Abstract: In this paper chemically sensitive layers in combination with universally applicable mass-sensitive devices are suggested for the development of integrated systems for multicomponent analyses of liquids. Completely reversible solid-phase extraction for the detection of ions by sol-gel phases are possible. The layers, applied to the quartz microbalance (QMB) in a one-step process, show excellent sensitivity and do not suffer from bleeding effects. For the measurement of polycyclic aromatic hydrocarbons (PAHs) in water, a new concept of generating selectivity is presented by the use of double imprinted layers, which allows to tune additional parameters such as accessibility to the bulk. By different combinations of template molecules every desired PAH selectivity pattern can be generated. (C) 2001 Elsevier Science B.V. All rights reserved