Solubility Guide

Solubility Guide (taken from two respected sauces, in anticipation of their sites no longer being accessible in the near future. RIP)

LGD-4033: Observation: White fine powder, odorless, tasteless. Storage (powder): Room temperature. Soluble: Propylene Glycol, DMSO and Ethanol

GW 501516: Observation: White to slight yellow fine powder. Storage (powder): Room temperature. Soluble: Water (partial), PEG-400, Ethanol

S4: Observation: Pale yellow fine powder, odorless, acrid bitter taste. Storage (powder): Room temperature. Soluble: Propylene Glycol, DMSO, Ethanol, PEG-400

MK-677: Observation: Off white to beige fine powder, hygroscopic, acrid odor, acrid metallic taste. Storage (powder): Cool, dry place. Minimize open air exposure/ Soluble: Water, DMSO, Ethanol, Propylene Glycol

RAD-140: Observation: Off white fine powder, mild odor and taste. Storage (powder): Room temperature. Soluble: DMSO, Ethanol, PEG-400

SR-9009: Observation: Slight off white fine powder, odorless, mild bitter taste. Storage (powder): Room temperature. Soluble: Propylene Glycol, DMSO, Ethanol

MK-2866: Observation: White crystalline powder, odorless, mild taste. Storage (powder): Room temperature. Soluble: Propylene Glycol, DMSO, Ethanol

YK-11: Observation: White fine powder. Storage (powder): Room temperature. Soluble: Propylene Glycol, DMSO, Ethanol


Introduction to Chemical Solutions

Chemical solutions involve dissolving a reagent in liquid to make it easier to measure, without relying on an expensive or imprecise scale. Assuming the solution is at a uniform concentration, measurement of the reagent can be done precisely using volumetric measurement tools like a beaker or pipette.

Selecting an adequate solvent

If you do not select an adequate solvent your solute will precipitate out of solution or lack uniformity, making handling difficult.

Selecting your concentration

Solutions are easier to make and handle at lower concentrations. If you saturate a solution the solute may precipitate out of solution thus ruining the uniformity. Changing the pH or temperature of your solution can also result in precipitation.

Solution Example: Using mass by volume (m/v) Formula

The formula for mass by volume (m/v) is: [Mass of solute (mg) / Volume of solution (ml)]

ExampleA 10mg/mL NaCl solution has 10 milligrams of sodium chloride dissolved in 1 ml of solution.

Procedure

  1. Select a concentration for your solution e.g. 10mg/mL.
  2. Select a total volume for your solution e.g. 50mL.
  3. Weigh out your solute by multiplying the concentration by total volume e.g. 10mg/mL * 50mL = 500mg.
  4. Select an adequate solvent for your concentration.
  5. Pour your solute into your solvent and mix.
  6. The solute should fully dissolve and the solution should become transparent. If there is sediment or visible particles then the solution is not uniform.

Notes:

  1. The procedure above is simplified. Simply measuring 50mL of solvent and adding 500mg of solute introduces error because adding the solid will change the final volume of the solution. The more correct procedure would be to mix solute with ~80% of your solvent and then add solvent until you reach your desired volume of 50mL.
  2. The most common causes of precipitation include selecting an inadequate solvent, selecting too high a concentration, not using adequate measurement equipment (milligram scale, graduated beaker), mixing multiple solutes together (which will affect pH and lower solubility).
  3. Recommend against heating or incubation if possible. The solute will precipitate out as it cools down.

Precipitation and Suspension

What if your solution precipitates? You have a few options. If you selected too high a concentration you can add more solvent or a cosolvent and lower the concentration.Another option, if the precipitation is minor, is to suspend the precipitate temporarily by agitating (shaking well, stirring vigorously) and then make your volumetric measurement. This will have some error, dependent on the level of precipitation and uniformity.

Definitions

Reagent – Any substance used in chemical reactions, analysis or research.

Solute – The substance which dissolves in a solution.

Solvent – The substance which dissolves another to form a solution. For example, in a sugar and water solution, water is the solvent; sugar is the solute.

Solution – A mixture of two or more pure substances. In a solution one pure substance is dissolved in another pure substance uniformly. For example, in a sugar and water solution, the solution has the same concentration throughout, ie. it is uniform.

Concentration – The ratio of solute to solution e.g. 10mg per mL, 10mg/mL, 10mg/cc.

Suspension – Typically a solution is transparent because solute particles are microscopic. A suspension has visible particles.