DR . R. MAHENDIRAN RAMASAMY

 It is an instrument used to measure the amount of absorbance of light by a sample.  It is used to measure the absorbance of light by placing samples in a cuvette in the instrument  It was invented by Arnold J. Beckman and his colleagues at National Technologies Laboratory (NTL) in 1940. Principle: It is used to measure the light intensity as a function of wavelength. The diffraction of light by a prism into different wavelengths was detected by the charged couplers or detectors. Instrumentation: Energy source Monochromator- used to break polychromatic radiation into its component wavelengths. Prism- types used are 600 Cornu quartz prism and 300 Littrow prism. Grating- used in monochromators of instruments operating in the ultraviolet, visible, and infrared regions. Cuvettes- It is made up of quartz material where the samples are loaded and placed in the instrument for operation. Detector- It is based on photoelectric current and is amplified and recorded. Applications: d...

  Centrifugation  is a term used to describe a method of separating mixtures using spinning and centrifugal force. Several characteristics can separate particles during centrifugation, including size, shape, density, and viscosity. British military engineer Benjamin Robins, who built a device that resembled an arm rotating around an axis to gauge drag on items. The Prandtl brothers later made the first practical centrifuge to separate milk from the cream by improving this design. By rapidly rotating a container containing material, separation is accomplished, the centrifugal force forces heavier elements to the outside of the container. Principles of Centrifuge: The centrifuge utilizes the sedimentation principle due to gravitational force. The centrifugation technique uses a centrifugal field to separate particles suspended in a liquid medium. These are put in the centrifuge’s rotor either in bottles or tubes. Sedimentation is a process in which gravity causes suspended parti...

An autoclave is a machine that provides a physical method of sterilization by killing bacteria, viruses, and even spores present in the material put inside the vessel using steam under pressure. Autoclave Principle/ Working The autoclave works on the principle of moist heat sterilization, where steam under pressure is used to sterilize the material present inside the chamber. The high pressure increases the boiling point of water and thus helps achieve a higher temperature for sterilization. Water usually boils at 100°C under normal atmospheric pressure (760 mm of Hg); however, the boiling point of water increases if the pressure is increased. Similarly, the high pressure also facilitates the rapid penetration of heat into deeper parts of the material, and the moisture present in the steam causes the coagulation of proteins, causing an irreversible loss of function and activity of microbes. This principle is employed in an autoclave where the water boils at 121°C at the pressure of 15 ...