Determining Micro- and Macro Metals by Flame Atomic Absorption Spectrometry

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 21 (2016) pp 264-272

Determining Micro- and Macro Metals by Flame Atomic Absorption Spectrometry

Shakeena Walker^†, Ben Stevenson^†, Jordhan Peterson^†, George Donati^‡, Bradley Jones^‡, Marilyn Tourne^§, David Pollard^†, and A Bakarr Kanu*^,†

^†Department of Chemistry, Winston-Salem State University, Winston-Salem, NC 27110, kanuabb@wssu.edu;^‡Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109; ^§Department of Chemistry, Tuskegee University, Tuskegee, AL 36088, USA
Received September 2, 2016. Accepted September 27, 2016.

Published: 16 November 2016

Abstract. The monitoring of micro- and macro minerals in food and other samples is essential for protecting public health against the hazards of metal toxicity. In this study, experimental protocols were designed to enable undergraduate students interested in research to develop laboratory techniques via hands-on-experience in the analysis of food, water, vitamins/dietary supplements, and toy samples using flame atomic absorption spectrometry (FAAS). Levels of Ca, Cd, Cr, Mg, Fe, and Pb were determined in unknown samples by FAAS. In addition to having students develop techniques in analyzing metal levels in different unknown samples, this project also enabled undergraduate students to better understand the principles and practical operations of FAAS. The limit of detection (LOD) determined for reference standards ranged from 0.003 to 0.12 µg g^–1 whereas the limit of quantification (LOQ) determined for reference standards ranged from 0.01 to 0.94 µg g^–1 using the FAAS instrument. Some of the food and vitamins/dietary supplements showed levels of micro metals well above the provisional tolerable weekly intake (PTWI) value recommended by the Food and Agriculture Organization of the United Nations and World Health Organization (FAO/WHO). In addition, some vitamins/dietary supplements showed metal levels not reported on the labels. Using the amount of metals reported on labels for some of the unknown samples, percent error was calculated. The percent error calculated falls in the range of 0.31% to 8.92% indicating our determination was within acceptable limits.

Key Words: Laboratories and Demonstrations; analytic chemistry

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

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