The present invention relates to a method and apparatus for monitoring a real-time quantification of multiple target molecules during their binding on capture molecules of a micro-array. Peripheral inner ring has encoder ring serving as transducer. A signal transmission line is arranged on the printed circuit board. If the received package of biometric information matches the registered package of biometric information, the vendor system may sign a document with an electronic signature. The information in the information element or transponder is readable by the reader unit and transmittable to the control unit.