Is it reliable to buy chromatography pure acetonitrile on the chemical reagent purchasing platform?

Domestic brand acetonitrile can be used on HPLC-UV small molecules, but batch stability needs to be controlled by oneself. It is recommended to purchase fewer bottles for the first time, such as 1-2 bottles. After arrival, perform a blank gradient elution to check the 210 and 254 nm baselines, and then run a needle with the existing sample to compare the retention time and peak area. Require merchants to provide COA for the current batch along with the goods, with a focus on UV transmittance and evaporation residue. If two to three consecutive batches of data are stable, then consider locking. After opening the bottle, pay attention to sealing as acetonitrile tends to float after absorbing moisture.

I prefer platform self-operated or manufacturer flagship stores, which are more expensive, but the warehousing and logistics conditions are more controllable, and problems are traced back quickly. The low price of third-party stores is often due to dispense, interim or unknown channels. The solvent of acetonitrile is most afraid to introduce plasticizers and moisture when dispense. When looking at the store, don't just look at the ratings, look at the feedback in the bad reviews about the batch number, packaging, and logistics damage, and ask whether it is the original factory and whether there is an agent authorization. Bottle labels, batch numbers and COAs can be requested. Do not buy bottles that have been divided into vials and do not have a production date.

If funds are tight, domestically produced chromatography pure acetonitrile can be used as an alternative, but it is recommended not to directly replace imported brands. Take a stable sample for parallel comparison and examine whether there are unknown small impurities, changes in resolution, and gradient blanks near the target peak. UV detection of small molecules is usually less sensitive to acetonitrile impurities, but low wavelengths, especially around 210 nm, are easily interfered by impurities. The monthly usage of 8-10 liters is not small. You can choose two companies to test 2-3 bottles each and keep samples for future reference. If there are significant differences in subsequent batches, communicate with the platform to return or exchange batches. Legitimate platforms generally recognize COA and abnormal testing.