Chapter 10

1. Chapter 10 Atomic Emission Spectrometry By: Alexa Kunch

2. Plasma Sources • Plasma: An electrically conducting gaseous mixture • that contains a significant concentration of • cations and electrons • Overall Net charge due to the concentration • of cations and electrons is zero • Plasmas that use Argon ions can sustain • temperatures as high as 10,000K • Total rate of Argon gas consumption • ranges from 5-20 L/min • The sample is first nebulized, then it is • introduced into the plasma

3. ICP Source Schematic of a typical ICP source similar to the one found on page 255 of the textbook

4. Applications of Plasma Sources • Useful for both qualitative and quantitative elemental • analysis because plasma sources produce spectra that • are rich in characteristic emission lines • High quality results due to: • High stability • Low noise • Low background • Freedom from interferences • Plasma emission spectrometry allows the determination • of all metallic elements

5. Detection Limits Table 10-3 Comparison of Detection Limits for Several Atomic Spectral Methods (page 269)

6. Chapter 13 An Introduction to Ultraviolet-Visible Molecular Absorption Spectrometry By Tim Cumming and Meg Dailey

7. Beer’s Law and Other Equations • Transmittance: T=P/P0 • Absorbance: A=log(P0/P) • Beer’s Law: A=-logT • A=logP0/P • A=εbc

8. Beer’s Law “Few exceptions are found to the generalization that absorbance is linearly related to path length. On the other hand, deviations from the direct proportionality between the measured absorbance and concentration frequently occur when I> is constant.”

10. Sources of Instrumental Noise • Case 1: Limited readout resolution or dark current and amplifier noise. • Case 2: Photon detector shot noise • Case 3: Cell positioning uncertainties and source flicker

11. Effect of Slit Width on Absorbance Measurements • As the bandwidth increases, fine detail is lost • Less peaks • Peaks are more rounded As the bandwidth increases, peak height decreases Higher peaks with smaller bandwidth

13. Instrumentation • Sources • Deuterium and Hydrogen lamps, Tungsten filament lamps, light-emitting diodes, and xenon arc lamps • Wavelength Selectors • Types are filters and monochromators • Sample Containers • Radiation Transducers • Types include photon transducers and heat transducers • Signal Processors and Readout Devices

14. Single-Beams vs. Double Beam • Single-beam instrumentation includes of a lamp, a filter or monochromator, cells, a transducer, an amplifier, and a readout device • Double-beam instruments includes a beamsplitter • Double-beam instruments have more advantages • Compensate for wide variations in source intensity with wavelength • Continuous recording of transmittance and absorbance spectra

15. Single-Beam vs. Double-Beam

17. Typical Instruments • Photometers • Visible photometers, probe-type photometers, filter selection • Ultraviolet Absorption Photometers • Spectrophotometers • Instruments for the visible region, single-beam instruments for the ultraviolet-visible region, single-beam computerized spectrophotometers, double-beam instruments, double-dispersing instruments, and multichannel instruments