LAUSR

Water molecules (H2O) often reduce luminescence lifetimes of various luminescence probes. The change of lifetime is usually caused by dynamic luminescence quenching induced by O-H oscillators which effectively take away energy from excited molecule. The process can be described by Stern-Volmer equation. We have studied selected luminescence systems where it is possible to detect considerable changes of lifetime in presence/absence of H2O and D2O in this work for analytical purposes. We have tested both, inorganic (Ln3+) and organic compounds using three different instrumentation in order to find the largest change between τH and τD. The Ln3+ containing systems have shown considerable increase/decrease of lifetimes in the presence/absence of D2O (Eu3+: τD/τH = 34.5) whereas organic systems gave significantly lower values of τD/τH (coumarin 123 lifetime ratio, τD/τH = 1.94). The calculated LOD varied from 0.04 mol l-1 (samarium nitrate) to 6.55 mol l-1 (riboflavin).