title: Ultrasensitive absorption spectroscopy of optically-trapped aerosol droplets.
abstract: High-sensitivity optical absorption measurements on individual sub-picoliter aqueous droplets are reported using aerosol optical tweezers to simultaneously manipulate and characterize a sample droplet and a control droplet for comparison. It is demonstrated that the detection sensitivity to trace analytes is set by the weak absorption by the solvent, water, and that absorbances less than 5 x 10(-7) can be measured over pathlengths of less than 10 microm. The potential applications of this approach to analyze aerosol particle composition and to perform trace analysis are discussed.
authors.forename: Kerry J
authors.initials: KJ
authors.lastname: Knox
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Reid
mesh_terms: D000336:Aerosols / Q000032:analysis*; D052898:Optical Tweezers; D010316:Particle Size; D012997:Solvents / Q000737:chemistry; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods*; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000336:Aerosols; D012997:Solvents; D014867:Water