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Chemical Education: Software Abstract for Volume 3 D, Number 2 WinDNMR: Dynamic NMR Spectra for Windows Hans J. Reich University of Wisconsin-Madison Madison. WI 53706-1396
This program was written specifically to demonstrate important concepts i n NMR spectroscopy. Varying spectral parameters to make a dynamic presentation of the resulting spectral changes aids i n understanding the more complex aspects of NMR spectroscopy. I n particular, the relat i o n s h i ~between the aowearance of a s ~ e c t r u mand the NMR p'arameters (che&al shift, coupli& constants, and line width) can be more easilv if the effects of . erasoed changes in these parameters can be viewed continuously. The program includes on-line help and is very easy to use. A
HPLC for Windows: A Computer Simulation of High-Performance Liquid Chromatography Robert C. Rittenhouse Walla Walla College College Place, WA 99324
HPLC for Windows is a new and updated version of a program previously published for DOS (2). I t includes a number of new features and has all the advantages of a Windows program. Like the earlier HPLC, i t combines emulation of a typical modem binary gradient HPLC system with sowhisticated modelinpof reversed-~hasecolumn behavior. The modeling, based primarily on the work of L. R. Snyder (3, 41, provides realistic chromatographic output for separations implemented over a broad range of operating conditions. The Droeram is intended as a ~ e d a m e i caid for people who want'to Larn HPLC theory andbrac%. As such, i t ~rovideseasv, inemensive access to manv of the features of a real i n s t r u k n t Gthout risk of damage, consumption of supplies, and the need for constant supervision. It can be used effectively in instrumentation courses as a training exercise prior to hands-on work with the real instrument. HPLC uses color graphic depictions of instrument modules, to create the "feel" of operating a n instrument. The simulated instrument, consists of six working modules:
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Sample Preparation Solvent Selection Column Selection Detector Instrument Control PsnelIGradient Programmer Computer Data System HPLC for Windows includes all of the features of the original HPLC program (5).These are described in detail in reference 5 . It also has these new features: Unknowns can be created with instructor-definedcamwsitian. I.'nknown.: cnn t w i o ~ k r d.so that S I U ~ P I I I Imust intbrpn.r a c h n r r n ~ t u ~tu ~ ~find m the u n k l w r n rumpuiltlun.
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Simulated N M R spectrum for AA'BB' system. Win DNMR. Other major program features include: Simulation of AB, AB2, ABX, ABC, ABCD, AA'BB', AAXX' patterns. First Order Multiplets of a nucleus coupled to others (e.g., the A part of AM3X4 or AMXY4 spectra). Spectra can be displayed in stick form or as Lorenzian lines. Spectral parameters are easily modified in a variety of ways. F u l l line-shape calculations of Dynamic NMR (DNMR)of 2 exehanang singlets WSpinj, 3 exchanging singlets (3-Spin), and 2 pairs of 2-spin systems are possible. Up to 10 simulations can be saved and restored. Spectra produced by PCNMR for Windows ( I ) can be loaded, displayed, and printed by WinDNMR. The spectra must have been Fourier transformed; WinDNMR cannot work with FID's. For accurate estimation of NMR parameters, any of the simulations can he performed while a n experimental spectrum is on the screen. Difference spectra (Spectrum - Simulation) are very useful for accurate Dynamic NMR line-shape fitting. Spectra, simulated spectra, andlor difference spectra can be copied to the Clipboard for transfer to other programs or printed directly. Here are some frequently asked questions that can be addressed with WinDNMR: W h y are the intensities of many multiplets distorted? Why don't equivalent nuclei show coupling to each other? Does it matter if coupling constants are positive or negative? Does coupling between equivalent nuclei affect the spectrum? 1086
Journal of Chemical Education
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Sample files and unknuan; w n be s w e d to dlsk.
The instrument control panel is more generic. The computer data station can save chromatagrams to disk. High-resolution color graphics depict instrument functions. The improved user interface uses slide bars to set parameters and conforms to Windows conventions. HPLC for Windows assumes familiarity with the fundamental principles of liquid chromatography, including the concepts of elution, retention time, resolution, peak area, mobile phase; some knowledge of characteristics of reversed-phase columns i s helpful. This material is com-
