Title: Smartphone Nanocolorimetric Determination of Hydrogen Sulfide in Biosamples after Silver-Gold Core-Shell Nanoprism-Based Headspace Single-Drop Microextraction

Recently, a new approach to detect hydrogen sulfide (H₂S) in biosamples by smartphone nanocolorimetric platform ^[1] was published on Analytical Chemistry by Associate Prof. Sheng Tang’s research group from School of Environmental and Chemical Engineering.

In this work, the sensitive detection of H₂S was realized at low cost and high efficiency through the application of silver-gold core-shell nanoprism (Ag@Au-np) combined with headspace single-drop microextraction (HS-SDME). After SDME, smartphone nanocolorimetry (SNC), with the aid of smartphone camera and color picker software, was used to detect and quantify the H₂S. The method took advantage of the inhibition of the UV-vis signal caused by H₂S etching of the Ag@Au-np pre-added to the SDME solvent to measure the H₂S concentration. The coating of the gold layer not only ensured the high stability of the nanomaterial but also enhanced the selectivity toward H₂S. The HS-SDME method was simple to process and required only a droplet of solvent for analysis to be realized. This HS-SDME-SCN approach exhibited a calibration graph linearity of between 0.1 and 100 μM and a limit of detection of 65 nM (relative standard deviations of N% (n = 3) < 4.80). The assay demonstrated a good applicability to genuine opaque and inhomogeneous biosamples(egg and milk).