Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) with an ArF 193-nm excimer laser was used to determine the Mn content of polystyrene beads (diameter ca. 400 mum) obtained by radical cross-linking suspension copolymerization of chiral, dendritically styryl-substituted salens with styrene and loading with Mn(OAc)(2)/LiCl to give polymer-bound Mn-Salen complexes (p-1 (.) and p-2 (.) Mn(Cl)). The beads were used to catalyze the enantioselective epoxidation of styrene to the corresponding epoxide. The spatial distribution of Mn (and Li) in freshly prepared, in multiply used (up to 20 times), or in "reloaded" beads was measured by drilling with laser craters (ablation) of ca. 40 pm into whole beads or into beads cut in half and analyzing the vaporized and ionized material in a plasma (detection limits down to 10 mug/g and depth resolution down to 0.3 mum/pulse). The following results were obtained: (i) the Mn content is evenly distributed within the freshly prepared and loaded beads; (ii) the high-performance polymer (p-2 (.) Mn(Cl)) leaches Mn down to a constant value of ca. 25 % of the original content after 15 sequential uses; (iii) the low-performance polymer (p-1 (.) Mn(Cl), a hydroquinone derivative) loses almost all Mn after six runs; (iv) reloading of beads with Mn causes increased Mn content only on the outer layers of the particle; (v) leaching occurs by loss of Mn, increasing from the surface to the center of the beads. It was demonstrated for the first time that LA-ICP-MS is well suited to assessing element distribution inside individual beads containing catalytically active transition metal sites and to detecting spatial changes upon multiple use. (C) 2003 Elsevier Science (USA). All rights reserved.