SOP for Operation, Cleaning and Maintenance of Microscope
1.0 Objective
1.1 To establish a procedure for the proper operation, cleaning, and maintenance of the microscope to ensure accurate observations and to maintain the instrument in good working condition.
2.0 Scope
2.1 This SOP is applicable to the operation, cleaning, and maintenance of microscopes used in the Microbiology Laboratory.
3.0 Responsibility
3.1 Microbiologist or above – Microbiology Laboratory:
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Preparation and implementation of this SOP.
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Operation, cleaning, and routine maintenance of the microscope as per procedure.
3.2 Head – Microbiology Section / Nominee:
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Review and approval of the SOP.
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Ensuring compliance with the procedure.
4.0 Accountability
4.1 Head – Quality Control / Nominee:
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Overall compliance with this SOP.
5.0 Procedure
5.1 Operation
5.1.1 Ensure that the microscope and the surrounding work area are clean and free from dust.
5.1.2 Connect the microscope power cord to the appropriate electrical outlet.
5.1.3 Switch on the microscope using the illumination control knob located at the lower left side of the instrument.
5.1.4 Adjust the illumination intensity to the lowest setting before beginning observation.
5.1.5 Fully open the condenser aperture diaphragm by rotating the diaphragm ring to the extreme right.
5.1.6 Using the sub-stage condenser focusing knob, raise the condenser to the topmost position.
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For critical illumination, if condenser travel is excessive, limit the travel using the thumbscrew beneath the sub-stage so that the top lens is just below the stage surface (approximately 0.35 mm).
5.1.7 Place the specimen slide securely on the stage.
5.1.8 Rotate the nosepiece to bring the appropriate objective lens into position:
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40X objective for dry mount observation
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10X objective for wet mount observation
5.1.9 Raise the stage using the coarse adjustment knob until it reaches its positive stop. Then, use the fine adjustment knob to bring the specimen into sharp focus.
5.1.10 Adjust the eyepiece tubes to match the inter-pupillary distance and compensate for refractive differences between eyes.
5.1.11 Focus the specimen through the right eyepiece only by covering the left eyepiece or closing the left eye. Use the fine adjustment knob for focusing.
5.1.12 Next, focus through the left eyepiece by adjusting the left eyepiece tube only. Cover the right eyepiece during this adjustment and do not use the focusing knob.
5.1.13 Remove one eyepiece and observe the back aperture of the objective. Close the condenser aperture diaphragm and then gradually reopen it until the diaphragm edges just disappear from view to obtain full resolving power. Replace the eyepiece.
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The aperture diaphragm may be adjusted to enhance contrast or increase depth of focus as required.
5.1.14 When switching to higher magnification objectives, readjust the aperture diaphragm accordingly. As magnification increases, open the diaphragm as required to maintain optimal resolution.
5.2 Cleaning and Maintenance
5.2.1 In case of reduced contrast, cloudiness, or poor image definition, clean the lower magnification objectives and accessible optical surfaces using a lint-free cloth or lens tissue slightly moistened (not wet) with methanol.
5.2.2 Clean the front lens carefully using a wooden toothpick wrapped with cotton and lightly moistened with methanol.
5.2.3 Avoid excessive use of cleaning solvents to prevent damage to optical components.
5.2.4 Always cover the microscope with a dust cover when not in use to protect it from dust and environmental contamination.
5.2.5 Before and after using the oil immersion lens, wipe the bottom surface gently with fast-absorbing tissue paper to remove immersion oil.
5.2.6 Use xylene, if required, for thorough cleaning of oil from lens surfaces.
SOP For Handling of Microbiological Data Deviation (MDD) in Microbiology Laboratory