The absorbance ratios are given in the table above, as are the natural logs of the ratios. Fit a straight line to the ratios, and one should get a 0 intercept and a slope of -k.
Red points are from the table, the green line is the regression fit.
The oxidizing agent for the previous experiment was pyruvic acid. If the reaction is also pseudo-first order in pyruvic acid, and the acid was 0.01 M for the data shown above, predict the absorption vs. time behavior if the concentration of pyruvic acid had been 0.025 M . Since all the NADH gets consumed in either case, the only difference is in how fast we get to total NADH consumption. Suppose you are using an enzyme which follows Michaelis-Menton kinetics to assay for substrate. The assumption behind standard addition methods is that signal is proportional to the concentration of analyte.