Sheryl A. Tucker, William E. Acree, Jr., Mary J. Tanga, Sumio Tokita, Kimihiro Hiruta, and Heinz ...... S. C. Rutan, D. D. Gerow, and G. Hartman, Intell. Lab. Syst.
Volume 46
No. 2
P a g e s 187-394
February 1992
Rapid Communication 187
Rapid Near-Infrared Raman Spectroscopy of Human Tissue with a Spectrograph and CCD Detector Joseph J. Baraga, Michael S. Feld, and Richard P. Rava
Feature Article 191
Lifetime Analysis of Weak Emissions and Time-Resolved Spectral Measurements with a Subnanosecond Dye Laser and Gated Analog Detection Lucas P. Hart and Malcolm Daniels
Camera-Ready Copy 206
Suggestion for the Improvement of Camera-Ready Copy (CRC) Papers Submitted to Applied Spectroscopy Jeffrey S. White
Submitted Papers 208 219 225
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Quantitative Characterization of Fe/Al 0 Catalysts. Part I: Oxidic Precursors Douglas P. Hoffman, Marwan Houalla, Andrew Proctor, Martin J. Fay, and David M. Hercules The Application of Linear PA/FT-IR to Polymer-Related Problems R. O. Carter III Probing the Concentration Profiles of Additives in Polymers by IR Microspectroscopy: The Diffusion of Cyasorb UV531 in Polypropylene S. C. Hsu, D. Lin-Vien, and R. N. French Spectroscopic Properties of Polycyclic Aromatic Compounds: Examination of Nitromethane as a Selective Fluorescence Quenching Agent for Alternant Polycyclic Aromatic Nitrogen Hetero-Atom Derivatives Sheryl A. Tucker, William E. Acree, Jr., Mary J. Tanga, Sumio Tokita, Kimihiro Hiruta, and Heinz Langhals Dioxygen NIR FT-Emission ( Δ - Σ~ ) and Raman Spectra of 1,4-Dimethylnaphthalene Endoperoxide: A Source of Singlet Molecular Oxygen Paolo Di Mascio, Etelvino J. H. Bechara, and Joel C. Rubim Improvements in the Generation of Quasi-Continuous, Tunable Ultraviolet Excitation for Raman Spectroscopy: Applications to Drug/Nucleotide Interactions Ronda L Benson, Koichi Iwata, William L. Weaver, and Terry L. Gustafson Lignin Determination by FT-IR Michael A. Friese and Sujit Banerjee Resonance Raman Spectroscopic Detection System for Liquid Chromatography Chan Kong Chong, Charles K. Mann, and Thomas J. Vickers Tunable, Coherent Vacuum Ultraviolet Radiation for Photoionization Mass Spectrometry S. E. Van Bramer and Μ. V. Johnston Fiber-Optic Sampling Combined with an Imaging Spectrograph for Routine Raman Spectroscopy Cathy D. Newman, Georges G. Bret, and Richard L. McCreery Fourier Transform Infrared Spectrometry/Attenuated Total Reflectance Study of the Reaction of Pentanal and Propanal with 2-(Hydroxymethyl)piperidine Eugene R. Kennedy and Kevin Ashley Eu Ion Luminescence Spectra from Lanthanide Sesquioxides Exhibiting Three Different Crystal Structures G. Chen, R. G. Haire, and J. R. Peterson 2
