Ibuprofen EP Impurity - N

p-Ethylhydratropic Acid; 4-Ethyl-α-methylbenzeneacetic Acid; 2-(4-Ethylphenyl)propionic Acid; 2-(p-Ethylphenyl)propionic Acid; (2RS)-2-(4-Ethylphenyl)propanoic Acid; Ibuprofen impurity N (IP);