As an important sterilization and particle removal instrument, the hydrophobic PVDF syringe filter has been widely used in the sample processing of pharmaceutical, particle detection and analysis instruments. As the most common hydrophobic PVDF syringe filter in laboratories, in addition to dissolution testing and chemical compatibility testing, integrity testing should also be done.
The integrity of the filter is a very important indicator in the filtration product. Whether a filtration system can guarantee its integrity before and after filtration is also an important parameter to measure the quality of a filtration product.
Sterility inspection of Chinese and Western medicines for injection and large transfusion. Microbial limit inspection, used for oral Chinese and Western medicine, cosmetics, food, health food and other bacteria count, can be used for semi-solid, suspension, solid and other samples. Clinical laboratory tests for bacteria in body fluids, blood products and veterinary drug products. Sterilization filtration of a small amount of test material.
Two training methods:
Add culture medium to the glass cylinder for closed direct culture. Take out the filter membrane for aerobic bacteria, anaerobic bacteria and fungi culture.
Introduction of usage
Before inhaling the sample, draw about 1ml of air into the syringe to minimize liquid residue. Draw the sample into the syringe, turn the syringe upside down and clear all residues on the tip. Connect the needle filter to the syringe and tighten gently to ensure a good seal. Filter the sample in the syringe and inject it into the sample bottle, and then follow the steps to maximize the recovery rate. Remove the filter, draw air into the syringe, reconnect the filter head, and push out all remaining samples.
For the filtration process, especially the sterilization-grade filtration, the integrity test is a necessary method to ensure the safety and reliability of the filtration and avoid unnecessary waste in work, including time, energy, and filtering samples. Through the integrity test, you can ensure: the integrity of the filter itself, the airtightness of the filter system. The filter membrane is not damaged and flawless, and the selected filter membrane meets the filtration requirements. The correctness of installation and operation of the filter in the process. The installed filter complies with the standards provided by the manufacturer, etc.
Integrity testing methods are divided into two categories, destructive and non-destructive. The so-called destructive test refers to the bacterial challenge test, which is a fundamental method to prove that the filter can meet the stringent sterilization filter standards.
In the bacterial challenge test, a certain number of samples need to be drawn from each batch of products based on statistical principles, and the defective pseudomonas solution is used to perform the bacterial challenge test in accordance with the standard test method. Usually the manufacturer of the filter material will carry out this destructive test to check whether the quality of its product is qualified.
Non-destructive testing methods mainly include bubble point test (also called starting point test) and diffusion test. For users of small filter products, the bubble point test is a simple and easy test method. The bubble point test can be used to screen the performance of the selected filter product and determine whether the filter result is effective.
Hydrophobic PVDF syringe filters are widely used by laboratory researchers in the field of analysis and life sciences because of their simplicity and convenience. The seemingly simple small filter plays a key role in the experimental link. It not only ensures the smooth progress of subsequent experiments and obtains accurate experimental data, but also uses it to remove impurities in chromatographic analysis experiments, which can guarantee precision instruments The service life of the machine reduces the risk of damage, thereby maximizing cost savings.
Of course, users will also have some confusion during use. The filter membrane in the hydrophobic PVDF syringe filter is sealed in it and cannot be seen. How can it be judged that a qualified filter membrane is used in the filter? Is the filter membrane properly sealed and not damaged?
Indeed, if a filter of unqualified quality is used, the sample only passes through the filter up and down, and the impurities are not completely trapped by the filter membrane in the filter, especially if the membrane is damaged or not completely sealed, the liquid will flow from the gap If it is leaked, follow-up experiments cannot be performed normally, and financial and material resources will be wasted.
In fact, these confusions are not difficult to eliminate. The quality of the hydrophobic PVDF syringe filter can be easily identified by the bubble point principle introduced above.