b o n d e d in high- a n d low-density regions. In s p e c t r u m b in Figure 4, t h e high-frequency b a n d arises from liga n d s t h a t c a n h y d r o g e n b o n d with u n r e a c t e d silanols, a n d t h e lower freq u e n c y b a n d arises from cyanoalkyl g r o u p s h i n d e r e d from such i n t e r a c tion. Also shown in Figure 4 for comp a r a t i v e p u r p o s e s is s p e c t r u m c o b t a i n e d from t h e c o r r e s p o n d i n g s t a b i lized m o n o m e r 3-cyanopropyl- t r i methylsilane. W h e n s p e c t r a were a c q u i r e d from t h e s e s a m e surfaces in c o n t a c t with a polar m o b i l e - p h a s e modifier, such as 1-butanol, t h e nitrile b a n d s were broad b u t symmetrical. These latter results a r e indicative of d i s p l a c e m e n t of t h e ligands from t h e surface a n d s u b s e q u e n t l i g a n d - s o l v e n t interaction. Conclusion T h e t h r e e t e c h n i q u e s considered in this REPORT a r e n o t t h e only ones t h a t have been used or t h a t can b e used. F u r t h e r m o r e , t h e r e a r e a n u m ber of variations on t h e t h r e e t e c h n i q u e s p r e s e n t e d t h a t p o t e n t i a l l y exp a n d their scope, for e x a m p l e , b r o a d line q u a d r u p o l e splitting N M R m e a s u r e m e n t s a n d t i m e correlation I R measurements. Perhaps the next major s t e p in t h e d e v e l o p m e n t of new c h r o m a t o g r a p h i c surfaces will b e t h e use of new base m a t e r i a l s such a s p o -
rous c a r b o n , in which case electrochemical t e c h n i q u e s will b e available as a d d i t i o n a l tools t o s t u d y t h e s e surfaces. References (1) Gilpin, R. K. J. Chromatogr. Sci. 1984, 22 371. (2) Gilpin, R. K.; Gangoda, M. E. J. Magn. Res. 1985, 64, 408. (3) McCormick, R. M.; Karger, B. L. Anal. Chem. 1980, 52, 2249. (4) Martire, D. E.; Boehm, R. E. J. Phys. Chem. 1983, 87, 1045. (5) Gilpin, R. K.; Gangoda, M. E. J. Chromatogr. Sci. 1983, 21, 352. (6) Sindorf, D. W.; Maciel, G. E. J. Am. Chem. Soc. 1983,105, 1848. (7) Sindorf, D. W.; Maciel, G. E. J. Am. Chem. Soc. 1983, 705, 3767. (8) Gilpin, R. K.; Gangoda, M. E. Anal. Chem. 1984,56, 1470. (9) O'Donnell, D. J. In "NMR and Macromolecules: Sequence, Dynamic, and Domain Structure"; ACS Symposium Series 247; Randall, J. C., Ed.; American Chemical Society: Washington, D.C., 1984; pp. 21^11. (10) Gangoda, M. E.; Gilpin, R. K. J. Magn. Res. 1983, 53, 140. (11) Palmer, A. R.; Maciel, G. E. Anal. Chem. 1982, 54, 2194. (12) Gilpin, R. K.; Squires, J. A. J. Chromatogr. Sci. 1981,19, 195. (13) Lochmûller, C. H.; Marshall, D. B.; Wilder, D. R. Anal. Chim. Acta 1981, 130, 31. (14) Lochmûller, C. H.; Colborn, A. S.; Hunnicutt, M. L.; Harris, J. M. Anal. Chem. 1983, 55, 1344. (15) Suffolk, B. R.; Gilpin, R. K. Anal. Chem. 1985, 57, 596.
(16) Suffolk, B. R.; Gilpin, R. K., submitted for publication in Anal. Chim. Acta. (17) Dowling, S. D.; Seitz, W. R. Anal. Chem. 1984, 57, 602. (18) Majors, R. E.; Hopper, M. J. J. Chromatogr. Sci. 1974,12, 767. (19) Sander, L. C ; Callis, J. B.; Field, L. R. Anal. Chem. 1983, 55, 1068. (20) Leyden, D. E.; Kendall, D. S.; Burgraff, L. W.; Pern, F. J.; DeBellow, M. Anal. Chem. 1982, 54, 101.
Roger Gilpin received his B.S. degree in 1969 from Indiana State University and his Ph.D. degree in 1973 from the University of Arizona. In 1978, he joined the faculty at Kent State University, where he is now associate professor of chemistry. His research interests are in fundamental and applied GC, LC, and TLC; chromatographic, IR, and NMR studies of chemically modified surfaces; and pharmaceutical analysis.
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