Which detergent used in the Lab now? Look like the contamination of the detergent/surfactant which was used for the glassware.Did you notice the m/z different of all the peaks in the mass spectrum?
Tips:
Calculated the most dominant five peaks in the mass spectrum.
305,349,393,437,481,525,569 -> there is 44 different in m/z.
Also checked the less dominant peaks:
333, 377, 421, 465, 509,553 -> there is also 44 different in m/z.
The m/a difference between the first line and second line is 16, look like [M+Na]+, for the second like [M+K]+.
As the m/z = 44.
I think that may be the PEG （polyethylene glycol）:-[-CH2-CH2-O-]-n .
The monomer of PEG is C2H4O ( m/z is 44).
That are the evidences why I doubt that is from the contamination of detergents/surfactant.
