金纳米棒吸收光谱法测定水中微量汞(Ⅱ)

Determination of trace mercury(Ⅱ) in water by the optical absorption spectra of gold nanorods

采用金纳米棒吸收光谱法测定水中Hg(Ⅱ)的浓度。研究表明,金纳米棒比金纳米球具有更高的长波等离激元共振峰(LSPR)位移,不同长径比的金纳米棒对LSPR位移影响不大;当p H<7时,溶液中p H越小LSPR位移越小,当p H>7时,LSPR位移基本不变。LSPR位移在Hg(Ⅱ)浓度为3μmol/L前后表现出两度线性关系,Hg(Ⅱ)浓度大于20μmol/L时金纳米棒与汞完全形成合金,测定Hg(Ⅱ)的检出限为41 nmol/L。

The concentration of mercury（ II） in water was determined by the optical absorption spectra of gold nanorods. The results showed that the longitudinal plasmon resonance（ LSPR） shifts of the gold nanorods were more clear than that of the gold nanospheres and the LSPR shifts were hardly affected by aspect ratio. At the lower p H,the more the LSPR shifted when the p H 〉7,while the LSPR shifts were almost the same when p H〈 7. When the concentration of mercury（ II） was near or lower than 3 μmol / L,the LSPR shift was linear with the concentration of mercury（ II）. When the concentration of mercury（ II） was higher than 20 μmol / L,the gold nanorods completely formed amalgam. Only Pb（ II） could result in negative interference at the determination of Mercury（ II） and the limit of detection was 41 nmol / L.