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The Chemical Educator
ISSN: 1430-4171 (electronic version)
Abstract Volume 23
(2018) pp 119-123
Determination of Zinc in Cough Drops by Standard Addition with Flame Atomic Absorption Spectroscopy An Instrumental Analysis Laboratory Experiment
Robert Ross, Anna M. Donnell, and Anne P. Vonderheide*
Department of Chemistry, McMicken College of Arts & Sciences, University of Cincinnati, Cincinnati, Ohio 45221, anne.vonderheide@uc.edu
Received January 3, 2018. Accepted June 5, 2018.
Published: 26 June 2018
Abstract. Zinc
is an essential element that can be found in some foods, but is also available
as a dietary supplement and is a constituent in many multi-vitamins. An
experiment was developed for a senior level analytical laboratory course
utilizing a Flame Atomic Absorption Spectrometer (FAAS) for the analysis of
this element in cold lozenges. FAAS is a well-established single element
spectrochemical technique and has proven to be a cost-effective and fairly
simple way to analyze for various elements at trace and ultra-trace levels in a
range of matrices. The objectives of this experimental laboratory were twofold.
The first objective involved demonstrating the strengths and weaknesses of
flame atomic absorption spectroscopy.
Prior to the conduction of this experiment, students were asked to determine
the amount of zinc in the same type of cold lozenge sample by titration with ethylenediaminetetraacetic acid (EDTA). The purpose of this dual analysis was to demonstrate the multiple
techniques open to the analytical chemist. Further, choosing one method over
another in the area of elemental analysis can depend on many factors, including
cost (both initial and operating), level of employee skill, required limits of
detection, specificity, requisite precision/accuracy and single/multiple
element application. The second objective of this experimental procedure was to
introduce the students to analyte quantitation by standard addition, a common method utilized with FAAS. While meeting these
two objectives, this laboratory exercise provided a novel and engaging
application of FAAS and allowed the students to use modern instrumentation and
analytical techniques to investigate the amount of zinc in cold lozenges.
Key Words: Laboratories and Demonstrations; analytical chemistry; inorganic chemistry; atomic spectroscopy; zinc
(*) Corresponding author. (E-mail: anne.vonderheide@uc.edu)
Article in PDF format (141 KB) HTML format
Supporting Materials:
The student laboratory manual and notes for the instructor are submitted as supporting material. (286 KB)
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