Department of Chemistry, University of Maine, Orono, ME 04469, USA.
Anal Chim Acta. 2012 May 30;728:57-63. doi: 10.1016/j.aca.2012.03.047. Epub 2012 Apr 6.
A new method that uses solid phase extraction (SPE) coupled with FTIR spectroscopy to detect Hg(II) in aqueous samples is described. The technique is envisioned for on-site, field evaluation rather than lab-based techniques. This paper presents the "proof of principle" of this new approach toward measurements of Hg(II) in water and identifies mass transport issues that would need to be overcome in order to migrate from a lab based method to field operation. The SPE material supported on a Si wafer is derivatized with an acylthiosemicarbazide, which undergoes a reaction in the presence of aqueous Hg(II) to form an oxadiazole ring. The progress of the reaction is monitored by IR spectroscopy. Following EPA guidelines, the method of detection limit (MDL) for the SPE/IR was 5 μg of Hg(II)cm(-2). In a 1L sample and a 1cm(2) Si wafer, this translates to a detection limit of 5 ppb. This system shows a high selectivity toward aqueous Hg(II) over other thiophilic heavy metal ions such as Pb(II), Cd(II), Fe(III), and Zn(II) and other metal ions such as Ni(II), Mn(II), Co(II), Cu(II), In(III), Ru(III), Na(I), and Ag(I) in aqueous solutions.
一种新的方法，使用固相萃取（SPE）与傅里叶变换红外光谱（FTIR）相结合，来检测水溶液中的 Hg(II)。该技术被设想用于现场、野外评估，而不是实验室技术。本文介绍了这种新方法用于测量水中 Hg(II)的“原理验证”，并确定了需要克服的质量传输问题，以便从基于实验室的方法迁移到野外作业。在硅片上支撑的 SPE 材料用酰基硫代半卡巴腙衍生化，在存在水合 Hg(II)的情况下，它会发生反应形成恶二唑环。通过红外光谱监测反应的进展。根据 EPA 指南，SPE/IR 的检测限（MDL）为 5μg Hg(II)cm(-2)。在 1L 样品和 1cm(2)的硅片上，这相当于 5ppb 的检测限。该系统对水溶液中的 Hg(II)表现出很高的选择性，超过了其他亲硫重金属离子，如 Pb(II)、Cd(II)、Fe(III)和 Zn(II)，以及其他金属离子，如 Ni(II)、Mn(II)、Co(II)、Cu(II)、In(III)、Ru(III)、Na(I)和 Ag(I)。
