Which of the top ten brands of domestically produced trichloromethane/isopropanol has low residue for RNA extraction?

The Trizol method for RNA extraction does indeed affect A260/280 and yield due to residual substances such as chloroform, isopropanol, and ethanol. Suggest ordering small packages first and performing 3-5 repeated extractions using the same animal tissue RNA positive sample. Compare with imported reagents A260/280, A260/230, yield, and electrophoresis 28S/18S in parallel. Brands can look at Chinese medicine, Shanghai trial, Aladdin, McLean, etc., but don't just look at the brand, you need to look at the specific batch number. Trichloromethane focuses on evaporation residue and free chlorine/aldehydes, while isopropanol and ethanol focus on moisture and evaporation residue. Small package trials can usually be applied for, and sales are generally supported if samples are used dozens of times a month.

In addition to brand, the storage and packaging of reagents after opening have a significant impact on RNA extraction. Trichloromethane is prone to oxidation and degradation when stored in an open mouth for a long time. Isopropanol and anhydrous ethanol should be protected from moisture absorption. It is recommended to pack them into small bottles according to the weekly dosage to reduce repeated lid opening. When changing to a domestic batch, a "reagent blank extraction" can be performed, following the Trizol process without tissue, and finally measuring A260/A280 and A260/230 to see if there are any residues causing a high background. If the extraction yield or A260/280 fluctuates, first check the moisture and evaporation residue of isopropanol and ethanol, and then consider switching to a different brand of chloroform.

Domestic reagents can be used as substitutes for imported ones in RNA extraction, but this must be done in stages of verification. It is recommended to first select 2 candidate brands, order small packages of each, and perform blinded sample comparisons with the currently used imported reagents; after passing, lock in inventory by lot number and avoid changing lot numbers easily. Negotiate with suppliers in advance: bulk pricing after small samples pass, supply lead time, and return conditions. For chloroform, isopropanol, and anhydrous ethanol, lead times in East China are generally 5–14 days, and precursor chemicals require advance filing. In terms of price, domestic products are usually much cheaper, but the time cost of nucleic acid extraction experiments is high, so it is not advisable to take risks just to save a little on reagent costs; prioritize channels with user cases in molecular biology.

Trichloromethane is a readily toxic/dangerous chemical. Procurement should be filed in advance, and the delivery time is usually longer than that of ordinary reagents. Regular first-class agents or manufacturers generally support the application of small packages for trial use. Especially if you can explain the subsequent batch dosage, you can sample with the same batch number, and then prepare according to the batch number. Don't just ask for the price, ask for the COA and residual metrics. The prices of domestic trichloromethane and isopropanol are much lower than those of imports, but do not directly load large products, buy small bottles first, confirm the extraction results, and then sign the bulk order. When purchasing in batches, write "batch failure can be refunded" into the contract, and keep the control samples.