1. Applications of CCD Array Spectrometers in Undergraduate Education at EIU Jonathan Blitz and Daniel Sheeran Department of Chemistry

2. The traditional educational spectrophotometer Single beam Single channel

3. Multichannel Spectrometer

4. Spectrophotometry – the mundane Output from Spec-20: Absorbance = 0.390 Entire spectrum shows λ max and choice of analysis wavelength 2 spectrometers for lab of 24 students is sufficient

5. The multichannel spectrometer is easily configured for emission spectrometry using a fiber optic probe for light input. This has been used as a portable fluorescence emission spectrometer.

6. Fluorescence A typical luminescence spectrometerOur luminescence spectrometer Handheld UV Source Multichannel Spectrometer Emission MonochromatorMulitchannel Detector

7. Fluorescence Emission Spectrum

8. Absorbance and Fluorescence Emission Spectra of Quinine in Water

9. Fluorescence Emission Spectra

10. The multichannel spectrometer has also been used as a detector for qualitative analysis in a traditional flame test …

11. Fiber Optic Collection of Na Flame Emission Spectrum

13. Qualitative Analysis “Group IV” Cations: Na +, K +, Ca 2+, Mg 2+, NH 4 + Visual Flame Test: Na: persistent yellow K : transient red or lavender Ca: unreliable, transient red Na masks K when both are present (Co blue filter) False + and false – for Ca common with visual flame test

14. Qualitative Analysis Spectrometer Flame Test: Na and K easily detected and distinguished Ca not detected, chemical test only

15. Qualitative Analysis Spectrometer Flame Test Student Results: Na > 95% correct on 1 st try K > 95% correct on 1 st try Ca > 98% correct on 1 st try Fewer false +, fewer false – No blue filter for visual observation of K

16. Quantitative Analysis Emission intensity is transient and variable Use another alkali as an internal standard Sample introduction with a nichrome wire does not provide adequate quantitative results Aspirate a sample using a continuous sprayer into the air intake of a Bunsen burner for improved sample introduction

17. Compressed Air Spectrometer Fiber optic

20. K unknown = 200.0 ppmMeasured = 202.5 ppm Student results not that good, but calibrations are OK Detection limits using spray: 30-40 ppm for all alkalis Detection limits much lower using nichrome wire

21. Conclusions A multichannel spectrometer is useful for teaching spectrophotometry Using a fiber optic probe the spectrometer was configured for the following tasks: As a fluorescence emission spectrometer For qualitative analysis of alkalis For quantitative analysis of alkalis using an internal standard calibration