Electrochemilumiscence method for detecting analytes

An electrochemiluminescence method of detecting an analyte in a liquid sample, said method comprising:

• (a) carrying out a reaction sequence comprising at least one specific biochemical binding reaction to form a complex as a result of the concentration of the analyte in the liquid sample, said complex comprising a marking substance capable of effecting an electrochemiluminescence reaction, said complex further being bound to magnetic microparticles, and
• (b) carrying out a detection cycle in a measuring cell having a working electrode for determination of the concentration of said bound microparticles, said detection cycle including a sequence comprising;
• (i) a cleaning step during which a strongly oxidizing and/or reducing potential is applied to said working electrode for electrochemical cleaning of said electrode,
• (ii) a conditioning step comprising applying a sequence of a number of alternating reducing and oxidizing potential pulses to said working electrode, wherein said sequence comprises a last pulse;
• (iii) a capturing step during which said sample containing said microparticles is contacted with said working electrode in such a manner that said microparticles are attracted by the magnetic field of a magnet positioned on the side of said working electrode facing away from said sample, thereby being deposited on a surface of said working electrode facing said sample, and
• (iv) a measuring step during which a potential is applied to said working electrode to trigger said electrochemiluminescence reaction and the light emitted by said marking substance is measured to determine the concentration of said substance on said deposit surface of said electrode, thereby determining the analyte in the liquid sample,
• said method further comprising applying at least one additional potential pulse having an oxidizing or reducing potential into the voltage curve of the detection cycle between said conditioning step and said capturing step, wherein said additional potential pulse is returned to a neutral potential prior to contacting of said working electrode by said sample.