Measurement of Mercury Levels in a Commercial Fish Oil Brand by Inductively Coupled Plasma Mass Spectrometry

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 20 (2015) pp 234-239

Measurement of Mercury Levels in a Commercial Fish Oil Brand by Inductively Coupled Plasma Mass Spectrometry

A Bakarr Kanu*^,†, Keith E. Levine^‡, Laura G. Haines^‡, Monique Massey^†, TeAsia Codio^†

^†Department of Chemistry, Winston-Salem State University, Winston-Salem, NC 27110, kanuabb@wssu.edu;^‡RTI International, 3040 E. Cornwallis Road, Durham, NC 27709
Received May 20, 2015. Accepted August 5, 2015.

Published: 28 August 2015

Abstract. One of the most important heavy metals to consider in food chain contamination is mercury (Hg). Fish oil consumption has long since been associated with decreased risk of coronary artery disease. On the other hand, fish oil intake has been reported to be a major source of exposure to organic Hg, since most fish contain methyl-mercury. There is however very little data available in the literature concerning levels of Hg in fish oil supplements. Because of the high toxicity levels of Hg, these data may prove critical if physicians continue to recommend fish oil supplements to patients with coronary artery disease, bipolar and affective disorders, and for cardio-protective benefits in the general population. In this study, undergraduate students were instructed to use a quality assurance (QA) approach with inductively coupled plasma mass spectrometry (ICP-MS) to investigate levels of Hg in a fish oil supplement brand sold over the internet. Levels of Hg reported in the fish oil supplement product chosen at random from three bottles were 12, 5, and 3 times higher than the recommended provisional tolerable weekly intake (PTWI) values set by the Food and Agriculture Organization of the United Nations and World Health Organization (FAO/WHO). These levels may pose health risks to consumers if these products are consumed above 3000 g (approximately 4300 capsules) per week. This work demonstrates there is a need to develop regular screening methods for pharmaceutical products and such methods are needed for students trying to learn the approach. Our experimental approach will be incorporated into an instrumental analysis class as part of a guided-inquiry (GI) lab. Such labs have been reported to enhance student learning and improve students’ critical and problem-solving ability.

Key Words: Laboratories and Demonstrations; instrumental analysis; ICP-MS; mercury; fish oil; method validation; limit of detection; guided-inquiry labs

(*) Corresponding author. (E-mail: kanuabb@wssu.edu )

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