Patent ID: 7295026

Claim:
A sampling system for sampling a surface array having an analyte, the system comprising: a sampling probe having a tip and which is adapted to sample the surface array for analysis when disposed at a desired spaced distance from the surface array so that an optimum liquid microjunction is presented between the tip of the sampling probe and the surface array; means for moving the sampling probe and the surface array toward and away from one another; means for capturing a camera-generated image of both the tip of the probe and the surface array and for generating signals which correspond to the captured image; means for receiving the signals which correspond to the captured image and for determining the actual distance between the tip of the probe and the surface array from the captured image; comparison means for comparing the actual distance between the tip of the probe and the surface array to the desired target distance and for initiating the movement of the surface array and the probe tip toward or away from one another when the difference between the actual distance between the tip of the probe and the surface array and the desired distance is outside of a predetermined range so that by moving the surface array and the probe tip toward or away from one another, the actual target distance approaches the desired distance; and wherein the means for capturing the camera-generated image includes means for directing a light beam toward the probe tip so that a shadow of the probe tip is cast upon the surface array and so that the image captured by the image-capturing means surface includes both the probe tip and the shadow of the probe tip.