70th training program of nitub shahin
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This document provides information on the use and maintenance of various small lab instruments. It describes 16 common instruments including an ultrasonic cleaner, homogenizer, drying oven, desiccators, pH meter, balance, rotary evaporator, freeze dryer, centrifuge, water bath, melting point apparatus, hot plate, heating mantle, UV chamber, vortex mixer, and filtration unit. For each instrument, it explains its typical uses and provides guidance on operation, maintenance, troubleshooting, and safety precautions.
70th training program of nitub shahin
- 1. 70th TRAINING PROGRAM OF NITUB
- 2. Use, Maintenance and Troubleshooting of Small Lab- Instruments Dr. Md Shahinul Haque Khan Professor (cc) Department of Chemistry Bangladesh University of Health Sciences 125/1, Darus salam, Mirpur 1 Emai: khanshahinul@yahoo.com
- 3. Name of the common Instruments used in a Laboratory 1. Ultrasonic cleaner 2. Homogenizer 3. Drying oven 4. Desiccators 5. pH meter 6. Balance, Weight box 7. Rotary Vacuum Evaporator 8. Freeze dryer 9. Centrifuge machine 10. Water bath 11. Melting point apparatus 12. Hot plate with Magnetic stirrer 13. Heating Mantle 14. UV Chamber 15. Vortex Mixer 16. Filtration Unit
- 4. Ultrasonic Cleaner Ultrasonic cleaning is a process that uses ultrasound (usually from 20–400 kHz) and an appropriate cleaning solvent to clean items. Ultrasonic cleaning uses cavitation bubbles induced by high frequency pressure (sound) waves to agitate a liquid. The agitation produces high forces on contaminants adhering to substrates like metals, plastics, glass, rubber, and ceramics. used to clean many different types of objects, including jewelry, lenses and other optical parts, watches, dental and surgical instruments, tools, car fuel injectors, musical instruments, industrial parts and electronic equipment. electronic repair workshops.
- 5. Homogenizer Used for the homogenization of various types of material, such as tissue, plant, food, soil, and many others. sample preparation step prior to the analysis of nucleic acids, proteins, Cell, pathogens, and many other targets.
- 6. Drying Oven
- 7. Desiccators Desiccators are sealable or sealable with vacuum enclosures containing desiccants. It is used to preserving moisture-sensitive items, protect chemicals which are hygroscopic , prevent reaction with water from humidity, keep materials in drying condition, reduce temperature during moisture determination
- 10. UV Blocking Vacuum Desiccator
- 11. Sizes of Desiccators 1. Desiccator, Glass, Clear, I.D. 110 mm 2. Desiccator, Glass, Clear, I.D. 180 mm 3. Desiccator, Glass, Clear, I.D. 240 mm 4. Vacuum Desiccator, Glass, Amber, I.D. 240 mm 5. Space Saver Vacuum Desiccator, 19.7cm ID 6. Desiccator, Glass, Clear, I.D. 150 mm 7. Cabinet type
- 12. Desiccant A desiccant is a hygroscopic substance that induces or sustains a state of dryness in its vicinity. Characteristics : chemically inert, non-toxic, water insoluble Performance efficiency # ratio or percentage (water storable : mass of desiccant) # relative humidity of the air or other substance being dried
- 14. pH meter It is a scientific instrument used to measure the hydrogen-ion activity in water-based solutions, the acidity or alkalinity, the difference in electrical potential between a pH electrode and a reference electrode.
- 15. Electrode: # pH electrode and # reference electrode design
- 16. pH-sensitive glass membrane, 0.4 mm thickness
- 17. Construction of an electrode 1. A sensing part, a bulb made from a specific glass 2. Internal electrode, silver chloride electrode or calomel electrode 3. Internal solution, usually a pH=7 buffered solution of 0.1 mol/L KCl for pH electrodes. 4. When using the silver chloride electrode, a small amount of AgCl can precipitate inside the glass electrode 5. Reference electrode, 6. Reference internal solution, usually 0.1 mol/L KCl 7. Junction with studied solution, usually made from ceramics or capillary with asbestos or quartz fiber. 8. Body of electrode, made from non-conductive glass or plastics.
- 19. Selection of pH electrode The types of pH electrodes are many and various. The epoxy bodied combination electrode is suitable for the majority of tests carried out on aqueous solutions. For other applications, such as low ionic strength, high temperatures and strongly acidic solutions a more suitable pH/reference electrode pair may be required
- 20. Storing the pH electrode 1. After Use - Rinse thoroughly with distilled water. Short Term Storage - Immerse in storage solution Long Term Storage - Fit wetting cap filled with storage solution and replace in original packaging. 2. Electrodes should be stored a) away from direct sunlight b) in a vertical position c) within their specified temperature range 3. Always ensure the electrode is used within its specified temperature range. Ageing of electrodes used above their specified temperature is rapid and irreversible.
