UV Spectrum of Lignin in Alkaline Solution

3 UV Spectrum of Sodium Borohydride-Reduced Lignin in Alkaline Solution 

An alkaline solution of the sodium borohydride-reduced lignin sample, prepared by mixing 2 ml of the stock solution and 1 ml of the 0.05 M sodium borohydride solution, is placed in a 10-mm cell and the UV spectrum (200-400 nm) is recorded against a reference solution composed of the 2-methoxyethanol-ethanol mixture and 0.03 M sodium hydroxide solution (2 1, v/v). UV spectra of the sodium borohydride-reduced lignin sample are obtained after reduction times of 100 min and 45 h (Note 9) at room temperature in the same manner as described for the corresponding lignin sample in Sect. 7.4.4.2. 

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