Please recommend a supplier of HPLC grade acetonitrile, with a large laboratory usage and stable delivery time

Plasma samples are sensitive to baseline cleanliness, and I value batch consistency more than brand reputation. It is recommended to fix a brand and a place of origin, do not change frequently. First perform blank gradient elution on each new batch, use 195/210 nm to look at baseline fluctuations and miscellaneous peaks, and compare with the previous batch; moisture can be sampled according to COA or Karl Fischer. Different batches of HPLC-grade acetonitrile may indeed have different absorbance at low wavelengths. Especially near 210 nm, the supplier COA will write UV cut-off and moisture, but don't just look at the report, it is more secure to enter a needle yourself. If the batch discrepancy affects the method, you can ask the agent to reserve a few more boxes from the same batch number to you, one quarter at a time. There are many brands in Shanghai in stock, and Merck, Fisher, and Honeywell can ask if they are stocking up.

For a monthly quantity of 40-50 liters, it is recommended to purchase them in full boxes of 4L, which is more stable than single bottles and less prone to transportation damage. Pay attention to three points: firstly, ask suppliers to report the delivery price including tax and freight. In the Shanghai area, check whether the delivery includes hazardous chemicals. Acetonitrile is a hazardous material, and logistics qualifications will affect the delivery time; The second requirement is to specify the delivery time and liability for breach of contract due to shortage in the contract, otherwise the supplier will claim that the goods are out of stock and you cannot pursue them; Thirdly, monthly settlement should not only be based on payment terms. Some agents may charge additional fees for monthly settlement, which should be included in the total cost. Later on, we switched between placing orders with two companies, and whoever had stock would ship it, without any interruption. If domestic manufacturers use acetonitrile as a plasma sample, it is recommended to conduct batch validation first. The purity is acceptable, but UV and moisture indicators need to be confirmed with emphasis.

Our laboratory is located in Shanghai, and we use about 30-40 liters of acetonitrile per month. I have signed an annual framework with both the main and backup suppliers, using Merck or Fisher's HPLC/gradient grade as the main supplier, and delivering 4L x 4 bottles in full boxes with relatively stable delivery. Local agents in Shanghai generally have bonded or spot warehouses. Before placing an order, it is necessary to confirm whether it is in stock or transferred, and to lock in inventory. Payment terms can be negotiated on a monthly basis, but the prerequisite is to provide a business license and laboratory qualifications. The first order may need to be settled on a cash basis first. The price of 4L containers may fluctuate among different suppliers, and acetonitrile is greatly affected by raw materials. Do not only focus on the unit price, but also include out of stock losses. It is recommended to have at least two agents who can ship within 48 hours.