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SERS is becoming ever more accessi ble to the analytical chemist. New sub strates such as "photocolloids" (30) and silver-coated membranes (15) are...
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$100,000 Raman or $30,000 FT-Raman detector should be compelling indeed. Frontiers SERS can provide unique insight for diverse chemical problems. When used in combination with other techniques such as IR spectroscopy and micros­ copy, SERS can contribute enormously to our understanding of complex inter­ faces and interfacial processes. The sensitivity and rich spectral informa­ tion that SERS provides have spurred the rapid development of technology for using SERS as an analytical detec­ tion method. SERS is becoming ever more accessi­ ble to the analytical chemist. New sub­ strates such as "photocolloids" (30) and silver-coated membranes (15) are eliminating the tedium of colloid and electrode preparation. The availability of IR lasers used with Fourier trans­ form Raman spectrometers considera­ bly augments the range of substrate materials for which the surface-en­ hancement effect can be observed, ex­ tending the range of analytical prob­ lems for which SERS can provide use­ ful insight (4,31,32). The feasibility of performing FTSERS experiments with Nd:YAG la­ sers and roughened noble metal elec­ trode substrates has recently been demonstrated (31, 32). New low-cost Raman spectrometers (approximately $20,000) based on diode lasers as well as small monochromators, inexpensive multichannel detectors, and personal computers, will make conventional Ra­ man spectroscopy, SERS, and SERRS readily available to analytical and pro­ cess control chemists. Advances in la­ ser and detector technology will facili­ tate surface-enhanced hyper-Raman scattering (SEHRS) experiments that provide even richer spectroscopic in­ formation than SERS. New approach­ es to Raman spectroscopy such as Hadamard imaging will also have an im­ pact on SERS. Finally, theoretical and experimental studies of the enhance­ ment mechanisms will contribute to our understanding of the chemical and physical interactions between adsorbates and surfaces, providing the fun­ damental basis for designing chemical interfaces for analytical applications. The author thanks the National Science Founda­ tion, the PPG Foundation, BP America, and the Eastman Kodak Company for support of this work, and Angela Ahem and Tonya Heme for thoughtful suggestions. References (1) Fleischmann, M.; Hendra, P. J.; McQuillan, A. J. Chem. Phys. Lett. 1974, 26,163. (2) Moskovits, M. Rev. Mod. Phys. 1985, 57,783.

