Colorimetric Method for the Detection of Mercury Ions Based on Gold Nanoparticles and Mercaptophenyl Boronic Acid.

In the present study, we found that phenylboronic acid derivatives including benzene-1,4-diboronic acid (BDBA) and mercaptophenyl boronic acid (MPBA) can induce the aggregation of citrate-capped gold nanoparticles (Au NPs). However, the speed of Au NP aggregation induced by MPBA was much faster than that of BDBA. The reaction between MPBA and Hg ions resulted in the formation of MPBA-Hg-MPBA, which was similar to BDBA having two free boronic acid groups. Based on the above phenomenon, a sensitive and selective colorimetric method for the detection of mercury ions (Hg) in aqueous solution was developed. The linear range for the detection of Hg ions was from 0.08 to 1.25 μmol dm with a detection limit of 37 nmol dm. The strategy offered excellent selectivity toward Hg against other metal ions. Meanwhile, this simple and cost-effective sensor was applied to determine the Hg in the lake water samples with satisfactory recoveries (91.3 - 100.7%).