Simulating a Minimal ORAC Kinetic System

rate constants

k

a

,

-1

h

0.008

k

p

,

-1

M

-1

h

36

k

x

,

-1

M

-1

h

1800

reactant concentrations

[RNNR], μM

80

[PH], μM

0.04

[XH], μM

1

[



ROO

], μM

0

This Demonstration shows a representative example of the concentration profiles of the probe over time in an oxygen radical absorbance capacity (ORAC) assay. The induction time and decay regions depend on the initial concentrations of the peroxyl radical initiator

RNNR

, probe

PH

and antioxidant

XH

, and the apparent first- and second-order rate constants

k

a

,

k

p

and

k

x

.