Method and apparatus for delivery of submicroliter volumes onto a substrate

A substrate for use in mass spectrometric analyses, comprising:

• a solid support comprising silicon or silicon dioxide;
• an array of target locations on a surface of the solid support;
• each target location of the array consists of a first material which is a positive photoresist material having a first contact angle and which is resistant to silation;
• each target location is surrounded by an area on the surface of the solid support comprising a silane having a second contact angle;
• and
• the first contact angle is at least about 20 degrees less than the second contact angle.