovery of DNA: In 1869, He isolated DNA from white blood cells and depicted its presence in the nucleus of cells.
2. Phoebus Levene's work on DNA composition:In the early 20th century, it was discovered by him that the four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) make up DNA.
-Key Players:
•James Watson and Francis Crick: They used X-ray crystallography data provided by Rosalind Franklin and Maurice Wilkins to develop the double helix model of DNA.
•Rosalind Franklin and Maurice Wilkins: They provided the X-ray crystallography data that played an important role in the development of the double helix model.
-The Double Helix Model:
1. Double-stranded helix: The two complementary strands of nucleotides constitute the structure of DNA which are twisted together in a double helix.
2. Base pairing: The nucleotide bases pair in a specific manner - A pairs with T, and G pairs with C - to form the rungs of the ladder.
3. Sugar-phosphate backbone:The backbone of the DNA molecule which provides the structural framework for the double helix.
-Impact of the Discovery:
☆Understanding of genetic inheritance: It provided a fundamental understanding of genetic inheritance and the transmission of traits from one generation to the next.
☆Advances in molecular biology: It paved the way for major advances in molecular biology which includes the development of recombinant DNA technology and gene editing.
☆Genomics and personalized medicine: It has enabled the development of genomics and personalized medicine, which hold great important in improving human health.