Laboratory Instruments 1 Lecture 2 PDF

Laboratory instruments 1 Lce 2 Asst. Lecturer Zahraa Alamery 1 alkafeel.edu.iq info...

Laboratory instruments 1 Lce 2 Asst. Lecturer Zahraa Alamery 1 alkafeel.edu.iq [email protected] 2023  CENTRIFUGE CENTRIFUGE: Is an instrument which is used for separation of solid material from liquid suspension by centrifugal force. In which the objects or samples put in the special tubes of various sizes (made of glass or plastic) 2 alkafeel.edu.iq [email protected] 2023  Principle The centrifuge works using the sedimentation principle, where more dense substance to separate out and become at the bottom of the tube , when we uses a centrifuge on blood the blood cells collect at the bottom while the blood plasma moves to the top The centrifugal force depends essentially on three variables.(mass, speed and radius) Centrifugal force causes any matter in the solution denser than* ,the liquid to be forced against the outer walls of the tubes.separating it from the fluid in the process 3 alkafeel.edu.iq [email protected]  Description of equipment -:The centrifuge consist of Electric motor to which is attached a head accessories for-1 carrying samples. Usually, the head turns on a spindle, which is.an extension of motor shaft A safety shield around the rotating head. The safety is -2 maintained by micro switch which cuts the current when the lid 4 alkafeel.edu.iq [email protected] 2023 Some models are equipped with display and a keyboard* enabling the user to program a specific speed or view device.status :Types of centrifuge 1.Low-Speed Centrifuge Low-speed centrifuges are the most common centrifuges commonly used in labs to perform the regular sorting of the particles. The centrifuges are operated at the maximum speed of 4000- 5000 rpm. 5 alkafeel.edu.iq [email protected] Tuesday, August 24, 2021 2.High-Speed Centrifuges High-speed centrifuge as the name implies is the type of centrifuge which can operate at speeds that are slightly higher. Speed of the centrifuge with high speed may vary between.and 30,000 rpm 15,000 The high-speed centrifuge is typically employed in laboratories that are more sophisticated for biochemical applications and requires a fast speed of operation. 3.Ultracentrifuges Ultracentrifuges run at very high speeds which allow separation of smaller molecules like proteins, ribosomes and even viruses. This is the highest advanced type of centrifuge which allows to separate molecules which can't be separated by other centrifuges. 6 alkafeel.edu.iq [email protected] Tuesday, August 24, 2021 4.Micro centrifuges Micro centrifuges can be employed to separate small volumes of samples that range from 0.5 and 2 ul. Micro centrifuges usually operate at around 12,000-13,000 rpm. This is utilized for to separate molecularly organelles in cells like DNA, nuclei and nuclei as well as for extraction with phenol. 8 alkafeel.edu.iq [email protected] 5.Hematocrit centrifuge Hematocrit centrifuges are specially designed centrifuges that are used to determine the amount of the volume fraction of the erythrocytes (RBCs) within a specific blood sample. The centrifuge can provide hematocrit levels which can be used for tests in biochemistry, immune as well as blood tests, among other tests in general clinical use. Hematocrit centrifuges can be used to determine the cause of bleeding as well as polycythemia (an an elevation of the number of erythrocytes to higher than normal levels) anemia bone marrow dysfunction, leukemia, and myeloma. Micro hematocrit's centrifuge is able to reach rates of around 11,000 rpm, and RCFs up to 15,000 g for spin tubes with samples. A hematocrit centrifuge's parts centrifuge for hematocrit are similar to those of the benchtop centrifuge, however this 9 alkafeel.edu.iq [email protected] 6. Benchtop centrifuge Benchtop centrifuges are compact centrifuge, which is widely used in research and clinical laboratories. It is powered through an electric motor. the tubes rotate around an undetermined axis, which results in force perpendicularly towards the tubes. Because they are small, they can be useful for smaller labs that have smaller space. A variety of centrifuges for benchtop use are available on the market for a variety of uses. A benchtop centrifuge is equipped with an rotor that has racks for the tubes that are used to test and a lid that covers the unit that is used to operate the centrifuge. 9 alkafeel.edu.iq [email protected] Autoclave : Is a device used to sterilize equipment and materials by subjecting them to high pressure saturated steam at 121 °C for around 15–20 minutes depending on the size of the load and contents, Common sterilization techniques include the application of wet heat, dry heat, chemicals, and radiation. The type of material, the container, and quantity of items to be sterilized determines which method to use. 9 alkafeel.edu.iq [email protected]  Autoclaves provide a physical method for disinfection and sterilization. They work with a combination of steam, pressure and time. Autoclaves operate at high temperature and pressure in order to kill microorganisms and spores. this means that all bacteria, viruses , fungi and spores are inactivated. Autoclave presents the possibility of serious injury to personnel from hot surfaces and from the release of steam. It is important, therefore, that laboratory personnel understand the proper operation, limitations, and safeguards for sterilization by autoclaving. 9 alkafeel.edu.iq [email protected]  9 alkafeel.edu.iq [email protected] Principle : The sterilizing action depends on the heat of pressurized steam which is about 2.2 bar at 134 °C , ( when heat water in a closed container like autoclave we can raise the temperature of water above boiling temperature). This process is also embodied by gas laws, which basically states that the higher the pressure is within the device, the higher the temperature increases. In other words, pressure and temperature are directly proportional to each other. It is also important to note that it is the temperature that kills the microorganisms, not pressure. Rather, higher pressures are capable of increasing the boiling point of water, which thus 9 alkafeel.edu.iq [email protected] Autoclaves made of: strong metal jackets ( strong enough to withstand high pressure required) , autoclave door is hermetically sealed , pressure gauge (indicate pressure), thermostat, safety valve, plastic rubber, timer, water level indicator, thermometer(give temperature), basket(loads or objects to be sterilized) and electrical heater (heat supply) located at the bottom of autoclave which is covered with water. *Autoclaves are widely used in microbiology, medicine, mycology, dentistry. They vary in size and function. *Typical loads include laboratory glassware, surgical instruments and medical waste. 9 alkafeel.edu.iq [email protected]  9 alkafeel.edu.iq [email protected]  Method of operation: 1Fill the bottom of autoclave with distilled water, but below the basket bottom. 2Place the articles within the basket. 3Close the lid and tighten the screws. 4Adjust the temperature, pressure and time. 5Upon completion of the sterilization time discards steam by opening the valve for that then opens the lid. 9 alkafeel.edu.iq [email protected]  Balance are one of most important instrument being used in labs for measuring ( chemicals , media , laboratory animals ). BALANCE ELECTRONIC 9 alkafeel.edu.iq [email protected]  How to weigh: 1.Put a clean container on the balance pan. 2.Press the zero switch (zeroes appear on the screen) *(Most electronicbalances havea tare function. The tare function resets the digital display to zero when pressed.) 3.Add the material on the plate and read the numbers and the unit , it preferred to use appropriate spatula. alkafeel.edu.iq [email protected]  19 Tuesday, August 24, 2021 alkafeel.edu.iq [email protected]