Question

Explain the working principle of the following devices:

Automated analyzer

Blood gas analyzer

Spectrophotometer

Centrifuge

Microtome

please short answers and no handwritten

Answer 1

1. Automated analyzers:

The automated analyzer worked on the coulter principle and it is widely used in the counting of erythrocytes. The Coulter principle for counting of cells is based upon the changes measured in electrical impedence produced by non conductive particle. In this the non conducting particles are suspended in the electrolytes and the changes are directly proportional to the particle volume.

2. Blood gas analyzer: In whole blood by using the blood gas analyzer, we can measure partial pressure of oxygen (pO2), partial pressure of carbon dioxide (pCO2), concentration of hydrogen ions (pH) and it can also used to measure metabolites and electrolytes.

Blood gas analyzer works with three in-built electrodes

1. pco? electrode

2. pO ? electrode

3. pH sensitive glass electrode

3. Spectrophotometer:

It can contains two devices, they are

A. spectrometer for producing light of a certain color (and hence certain wavelength).

B. Photometer detects the intensity of light passing through a sample solution.

The two basic requirements for spectrophotometry are:

i) The absorption of light by a substance must produce a visible change in the compound, namely a change in the colour of the compound. The colour that the substance assumes is decided by the color (and hence wavelength) of the light incident on the substance.

ii) The amount of light absorbed by the substance is proportional to the concentration of the substance. The higher the concentration, more light is absorbed and viceversa. The relationship between the amount of light absorbed and the concentration of the substance is given by Beer’s law.

4. Centrifuge:

Centrifugation is one of the most common methods used in chemistry and biochemical Labs for separation of substance with different densities. Centrifugation is a method in which liquid samples are rotated at high speeds. This creates a centrifugal force on the particles due to which the denser particles settle down faster than the wood under normal Gravity.

Three Types of centrifuges are used in laboratory commonly.

1. Microfuge centrifuge.

2. Super speed centrifuge

3. Ultracentrifuge.

5. Microtome: A microtome is a tool used to cut extremely thin slices of material, which are called as sections. The microtomes are widely used in microscopy. In this the prepared sampels are allowed for observation under transmitted light or electron radiation. depending upon the specimen diamond, glass or steel blades are used in the specimen slicing.