Determination and speciation of Hg using HPLC-AFS by atomization of this metal on a UV/nano-ZrO2/HCOOH photocatalytic reduction unit

Abstract

A novel UV/nano-ZrO₂/HCOOH system was developed and fabricated as an atomization unit and as an online interface between HPLC and AFS for Hg determination and speciation for the first time. UV-generated electrons at the conduction band of nano-ZrO₂ reduce mercury species into mercury cold vapor, achieving mercury atomization for AFS determination. The LODs (3σ) of inorganic mercury (Hg²⁺), methylmercury (MeHg) and ethylmercury (EtHg) tested in this study were respectively reduced to 10, 6, and 8 ng L⁻¹ when using AFS under flow injection mode (FI). Moreover, Hg speciation could also be performed when coupled with HPLC, and the LODs (3σ) of Hg²⁺, MeHg and EtHg were 24, 13, and 16 ng L⁻¹, respectively, using the HPLC-(UV/nano-ZrO₂/HCOOH)-AFS system, with the RSDs better than 4.6% (n = 6) at 20 μg L⁻¹ each. FI-(UV/nano-ZrO₂/HCOOH)-AFS and HPLC-(UV/nano-ZrO₂/HCOOH)-AFS were validated by analyzing a certified reference material (GBW10029, tuna fish) and applied to mercury determination and speciation of the local seafood around Xiamen Island.