The microspherical shape and the narrow particle size distribution of this polystyrene resin allow applications in automated sorters, for creating huge libraries, high speed synthesis etc. The phenethyl bond is more stable than the benzyl bond towards acid treatments. The narrow particle size distribution of this polystyrene microparticles is lot-dependent. The main particle size of an individual lot will be in a size window between 13 and 17 µm. The particle size distribution for each individual lot is +/-15% from the main size of this lot or less.