How do I verify if a Freund's incomplete adjuvant purchased on the reagent platform has deteriorated?

Freund's incomplete adjuvant can actually be stored at room temperature and away from light, and does not strongly rely on cold chain. High temperature is the main risk. If ice packs or insulated boxes are used during platform transportation, it may lead to condensation and more obvious bottle wall hanging, but it is not necessarily damaged. Check the bottle cap for leakage and ensure the label, batch number, and expiration date are clear upon arrival, and then request a COA or MSDS. If the store is a third-party, inquire about the shipping location and whether the original bottle is genuine, and try to avoid long-distance exposure to sunlight in summer. Be cautious when receiving goods if the bottle body becomes hot or the oil phase becomes thin.

Adherence to the wall does not necessarily indicate spoilage. Freund's incomplete adjuvant itself is a viscous mixture of mineral oil and emulsifier, and it easily adheres to the wall after low-temperature storage or transport vibration. Let it stand at room temperature for a few hours and then shake well; if it can return to a uniform state, it can generally continue to be used. The key is to check for obvious layering, aqueous phase separation, darkening of color, or a rancid smell. Place a small drop on the surface of physiological saline. If it disperses quickly or oil droplets appear, it indicates that the emulsifying property may have decreased; alternatively, emulsify it with antigen in proportion and drop it onto the water surface. If it can maintain intact emulsion droplets without dispersing, there is generally no major problem.

Multi-antibody preparation in mice has a long preparation cycle, and it is not recommended to take inaccurate adjuvants directly to the whole group. You can do an emulsification test first: the antigenic aqueous phase and the adjuvant are pushed back and forth with a three-way tube or syringe in proportion, and a stable emulsion is formed in the first few minutes. The emulsion is kept for half an hour without oil-water separation, which is basically usable. If irreversible flocculation, granulation or delamination appears in the bottle after shaking, do not take any risks even if you can shake it. If necessary, use 2-3 mice for pre-immunization, observe the absorption and subsequent antibody titers at the injection site, and then decide to use the whole batch. Third-party cold chains are uneven, giving priority to merchants in the same city and the next day, and requiring shockproofing and shading when shipping.