Keith U. Ingold
= Keith U. Ingold
{c}
= K. U. Ingold
{c}
{synonym}
\b[K. U. Ingold] coauthored the 1983 study with <G. W. Burton> and <A. Joyce> comparing lipid-soluble chain-breaking antioxidant activity with independently measured <vitamin E>. The activity measurement used an <inhibited autoxidation assay>, while <high-performance liquid chromatography> supplied a compositional measurement.<Is vitamin E the only lipid-soluble, chain-breaking antioxidant in human blood plasma and erythrocyte membranes? by G. W. Burton and others>[1983, byline and Abstract, assay comparison]{ref}
The scientific distinction is between how quickly a <radical-trapping antioxidant> intercepts reactive intermediates and how much trapping capacity a finite sample contains. <Antioxidant reaction competition> concerns rates; an inhibited interval can instead report a finite capacity under a specified initiation model.
For an original idealization, suppose each donor molecule intercepts $\nu$ radical events and radicals enter at constant concentration rate $R_i$. Complete interception until exhaustion gives
$$
t_{\mathrm{ind}}=\frac{\nu c_A}{R_i}.
$$
An observed interval of $200\,\mathrm s$ at chosen $R_i=0.10\,\mathrm{\mu mol\,L^{-1}\,s^{-1}}$ identifies capacity $\nu c_A=20\,\mathrm{\mu mol\,L^{-1}}$. It is consistent with $c_A=10\,\mathrm{\mu mol\,L^{-1}}$ and $\nu=2$, or $c_A=20\,\mathrm{\mu mol\,L^{-1}}$ and $\nu=1$.
Thus timing alone does not identify molecular stoichiometry and concentration separately. A chromatographic measurement can supply independent information, provided the chemical identity and response calibration are appropriate. This is an illustrative identifiability argument, not a fitted value or individual experimental task assigned to Ingold.