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Simultaneous GC-FT-IR/GC-MS Analysis for Isomer-Specific Identification and Quantitation of Complex Mixture Components N. R. Smyrl, D. M. Hembree, Jr., W. E. Davis, D. M. Williams, and J. C. Vance An Optimized Background Correction Algorithm in Automated Spectral Analysis Based on Convolution Signals F. Janssens and J.-P. Frangois Infrared Study of Benzaldehyde and 4-Substituted Benzaldehydes in Carbon Tetrachloride and/or Chloroform Solutions: Aldehydic CH Group Richard A. Nyquist, Sam E. Settineri, and Davin A. Luoma Infrared Study of 4-Substituted Benzaldehydes in Dilute Solution in Various Solvents: The Carbonyl Stretching Mode Richard A. Nyquist A Novel Fiber-Optic-Based Pump-Probe Instrument for the Acquisition of Kinetic Information Mary K. Carroll and Gary M. Hieftje Scanning Multichannel Technique for Improved Spectrochemical Measurements with a CCD Camera and its Application to Raman Spectroscopy V. Deckert and W. Kiefer Microheterogeneity of Sodium Dodecylsufate Micelles Probed by Frequency-Domain Fluorometry Jingfan Huang and Frank V. Bright Quantitative Infrared Emission Spectroscopy of Phosphosilicate Glass on Silicon Wafers Using Multivariate Calibration B. Wangmaneerat, J. A. McGuire, T. M. Niemczyk, D. M. Haaland, and J. H. Linn Characterization of Boron-Modified Co/AI 0 Catalysts by EXAFS Spectroscopy Martin J. Fay, Andrew Proctor, Douglas P. Hoffmann, Marwan Houalla, and David M. Hercules First Observation of the Urbach Tail in a Multicomponent Organic System Oliver C. Mullins and Yifu Zhu UV Resonance Raman Spectra of Bacillus Spores E. Ghiamati, R. Manoharan, W. H. Nelson, and J. F. Sperry Optical Effects in IR Spectroscopy: Thickness-Dependent Positions of Absorbance Lines in Spectra of Thin Films Marta Klanßek Gunde 2
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The Use of CCDs in Fabry-Perot Spectrometers D. Walton, J. J. Vanderwal, and P. Zhao Temperature Measurement by Observation of the Raman Spectrum of Diamond Sheng Dai, J. P. Young, G. M. Begun, and Gleb Mamantov Measurement of Radical Cation UV-Visible Spectra in a Polycrystalline Freon Matrix at Liquid Nitrogen Temperature by Diffuse Reflectance Spectroscopy Sheng Dai, J. P. Young, G. Mamantov, J. T. Wang, and F. Williams
Spectroscopic Techniques 379
A New Approach to Highly Efficient Raman Spectroscopy Using a Laser Diode and AgGaSe Crystal Filter 2
H. Horinaka, N. Yamamoto, and H. Hamaguchi 8A 14A 16A 18A 22A 28A
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Columns and Features Society Information Editor's Notes Special Communication Spectroscopists' Calendar Book Reviews What's New—1992 Buyer's Guide
Volume 46, Number 2, 1992
44A 382 383 386 389
Advertising Index Obituary Society News News of Other Societies and Institutions Coblentz Society Newsletter
Spectroscopic Properties of Polycyclic Aromatic Compounds: Examination of Nitromethane as a Selective Fluorescence Quenching Agent for Alternant Polycyclic Aromatic Nitrogen Hetero-Atom Derivatives S H E R Y L A. T U C K E R , W I L L I A M E . A C R E E , JR.,* M A R Y J . TANGA, S U M I O T O K I T A , K I M I H I R O H I R U T A , and H E I N Z L A N G H A L S Department of Chemistry, University of North Texas, Denton, Texas 76203-5068, USA (S.A.T., W.E.A.); S R I 333 Ravenswood Avenue, Menlo Park, California 94025, USA (M.J.T.); Department of Applied Chemistry, Saitama Shimo-Ohkubo, Urawa-shi, 338 Japan (S.T., K.H.); and Institut für Organische Chemie der Universität München, 23, D-8000 München, Germany (H.L.)
