HPLC is an improved form of column chromatography. It uses high pressures to force the solvent through the column instead of just using gravity. By using much higher pressure than normal, the process becomes much faster and it allows the use of smaller particle size for the column packing material. Having smaller particles gives a larger surface area for interactions between the stationary phase and the molecules flowing through it which means better separation. Absorbance There are two main ways HPLC are used, normal phase and reverse phase.
2. EXPERIMENTAL DETAILS 2.1 Materials and Method All the chemicals used were in analytical grade and were used without further purification. In a typical experiment, 0.1 M of copper (II) nitrate trihydrate (Cu(NO3)2.3H2O), 98%;Merck) was dissolved in 350 ml deionized water and allowed to stir for complete dissolution of the compound. 0.05 M of hexamethylenetetramine (HMT) (C6H12N4,ACS reagent, ≥99.0%) was added drop wise to the above solution. The CuO precursors containing Na+-dopant was prepared with 1.0 mole% and 2.0 mole % of sodium nitrate concentration.
enthalpy change of solution is the enthalpy change when 1 mole of an ionic substance dissolves in water to give a solution of infinite dilution. Enthalpies of solution may be either positive or negative - in other words, some ionic substances dissolved endothermically (for example, NaCl); others dissolve exothermically (for example NaOH). An infinitely dilute solution is one where there is a sufficiently large excess of water that adding any more doesn't cause any further heat to be absorbed or evolved. So, when 1 mole of sodium chloride crystals are dissolved in an excess of water, the enthalpy change of solution is found to be +3.9 kJ mol-1. The change is slightly endothermic, and so the temperature of the solution will be slightly lower
Molecules of a hydrophilic colloid have an affinity for water molecules and thus when they are dispersed in water they become hydrated. Hydrated colloids swell and increase the viscosity of the system, hence improving stability by reducing the interaction between particles and their tendency to settle. A hydrophobic colloid has little or no affinity for water molecules in solution and produces no change in system viscosity. Some colloids are translucent because of the Tyndall effect, which is the scattering of light by particles in the colloid. Otherwise
Method of preparation: - The preparation method for lecithin organogel is quite simple and easy. Weighed amount of lecithin (350mM) is to be dissolved in non-polar solvent like isopropyl palmitate (IPP) or isopropyl myristate (IPM) with the help of vortexing and bath sonication. Triamcinolone acetonide (0.5%) was dissolved in previously formed micellar dispersion of Lecithin-IPP. Most critical and important step in gel formation is addition of polar solvent. As the above solution becomes clear and transparent, polar solvent is to be added, mostly water to it in very much less quantity.
DETERMINATION OF A SOLUBILITY PRODUCT CONSTANT Introduction Parsimoniously soluble ionic solids, when placed in water, go through an equilibrium reaction. This equilibrium reaction is the same as a hypothetical reaction of solid, WxZy as shown in equation 1. WxZy (s)↔xWy+ + yZx- ………………………………………….. Equation 1 From equation 1, the equilibrium constant (Keq) of any reaction is called Ksp (solubility product constant) of the ionic solid. Fundamentally, solubility product constant is the quantification of the association of the ionic solid and its ions.
When no movement occurs, then there is no difference meaning there is an equilibrium present within the two solutions. With the yellow tubing, it was a hypotonic solution compared to beaker 2 causing the solution outside of the tubing to cross over the membrane inside the
In a marine fluid flow system, especially in piping system and centrifugal pumps, occurs a typical problem known as cavitation. That according to Matthew A. Carr (2012) “cavitation is the formation and subsequent collapse of bubbles (or cavities) of working fluid vapors.” These bubbles, which are compressible reducing the fluid density, are originated when the local pressure is too low (below the vapour pressure), or its temperature is too high making that some fluid became vapour, and when the pressure is increased the bubbles returns to its liquid phase collapsing. When near solid surfaces such as pump impeller, which is location where it happens frequently in centrifugal pumps, or pipe wall the collapsed cavities result in shock waves that
The sample is dissolved in solvent , treated with potassium iodide, and the iodine liberated by the peroxides present in rancid fat or oil is treated with sodium thiosulphate solution often the number of millimoles of peroxide oxygen is reported , and the result is then half that of peroxide value. In case , the term “lea-value” is frequently used. Reagents: 1. Solvent: Mix 2 volumes of glacial acetic acid and 1 volume of chloroform. 2.