Elastomeric sealants may contain organic silicon compounds. The use of these sealants for housings for electronic components is harmful for the reliability of electric contacts inside. In order to prevent electronic components from malfunction, quality control of elastomeric sealants is required. An analytical procedure developed to fulfil this requirement was developed. It is based on electron spectroscopy for chemical analysis (ESCA). Information on the silicon compounds existing at the surface of elastomeric sealants is provided by this method. Silicon in organic and inorganic compounds can be differentiated with the help of Si 2p photoelectron spectra. Quantitative results can be obtained too. The uncertainty budget of the quantitative procedure is estimated.