Method for sampling reaction products

1. A method for sampling reaction products, said method comprising the steps of:

delivering a reactant through a sampling probe to contact a substance deposited on a substrate;

allowing the reactant to react with the substance to form a reaction product;

withdrawing at least a portion of the reaction product through the sampling probe;

contacting the sampling probe with the substrate during at least a portion of the delivering, allowing and withdrawing steps so that a tip of the sampling probe may tilt to engage the substrate entirely around the substance; and

analyzing, the withdrawn portion of the reaction product.

2. A method as set forth in claim 1 wherein the contacting step includes tilting a tip of the sampling probe so that the tip of the probe engages the substrate entirely around the substance.

3. A method as set forth in claim 1 wherein the probe is contacted with the substrate for less than about 2 minutes during the delivering, allowing and withdrawing steps.

4. A method as set forth in claim 3 wherein said substance is a first substance of a plurality of substances deposited in an array on the substrate, and the steps of delivering, allowing, withdrawing, contacting and analyzing are performed sequentially for each of the substances deposited on the substrate.

5. A method as set forth in claim 1 wherein the reactant has a contact time with the substance of greater than about 1 second.

6. A method as set forth in claim 1 wherein the reactant has a contact time with the substance of between about 2 seconds and about 10 seconds.

7. A method as set forth in claim 1 further comprising the step of venting excess reaction product through the sampling probe.