- 21. Precautions 1. DO NOT touch the sensitive glass pH membrane or reference junction. Excess droplets of solution may be removed by gently blotting with filter paper or tissue. 2. DO NOT wipe the electrode as this may induce an electrostatic charge
- 22. CLEANING OF GLASS ELECTRODES Deposit Cleaning agents General deposits Mild detergent solution Inorganic coatings Commercial glass cleaning solution (not strongly acidic) Metal compounds Acid solution, not stronger than 1M Oil/Grease Complexing agent (EDTA) or suitable solvent Resins/Lignins Acetone, alcohol or detergent (not strongly alkaline). Proteins (blood, etc) Enzyme solutions e.g. Pepsin in 0.1M HCl Stubborn deposits Weak hydrogen peroxide solution, Sodium Hypochlorite solution or domestic bleach. If Electrodes is dried out, (dry deposit of KCl crystals on the electrode body), by soaking overnight in warm deionised water. Note: The epoxy bodied electrode should not be cleaned with aggressive solvents.
- 23. ROUBLESHOOTING GUIDE FAULT PROBABLE CAUSE ACTION power a. Battery failure b. Battery polarity incorrect a. Replace batteries b. Refit batteries Cal error 1, 2 or 3 a. Incorrect value buffer used b. Contaminated buffer solution a. Use correct value b. Use fresh buffer solutions Cal error No 1 or 2 a. pH electrode defective b. Same buffer used for 2 point cal a. Replace pH electrode b. Recalibrate by 2 point buffer solution Unstable display pH electrode defective Replace pH electrode Display shows 1 or - 1 only a. Intermittant or no connection b. pH electrode defective c. Contaminated solutions a. Check electrode connection to unit b. Replace pH electrode c. Replace solutions Intermittant display Probes not fitted correctly Check connections I/O switch not working a. I/O key not held down >2 secs b. Batteries not fitted a. Retry holding key for 2 seconds b. Fit batteries
- 24. CHECKING the pH METER FUNCTION Adjust temperature to 25°C using the keys. Check buffer solution pH 7 and the display should read 7 pH. pH 4 and the display should read 4 pH. pH 10 the display should show 10 pH. the run unknown sample to read its pH value.
- 25. Weighing Scales These are devices to measure weight or calculate mass. a. Spring balances or spring scales: measure force (weight) of gravity against the force on a spring. Example: electronic balance, digital scale. b. A balance or pair of scales: compares masses by balancing the weight due to the mass of an object against the weight of a known mass. Example: Pan balance
- 26. Installation of a balance # On a solid, vibration-free surface, away from direct sunlight and at an constant temperature. # precisely levelled, using the built-in spirit level: # Protect the balance from drafts of air. Air moving across the pans will cause inaccurate readings. # Always keep the balance and weights clean and dry to protect them from corrosion. # Check the weight 10 mg, 50 mg and 100 mg and keep note Other items Weighing paper; Set of calibrating weights; Dust brush. Silica blue desiccant
- 27. Precautions # Never put materials directly on the pan of the balance. # Use the weighing container or paper. # Keep container or the weighing paper in the middle of the pan. # Clean the balance with a soft, clean brush after use. # Pans and the working area can be disinfected with 70% ethanol
- 28. Operating procedure # Check the power cord # Keep the balance ‘ON’ for 15 min before use # Check whether the sensitivity # Zero the balance with weighing paper keeping door closed # Put material on weighing paper # Read the weight of the substance directly from the screen Note: When the balance is not in use, keep it under an airtight plastic cover for protection against dust. Place a dish of with blue silica under the cover to remove humidity from the air. (When the silica desiccant has turned red, it must be regenerated by heating.)
- 29. Quality Control Daily Using an appropriate milligram/gram weight, check daily that the weight registered by the balance agrees with the calibrating weights. Record this check in the logbook. Annually Calibration of the balance should be carried out annually or after any repair or re-siting by a qualified service technician and registered in the logbook. Repair of the balance should be carried out by a qualified service technician.