Nitromethane is examined as a selective fluorescence quenching agent for alternant polycyclic aromatic nitrogen hetero-atoms ( P A N H s ) . F l u orescence emission behavior is reported for 1-azapyrene, 2-azapyrene, 4-azapyrene, 4-azachrysene, 12-azabenzo[a]pyrene, phenanthro[9, lOgjisoquinoline, phenanthro[2,3h]isoquinoline, phenanthro[3,2h]isoquino-line, 2-azabenz(a]anthracene, l - a z a b e n z [ a ] a n t h r a c e n e , 9-azabenz[a]anthracene, dibenzo[c,i]phenanthro[l,10,9,8anmlk]phenanthridine, d i p h e n a n t h r o I 9 , 1 0 , l d e f ; r , 1 0 ' , 9 ' h i j ) p h t h a l a z i n e , and benz[de]isoquino[l,8gh]quinoline dissolved in acetonitrile or aqueousacetonitrile solvent mixtures at various nitromethane concentrations. Results of these measurements show that nitromethane does quench fluorescence emission of ten of the solutes studied; however, phenanthro[2,3h]isoquinoline, 9-azabenz[a]anthracene, benz(de]isoquino[ 1,8gh|quinoline, and dibenzo(cJlphenanthro(l,10,9,8anmlk|phenanthridine are notable exceptions. Index Headings: Fluorescence; Spectroscopic techniques.
INTRODUCTION Fluorescence spectroscopy is r a p i d l y becoming a n ext r e m e l y versatile, sensitive e x p e r i m e n t a l technique for identifying and quantifying numerous environmentally i m p o r t a n t polycyclic a r o m a t i c hydrocarbons ( P A H s ) a n d p o l y c y c l i c aromatic nitrogen heterocycles ( P A N H s ) . P A H / P A N H identification a n d quantification in u n k n o w n mixtures require accurate fluorescence emission i n t e n s i t y measurements a n d availability of a large spect r a l d a t a file for c o m p a r i n g the u n k n o w n ' s s p e c t r u m a g a i n s t P A H / P A N H s t a n d a r d s . K a i m a n filtering a n d G a u s s i a n or other curve-fitting m e t h o d s , along w i t h s e l e c t i v e p h o t o c h e m i c a l q u e n c h i n g a g e n t s s u c h as nitromethane and 1,2,4-trimethoxybenzene, m a y be n e e d e d to uncouple overlapping spectra if more t h a n one fluorescent species is present. T o prevent misidentific a t i o n , the data file s h o u l d include both polar a n d n o n p o l a r solvents, since electronic interactions between a s o l v e n t dipole and a n excited P A H / P A N H solute c a n l e a d to spectral distortions, wavelength shifts a n d / o r i n t e n s i t y ratio variations, as was the case w i t h m a n y of the polycyclic aromatic compounds examined previously. 1-4
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S o l v e n t - i n d u c e d fluorescence spectral changes c a n be rationalized qualitatively i n a relatively straightforward Received 15 July 1991; revision received 9 August 1991. * A u t h o r to whom correspondence should be sent.
Volume 46, Number 2, 1992
International, University, Karlstrasse
