As a follow-up to a couple of other questions:
How do you measure oxygenation of wort? What methods are available for a beginner brewer (low-cost), or a more seasoned veteran?
There's a relatively inexpensive procedure, known as the Winkler method, that's used by ecologists to measure the oxygen concentration in streams and ponds. It relies on titration using sodium thiosulfate (among other chemicals).
I don't think this test works on wort, however, due to wort chemistry. At the very least, titration would be difficult with any beer darker than a pale.
The best method is to use a dissolved oxygen (DO) meter. Good DO meters cost around $1000, although I've seen a few handheld units online in the $300 - $500 range.
It's not very common practice to measure wort oxygenation, sadly. Most microbreweries don't even invest in this equipment, although more recently, the trend is changing.
I don't know of any homebrewers that are actually measuring the ppm of O2 dissolved in their wort. The best practice is to get an O2 cylinder with a medical grade flow meter (not a pressure regulator, but a flow meter). Then experiment with time on the meter and good results in the final product.