AIR SAMPLING DEVICES.pptx

The quality of the air is determined by the different types of air sampling devices including hesse's tube, well centrifuge, tube sampler, etc.,

1. AIR SAMPLING DEVICES ASSISTANT PROFESSOR DEPARTMENT OF MICROBIOLOGY

2. INTRODUCTION Air can harvest many different kinds of microorganisms. M onitoring air quality is an essential criterion in quality control in laboratories. Air quality monitoring can be done either by collecting air samples or passively by settled plate methods . The microbial air sampler is a way to collect air samples for active air quality monitoring .

3. TYPES

4. SETTLING UNDER GRAVITY Method used for collecting the air with particles by gravity. Eg : Hesse’s Tube

5. AIR CENTRIFUGE Developed by Wells – 1993. The air containing particles are centrifuged on to the culture medium.

6. FILTRATION Simple method for collecting air. The filter can be made up of glass fibre, sand, alginate wool etc., The recovery of organisms from the filter is not easy

7. FILTRATION TUBE SAMPLER:

8. RAISED IMPINGER BEAD – BUBBLER DEVICES IMPINGEMENT INTO LIQUIDS

9. IMPINGEMENT INTO SOLIDS

10. A. HOLLAENDER & DALLA VALLE SAMPLER Brass container with removable bottom. Lower portion contain agar medium. Air passes through the funnel. The air borne microorganisms are impinged on the agar medium. Simple, portable and efficient method.

11. B. SLIT SAMPLER Has an enclosed chamber. Air drawn into the sampler through the slit and the particles get impinged on the medium. The plates are incubated at 37C for 24 hours.

12. C. SIEVE SAMPLER MULTISTAGE SEIVE SAMPLER SINGLESTAGE SEIVE SAMPLER Simple & efficient method. The particles are separated based on size.

13. D. ELECTROSTATIC PRECIPITATION Litton Air Sampler. The air is allowed to pass through the electrodes. The charged particles fall on the rotating disc which is later fed into the collecting fluid.

14. QUICK RECALL What is meant by air sampling? Techniques involved based on medium? Types of methods employed based on size? Example of settling under gravity. Two example of impingement into liquids. Principle of Sieve sampler. Electrostatic precipitation is based on what? 14

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