[A rapid colorimetrical micro method for histidine determination from culture plant seeds]
1995
Namigean, Mirela | Drochioiu, G. | Murariu, Daniela (Banca de Resurse Genetice, Suceava (Romania))
Histidine, in an alkaline medium, has a coupling reaction with diazonium salt of sulfanilic acid (Pauly reaction). This reaction can not be used for the quantitative determination of this amino-acid because the obtained colouring is not stable and the blank colouring increases rapidly until it exceeds the colouring of the analysed sample. That's why this work conditions to determine histidine by stabilising the colouring in Pauly reaction with sulphuric acid. In 1 ml of analysed sample, containing histidine are added consecutively 1 ml R4 and 3 ml R11, stirring strongly. Sample are maintaining 30 minutes at room temperature and then read the extinctions of solution colourings at 400 nm in the tub of 0.5 cm, in comparison with a witness achieved only with reagents.
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