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  2. Henderson–Hasselbalch equation - Wikipedia

    en.wikipedia.org/wiki/Henderson–Hasselbalch...

    C A is the analytical concentration of the acid and C H is the concentration the hydrogen ion that has been added to the solution. The self-dissociation of water is ignored. A quantity in square brackets, [X], represents the concentration of the chemical substance X. It is understood that the symbol H + stands for the hydrated hydronium ion.

  3. Molar absorption coefficient - Wikipedia

    en.wikipedia.org/wiki/Molar_absorption_coefficient

    c is the molar concentration of those species; ℓ is the path length. Different disciplines have different conventions as to whether absorbance is decadic (10-based) or Napierian (e-based), i.e., defined with respect to the transmission via common logarithm (log 10) or a natural logarithm (ln). The molar absorption coefficient is usually decadic.

  4. Acid dissociation constant - Wikipedia

    en.wikipedia.org/wiki/Acid_dissociation_constant

    If the pH is known, the ratio may be calculated. This ratio is independent of the analytical concentration of the acid. In water, measurable pK a values range from about −2 for a strong acid to about 12 for a very weak acid (or strong base). A buffer solution of a desired pH can be prepared as a mixture of a weak acid and its conjugate base ...

  5. Ion speciation - Wikipedia

    en.wikipedia.org/wiki/Ion_speciation

    Speciation of ions refers to the changing concentration of varying forms of an ion as the pH of the solution changes. [ 1 ] The ratio of acid, AH and conjugate base, A − , concentrations varies as the difference between the pH and the p K a varies, in accordance with the Henderson-Hasselbalch equation .

  6. Isosbestic point - Wikipedia

    en.wikipedia.org/wiki/Isosbestic_point

    The spectra of basic, acid and intermediate pH solutions are shown. The analytical concentration of the dye is the same in all solutions. In spectroscopy, an isosbestic point is a specific wavelength, wavenumber or frequency at which the total absorbance of a sample does not change during a chemical reaction or a physical change of the sample ...

  7. Dissociation constant - Wikipedia

    en.wikipedia.org/wiki/Dissociation_constant

    The concentration of water, [H 2 O], is omitted by convention, which means that the value of K w differs from the value of K eq that would be computed using that concentration. The value of K w varies with temperature, as shown in the table below. This variation must be taken into account when making precise measurements of quantities such as pH.

  8. Bradford protein assay - Wikipedia

    en.wikipedia.org/wiki/Bradford_protein_assay

    The equation displayed on the chart gives a means for calculating the absorbance and therefore concentration of the unknown samples. In Graph 1, x is concentration and y is absorbance, so one must rearrange the equation to solve for x and enter the absorbance of the measured unknown. [25]

  9. Absorbance - Wikipedia

    en.wikipedia.org/wiki/Absorbance

    Absorbance is defined as "the logarithm of the ratio of incident to transmitted radiant power through a sample (excluding the effects on cell walls)". [1] Alternatively, for samples which scatter light, absorbance may be defined as "the negative logarithm of one minus absorptance, as measured on a uniform sample". [ 2 ]