Analytical Spectroscopy

There is an article to read for the Raman spectroscopy section of class.

You should read "Raman microscopy techniques for the characterisation of pigments"by Robin J. H. Clark and coworkers before class on 11/30/09.

Discussion Questions:

1. What are the advantages and disadvantages of using Raman scattering to study important historical artifacts?

2. What is the purpose of the interference filter, the spatial filter, and the double monochromator in the common Raman instrumentation described?

3. In one described example, why are some of the white features in the text turning black? How was this revealed? Where would you find the Raman bands relevant for this discovery?

4. Can you think of other sample types where non-destructive Raman analysis would be particularly applicable?

Posted by Christy Haynes at 8:04 AM | Permalink | Comments (0)

There are two Analytical Chemistry A-Pages articles to read for the luminescence section of class. You should read both before class on 11/23/09

You should read "Oxygen Sensors Based on Luminescence Quenching"by James N. Demas and coworkers.

Discussion Questions for "Oxygen Sensors Based on Luminescence Quenching"

1. According to the Stern-Volmer expressions, what combination of rate constants will yield the highest sensitivity quenching sensor?

2. Why is it important that the quencher molecule have a significant Stokes shift?

3. Why is it advantageous to use a fluorophore with a long lifetime in oxygen sensor applications?

4. Come up with one experimental scenario not discussed within this paper where a luminescence-based oxygen sensor would be useful?

You should read "Analytical Bioluminescence and Chemiluminscence".

Discussion Questions for "Analytical Bioluminescence and Chemiluminescence"

1. What molecule(s) could be sensed quantitatively using a luciferin/luciferase reaction?

2. What are the advantages and disadvantages of chemiluminescence compared to fluorescence?

3. What is the difference between FRET and BRET?

4. What are the major challenges to performing in vivo spectroscopic imaging?

Posted by Christy Haynes at 8:40 AM | Permalink | Comments (0)

There is an Analytical Chemistry A-Pages articles to read for the infrared spectroscopy section of class.

You should read "IR Spectroscopy: Clinical and Diagnostic Applications" by Janie Dubois and coworkers before class on 11/13/09.

Discussion Questions for "IR Spectroscopy - Clinical and Diagnostic Applications":

1. What artifacts might be introduced while performing IR absorption measurements of biological fluids?

2. Where are the major biological IR absorption bands?

3. Is infrared absorption spectroscopy a good method to diagnose arthritis? Do infrared absorption spectroscopy diagnostics give information about the cause or progression of the disease?

4. Compare FT-IR and IR microscopy as diagnostic/clinical tools.

5. What is the diffraction limited spatial resolution in mid-IR absorption spectroscopy? Is this sufficient to probe biological tissue?

Posted by Christy Haynes at 2:01 PM | Permalink | Comments (0)

There is an Analytical Chemistry A-Pages article to read for the atomic fluorescence spectroscopy section of class.

You should read "Sub-Part-per-Billion Analysis of Aqueous Lead Colloids by ArF Laser Induced Atomic Fluorescence" by S. K. Ho and coworkers before class on 11/02/09.

Discussion Questions:

1. What is colloidal lead?
2. Why is the spectral background significantly reduced when using atomic fluorescence compared to this group's earlier laser-induced plasma spectroscopy experiment?
3. The excitation wavelength is 193 nm while the main fluorescence is at 405.8 nm. Identify the type of fluorescence observed in this work.
4. Why does the colloid size influence the signal strength?
5. Why couldn't the authors use their original calibration curve when analyzing tap water? What advantage do they gain by using standard addition instead?
6. How would AES or AAS analysis of the lead colloid samples compare to the work presented herein?

Posted by Christy Haynes at 8:37 AM | Permalink | Comments (0)

Please read this paper for in-class discussion on 10/28/09.

Discussion Questions:

1. Why is background correction so important when using a furnace as the atomizer?
2. What is meant in the statement, "...possibility of inaccurate correction if the background is structured..."? Why is a continuum source background correction insufficient in this case?
3. The authors state that one of their goals in this work is to "... indicate how implementation of the Zeeman effect influences such factors as sensitivity and analytical range for many of the commonly determined elements." Summarize their results related to this goal.
4. Are the sensitivity trends the same for normal and anomalous Zeeman splitting? Why or why not?
5. Why does hyperfine structure (splitting of different J values) influence Zeeman corrected sensitivity?
6. Why is the artificial seawater sample matrix so disadvantageous when using continuum source background correction? Why is the Zeeman corrected spectrum improved?
7. What is the role of the monochromator's spectral bandpass in both continuum source and Zeeman corrected AA spectra?
8. Compare and contrast the three methods used to perform Zeeman correction: DC magnet around the atomizer, AC magnet around the atomizer, and DC magnet around the hollow cathode lamp.

Posted by Christy Haynes at 1:57 PM | Permalink | Comments (0)

This paper is a good reference:
http://pubs.acs.org/cgi-bin/article.cgi/ancham/2002/74/i12/pdf/ac020190r.pdf

Posted by Christy Haynes at 9:52 AM | Permalink | Comments (0)

There is an Analytical Chemistry article to read for the detector section of class.

You should read "A Charge Coupled Device Array Detector for Single-Wavelength and Multiwavelength Ultraviolet Absorbance in Capillary Electrophoresis" by Edmund T. Bergstrom and coworkers before class on 10/16/09.

Download discussion questions.

Posted by Christy Haynes at 8:32 AM | Permalink | Comments (0)

There are two Analytical Chemistry A-Pages articles to read for the classical optics section of class.

You should read "Planar Integrated Optical Waveguide Spectroscopy" by John T. Bradshaw and coworkers before class on 09/28/09.

You should read "Mid-IR Fiber-Optic Sensors" by Boris Mizaikoff and coworkers before class on 09/30/09.

Download discussion questions.

Posted by Christy Haynes at 10:28 AM | Permalink | Comments (0)

There are two articles to read for the laser section of class.

You should read "25 years of lasers and analytical chemistry: A reluctant pairing with a promising future" by Ben Smith before class on 09/18/09.

You should read "Tunable Deep Blue Light for Laser Spectrochemistry" by Kay Niemax and coworkers before class on 09/21/09.

Download "Questions to consider while reading "Tunable Deep Blue Light...".

Posted by Christy Haynes at 2:21 PM | Permalink | Comments (0)