m a n n e r . E x c i t a t i o n promotes the P A H / P A N H solute from a ground state of low dipole m o m e n t to one of the vibrational levels of the first electronic e x c i t e d state, S * , w i t h an a c c o m p a n y i n g electron d i s t r i b u t i o n i n the s u r r o u n d i n g solvent molecules. Insufficient t i m e exists, however, for s o l v a t i o n a l - s p h e r e molecules to p h y s i c a l l y reorient w i t h the new P A H / P A N H dipole m o m e n t . R e laxation from the v i b r a t i o n a l l y excited SI level to the excited S* level occurs w h e n e v e r solvent molecules r o tationally reorient to a more stable dipole configuration d u r i n g the excited state's lifetime. E m i s s i o n of the fluorescence photon r e t u r n s b o t h t h e P A H / P A N H molecule to the ground S state a n d s o l v a t i o n a l molecules to t h e i r i n i t i a l electronic configuration. S u b s e q u e n t rotation of solvent molecules to t h e g r o u n d - s t a t e dipole orientation restores the s y s t e m to its o r i g i n a l state. T r a n s i t i o n p r o b abilities a n d energy s e p a r a t i o n s between the different energy levels v a r y w i t h e a c h s o l u t e - s o l v e n t pair, a n d give rise to observed i n t e n s i t y ratio changes a n d e m i s s i o n wavelength s h i f t s . 0
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T h e emission s p e c t r u m of m a n y p o l y c y c l i c a r o m a t i c compounds consists of s e v e r a l m a j o r v i b r o n i c b a n d s l a beled I , I I , etc., i n progressive order. P r e v i o u s m e a s u r e ments revealed t h a t p y r e n e , benzo[ghi]perylene, o v a lene, coronene benzo[a]coronene, naphtho[2,3a]coronene, benzo[e]pyrene, n a p h t h o [8, l , 2 a b c ] coronene, d i n a p h t h o [8,l,2abc;2',r,8'klm]coronene, dibenzo[def,p]chrysene, phenanthro[5,4,3,2efghi]perylene, benzo[rst]pentaphene, 1- azabenz[a]anthracene, 2-azabenz[a]anthracene, 12-azabenz[a]pyrene, phenanthro[2,3h]isoquinoline, a n d p h e n a n t h r o [ 3 , 2 h ] i s o q u i n o l i n e e x h i b i t probe c h a r a c t e r as evidenced by s y s t e m a t i c v a r i a t i o n of e m i s s i o n i n t e n s i t y ratios w i t h solvent p o l a r i t y . I n t e r e s t i n g l y , only 25 of the 73 compounds s t u d i e d to date behave i n t h i s fashion. V a r i o u s emission i n t e n s i t y ratios of p e r y l e n e , dibenzo [bc,ef]coronene, b e n z o [ a ] p y r e n e , b e n z o [ p q r ] n a p h t h o [ 8 , l , 2 b c d ] p e r y l e n e , dibenzo[fg,ij]pentaphene, 1-azapyrene, 1 0 - 2 1
2- azapyrene, 4 - a z a p y r e n e , a n d s e v e r a l other P A H s / P A N H s r e m a i n e d e s s e n t i a l l y c o n s t a n t , i r r e s p e c t i v e of solvent polarity. N o w t h a t studies on P A H / P A N H probes are n e a r l y complete, we h a v e d e c i d e d to r e d i r e c t our e x p e r i m e n t a l efforts to a c o m p r e h e n s i v e e x a m i n a t i o n of selective fluorescence q u e n c h i n g agents. O n t h e basis of l i m i t e d fluorescence m e a s u r e m e n t s for p e r y l e n e , d i b e n z o [ b , k ] -
0003-7028/92/4602-0229$2.00/0 © 1992 Society for Applied Spectroscopy
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Ε F I G . 1. Molecular structures of P A N H solutes: ( A ) 1-azapyrene; (B) 2-azapyrene; (C) 4-azapyrene; (D) 12-azabenz[a]pyrene; (E) phenanthro[9,10g]isoquinoline; ( F ) phenanthro[2,3h]isoquinoline; and ( G ) phenanthro[3,2h] isoquinoline.
