Dioctyl phthalate is a ubiquitous background substance in most labs because it is a plasticizer used in Tygon tubing.

a. Suggest a structure for the base peak cation at m/z 149 m/z 149 and the second most abundant peak at m/z 279m/z 279 observed by electron ionization.

b. In negative chemical ionization with NH3NH₃ reagent gas, there is a prominent parent anion M→M→ at m/z 390 m/z 390 and domain fragment anions are observed at m/z 277 m/z 277 and 221.221. Suggest structures for these anions.

Transcribed Image Text:

0 Ö O(n-C8H₁7) -O(n-CgH₁7) Dioctyl phthalate C24H3804 Nominal mass 390