Abstract: A method of measuring ultra-low concentration of a target analyte in a host fluid includes placing a droplet by a micropipette having an ejection tip, positioned by a micro-positioner, configured to position the ejection tip atop a first electrode in electrochemical contact with an electrolyte disposed in a first vessel, iteratively applying a potential to the first electrode and measure electrical current between the first electrode and a second electrode in electrochemical contact with the electrolyte, obtaining current vs. voltage curves for each voltameter iteration, identifying redox or oxidation peaks for each voltameter iteration, determining initial target analyte concentration based on the identified redox or oxidation peaks.