A method is described for identifying compounds in a complex mixture exhibiting a predetermined characteristic. Such methods include the use of low dielectric constant material prepared by using a removable porogen material. Multiple sample sets are retrieved from the signal over time. In some embodiments, the lenses and diodes have a ratio of mean diameters or lengths between about 10:1 and 2:1. A probe for introducing ultrasound vibration is placed in close proximity to the first surface and immersed in a condensate layer from the vapor phase. The tripper assembly incorporates a solenoid for selectively incrementally advancing the tool against the work piece.