title: Attogram detection limit for aqueous dye samples by laser-induced fluorescence.
abstract: A modified flow cytometer has been used to detect attogram quantities of aqueous rhodamine 6G by laser-induced fluorescence analysis. A detection limit of 28 attograms (35,000 molecules) was obtained, nearly two orders of magnitude better than earlier measurements. The detection limit in concentration units was 1.4 x 10(-13) mole per liter. During the 1-second measurement period, the total volume sampled was 0.42 microliter. On average, only half a rhodamine 6G molecule was present in the 6-picoliter probed volume.
mesh_terms: D005434:Flow Cytometry / Q000379:methods*; D007834:Lasers; D012235:Rhodamines / Q000032:analysis*; D014966:Xanthenes / Q000032:analysis*
chemical_list: D012235:Rhodamines; D014966:Xanthenes