SERS optrode as a fishing rod to direct preconcentrate analytes from superhydrophobic surfaces

SERS optrodes were used to fish aqueous drops from super-hydrophobic surfaces. The technique led to an improvement of 2-3 orders of magnitude in the lowest detectable amount of the Raman probe nile blue A, reaching 25 fg (34 attomoles). Further tests run on samples containing pesticide revealed that 20 pg of triazophos could be clearly detected from a single drop.