Metal-assisted (MetA) SIMS using the deposition of a thin Au or Ag layer on non-conducting samples prior to analysis has been advocated as a means to improve the secondary ion (S.I.) yields of organic analytes. This study focuses on the influence of time and temperature on the yield enhancement in MetA-SIMS using thick layers of poly(vinylbutyral-co-vinylatcohol-co-vinylacetate) (PVB) containing dihydroxybenzophenone (DHBPh) or a cationic carbocyanine dye (CBC) and spin-coated layers of the cationic dye on Si. Pristine samples as well as Au- and Ag-coated ones were kept between -8 degrees C and 80 degrees C and analysed with S-SIMS at intervals of a few days over a period of I month. The yield enhancement was found to depend strongly on the kind of evaporated metal, the storage temperature and time between coating and analysis. (c) 2006 Elsevier B.V. All rights reserved.