- 30. Rotary Vacuum Evaporator It’s a Laboratory Instruments used to reduce solvent by reducing pressure at an elevated temperature (less than the boiling point of the solvent to be evaporated). This promotes the rapid removal of excess solvent from less volatile samples. Parts of the 1. Water bath 2. Evaporating tube coupled with a rotor 3. Condenser 4. Solvent trap 5. Chiller / cooling water 6. Vacuum pump
- 31. What to do before start rotary evaporator? Pour the required volume of water to the water bath Connect the tubing between vacuum pump and condenser Connect cooling water inlet and outlet tubing Clamp the solvent trap flask Connect all the electric cord to the mains Keep close the air releasing bulb
- 32. How to start a Rotary Evaporator? Turn the mains ON position Turn the switch of the water bath to ON Set the desired temperature i.e. 400C Wait until the bath temperature reached to set temperature Connect the round bottomed flask with sample to the evaporating tube Close the air release bulb Turn on the vacuum pump Turn on the rotor
- 33. Quickly evaporating solvents 1. n-Hexane 2. DCM 3. Chloroform 4. Ethyl acetate 5. Methanol 6. Ethanol Slowly evaporating solvent 1. n- Butanol 2. Water
- 34. How to turn off the rotary evaporator? Stop the rotation Release the vacuum Take out the flask with semidried sample Turn off the switch Close the cooling water tap.
- 35. Maintenance and care Distilled water should be used in the heating bath to minimize the scale build up in the bath. Clean the water bath regularly To remove algae gunk from the inside of a coiled water condenser, the condenser has to be removed from the rotavap and the coil is soaked in a dilute nitric acid solution for a few hours. The ground glass joint holding the flask does not need to be greased, If a mechanical pump is used instead of an aspirator to produce a vacuum, a secondary trap has to be used to prevent that the solvent destroys the membrane or is absorbed in the oil.
- 36. Freeze Dryer Freeze-drying or lyophilisation, lyophilization, or cryodesiccation— It’s a dehydration process Solid phase to gas phase (sublime method) i.e. Ice to vapor It is used to # preserve a perishable material or # make the material more convenient for transport. # dry frozen material under reduced pressure.
- 37. 1 atm = 101.325 kPa = 760 torr
- 39. Operating procedure Turing ON the freeze dryer Turn on the mains Turn on the refrigerator Turn on pump after <- 400C has reached until the vacuum has reached < 400 mTorr Connect sample and open vacuum bulb
- 40. Turning OFF the freeze dryer Release the vacuum Turning off the pump Defrost the chamber Turning off the mains
- 41. Maintenance and troubleshooting If the freeze dryer does not obtain a satisfactory vacuum, perform the following maintenance tests Gaskets, Tubing, Connections, Sample Valves A. Ensure the gasket is clean. Apply vacuum grease to the gasket. B. Check the drain line and ensure the drain plug. C. Check all rubber vacuum tubing for signs of deterioration or cracking. D. Check all connections and make sure they are secure and leak tight. E. Check all sample valves on the drying chamber F. When checking the sample valves, g. check the vacuum pump
- 42. Centrifuge machine It is a piece of equipment that puts an object in rotation around a fixed axis (spins it in a circle), applying a potentially strong force perpendicular to the axis of spin (outward). The centrifuge works using the sedimentation principle, where the centripetal acceleration causes denser substances and particles to move outward in the radial direction. Objects that are less dense are displaced and move to the center. Denser particles to settle to the bottom of the tube, while low-density substances rise to the top.
- 44. Maintenance and care Avoiding Rotor Failures Tube Breakage Chemical Resistance : If uncommon solvents are used then precautions should be taken Aerosol Generation: If any liquid is spilled on a rotor, it will be dispersed as a particulate mist when the centrifuge is run. Rotor should be cleaned immediately. Handling Human Samples: Human blood or blood components can transmit an infectious disease or virus if the patient or donor carries these. Lubricating Disinfection
- 45. Water bath Used to incubate samples warming of reagents, melting of substrates incubation of cell cultures enable certain chemical reactions heating flammable chemicals instead of an open flame to prevent ignition Precaution Do not use moisture sensitive substances Use distilled water only It should be use inside the fume- hood Raise temperature up to 900 C for decontamination,
- 46. Melting point apparatus Used to determine the melting point of a substance.
- 47. Hot Plate with magnetic stirrer Used for chemical reactions making homogeneous solution
- 48. Heating mantle Used to apply heat to containers extract oil using Soxhlet extractor prevent excessive temperature gradients distillate solvent heat oil bath
- 49. UV Chamber Used to Set wavelength at 254 nm and 366 nm used to detect the spot or band sample on the tlc plate
- 50. Vortex Mixer The variable rotational speed settings ranging from 100 to 3,200 rpm Used to properly mix solution in a small vials mix the reagents of an assay mix an experimental sample and a dilutant.
- 51. Filtration unit Used to filter mobile phase filter solvent or mixutre solvents
- 52. Thank you for your kind patience