Excerpts from the history of absolute statements: 'Mom u/léPtiam utaticOH~&e UWOH" 'ttï mpowbte. &v Hue Tîteuac to iutk!' 'The. ewtfU a Act!' 'Twuvuf g/tackeut LCEC cmv't be done
Oops! another absolute bites the dust! The BAS 2 0 0 makes gradient elution with multichannel electrochemical detection a viable option for determinations of amino acids and other molecules of varying polarity. Even reductive gradient-LCEC is a breeze, thanks to a deoxygenation utility built into the instrument. Superior mixing dynamics in the BAS solvent delivery system eliminate the high baseline noise which can sabotage gradient-elution LCEC with minimum distortion of gradient profiles. Single or 4-channel variable wavelength UV/VIS detection provide still more options.
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Briefs Proton Nuclear Magnetic Resonance Spectroscopy of Aqueous Solutions: Complete Elimination of the Water Resonance by Spin-Spin Relaxation 3178 NMR pH indicators are used to measure the solution pH. The method is applied to the measurement of XH NMR spectra of human plasma, hemolyzed red blood cells, grapefruit juice, and coffee. Dallas L. Rabenstein* and Shiyan Fan, Department of Chemistry, University of California, Riverside, Calif. 92521 Anal. Chem., 58 (1986)
Identification and Colorimetric Determination of Organic Cyanates in Nanomolar Quantities 3184 The spot test procedure has an identification limit of 60 ng and a dilution limit of 1:833000 for phenyl cyanate. On TLC plates, as little as 20 pmol of organic cyanate is detected. Joachim Kohn, Elizabeth C. Albert, Meir Wilchek, and Robert Langer*, Department of Applied Biological Sciences, Massachusetts Institute of Technology, Cambridge, Mass. 02139, and Department of Biophysics, Weizmann Institute of Science, Rehovot, 76100, Israel Anal. Chem., 58 (1986)
Identification of Organic Additives in Rubber Vulcanizates Using Mass Spectrometry 3188 Various desorption/ionization methods are used to characterize the additives in cross-linked rubbers. Direct thermal desorption and solvent extraction methods are described. R. P. Lattimer*, R. E. Harris, and C. K. Rhee, The BFGoodrich Research and Development Center, Brecksville, Ohio 44141, and H.-R. Schulten, Fachhochschule Fresenius, 6200 Wiesbaden, Federal Republic of Germany Anal. Chem., 58 (1986)
Laser-Desorption Fourier Transform Mass Spectrometry of Synthetic Porphyrins 3196 Both positive- and negative-ion LD-FT mass spectra are presented for a variety of synthetic porphyrins and metalloporphyrins. Abundant molecular ion species are present in all cases. R. S. Brown and C. L. Wilkins*, Department of Chemistry, University of California, Riverside, Riverside, Calif. 92521 Anal. Chem., 58 (1986)
Square Wave Voltammetry at the Mercury Film Electrode: Theoretical Treatment
3199
Theoretical response for SWV at MFE is derived and used to characterize the response as a function of the dimensionless thickness parameter. S. P. Kounaves, J. J. O'Dea, P. Chandresekhar, and Janet Osteryoung*, Department of Chemistry, State University of New York at Buffalo, Buffalo, N.Y. 14214 Anal. Chem., 58 (1986)
Ternary gradient LCEC/LCUV is only one of 2 0 great ideas built into the BAS 2 0 0 Problem Solver. 2701 K e n t A v e West Lafayette Indiana 47906 Bioanalytical Systems, Inc
Telex: 276141 (317) 4 6 3 - 4 5 2 7
CIRCLE 17 ON READER SERVICE CARD 1388 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 14, DECEMBER
1986
