Solvent Density
Solvent Density - Related Videos
01:12
Solvents
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2019
A solvent is a substance, most often a liquid, that can dissolve other substances. Here, the substance being dissolved is called a solute. When a solvent and a solute combine, they form a solution - a homogenous mixture of both the solvent and the solute. Water is a universal biological solvent. Its polar structure allows it to dissolve many other polar compounds. The ability of water to dissolve is governed by a balance between water molecules binding to each other and binding to the solute. A...
08:13
Preparation of Biopolymer Aerogels Using Green Solvents
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Cited by 44 •
2016
A new way for the production of biopolymer-based aerogels by carbon dioxide (CO2) induced gelation is shown. The technique utilizes pressurized carbon dioxide (5 MPa) for the production of biopolymer hydrogels and supercritical CO2 (12 MPa) to convert gels into aerogels. The only solvents needed besides CO2 are water and ethanol.
06:43
Rotary Evaporation to Remove Solvent
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2023
Source: Dr. Melanie Pribisko Yen and Grace Tang — California Institute of Technology Rotary evaporation is a technique most commonly used in organic chemistry to remove a solvent from a higher-boiling point compound of interest. The rotary evaporator, or "rotovap", was invented in 1950 by the chemist Lyman C. Craig. The primary use of a rotovap is to dry and purify samples for downstream applications. Its speed and ability to handle large volumes of solvent make rotary evaporation a preferred...
09:41
Schlenk Lines Transfer of Solvents
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2023
Source: Hsin-Chun Chiu and Tyler J. Morin, laboratory of Dr. Ian Tonks—University of Minnesota Twin Cities Schlenk lines and high vacuum lines are both used to exclude moisture and oxygen from reactions by running reactions under a slight overpressure of inert gas (usually N2 or Ar) or under vacuum. Vacuum transfer has been developed as a method separate solvents (other volatile reagents) from drying agents (or other nonvolatile agents) and dispense them to reaction or storage vessels while...
08:42
Density Gradient Ultracentrifugation
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2023
Density gradient ultracentrifugation is a common technique used to isolate and purify biomolecules and cell structures. This technique exploits the fact that, in suspension, particles that are more dense than the solvent will sediment, while those that are less dense will float. A high-speed ultracentrifuge is used to accelerate this process in order to separate biomolecules within a density gradient, which can be established by layering liquids of decreasing density in a centrifuge tube. The...
FAQs
Temperature, pressure, and solvent composition can each change solvent density, so a value is meaningful only when those conditions are specified. A density measured for one solvent mixture at one temperature should not automatically be transferred to another mixture or experimental setting. Controlling or recording these variables improves the reliability of solution preparation and comparisons between biological experiments.
Comparing solvent densities helps predict how liquids will layer and how particles or biological structures may move within them. In a biological sample, the relationship between the surrounding solvent and the material being handled influences sedimentation and buoyancy. Recognizing these density relationships helps researchers anticipate sample behavior during handling and choose conditions that support consistent separation.
In density-gradient separation, researchers use controlled density differences to influence the movement of cells, organelles, or biomolecules during centrifugation. Components with different buoyancy respond differently as the sample is spun, allowing separation based on how they behave in the gradient. Solvent densities therefore affect where separated material collects and how consistently fractions can be recovered.
Accurate solvent density supports concentration calculations because the measured mass and volume of a liquid are linked through density. If density is wrong or conditions differ from those used in the calculation, the prepared solution may not match its intended concentration. This matters particularly for buffers and other biological solutions whose composition must be reproducible across experiments.
To use solvent density reliably, researchers first identify the solvent or mixture and establish the temperature and pressure relevant to the experiment. They then measure or calculate density under those defined conditions and use the result for solution preparation, sample handling, or gradient design. Recording the conditions makes later calculations and experimental comparisons easier to interpret.
In biology, density information helps coordinate several connected tasks rather than serving only as a physical-property measurement. It supports preparing buffers, handling samples, setting up centrifugation, and designing gradients for separating cells, organelles, and biomolecules. By anticipating layering, sedimentation, and buoyancy, researchers can improve experimental consistency and interpret separation outcomes more confidently.