Analytical Chemistry75(13),3019–3030(2003), DOI10.1021/ac020361s. Verified indexed byline B. K. Matuszewski, M. L. Constanzer, C. M. Chavez-Eng; initials retained without inferred identities. Abstract: distinguishing matrix effects and recovery, and comparison of ion-spray versus heated-nebulizer interfaces for the investigated compound under otherwise matched preparation/chromatography.