Abstract
At pH 6.9 the totally ionized form of vit. C showed u.-v. absorption maxima at 265 m[mu], whereas the non-ionized form at pH 3.0 is maximal at 245 m[mu]. Measurement at both of these values was used for the assay of vit. C. The results obtained on walnut extracts paralleded those obtained with indophenol dye titration.