Yankuang ceshi (Sep 2020)
Determination of Heavy Metal Elements in Leaching Solution of Electrolytic Manganese Dioxide Waste Residue by Inductively Coupled Plasma-Tandem Mass Spectrometry
Abstract
BACKGROUND The heavy metals in electrolytic manganese dioxide waste residue can cause different degrees of environmental pollution and hidden dangers to downstream aquatic ecosystems and agricultural ecosystems through surface runoff under rainwater leaching. Therefore, it is of great practical significance to determine the content of heavy metal elements in leaching solution of electrolytic manganese dioxide waste residue. Usually, the detection limits of atomic absorption spectrometry and inductively coupled plasma-optical emission spectrometry are insufficient to meet the measurement requirements, since the content of heavy metal elements in the leaching solution of electrolytic manganese dioxide waste residue is typically very low. The challenge is to eliminate complex spectral interference. OBJECTIVES To find an efficient method for the determination of six heavy metal elements in leaching solution of electrolytic manganese dioxide waste residue. METHODS The objective was determined by inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS). The six heavy metal elements Cr, Ni, As, Cd, Hg and Pb in the electrolytic manganese dioxide waste residue were directly measured by ICP-MS/MS after H2SO4-HNO3 mixed acid leaching. The O2 reaction mode was adopted to eliminate the spectral interference of Cr, Ni, As and Cd during analysis. The background equivalent concentrations (BECs) of 52Cr, 60Ni, 75As and 111Cd in the different analytical mode were investigated to evaluate the influence of spectral interference on the analysis results. RESULTS In the MS/MS mode, O2 was selected as the reaction gas, and the spectral interference of 52Cr, 60Ni, 75As and 111Cd was eliminated by using mass shift method and on-mass method. The limits of detection for Cr, Ni, As, Cd, Hg and Pb were 3.06, 9.31, 3.50, 2.72, 2.03, 1.89ng/L, respectively. The spiked recoveries were between 95.6% and 106.2%. The relative standard deviation was no higher than 3.9%. CONCLUSIONS The method has been successfully applied to the determination of heavy metal elements in leaching solution of electrolytic manganese dioxide waste residue.
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