ORIGINAL PAPER Design and Synthesis of a Terbium(III) Complex-Based Luminescence Probe for Time-Gated Luminescence Detection of Mercury(II) Ions Guanfeng Cui & Zhiqiang Ye & Run Zhang & Guilan Wang & Jingli Yuan Received: 9 June 2011 /Accepted: 10 August 2011 /Published online: 20 August 2011 # Springer Science+Business Media, LLC 2011 Abstract Time-gated luminescence detection technique using lanthanide complexes as luminescent probes is a useful and highly sensitive method. However, the effective application of this technique is limited by the lack of the target-responsive luminescent lanthanide complexes that can specifically recognize various analytes in aqueous solutions. In this work, a dual-functional ligand that can form a stable complex with Tb 3+ and specifically recognize Hg 2+ ions in aqueous solutions, N,N,N 1 ,N 1 -{[2,6-bis(3′- aminomethyl-1′-pyrazolyl)-4-[N,N-bis(3″,6″-dithiaoctyl)- aminomethyl]- pyridine]} tetrakis(acetic acid) (BBAPTA), has been designed and synthesized. The luminescence of its Tb 3+ complex is weak, but can be effectively enhanced upon reaction with Hg 2+ ions in aqueous solutions. The luminescence response investigations of BBAPTA-Tb 3+ to various metal ions indicate that the complex has a good luminescence sensing selectivity for Hg 2+ ions, but not for other metal ions. Thus a highly sensitive time-gated luminescence detection method for Hg 2+ ions was developed by using BBAPTA-Tb 3+ as a luminescent probe. The dose- dependent luminescence enhancement of the probe shows a good linearity with a detection limit of 17 nM for Hg 2+ ions. These results demonstrated the efficacy and advantages of the new Tb 3+ complex-based luminescence probe for the sensitive and selective detection of Hg 2+ ions. Keywords Luminescent probe . Terbium complex . Mercury ions . Time-gated luminescence detection Introduction As one of heavy metal ions, Hg 2+ can cause severe health problems to human beings when it is ingested or inhaled due to its high toxicity [1–3]. The excessive exposure of the body to mercury can lead to neurological diseases, mitosis impairment, DNA damage and nervous system defects [4–6]. Mercury is present in many environments, either as a naturally occurring species or as a by-product of manufac- turing and industrial processes, such as oceanic and volcanic emission, solid-waste incineration, gold mining and combustion of fossil fuel [7–10]. Thus, its contamina- tion is a global problem that has received considerable attention from the industrial and biological points of view. Due to the above imperilment, the implementation of securing the health and safety requires the availability of rapid, selective and sensitive methods to detect the concentration of mercury in environmental and biological systems. To date, a variety of analytical methods have been developed for the detection of Hg 2+ , such as atomic absorption spectroscopy, fluorescence spectrometry, gas chromatography, high performance liquid chromatography and capillary electrophoresis [11–15]. Fluorometric assays using a fluorescent probe that can specifically respond to Hg 2+ are considered to be one of the most promising methods due to its high sensitivity, selectivity, experimental convenience and availability for living systems. Towards this end, a number of fluorescent probes for the detection of G. Cui : Z. Ye (*) : R. Zhang : G. Wang : J. Yuan (*) State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, People’ s Republic of China e-mail: zhiqiangye2001@yahoo.com.cn e-mail: jingliyuan@yahoo.com.cn J Fluoresc (2012) 22:261–267 DOI 10.1007/s10895-011-0956-6