Evaluation of Horibe traps for cryogenic collection of hydrogen peroxide and methyl hydroperoxide

Efficiencies were measured for Horibe trap cryogenic collection of gas-phase hydrogen peroxide, (H2O2), and methyl hydroperoxide (MHP). The Horibe trap efficiency was compared to preconcentration using a standard vacuum trap with cryogenic sampling. Gas standard samples were collected in traps cooled to two temperatures, − 85°C and − 196°C. The interference of ozone, ethylene and sulfur dioxide in the cryogenic collection of H2O2 and MHP using Horibe traps was determined. Ozone was added at a concentration of 110 ppbv to a gas-phase peroxide standard consisting of 0.5 ppbv H2O2 plus 1.6 ppbv MHP. No statistically significant interferences in either hydroperoxide were observed. After addition of 110 ppbv ozone and 2.5 ppbv ethylene to a 2 ppbv MHP standard, a 180 pptv average increase in H2O2 was observed, with no affect on MHP levels. At the same concentrations, ozone added to ethylene in the absence of gas-phase peroxide produced the same amount of H2O2 on average, with no detectable MHP. Addition of 60 ppbv ozone plus 13 ppbv SO2 to the H2O2 Standard produced a 65% loss of measured peroxide, and a 3 ppbv SO2 addition gave a 20% H2O2 loss.