We study the impact of binary interaction processes on the evolution of low- and intermediate-mass stars using long-term monitoring of their radial velocity. Here we report on our results on the central stars of two planetary nebulae (PNe): the well-studied spectrophotometric standard BD+33 2642 (central star of PNG 052.7+50.7) and HD 112313 (central star of PN LoTr5), the optical light of which is dominated by a rapidly rotating G star.