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In United States Pharmacopeia (USP) General Chapter <711> Dissolution, there are four dissolution apparatuses standardized and specified. [6] They are: USP Dissolution Apparatus 1 – Basket (37 °C ± 0.5 °C ) USP Dissolution Apparatus 2 – Paddle (37 °C ± 0.5 °C) USP Dissolution Apparatus 3 – Reciprocating Cylinder (37 °C ± 0.5 °C)
Pure deuterated DMSO shows no peaks in 1 H NMR spectroscopy and as a result is commonly used as an NMR solvent. [2] However commercially available samples are not 100% pure and a residual DMSO-d 5 1 H NMR signal is observed at 2.50ppm (quintet, J HD =1.9Hz). The 13 C chemical shift of DMSO-d 6 is 39.52ppm (septet). [3]
The integral heat of dissolution is defined as a process of obtaining a certain amount of solution with a final concentration. The enthalpy change in this process, normalized by the mole number of solute, is evaluated as the molar integral heat of dissolution. Mathematically, the molar integral heat of dissolution is denoted as
Biological substances can experience leaching themselves, [2] as well as be used for leaching as part of the solvent substance to recover heavy metals. [6] Many plants experience leaching of phenolics, carbohydrates, and amino acids, and can experience as much as 30% mass loss from leaching, [5] just from sources of water such as rain, dew, mist, and fog. [2]
In chemistry, solvent effects are the influence of a solvent on chemical reactivity or molecular associations. Solvents can have an effect on solubility , stability and reaction rates and choosing the appropriate solvent allows for thermodynamic and kinetic control over a chemical reaction.
Gases are removed for various reasons. Chemists remove gases from solvents when the compounds they are working on are possibly air- or oxygen-sensitive (air-free technique), or when bubble formation at solid-liquid interfaces becomes a problem. The formation of gas bubbles when a liquid is frozen can also be undesirable, necessitating degassing ...
In solvent casting and particulate leaching (SCPL), a polymer is dissolved in an organic solvent. Particles, mainly salts, with specific dimensions are then added to the solution. The mixture is shaped into its final geometry. For example, it can be cast onto a glass plate to produce a membrane or in a three-dimensional mold to produce a scaffold.
In general terms, any solvent that contains a labile H + is called a protic solvent. The molecules of such solvents readily donate protons (H +) to solutes, often via hydrogen bonding. Water is the most common protic solvent. Conversely, polar aprotic solvents cannot donate protons but still have the ability to dissolve many salts. [1] [2]