(3) Jiang, X.; Campion, A. Chem. Phys. Lett. 1987,140,95. (4) Zeman, E. J.; Schatz, G. C. J. Phys. Chem. 1987,97,634. (5) Weitz, D. Α.; Garoff, S.; Gramila, T. J. Opt. Lett. 1982, 7,168. (6) Moskovits, M.; DiLella, D. P.; Maynard, K. J. Langmuir 1988,4,67. (7) Golab, J. T.; Sprague, J. R.; Carron, K. T.; Schatz, G. C.; Van Duyne, R. P. J. Chem. Phys. 1988,88,7942. (8) Garrell, R. L.; Shaw, K. D.; Krimm, S. Surf. Sci. 1983,124,613. (9) Garrell, R. L.; Beer, K. D. Spectrochim. Acta Β 1988,435,617. (10) Liao, P. F.; Bergman, J. G.; Chemla, D. S.; Wokaun, Α.; Melngailis, J.; Hawryluk, A. M.; Economou, N. P. Chem. Phys. Lett. 1981,82,355. (11) Moody, R. L.; Vo-Dinh, T.; Fletcher, W. H. Appl. Spectrosc. 1987,41,966. (12) Cooney, R. P.; Mernagh, T. P.; Mahoney, M. R.; Spink, J. A. J. Phys. Chem. 1983,87,5314. (13) Stolberg, L.; Richer, J.; Lipkowski, J.; Irish, D. E. J. Electroanal. Chem. 1986, 207 213. (14) Vo-Dinh, T.; Hiromoto, M.Y.K.; Be­ gun, G. M.; Moody, R. I. Anal. Chem. 1984,56,1667. (15) Vo-Dinh, T.; Alak, Α.; Moody, R. L. Spectrochim. Acta Β 1988,43B, 605. (16) Alak, A. M.; Vo-Dinh, T. Anal. Chem. 1987,59,2149. (17) Carrabba, M. M.; Edmonds, R. B.; Rauh, R. D. Anal. Chem. 1987,59,2559. (18) Garrell, R. L.; Beer, K. D. Langmuir, in press. (19) Ahem, A. M.; Heme, T. M.; Garrell, R. L., manuscript in preparation. (20) Garrell, R. L.; Tanner, W.; Beer, K. D., submitted for publication in J. Elec­ troanal. Chem. (21) Kaul, B. B.; Holt, R. E.; Schlegel, V. L.; Cotton, T. M. Anal. Chem. 1988,60,1580. (22) Irish, D. E.; Stolberg, L.; Shoesmith, D. W. Surf. Sci. 1985, /58,238. (23) Dorain, P. B. J. Phys. Chem. 1986,90, 5808. (24) Niki, K.; Kawasaki, Y.; Kimura, Y.; Higuchi, Y.; Yasuoka, N. Langmuir 1987,3, 982. (25) Séquaris, J.-M.L.; Koglin, E. Anal. Chem. 1987,59, 527. (26) Ahem, A. M.; Garrell, R. L. Langmuir 1988,4,1162. (27) Cheng, Y-F; Dovichi, N. J. Science 1988,242, 562. (28) Freeman, R. D.; Hammaker, R. M.; Meloan, C. E.; Fateley, W. G. Appl. Spectrosc. 1988,42,456. (29) Forcé, R. K. Anal. Chem. 1988, 60, 1989. (30) Ahem, A. M.; Garrell, R. L. Anal. Chem. 1987,59, 2813. (31) Crookell, Α.; Fleischmann, M.; Hanniet, M.; Hendra, P. J. Chem. Phys. Lett. 1988 149 123 (32) Chase,' D. B.; Parkinson, B. A. Appl. Spectrosc. 1988,42,1186.

Moskovits, M. Rev. Mod. Phys. 1985, 57, 783. Seki, H. J. Electron Spectrosc. Relat. Phenom. 1986,39, 289. Weitz, D. Α.; Moskovits, M.; Creighton, J. A. In Chemical Structure at Interfaces; Hall, R. B.; Ellis, A. B., Eds.; VCH: Deerfield Beach, FL, 1986; Chapter 5, p. 197.

Robin L. Garrell received her B.S. Hon. degree in biochemistry from Cor­ nell University in 1978 and her Ph.D. in macromolecular science and engi­ neering from the University of Michi­ gan in 1984. She is an NSF Presiden­ tial Young Investigator. Her research involves using spectroscopic tech­ niques such as SERS to characterize protein-metal and polymer-metal in­ teractions and adsorption processes and designing polymer-modified sur­ faces. She is an avid squash player and photographer and has appeared as a guest chef on TV.

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Suggested reading Beer, K. D.; Tanner, W.; Garrell, R. L. J. Electroanal. Chem., in press. Cotton, T. M. In Spectroscopy of Surfaces; Clark, R.J.H.; Hester, R. E., Eds.; Wiley: New York, 1988; Chapter 3, p. 91. Creighton, J. A. In Spectroscopy of Sur­ faces; Clark, R.J.H.; Hester, R. E., Eds.; Wiley: New York, 1988; Chapter 2, p. 37. Gao, P.; Gosztola, D.; Leung, L.-W.H.; Weaver, M. J. J. Electroanal. Chem. 1987,233,211. Koglin, E.; Séquaris, J.-M. Top. Curr. Chem. 1986,134,1.

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ANALYTICAL CHEMISTRY, VOL. 61, NO. 6, MARCH 15, 1989 · 411 A