Before microbiological experiments, we need to prepare sterile diluent (usually 0.85% sterile saline). Next, Elex Biological Products (Shanghai) Co., Ltd. will share the preparation and sterilization process of the experimental normal saline diluent.
(1) Prepare distilled water in advance
Operate according to the method of using the distiller, and prepare a distillation seal for later use.
(2) Preparation of 0.85% normal saline
Weigh 8.5g of sodium chloride and dissolve it in 1000ml of distilled water, stir with a glass stirring rod to make it dissolve quickly and evenly.
(3) Dispensing of normal saline
Pour the sterile diluent solutions into separate diluent containers with 225 ml graduations.
Pipette 9ml of the solution into a test tube with a 10ml pipette and ear washing bulb respectively, plug the mouth of the test tube with a rubber stopper, and place it in a test tube rack.
(4) Sterilization of physiological saline
Adjust to determine the sterilization time and temperature.
Sterilization temperature: 121℃
Sterilization time: 15min
(5) Take out physiological saline to cool
Turn off the power, open the lid of the autoclave, take out the sterilized saline, and place it in a cooling area to cool naturally.
The automatic autoclave sterilizer is used here. If using an old-fashioned autoclave, turn off the power, open the vent valve, and empty the gas until the pressure drops to 0, and then open the sterilizer, otherwise it will cause a safety accident.
(6) Put the cooled sterile normal saline solvent diluent in the refrigerator, and mark it: preparation date, preparation person, use expiration date, etc. Generally, it will be stored for 3-5 days. For details, please refer to the relevant document requirements of the company's laboratory.
When doing the microbiological experiment, carry out the blank experiment at the same time, verify again and ensure that the sterile normal saline diluent meets the requirements (blank experiment result: aseptic growth on the plate medium, if there is bacterial growth, the result of this experiment is invalid, and the reason needs to be found out and correct it, and then re-run the experiment).