Efficiencies were measured for Horibe trap cryogenic collection of gas-phase hydrogen peroxide, (H 2O 2), 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 H 2O 2 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 H 2O 2 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 H 2O 2 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 H 2O 2 on average, with no detectable MHP. Addition of 60 ppbv ozone plus 13 ppbv SO 2 to the H 2O 2 Standard produced a 65% loss of measured peroxide, and a 3 ppbv SO 2 addition gave a 20% H 2O 2 loss.