We examined several parameters of the vanillin assay
for tannin in addition to those we previously investigated
(Price et al., 1978). A brief survey of vanillin (4-
hydroxy-3-methoxybenaldehyde) analogues demonstrated
that 2,4-dimethoxybenzaldehyde gave absorbance values
2-5 times greater than those obtained with vanillin and
may therefore warrant further investigation if greater
sensitivity is needed. All data presented in this paper were
obtained by using vanillin.