A derivatization-assisted SERS platform using Au TOHs/hydrogel for point-of-use detection of trace ozone in air.

A portable ozone detection strategy is reported based on derivatization-assisted surface-enhanced Raman spectroscopy (SERS). The strategy integrates active sampling, chemical derivatization, and signal enhancement using high-index gold trisoctahedrons embedded in a porous hydrogel (Au TOHs/hydrogel), assembled into a 48-well microdevice. Ozone is selectively captured by eugenol and converted to formaldehyde, which reacts with 3-methyl-2-benzothiazolinone hydrazone (MBTH) to form a Raman-active azo compound, enabling sensitive detection. The SERS signal at 1270 cm- 1 exhibited a strong linear correlation with the logarithm of analyte concentration (R2 = 0.996). The limit of detection under simulated air conditions is 5.80 × 10- 6 mg/m3. The SERS sensor demonstrated high stability, spatial uniformity, and reproducibility (RSD < 10%), along with good selectivity against common volatile organic compounds. Validation with air samples and comparison with ultraviolet-visible UV-vis spectrophotometry further supports its applicability. This cost-effective and user-friendly platform shows potential for point-of-use detection of trace ozone.