Good question! At this step, 95-100% ethanol can be used and the kit performance/RNA yield will be the same. The more important thing is that the ratio remains at 1:1 with the volume of TRIzol.
Hello, the strong fumes are usually from the TRIzol reagent. In low amounts, the fumes are not harmful. However, we recommend performing the sample lysis and loading step in a fume hood to minimize the amount of exposure to the fumes.