The symmetric curve means that the curve is symmetrical and the equal point is the inflection point of the curve. This type of curve is evaluated by plotting the "first derivative dE/dV" and "titrant consumption V" profiles. The maximum value of the first derivative is at the inflection point and indicates that this point is the equivalent point. The titrator has a corresponding step ("STANDARD") to automatically evaluate the symmetry curve (S-curve).
The shape of the asymmetric curve is different from the standard symmetric curve (S-curve), and therefore its evaluation procedure is also different. Tubbs method was used for evaluation (for details, see "Basics of titration", ME-704153). The asymmetry of the curve must be considered in the evaluation: the equal points will move into the area with large curvature. The curve is tangent to two circles (preferably two hyperbolas), and the point where the line connecting the two center points intersects the curve is the equal point. For example: photometric titration, redox titration, turbidity titration.
The most typical example of the minimum (maximum) curve is a turbidity titration, such as the determination of the content of an anionic surfactant, which, when added to the titrant, forms a gelatinous precipitate. The turbidity of the solution will increase at this time. The profile of the curve is determined by the minimum value of the curve indicating the equal point EQP. The photoelectrode monitors the formation of precipitates and measures the amount of light in the solution. At the point of equalization, the turbidity reaches the maximum, that is, the light yield is the smallest. Use a special evaluation method to determine the minimum value of the curve ("MINIMUM"). To evaluate the maximum curve use the step "MAXIMUM". Such as cooling lubricants anionic surfactant content determination.
The section curve has a very clear transition at the equal point. This type of curve is usually obtained when performing conductometric titration (note the unit of measurement for the graphical coordinates: S/cm, Howe-Siemens). EQP occurs when the conductivity value jumps. The curve is evaluated by determining the maximum of the second derivative. Such as beer a acid measurement (conductivity titration), vitamin C determination (coulometric titration).
The shape of the asymmetric curve is different from the standard symmetric curve (S-curve), and therefore its evaluation procedure is also different. Tubbs method was used for evaluation (for details, see "Basics of titration", ME-704153). The asymmetry of the curve must be considered in the evaluation: the equal points will move into the area with large curvature. The curve is tangent to two circles (preferably two hyperbolas), and the point where the line connecting the two center points intersects the curve is the equal point. For example: photometric titration, redox titration, turbidity titration.
The most typical example of the minimum (maximum) curve is a turbidity titration, such as the determination of the content of an anionic surfactant, which, when added to the titrant, forms a gelatinous precipitate. The turbidity of the solution will increase at this time. The profile of the curve is determined by the minimum value of the curve indicating the equal point EQP. The photoelectrode monitors the formation of precipitates and measures the amount of light in the solution. At the point of equalization, the turbidity reaches the maximum, that is, the light yield is the smallest. Use a special evaluation method to determine the minimum value of the curve ("MINIMUM"). To evaluate the maximum curve use the step "MAXIMUM". Such as cooling lubricants anionic surfactant content determination.
The section curve has a very clear transition at the equal point. This type of curve is usually obtained when performing conductometric titration (note the unit of measurement for the graphical coordinates: S/cm, Howe-Siemens). EQP occurs when the conductivity value jumps. The curve is evaluated by determining the maximum of the second derivative. Such as beer a acid measurement (conductivity titration), vitamin C determination (coulometric titration).
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