Sensitive luminescent paper-based sensor for the determination of gaseous hydrogen sulfide

Abstract

H₂S is an extremely malodorous, toxic and corrosive gas. These properties make the localized emission of hydrogen sulfide an air pollution issue. Despite there being a relatively large number of papers in literature dedicated to developing analytical methods to determine gaseous H₂S, it remains an analytical problem. In this paper, we describe a luminescent cellulose filter-based sensor for gaseous H₂S determination. The cellulose filter is impregnated with a palladium complex, containing a ligand with fluorescent properties. The measurements are made directly on the cellulose filter, and thus do not require an extraction step. The palladium complex – bis(2-aminobenzoic)palladium(II) – impregnated on the surface of the cellulose filter paper reacts with gaseous H₂S. The reaction results in the release of the fluorescent ligand, increasing the fluorescence intensity of the filter surface observed at 410 nm when excited at 338 nm. The linear calibration curve covers the range from 8 to 110 ppb, with a limit of detection (LOD) of 2 ppb. The sampling time is approximately 15 min for this range of H₂S; however, a longer sampling may decrease the detection limit. The factors affecting the collection characteristics, such as sampling flow, media moisture, cellulose filter paper type and amount of humectant (ethylene glycol) in the impregnating solution amount, were optimized.