Lignin-containing paper

Inhibition of Light-Induced Yellowing of Lignin-Containing Paper... 

Subsequent efforts to inhibit photochemical yellowing of lignin-containing paper were based on what was believed to be the dominant reaction pathways to yellow chromophores the formation of phenoxy free-radicals by direct excitation of phenolic groups and the abstraction of phenolic hydrogen by the aromatic carbonyl triplet excited state, as shown by reactions 1 and 2 in Scheme 1. The approaches used by researchers were modification of lignin by ... 

Ascorbates. The fact that ascorbic acid and sodium ascorbate inhibit light-induced yellowing of lignin-containing papers was first reported 25 years ago (15). For a limited time ascorbic acid stops yellowing, but eventually yellowing proceeds at the same rate as the untreated paper (6,17), as seen in Figure 2. 

Amanitins can be differentiated analytically from phalloidins by a sensitive test reaction with cinnamaldehyde that yields a deep violet color in an atmosphere of hydrogen chloride. Also, the simple color test in which a trace of a toadstool impressed on a lignin-containing paper (e.g., newsprint) moistened with concentrated hydrochloric acid develops within 5-10 min a greenish-blue color when amanitines are present 86,104) may be of some analytical value. This reaction is also characteristic of other... 

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