c h r y s e n e , d i b e n z o [ h , r s t ] p e n t a p h e n e , naphtho[1,2b]fluoranthene, indeno[l,2,3cd]pyrene, and 1 0 , l l - ( p e r i n a p h t h y l e n e ) f l u o r a n t h e n e d i s s o l v e d i n a b i n a r y aqueousacetonitrile solvent m i x t u r e , Blümer a n d Z a n d e r noted t h a t nitromethane a n d nitrobenzene selectively q u e n c h e d fluorescence e m i s s i o n of only t h e s o - c a l l e d " a l t e r n a n t " p o l y c y c l i c a r o m a t i c h y d r o c a r b o n s . E m i s s i o n intensities of the three n o n a l t e r n a n t P A H s (e.g., naphtho[l,2b]fluoranthene, indeno[l,2,3cd]pyrene, a n d 1 0 , l l ( p e r i n a p h t h y l e n e ) f l u o r a n t h e n e ) were unaffected. T h e a u t h o r s failed to investigate the h e t e r o - a t o m analogs or m e t h y l - s u b s t i t u t e d d e r i v a t i v e s . F o r t h i s r e a s o n , we report the effect t h a t n i t r o m e t h a n e has on the fluorescence e m i s s i o n of 1-azapyrene ( 1 - A z P y ) , 2 - a z a p y r e n e ( 2 - A z P y ) , 4 - a z a p y rene ( 4 - A z P y ) , 12-azabenzo[a]pyrene ( 1 2 - A z B P y ) , p h e n anthro[9,10g]isoquinoline ( 9 , 1 0 - P I Q ) , p h e n a n t h r o [ 2 , 3 h ] isoquinoline ( 2 , 3 - P I Q ) , phenanthro[3,2h]isoquinoline ( 3 , 2 - P I Q ) , 2-azabenz[a]anthracene ( 2 - A z B A ) , 9-azabenz[ a ] a n t h r a c e n e ( 9 - A z B A ) , l - a z a b e n z [ a ] a n t h r a c e n e (1A z B A ) , 4-azachrysene ( 4 - A z C h ) , dibenzo[c,i]phenanthro[ l , 1 0 , 9 , 8 a n m l k ] p h e n a n t h r i d i n e ( D B P P ) , diphenanthro[9, 10,ldef;l',10',9'hij]phthalazine ( D P P ) , and benz[de]isoq u i n o [ l , 8 g h ] q u i n o l i n e ( B I Q Q ) . T h e various m o l e c u l a r s t r u c t u r e s are depicted i n F i g s . 1 a n d 2. T h e s e 14 solutes are classified as a l t e r n a n t P A N H s because every a l t e r n a n t c a r b o n a n d nitrogen a t o m i n the a r o m a t i c ring syst e m c a n be " s t a r r e d . " N o n a l t e r n a n t P A H s / P A N H s , on t h e other h a n d , w o u l d h a v e at least one p a i r of a d j a c e n t starred atoms. A l s o i n c l u d e d is a d i s c u s s i o n of both p r i m a r y a n d s e c o n d a r y i n n e r - f i l t e r i n g artifacts associated with quenching determinations, and new experim e n t a l fluorescence results for D B P P , D P P , a n d B I Q Q dissolved i n nonelectrolyte organic solvents of v a r y i n g solvent p o l a r i t y a n d acidity. 6
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M A T E R I A L S AND M E T H O D S T h e v a r i o u s P A N H s were s y n t h e s i z e d a n d p u r i f i e d by p r o c e d u r e s d e s c r i b e d i n t h e l i t e r a t u r e . - S t o c k solutions were p r e p a r e d by d i s s o l v i n g the solutes i n d i c h l o r o m e t h a n e . S m a l l aliquots of t h e stock solutions were t r a n s f e r r e d into test tubes, allowed to evaporate, a n d d i l u t e d w i t h t h e solvent of i n t e r e s t . F i n a l solute c o n c e n 2 6
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N F I G . 2. Molecular structures of P A N H solutes: ( H ) 9-azabenz[a] a n t h r a cene; ( I ) l-azbenz[a]anthracene; ( J ) 2-azabenz[a]anthracene; ( K ) diphenanthro[9,10,ldef;r,10',9'hij]phthalazine; (L) benz[de]isoquino[l, 8gh]quinoline; ( M ) dibenzo[c,i]phenanthro[ 1,10,9,8anmlk]phenanthridine; and ( N ) 4-azachrysene.
trations were sufficiently dilute to m i n i m i z e i n n e r - f i l t e r ing artifacts. Solvents were of H P L C , spectroquality, or A R grade, p u r c h a s e d c o m m e r c i a l l y from either A l d r i c h or F i s h e r Scientific, a n d the resulting solutions were optically dilute (absorbances c m
