My first thought is that you might have a typo. Did you start with 98% MPA or 98% MPB? My second thought is to ask whether or not you have searched the literature for previous work. It's a fairly common compound, although perhaps your derivatives are novel.
In the system, solvent A is DI (0.1% formic acid) and solvent B is MeOH or ACN with 0.1% formic acid. I started with 98% of my solvent B, which is MeOH or Acetonitrile containing 0.1% formic acid. Using this condition, I could see a peak in UV spectra but not in MS spectra. The compound is quite non-polar and, I guess, not easily ionizalbe. I could not see any peaks when I lowered the initial concentration of MeOH or ACN. Yes, it is a farily common compound and there are available literatures. Although there are reported MS values by ESI or CI in the literature, I could not find LC/MS method authors used for analysis. Here are some of the papers I referred to: 10.1002/cmdc.200900492, 10.1038/sj.bjc.6600981, 10.1194/jlr.D400044-JLR200.
I also think it is strange that I am not getting MS peaks when there are reported MS values. I must be missing something and I can not figure out what it is. I tried to manipulate MS scan range, capillary voltage, convoltage, detector gain, and neg/pos mode. I am so desperate to optimize LC/MS condition for this series of compounds. If you need more info, please let me know and if there are people with experience on tocopherols, I need your wisdom.