Patent ID: 9316613
Filing Date: 2016-04-19
CPC Classification: B82Y,G01N,G01Q

Claim Text:
1. A method comprising: providing a pipet comprising first and second channels separated by a septum and having a tip at which each of the first and second channels is open; providing an electrolyte solution within both the first and second channels of the pipet; providing a first electrode extending into the electrolyte in the first channel of the pipet; providing a second electrode extending into the electrolyte in the second channel of the pipet, the second electrode at a ground potential; applying a potential difference between the first and second electrodes; applying an oscillatory perturbation to the pipet at a perturbation frequency; measuring alternating current components of a current flowing to or from the first electrode; and responding to alternating current at the perturbation frequency or at a harmonic of the perturbation frequency measured to be flowing to or from the first electrode by adjusting a position of the pipet so as to maintain a separation between the tip of the pipet and a surface of interest.