Procedure
Proceed as directed in the test for
Content of dodecatetraenoic acid isobutylamides under
Echinacea angustifolia.Calculate the percentage of

dodecatetraenoic acid isobutylamides
USP28in the portion of Powdered Extract taken by the formula:
10(1.353)(C/W)(ri/rS),
in which 1.353is the response factor for 2
E,4
E-hexadienoic acid isobutylamide;
Cis the concentration,in mg per mL,of USP2
E,4
E-Hexadienoic Acid Isobutylamide RSin
Standard solution 2;Wis the weight,in g,of the portion of Powdered Extract taken;
riis the sum of the peak responses of the relevant analytes obtained from the
Test solution;and
rSis the peak response obtained from
Standard solution 2.