Recommendation for inorganic acid-base reagents: Which of the top ten domestic brands has a more stable batch?

I want to switch from imports to domestic production. It is basically feasible to use high-quality pure inorganic acid bases for environmental digestion. However, for projects with low background requirements for ICP-MS and high background requirements, there may be occasional fluctuations in Cr, Ni, and Fe background for domestic acids. It is recommended to first conduct a batch of parallel digestion on the superior grade pure samples of Shanghai Trial and National Medical Products, and compare the blank and internal standard recovery with the imported batch; If individual elements do not meet the standards, a sub boiling still can be used for secondary purification, and it is not necessary to replace them all with imported ones. Don't just rely on brand promotion for heavy metal residue, follow your actual method blank. The price of 500ml is about 1/3-1/2 of that of domestic imports, and the normal delivery time in East China is 3-7 days.

I am in the East China laboratory, and there are many domestically produced high-quality pure nitric acid and hydrochloric acid used for environmental digestion. It is recommended not to directly look at the brand ranking list. First, each candidate brand should send 2-3 batches of samples, and use the same batch of quality control soil samples for the entire process of blank and spiked recovery, with a focus on Pb, As, Cd, Cr, and Fe. Guoyao, Shanghai Trial, Xilong, and Yonghua are relatively mature suppliers in East China, and their batch stability can be traced, but not every batch number is stable. The common trade price for 500ml high-quality pure nitric acid/hydrochloric acid is mostly in the range of 20-60 yuan, depending on the purchase quantity and distributors. The delivery time is generally 48-72 hours for spot goods and 7-10 days for non spot goods. Conduct supplier admission before signing the annual agreement.

The monthly use of 40-60 bottles is not small. It is recommended that East China set up one main supplier and one backup supplier. Require batch COA and heavy metal/evaporation residue data. It is best to accept on-site audits or sample verification. Sinopharm, Guanghua, Comio, and Xilong on the brand can be included in the comparison, not to be kidnapped by the "top ten brands", and many differences are in the warehousing and transportation of dealers. The samples are retained for each batch number on arrival, and the problems can be traced back. The price can be negotiated according to the annual usage, generally 5% -15% fluctuation, futures spot 2-3 days, stock 7-10 days. The key is to stabilize the supply, and it is not recommended to change cards frequently.

Inorganic acids and alkalis are dangerous chemicals. In East China, it is recommended to prioritize brands with dangerous chemical warehouses in Shanghai or Jiangsu, such as Sinopharm, Titan, Yonghua, etc. Logistics and filing will save a lot of things. Arrival focuses on checking whether the bottle opening seal, production batch number, and COA come with the goods. When the same batch number arrives multiple times, be vigilant when serializing the goods. The batch stability can be measured on the machine after the blank is dissolved, and the internal control limit is set. For example, the blank response is not higher than a certain proportion of the detection limit of your method. The price of 500ml products should not be too entangled. The monthly price of 40-60 bottles can be negotiated, which is generally more than half lower than the imported price. The futures are in stock for about 3 days, and the bulk shipment is 7-14 days.