Anal. Chem. 1995, 67,2562-2566
Analytical Chemistry in a Liquid Film/Droplet Amaldo A. Cardosot and Pumendu K. Dasgupta*
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061
The measurement of nitrogen dioxide at the parts-perbillion level is described. The experimental arrangement consists of two optical fibers placed on opposite sides of and in contact with a liquid film (14-57 p L in volume) supported on a U-shaped wire guide and two tubular conduits (one of which constitutes the means for the delivery of the liquid). Light from a green (555 nm)lightcomposed of Griessemitting diode enters the liquid h, Sallzman reagent. The transmitted light is measured by a referenced photodetection arrangement. Sample gas flows past the droplet at a low flow rate (typically 0.100.25 Wmin). The response is proportional to the sampling period and the analyte concentration. The limit of detection for this nonoptimized arrangementis estimated to be
