Inductively Coupled Plasma-Atomic Emission Spectroscopy: Two Laboratory Activities for the Undergraduate Instrumental Analysis Course

Abstract

Two inductively coupled plasma–atomic emission spectroscopy exercises are described for use in an undergraduate instrumental analysis course. The first activity looks at the emission signal produced by two different ionization states of the same element. The ionization states are in equilibrium within the plasma, and by observing the emission signal in different spatial regions of the plasma one can deduce information about the predominant ionic state and see suppression of the emission signal from the minor state. In the second exercise, the excitation temperature of the plasma is measured as a function of the power applied to the plasma induction coils. This temperature derives from the Boltzmann distribution, and can be determined by monitoring the intensity of a series of well-characterized emission transitions that emanate from a single ionization state of the element being observed.

Exploring Emission and Absorption Spectroscopy in the First-Year General Chemistry Laboratory

“…Historically, experiments studying emission spectroscopy in large enrollment general chemistry courses have often been carried out utilizing handheld spectrographs or spectroscopes. − For upper level, lower enrollment courses, many quantitative absorption and emission studies requiring the use of sophisticated instrumental techniques such as atomic absorption spectroscopy (AAS) or inductively coupled plasma atomic emission spectroscopy (ICP-AES) have been published in the chemical education literature. − While AAS and ICP-AES are highly sensitive and accurate techniques, they are often not used in general chemistry courses due to cost and availability. Technological advances have made devices like emission and absorption spectrometers more portable and affordable, providing opportunities to incorporate these techniques into large classes which would not have been previously feasible.…”

Development of a Multiple-Element Flame Emission Spectrometer Using CCD Detection

“…Throughout the literature a number of AES laboratory experiments ranging from quantitative flame emission procedures (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) to the construction of inexpensive emission spectrometers for the undergraduate laboratory (25-28) have been described. Our instrument design utilizes the characteristics of the CCD detector, allowing students to align, collect, and manipulate data, thereby gaining a deeper understanding of the instrument, multiple-element emission analysis, and limitations imposed by either solution preparation or instrumental parameters; all of which can be studied within five, three-hour laboratory periods.…”

“…The experiment described herein is not designed for immediate implementation by instructors, but is instead an adaptation of a common multiple-element ICP-AES experiment to a multiple-element flame AES experiment for smaller chemistry departments that may not have an ICP-AES instrument but may have a flame atomic absorption (AA) instrument that can be adapted by the purchase of a monochromator and CCD system for a reasonable price. Useful experiments that might be adapted include ones for AAS (14,15,20,22), AES (16,23), and ICP-AES (19,21).…”