We are tasked with testing the pH of a series of oil samples that have undergone various levels of imposed oxidation.
The oil is a Capric Oil (C-8?) and had been exposed to open air and or hydro peroxide for 0 days, 1 day, 3 days, 5 days and 10 days. So, the expectation is that the oil had become degraded (i.e., increased acidity). The project sponsor gave us some crappy test method that says: "...use 10 mL of water and 10 mL of oil sample, shake 5 minutes, then recover the oil layer, and add 100 uL of KCl, then test for pH." But, all the readings are turning out the same result of pH = 5.3. It says that the day 0 pH should be betw 6.0 and 7.5 pH; however, we are getting for day 0 a pH value of 5.2 and it is not stablilizing. We are using a wide/open junction pH electrode.
This is a erroneous test method, as first of all, isn't it atypical to even test for oil pH because pH is a function of ion flow in aqueous medium? Yet we are pulling the aqueous laye and still don't get a sensible result. Anybody confused?