IMPROVED TITANIUM METHOD FOR DETERMINATION OF ATMOSPHERIC H2O2

Gaseous H2O2 is sampled on a Ti(IV)-H2SO4 coated filter, where titaniu m peroxy complex is formed. After sampling the filter is leached in a phosphate buffer (pH 7) and the peroxide concentration analysed spectr ophotometrically at 505 nm after having added 4-(2-pyridylazo)resorcin oi (PAR). The triple complex formed shows an extinction coefficient (3 .5 X 10(4) 1 mol(-1) cm(-1)) about 2.5 times higher than that of the [ FeNCS](2+) complex, which is formed when the titanium complex is broke n by addition of ferrous thiocyanate reagent. The detection limit of H 2O2 for 1-h sampling can be lowered to 0.03 ppb when this new reagent is used.