Plasticisers and other impurities from polyethylene laboratory bottles?
Polyethylene (polythene, to some) may have plasticizers, such as adipates, terephthalates, or phthalates, but they are not inherently needed in all cases. Hopefully, the supplier of those alcohols does not bottle them in cntainers with plasticizers, but a wash bottle, purchased separately, might very well have them added to the plastic, particularly because a squeeze bottle must be very flexible.
It is also possible that the polymer itself degraded over time, and with exposure to light, yielding ethylene monomer and other scission products. Compare the odor of the alcohol with that of ethylene, a faint sweet and musky odor (or &quot;odour&quot; if it's ethene).
As to which plasticizer is used, if any, you'd need to consult the bottle manufacturer. You could substitute a glass wash bottle, e.g. a gas wash bottle with aspirator tube, or a PTFE pipette pump, if you're concerned about contamination, e.g. because your measuring phthalates.
However, if your concerned about personal health, this is not the correct forum.