Emerging Science Journal
|
Vol. 3, No. 2
Page | 106
3-4-2- Qualitative Analysis of Extracted Lignin
Greenish blue colouration obtained from lignin treated with phenol and HCl. And Yellow colouration obtained from
lignin treated with aniline sulphite.
3-4-3- Quantitative Analysis
𝐿𝑖𝑔𝑛𝑖𝑛, % =
𝐴 × 100
𝑊
(3)
Where: A = weight of lignin, g; W = oven-dry weight of extractive-free sawdust, g, So the yield percentage of isolated
lignin was 33%.
5g
15g
× 100 = 33.33%
3-4-5- UV Spectral Analysis of LPFR
UV spectrum had an absorption maximum at wavelength of 210 nm, and the second maximum was at 278 nm. The
appearance of two characteristic peaks in the lignin spectrum originated from non-condensed phenolic groups (aromatic
ring) in lignin. Small portion of unsaturated aliphatic units contained in lignin molecule also results in peak. Therefore,
the absorbance maximum value at short wavelength was higher than that at long wavelength. The absorbance of UV
spectra is directly proportional to the purity level of lignin.
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