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The Van Slyke determination is a chemical test for the determination of amino acids containing a primary amine group. It is named after the biochemist Donald Dexter Van Slyke (1883-1971). [1] One of Van Slyke's first professional achievements was the quantification of amino acids by the Van Slyke determination reaction. [2]
Donald Dexter Van Slyke (March 29, 1883 – May 4, 1971), nicknamed Van, was a Dutch American biochemist. His achievements included the publication of 317 journal articles and 5 books, [ 1 ] as well as numerous awards, among them the National Medal of Science and the first AMA Scientific Achievement Award . [ 1 ]
By contrast, at almost the same time, Donald Van Slyke and G. E. Cullen [79] treated the binding step as an irreversible reaction. The Briggs–Haldane equation was of the same algebraic form as both of the earlier equations, but their derivation is based on the quasi- steady state approximation, which is the concentration of intermediate ...
Buffer capacity rises to a local maximum at pH = pK a. The height of this peak depends on the value of pK a. Buffer capacity is negligible when the concentration [HA] of buffering agent is very small and increases with increasing concentration of the buffering agent. [3] Some authors show only this region in graphs of buffer capacity. [2]
The Van Slyke determination tests for specific amino acids; The Zimmermann test tests for ketosteroids; Seliwanoff's test differentiates between aldose and ketose sugars; Test for lipids: add ethanol to sample, then shake; add water to the solution, and shake again. If fat is present, the product turns milky white.
For example, a motorized pipette controller can aid liquid aspiration or dispensing using volumetric pipettes or graduated pipettes; [13] a tablet can interact in real-time with the pipette and guide a user through a protocol; [14] and a pipette station can help to control the pipette tip immersion depth and improve ergonomics.
With nitrous acid, one obtains glycolic acid (van Slyke determination). With methyl iodide, the amine becomes quaternized to give trimethylglycine, a natural product: H 3 N + CH 2 COO − + 3 CH 3 I → (CH 3) 3 N + CH 2 COO − + 3 HI. Glycine condenses with itself to give peptides, beginning with the formation of glycylglycine: [34] 2 H 3 N ...
Other examples of inorganic polyprotic acids include anions of sulfuric acid, phosphoric acid and hydrogen sulfide that have lost one or more protons. In organic chemistry and biochemistry, important examples include amino acids and derivatives of citric acid. Although an amphiprotic species must be amphoteric, the converse is not true.