so, DigiSim 2.0 always makes sure that there is initial equilibrium, both at the interface and throughout the simulation space. This feature can be disabled, and it is quite instructive to experiment with the two modes. The outstanding feature oi DigiSim 2.0 is the parameter-fitting option. Pick up a datafile,specify a mechanism, suggest values for the parameters you want to optimize, and let it run. If afitis possible, it is a pleasure to see the two curves (the data and the simulation) merge into one within just a few iterations. At the end, the fitted values can be read off the parameter table. The optimized simulation for a given datafilemay be saved. How accurate are the simulations? In a case where I knew what the current should be, I found that it was correct to 3 decimals, a very impressive result given that only 13 boxes were used for that run. You can read current and potential off the CV curves by clicking on parts of the curve. No program is perfect, and I encountered some problems. First, the manual states that the program will run on a 386based system with a math coprocessor, but the Win 32 installation failed on our 386-based PC. Second, one would also like to see true batch-run capability in the program (i.e., a number of simulations or parameter fits running in sequence, without the necessity for user intervention). Third, although error checking is good, the messages are not always explicit. Presumably, there will soon be no more 386-based PCs, so the first problem will go away, and no doubt DigiSim will add features as it evolves. The most serious drawback for me is the strict format required for imported data in parameterfitting.CV datafilesproduced by the major manufacturers' instruments can be read, as well as general userfiles.DigiSim 2.0 expects these files to have a header containing a set of specifications, but it ought to find out some of
build a complete audit trail for GLP/GMP the information for itself (e.g., minimum compliance. Also integrated into the proand maximum current, number of data gram is HPLC Reference Manager, a suite points). With one data file from an actual experiment, I took great care to write of more than a dozen reference utilities, libraries, and tools for chromatographers. a correct header (using a DigiSim 2.0Minimum system requirements include generated template) but never did manan IBM or compatible PC with a 386DX or age to convince the program that the data faster processor, 8 MB of RAM, 10 MB of file was acceptable. In the end, the program did grudgingly try tofitto it (with an free disk space, MS-DOS 5.0 or later, Windows 3.1 or later, and a mouse. A neterror message at every iteration). Admittedly, in most cases, the data will be gener- work version is available. ated by some program that can be made to write the header correctly. NevertheDOE-101 less, I suggest that a future version Scientific Software should allow the import of "foreign" data 5 Birch St. consisting only of CV data points. Users Mundelein, IL 60060 would then have to type in a lot of infor708-949-1764; fax 708-949-4478 mation for the suggested mechanism and Version 1.0; $300 parameters, but this might often take less time than writing an acceptable header. DOE-101, an experimental design package for nonstatisticians, guides the user This program is a wonderful tool (and through each step of planning, designing, toy!) that frees electrochemists from the need to learn how to program simulations. conducting, and analyzing the results of Long computing times, more or less taken multifactor experiments. Features include for granted in CV simulations, are a thing randomization of runs, data transformaof the past. If the price were not so high, no tions, presentation of results in a variety of graphic formats, and automatic report one would think twice about buying DigiSim 2.0. This program will no doubt set writing. Minimum system requirements include an Apple Macintosh computer a standard for competitors to follow, and I with 2.5 MBfreeRAM and at least 8 MB look forward to future versions. Reviewed by Dieter Britz, Aarhus Uni-free disk space. A demo disk is available. versity (Denmark) Alarm! SOFTWARE RELEASED HPLC Column Manager Phenomenex 2320 W. 205th St. Torrance, CA 90501 310-212-0555; fax 310-328-7768 Version 3.0; $650
Justice Innovations, Inc. 1240 L'Avenida Ave. Mountain View, CA 94043 415-969-6122; fax 415-969-6140 Version 1.0; $395
Alarm!, an enhancement to the ChromPerfect chromatography data system, enables fully automatic real-time monitoring of chromatographic analyses to initiate HPLC Column Manager is a relational quality or process control actions. It can database program for managing HPLC col- check up to 100 alarm events, such as outof-range peak area or width, and can umn inventories and tracking column ensure GLP compliance by automatically performance. Features include the ability checking system suitability values such as to set validation and performance test criresolution, skew, and noise. teria, troubleshoot column problems, and Analytical Chemistry, October 1, 1995 601 A
