A novel tubular device has been developed for hydrogen sulfide determination in air. Several substrates such as commercial silica gel and alumina TLC plates, silica gel powder, alumina, CaSO 4 , CaCO 3 , BaSO 4 , MgO, chalk, h-cellulose and ethyl cellulose were tested as solid substrates. 30 -70-mesh silica gel was finally employed in glass tubes of 4.0 mm internal diameter. Silica gel is treated with 0.5 M aqueous CdCl 2 solution, dried, filled into the glass tube and sample gas is passed through the device using nitrogen as the carrier gas where 70% relative humidity is employed. The analyte reacts with the solid substrate to form a luminescent spot whose length in the tube is measured and correlated to concentration. The flow rate was 68 ml min − 1 . The analytical system is linear in the range of 0.2-1.3 ppm H 2 S for the specified conditions. The prepared devices are stable at least for 3 months prior to sampling; and after sampling, the luminescing spot is stable also at least for 3 months.