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thinking about pee tests I thought of a way to make them
more effective, actually this could work with a variety of
Use polymethylmethacrylate gel to absorb all the pure
water of a sample then the chemicals being measured
could be concentrated 20 times.
One approach to making sure
the preferrred protein stays
at solution is to use the isoelectric point of the protein.
Thats the place at gel electrophoresis where a particular
band of protein likes to go. It has an electron affinity pH
equivalent(link). Thus making the PMMA gel at a slightly
different than isolectric pH would tend to keep the protein
from adsorbing or absorbing Another approach is to make
the PMMA get an electret that simply repels proteins of
same charge to keep them at the solution.
Going further you could place a PTFE coating with water
only micropores on the surface to make sure the PMMA just
absorbed water molecules.
These approaches should work with other body fluids as
well, making a variety of physical tests more accurate or
Polymethylmethacrylate is pretty cheap its the
superabsorber at diapers, thus a thing like the 2 or 3¢ birth
defect screening test wetnap could actually have a coating
or area of PMMA on rather cheaply. That could matter for
wikipedia isoelectric point pH
The pI value can affect the solubility of a molecule at a given pH. Such molecules have minimum solubility in water or salt solutions at the pH that corresponds to their pI and often precipitate out of solution. Biological amphoteric molecules such as proteins contain both acidic and basic functional groups. Amino acids that make up proteins may be positive, negative, neutral, or polar in nature, and together give a protein its overall charge. At a pH below their pI, proteins carry a net positive charge; above their pI they carry a net negative charge. Proteins can, thus, be separated according to their isoelectric point (overall charge) on a polyacrylamide gel using a technique called isoelectric focusing, which uses a pH gradient to separate proteins. [beanangel, Jun 08 2011]
||If you just want to concentrate solutes, a simple
way is to shake the sample with a larger volume of
butanol. The butanol absorbs a predictable amount
of the water, concentrating anything that's in it
(apart from lipids, I guess, which might partition into
the butanol). No need to adapt it for each protein.