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    Home > Biochemistry News > Biotechnology News > The UV content determination method of amino acids.

    The UV content determination method of amino acids.

    • Last Update: 2020-10-23
    • Source: Internet
    • Author: User
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    : Want to know
    amino acid
    UV content measurement method, is about otters!
    : It is recommended to refer to the cerebral protein hydrolyte (oral use, injection with two) standards, to determine the total amount of "amino nitrogen." I have the standard of oral use (ws-xg-130-2002, volume 16, p. 324) but there is no electronic version, I will give you the amino nitrogen measurement method to knock it again:
    products per 1g of total nitrogen should be 30 to 100 mg, ammonia nitrogen should be 40% to 50% of total nitrogen.
    amino nitrogen take this product 0.5g, precision weighing, in research, add water 30ml, grinding to make full dissolution, with 0.1mol/L hydrochloric acid solution or 0.1mol/L sodium hydroxide solution, adjust pH to 7.0, and then add pre-adjusted pH 9 .0 formaldehyde solution 10 ml, stir well, with sodium hydroxide titration solution (0.1mol/L) titration to the solution pH of 9.0, according to the amount of sodium hydroxide titration (0.1mol/L) consumed after adding formaldehyde solution (ml). Each 1 ml of sodium hydroxide titration (0.1mol/L) is equivalent to 1.401 mg of amino nitrogen.
    : OPA: O-pathaldialdehyde, or phthalates. It is highly recommended
    imported
    (Sigma or Fluka). OPA commodity is a solid powder, the solution is made as follows: 10mgOPA powder with 0.1 ml methanol or ethanol dissolved with 0.9 ml 0.4N (pH 10.2) boric acid buffer, and then add 0.01 ml of 3-MPA (3- base propylene acid), mixed and divided to save!
    : 1, OPA once the preparation of solution is very unstable, easy to be oxidized, so the derivative process if possible, through N2 protection.
    2, OPA amino acids
    bio
    , 3-MPA is a must.
    3, boric acid solution with 10N NaOH to adjust the pH.
    4, the derivative reaction is carried out in the boric acid buffer system (sample and boric acid dissolved liquid accumulation ratio is 1:5), the molar volume of OPA is controlled to more than 5 times the total amount of AA (insurance value).
    : I've been doing all-amino acid analysis recently, and of course pre-bar deriving is the most accurate method, including OPA-FMOC co-derived, 2,4-denitrofluorobenzene, waters patented A
    . QC
    (Accq.Tag) and others. Among them is now more commonly used is OPA-FMOC derivatives and AQC method derivatives, the former derivatives instability, the latter is mainly analysis time between 45-60 (can also be controlled within 25 minutes) and reagent pack is too expensive, of course, you can reduce costs if you use a lot of words.
    And the latter on the AOAC is officially recommended to use (originally only with fluorescence detection, later developed with UV can also be detected), its detection sensitivity can reach the pmol level, the same as OPA, but its derivatives are more stable, can be placed for a week, in front of the column derived analysis of amino acid HPLC method, this method in addition to the time to be longer than other methods, expensive is also one of its characteristics, but do full amino acid analysis results are very good. Because you want to be used for standard-set, or recommended to use this method, after all, is still officially certified by AOAC.
    .
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