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Ultrasound microdroplets make H2O2 from dissolved O2
Water-in-hexadecane droplets under 40 kHz ultrasound produce H2O2 at 0.24 mM min−1, almost entirely at the oil–water interface via superoxide from dissolved oxygen.
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What H2O2 rate and 1-hour titer were measured in ultrasound water-in-oil droplets?
About 0.24 mM min−1, reaching 14.37 mM after 1 h.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
What fraction of H2O2 is attributed to the water–oil interface?
About 99%, with a surface-normalized rate ~0.10 mM m−2 min−1.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
How does bulk water compare after 1 hour of ultrasound?
0.14 mM H2O2 at 0.0024 mM min−1—only 1% of the droplet yield.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
What happens if the interface is blocked with surfactant for 60 s?
H2O2 falls to 15.50 μM, about 7% of the unblocked yield.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
What is the principal radical intermediate?
Superoxide (·O2−), in the sequence O2 → ·O2− → H2O2.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
How do superoxide, H2O2 and ·OH yields compare?
·O2− is nearly 10× H2O2 and ~1000× hydroxyl radical.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
What did 18O2 versus H218O mass spectrometry show?
Peroxide oxygen atoms come predominantly from dissolved O2, not water.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
How did N2 purging affect 60 s H2O2?
Dropped to 33.76 μM, about 16% of the air-atmosphere yield.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
What ultrasound conditions made the emulsion?
200 μL water in 2 mL hexadecane, 40 kHz, 200 W bath.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
How was superoxide quantified?
NBT forming monoformazan (1 NBT : 2 ·O2−), 0.033 mM s−1, 1.98 mM after 60 s.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified
Is this the same as spontaneous sprayed-microdroplet H2O2?
No—the authors note ultrasound-mediated conditions differ from spontaneous generation.
Source: Deciphering the mechanism of hydrogen peroxide formation in ultrasound-mediated water-in-oil microdroplets · DOI · quote verified