This is an interesting question that does not have a straightforward answer. In fact, there are many materials that are potentially useful sorbents for dry loading crude mixtures. Some of the more popular are silica, diatomaceous earth (e.g. ISOLUTE® HM-N, Celite®), alumina, and Florisil®. The sorbent choice can influence your purification results because each of the available media have different chemistry and capacity. In most cases, sample/sorbent reactivity really is not a major concern, though it can occur. What is important is the sorbent’s capacity to adsorb/absorb all of your sample and the ratio of your crude sample to the amount of dry load sorbent.
Dry loading crude samples for flash purification typically works better than liquid loading, especially for challenging purifications. In this post, I discuss how the ratio of crude sample to dry load sorbent impacts purification performance.