Notes: para-methoxy 4-ANPP (Item No. 27946) is an analytical reference standard that is structurally similar to known opioids. para-methoxy 4-ANPP is a precursor in the synthesis of para-methoxyfentanyl (Item No. 20035). para-methoxy 4-ANPP is a potential impurity in para-methoxyfentanyl preparations. This product is intended for research and forensic applications.