I also recommend the use of kits because the use of colorimetric techniques in spectrometry is associated with many problems in the results I prefer the use of special kits especially in determination of SOD
Moreover I used Elisa techniques in most of oxidative stress parameters and it produced better impact
I suggest using the manual methods for measurements of different parameters: especially the enzymes, I think not all kits give an accurate result and this depends on the manufacturing company.& you can have look on my publications present on research gate to learn about the manual methods to measure different parameters & even TOS , TAS &OSI. we have carried out many researches dealing with different parameters related to this subject In different diseases. & I hope you will find what you are looking for among them. Good Luck.
We recently described a simple and cheap method for measurement of total reductive (antioxidant) capacity with great precision and accuracy. You can see the details here:
Preprint Nitrocellulose redox permanganometry: a simple method for re...
You can look to the protocols used by Dr. Debasis Sahu in his PhD. Below I have attached one of his paper, that mentioned the every single step for these assays. I hope, You may find it good.