 Andrew L. Waterhouse

Andrew L. Waterhouse is a wine chemist whose UC Davis profile describes research in phenolic compounds and wine oxidation.^[ref] With Brent C. Trela, he coauthored the 1996 primary study of resveratrol isomer absorptivities and stability.^[ref]

An original mixture example illustrates why identifying both isomers requires more than a total optical signal. Suppose two calibrated channels obeywhere $c_t,c_c$ are trans- and cis-isomer concentrations expressed numerically in $\mu \mathrm{mol}{\mathrm{L}}^{-1}$. These coefficients are chosen for the example, not taken from the paper. Readings $A_1=0.35$ and $A_2=0.20$ giveDifferent spectral responses make the two channels informative jointly. If their response rows were proportional, greater reading precision would not distinguish both concentrations. Multivariate calibration or separation by chromatography must establish the required selectivity. The measured composition is an analytical result; it does not by itself establish a health effect of consuming the preparation.