Laboratory medical microbiology commonly used equipment generally includes glass equipment, metal instruments, rubber products and plastic products, etc., each type of equipment treatment and sterilization measures are different. Strict sterilization is extremely important, directly affecting the entire experiment can be carried out smoothly. At present, the commonly used sterilization methods have physical methods (such as dry heat sterilization method, wet heat sterilization method, filtration sterilization method, ray sterilization method, etc.) and chemical methods (disinfectant, antibiotic) two categories.
1, dry heat sterilization method, is the use of constant temperature drying oven 120oC ~ 150oC high heat, and keep 90 ~ 120 minutes, kill bacteria and spores, to achieve the purpose of sterilization of a method. Mainly applicable to the inconvenience of sterilization in the pressure steam sterilizer, and is not easy to be damaged by high temperature glassware, metal instruments and can not be in contact with the steam sterilization of items. Disadvantages: applicability is not strong.
2, moist heat sterilization method, pressure steam moist heat sterilization method is currently the most commonly used sterilization method. It uses high-pressure steam and the presence of latent heat in the steam environment and good penetration, so that the bacterial protein coagulation denaturation and microbial death. Disadvantages: If the culture medium or liquid solution sterilization, sterilization time is closely related to the volume of culture medium or liquid solution needed. Insufficient time can not achieve the sterilization effect, too long time inside the medium of the chemical substances have been destroyed. The cost of the medium is affected.
3, ray sterilization method, the use of ultraviolet light irradiation sterilization method. Ultraviolet light is a low-energy electromagnetic radiation, can kill a variety of microorganisms. The mechanism of action of ultraviolet light is to inactivate microorganisms by destroying their nucleic acids and proteins and so on. It is suitable for sterilizing laboratory air, floors, and operating tables. Disadvantages: sterilization with ultraviolet light can not be irradiated while conducting experimental operations, because the ultraviolet light is not only harmful to human skin, but also on the culture and some reagents, etc. will also have an adverse effect.
4, filtration sterilization method, is the liquid or gas through the porous membrane filtration, so that greater than the pore size of the membrane bacteria and other microbial particles retained, so as to achieve sterilization method. Disadvantages: Filtration sterilization method is mostly used for reagents, enzymes, serums, culture fluid, etc., which are easy to decompose and denature when exposed to heat and become invalid. In filtration sterilization, it is generally not possible to monitor the key parameters of the filter during the whole process (size and distribution of the pore size of the filter membrane, the integrity of the filter membrane and LRV).
5, chemical disinfectants disinfection method, for those who can not use physical methods for sterilization of objects, air, environment, laboratory equipment, work surfaces, operator skin, certain laboratory vessels. Commonly used chemical disinfectants, including formaldehyde, potassium permanganate, 70% to 75% ethanol, peroxyacetic acid, hydrogen peroxide, silver ion composite, Lysol water, ethylene oxide, iodine or tincture of iodine. In the use of safety should be noted, especially in the skin or experimental materials used in the disinfectant, must choose the appropriate type of agent, concentration and processing time, in order to achieve the purpose of safety and sterilization.
Two, laboratory equipment troubleshooting method is what
Laboratory equipment after the problem, the principle of maintenance is to move the mouth first after the hands, the first move outside after the move inside, the first mechanical after the move electricity, the first move to clean and then move the maintenance. The following is the introduction:
1, first discuss and then do it
For some faulty electrical equipment, such as laboratory fume hoods, ultra-clean bench, etc., do not rush to start. First of all, we must understand the process and failure phenomena before and after the accident of electrical equipment. If the equipment has a complex circuit connection, you also need to familiarize yourself with the circuit principle and structural characteristics. Before disassembly, understand the function, position, connection and relationship with other equipment around each electrical component. If there is no assembly diagram, you can first decompose and then draw a sketch to mark.
2, from the outside to the inside
Check the outside of the faulty equipment for obvious cracks and defects, understand its maintenance history and service life, eliminate the fault factors around the equipment, and disassemble it after determining that it is an internal fault. Do not blindly disassemble the design or it may get worse.
3, first mechanical and then electrical
Only after determining that the mechanical components of the equipment is not faulty can be electrical testing. Detect circuit failure, check the circuit with a multimeter and other testing instruments to determine whether the button, contactor, thermal relay, fuse of the electrical equipment is normal. After confirming that there is no poor contact failure, turn on the power, listen to the sound, measure the parameters, determine the fault, and then check the relationship between the line and mechanical operation to avoid misjudgment.
4, clean before maintenance
For some serious pollution of electrical equipment, many causes of failure are caused by dirt and conductive dust blocks. Therefore, before maintenance, clean its buttons, connections and contacts to check whether its external control keys fail, etc.