In the most common form of silica chromatography, more polar molecules stick to the stationary phase. Silica is just sand, and the polar silanol groups (-Si-OH) interact with the polar parts of the molecule. You can "reverse" the properties of silica by converting the silanols into something nonpolar.
ODS-Cl was the first reagent commonly used to do this - it converts the -Si-OH into -Si-O-Si-O-(CH2)15CH3. This means that polar molecules are effectively indifferent to this modified silica and will flow right past, while greasy things will stick like crazy. This is often a useful thing, and "reversed phase" chromatography is ubiquitous in HPLC.
- Log in to post comments
More like this
The point of set theory isn't just to sit around and twiddle our thumbs about
the various definitions we can heap together. It's to create a basis on which we
can build and study interesting things. A great example of that is something
called a group. Once we've built up sets enough to be able to…
I'm not certain you can have all four. Let's start at the beginning.
Just to review, one way to examine the human microbiome--the organisms that live on and in us--is extract the DNA from a biological sample (usually something from a person that is slimy, stinky, or both, such as feces or a…
Not all the email I get is from cranks and creationist loons. Sometimes I get sincere questions. In today's edition of "Ask Mr Science Guy!", Hank Fox asks,
I was thinking recently about the fact that wax collects in one's ears, and suddenly thought to be amazed that some part of the HUMAN body…
This post is something that I'm thinking of including in my
book. I haven't decided whether I want to spend this much time on
logics; they're really interesting and fun - but there's lots of
other interesting and fun stuff, and there's only so much space.
The topic of the moment is temporal logic…