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Colorimetric PBG Assay (Ehrlich)

COLORIMETRIC PORPHOBILINOGEN ASSAY (EHRLICH)

Modified Ehrlich Reagent

    Dissolve 1.0 gm p-dimethyl aminobenzaldehyde in 30mL glacial acetic acid. Add 8.0 mL 70% perchloric acid. Bring to 50 mL with glacial acetic acid. Store in the dark at 4˚C for about 2 weeks.

    Porphobilinogen (PBG) Assay

      Mix 2.0mL sample with 2.0mL fresh modified Ehrlich reagent. Measure absorbance at 555nm.

      Standard PBG

        Prepare 0.54mg/mL (2.2mM) PBG stock in 0.1M Tris pH 7.65. (Store at -20˚C until needed.) Dilute 1:1000 in H2O. Mix 2mL with 2mL fresh modified Erlich reagent. Measure absorbance at 555nm.
          1mM PBG = 61 abs units at A555.
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