Determination of Essential and Toxic Elements in Tropical Fruit by Microwave-Assisted Digestion and Inductively Coupled Plasma–Mass Spectrometry

ABSTRACT

The concentrations of eight essential (Co, Cr, Cu, Mn, Ni, Se, V, and Zn) and five toxic elements (Al, As, Cd, Hg, and Pb) were determined in 457 samples of commonly consumed fresh tropical fruit including bananas (Musa acuminata), kiwi (Actinidia deliciosa), mangos (Mangifera indica), and pineapple (Ananas comosus) from supermarkets from Seoul, Busan, Gangneung, Daegu, Daejeon, and Gwangju, South Korea. The samples were digested by microwave-assisted combustion using HNO₃ and H₂O₂ and determined by inductively coupled plasma mass spectrometry. The Hg concentrations were evaluated by furnace-gold amalgamation direct mercury analysis. The techniques were validated by linearity, limits of detection and quantification, precision, recovery, and the analysis of a NIST-1570a spinach leaves certified reference material. The concentrations of essential elements varied considerably among the tropical fruit. Overall, the tropical fruit was higher in Mn (0.027–13.2 µg/g) and Zn (0.514–2.20 µg/g), while lower in Co (0.002–0.005 µg/g) and V (0.001–0.002 µg/g). The concentrations (µg/g) of toxic elements were 0.001 (kiwi) to 0.003 (mango) for As and Cd, 0.0004 (pineapple) to 0.002 (banana) for Hg, and 0.005 (kiwi) to 0.013 (mango) for Pb. The calculated values of estimated dietary intake, target hazard quotients and hazard indices were lower than one and the safety limits established by World Health Organization. The tropical fruits were therefore safe and did not pose any threat to consumers.

KEYWORDS:

• Direct mercury analyzer
• inductively coupled plasma–mass spectrometry
• microwave digestion
• toxic elements
• tropical fruit