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The van Deemter equation is a hyperbolic function that predicts that there is an optimum velocity at which there will be the minimum variance per unit column length and, thence, a maximum efficiency. The van Deemter equation was the result of the first application of rate theory to the chromatography elution process.
A review by Berthod [19] studied the combined theories presented above and applied the Knox equation to independently determine the cause of the reduced efficiency. The Knox equation is commonly used in HPLC to describe the different contributions to overall band broadening of a solute. The Knox equation is expressed as: h = An^(1/3)+ B/n + Cn ...
The tangential arrow represents the tangential linear velocity (m/min or sfm) at the outer diameter of the cutter, called the "cutting speed", "surface speed", or simply the "speed" by machinists. The arrow colinear with the slot that has been milled represents the linear velocity at which the cutter is advanced laterally (usually mm/min or ...
A calibration curve plot showing limit of detection (LOD), limit of quantification (LOQ), dynamic range, and limit of linearity (LOL).. In analytical chemistry, a calibration curve, also known as a standard curve, is a general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration. [1]
HPLC has many applications in both laboratory and clinical science. It is a common technique used in pharmaceutical development, as it is a dependable way to obtain and ensure product purity. [59] While HPLC can produce extremely high quality (pure) products, it is not always the primary method used in the production of bulk drug materials. [60]
Darcy's law is an equation that describes the flow of a fluid through a porous medium and through a Hele-Shaw cell.The law was formulated by Henry Darcy based on results of experiments [1] on the flow of water through beds of sand, forming the basis of hydrogeology, a branch of earth sciences.
A vortex sheet is a term used in fluid mechanics for a surface across which there is a discontinuity in fluid velocity, such as in slippage of one layer of fluid over another. [1] While the tangential components of the flow velocity are discontinuous across the vortex sheet, the normal component of the flow velocity is continuous.
The concentration of particles usually spreads out in a straight line, and the Rouse distribution works in the water column above the sheet-flow layer where the particles are less concentrated. However, velocity distribution formulas are still being refined to accurately describe particle velocity profiles in steady or oscillatory sheet flows. [2]