Circular 230 § 10.26
Notaries.
eCFR amendment effective 2016-12-30 · current text
A practitioner may not take acknowledgments, administer oaths, certify papers, or perform any official act as a notary public with respect to any matter administered by the Internal Revenue Service and for which he or she is employed as counsel, attorney, or agent, or in which he or she may be in any way interested.