In modern society, protocatechuic acid can play a huge role. So, what do you know about it? How to measure? To this end, Xiaobian specially collected some information.
1) preparation of solution
Prepare 2mol / L sulfuric acid solution, 0.5mol/l sodium bromate solution, 2.0mol/l malic acid solution and 1.84 × 10-2mol / L [cul] (ClO4) 2 solution respectively.
Then, add 20ml, 2.0mol/l sulfuric acid solution, 1.2ml, 0.5mol/l sodium bromate solution, 4.5ml, 2.0mol/l malic acid solution, 8.5ml, 1.84 × 10-2mol / L catalyst solution to the open system of 50ml beaker.
Finally, the concentration of sulfuric acid, sodium bromate, malic acid and catalyst were 1.0mol/l, 0.0150mol/l, 0.225mol/l, 3.91 × 10-3mol / L, respectively.
At the same time, a series of protocatechuic acid sample solutions with different concentrations were prepared.
2) obtain the oscillation map
The oscillogram of the prepared system is recorded by recorder or computer. Add a small amount of protocatechuic acid solution into the prepared oscillation solution, and the time of each addition is at the 7th lowest potential amplitude generated by stable oscillation. The added protocatechuic acid will participate in the oscillating reaction, that is, the oscillating response will increase the oscillating amplitude.
The working curve was established according to the relationship between the amount of protocatechuic acid added and the value of the maximum potential increase. The abscissa is the concentration of protocatechuic acid in the oscillating solution, and the ordinate is the logarithm of the highest potential increase value 1g (Δ E).
When the concentration of protocatechuic acid is between 1.5 × 10-5 and 1.0 × 10-4mol / L, the concentration of protocatechuic acid solution has a linear relationship with 1g δ E. The quantitative analysis of protocatechuic acid in the sample can be realized.