Phenylboronic Acid-Functionalized Au Nanostructured Film for Ultrasensitive Detection of cis-Hydroxy Inorganic Arsenate in Environmental and Biological Samples

Arsenic is considered one of the major threats to human health, and development of chemical sensors for rapid and simple arsenic detection is increasing attention. In this paper, we developed a chemical sensing platform targeting arsenic oxide (As(V)) based on phenylboronic acid’s unique recognition capability, which could covalently bind cis-diol-containing molecules by the boronate affinity reaction in alkaline media. As far as we know, this is the first example of using phenylboronic acid to selectively capture the cis-hydroxy-containing inorganic anions, which will open up a horizon in molecular recognition. The covalent interaction between As(V) and phenylboronic acid was confirmed by mass spectroscopy. The phenylboronic acid was immobilized on a Au nanostructured film to fabricate a chemical sensing platform coupled with a surface-enhanced Raman scattering (SERS) technique. The chemical SERS sensor was pH-dependent because of the pH-controllable boronate reaction and displayed a high selectivity and sensitivity to As(V) with a detection limit of 1 ppb. Such a SERS sensor was applied to detect As(V) spiked in urine samples, water quality, domestic drinking water, and seawater with accuracy and short assay time. The developed SERS sensor offers distinct advantages over existing methods since it is highly selective and sensitive and can be used in practical applications such as urine samples, water quality, domestic drinking water, and seawater.