= Antonius T. M. Van Kessel
{c}
\b[Antonius T. M. Van Kessel] coauthored the visible-light co-oxidation assay with <Evan A. Haidasz> and <Derek A. Pratt> for characterizing <radical-trapping antioxidants>.<A Continuous Visible Light Spectrophotometric Approach To Accurately Determine the Reactivity of Radical-Trapping Antioxidants by Evan A. Haidasz and others>[Byline and Abstract]{ref} A central analytical distinction is between reaction speed and finite trapping capacity: an inhibitor can intercept radicals rapidly yet be exhausted after relatively few events.
An original competition model holds the concentrations of donor and reporter approximately constant over a short interval. Let the effective rates for a radical be $a=k_Ac_A$ for interception and $b$ for a competing reporter route. The probability of interception as the first event is
$$
f_A=\frac a{a+b}.
$$
Choosing $a=10\,\mathrm{s^{-1}}$ and $b=2\,\mathrm{s^{-1}}$ gives $f_A=5/6$. Halving $k_A$ without changing concentration gives $f_A=5/7$. The kinetic response changes even if the two preparations have the same total number of donor molecules.
Under a separate ideal capacity model, two intercepted radicals per donor at $c_A=10\,\mathrm{\mu mol\,L^{-1}}$ and constant initiation rate $R_i=0.10\,\mathrm{\mu mol\,L^{-1}\,s^{-1}}$ give an inhibited interval $2c_A/R_i=200\,\mathrm s$. That capacity estimate alone does not distinguish the two chosen rate constants. Actual co-oxidation traces require the appropriate chain-reaction and reporter model; the simple competition and capacity calculations illustrate different kinds of information, not individual experimental tasks attributed to Van Kessel.
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