REPORT
Kontes' ULTRAWARE Solvent System
Your Chromatograph and Autosampler
+
ULTRWARE Integrated Analytical HPLC Mobile Phase Handling Systems • Unique four valve cap for single system stepwise filtration, sparging, storage and delivery. Ask for our FREE brochure.
+
Kimble's NEW Large Opening Vials
NEW LOVIAL Large Opening Vials Designed to Fit Newer Autosamplers • 40% larger opening means fewer bent needles and more flexibility when using inserts. Ask for our FREE brochure.
most complete source KIMBLEYour for laboratory glassware products. KONTESAlso available through major scientific distributors. Call 1-800-223-7150. CIRCLE 72 ON READER SERVICE CARD
NIST CSMC,MVF,VF,MBFB DXMVDVFBF,BFBF. CXVMD,V;F'F.';F'.F'\.
SKKSSKDLDLDD;;D;D;D;D;D;;D;D;D; SLDLD;L;D'F'F'F'FF''FLHFLGF;GLFL'F DJKFLDJGL;DJG'LDJG;LKG;FKG;FKGK SDBNFVKJDSBGVLKJDFGKFGHFKLFK
age of CO B is comparable to that of CO L and increases at negative potentials (33). Recent in situ scanning tunneling microscopy measurements on CO adsorbed at R h ( l l l ) (34) appear to be in agreement with the composition of the adsorbed CO layer predetermined by IR spectroscopy (33). When the Rh electrode is partially covered with Cu atoms (9 C u ~ 0.2) the CO B species disappear almost entirely, whereas the CO L adsorption remains unaffected. One possible explanation for this phenomenon is that the presence of the Cu atoms leads to a decrease in the number of free neighboring Rh sites necessary for the CO species to adopt a bridge configuration. Access to this type of molecular-specific information would have been difficult to obtain by employing only conventional electrochemical measurements.
Conducting polymer thin films. Thin films of electronically conductive polymers such as polypyrrole, polythiophene, and polyaniline are being considered for diverse applications ranging from controlled drug release and chemical sensors to electrochromic displays and s m a r t windows (35). Most of these applications depend critically on the ability of the polymer to switch from an insulating (reduced) form to an electronically conductive (oxidized) form. The dynamics of this process, however, depend critically on the ionic fluxes that accompany the polymer redox process, and both anion and
The National Institute of Standards and Technology has developed a series of SRM's to serve as calibrants, test mixtures, and standardization materials for Quality Control of analytical instrumentation and methodology. MEASUREMENTS and STANDARDS are important to everyone who needs quality. NIST has over 1,000 Standard Reference Materials that can help you calibrate instruments and check on measurement accuracy. For more information phone or write for a free catalog. Telephone (301) 975-OSRM (6776) FAX (301) 948-3730 STANDARD REFERENCE MATERIAL PROGRAM
SRM
Building 202, Room 204 National Institute of Standards and Technology Gaithersburg, MD. 20899
CIRCLE 98 ON READER SERVICE CARD
438 A · ANALYTICAL CHEMISTRY, VOL. 64, NO. 7, APRIL 1, 1992
Figure 10. Scheme for in situ luminescence monitoring of ion transport during redox electrochemistry of a polypyrrole-modified electrode. Strategies for monitoring (a) anion (A~) and (b) cation (C*) fluxes. (Adapted from Reference 36.)
