How to mark the expiration date of chemical reagents after opening? How to make inventory ledger?

Combining inventory and procurement is not complicated. Three sheets can be created in the same table: inventory, procurement plan, and supplier comparison. The inventory table uses a formula to calculate the gap based on current inventory+in transit - predicted consumption in the past two weeks. If it is lower than the safety stock, it will be automatically included in the procurement plan. The price comparison table records the recent unit prices, delivery cycles, and batch consistency of different suppliers, but key reagents should not be replaced frequently. Control costs by consolidating orders and restocking on a quarterly basis, rather than buying from scratch when out of stock; Conventional reagents should be prepared for 1-2 months, with small amounts that are prone to moisture absorption and expensive.

The ledger template is recommended to use Excel or Tencent documents, and the fields at least include: reagent name, CAS, product number/batch number, opening date, recommended use period, storage location, inventory, safety inventory, supplier. Set conditional format: The stock is lower than the safety stock mark red, and the yellow mark is about to expire. It is best to print the QR code on the bottle body, and scan the code to update the inventory when using it. Don't just remember the purchase date, you can't judge the status at the end of the opening date.

It is recommended to check both the expiration date of the bottle and the recommended usage period after opening, whichever is shorter. Tris、 Solids such as glycine and SDS can usually be used for two to three years after opening if they are kept sealed and dry. However, clumping indicates moisture absorption, inaccurate weighing, and possible pH drift. It is not recommended to use them again for critical experiments. When opening, directly use an oil-based pen to write the opening date and recommended retest period on the bottle body. Powder can be retested for 2 years, and liquid can be retested for 1 year. Please refer to the COA for details. Check the appearance, pH or conductivity of the solution during retesting.