Understanding the growth of nanoparticles requires knowledge of chemical processes in the plasma. In a plasma ions, neutrals and radicals of dissociated species are formed. During different stages of particle growth the plasma density and electron temperature vary which affects not only the density of ions but also the dissociation of the precursor and, thereby, the chemical composition of the process gas. In this study particle synthesis from an acetylene containing CCRF-plasma was observed for masses from 1 to 100 amu. Choosing the total gas pressure and acetylene admixture to argon allows to generate distinct particle growth cycles [1] with mono-disperse sizes of the particles, so that the growth process can be monitored in-situ by mass spectrometric investigations. Correlating the mass spectra with electrical measurements of the selfbias voltage in combination with former studies [2] makes it possible to link the spectra directly to a particle size. In this way the importance of different chemical species during nucleation, agglomeration and accretion will be discussed. [1] M. Hundt et al., J. Appl. Phys. 109, 123305 (2011) [2] A. M. Hinz et al., J. Phys. D: Appl. Phys. 48 055203 (2015)