Focus vent additives. Currently we're work ing on an optimization program devel oped by Leo de Galan of the Technische Hogeschool Delft, which takes these recommendations and then de cides whether to run isocratic or gradi ent elution chromatography. "The ultimate goal would be a closed-loop system," Abbott contin ues, "but we're not there yet. It's going to happen, but it will take a while. Also, it should be feasible for us to transport the system to a PC with ei ther an 80286 or 80386 processor, from the MicroVAX-II it currently resides on. Clearly, we can reach a lot more users with a PC-based program than a Micro VAX-based program." Optimization packages The expert systems currently under development will have to contend with the problem that many users have en countered in the use of LC solvent op timization programs: the fact that they don't always work. "About half the time our optimization package doesn't pick an optimum," explains Joseph Kosman of the Standard Oil Research and Development Center. "It sometimes interprets the data in correctly and then goes off into the
".. .if you put one up against the other, the topnotch analytical chemist is still going to do a better job." wrong part of the solvent diagram. It does work sometimes, but how well it works is dependent on the type of sample involved." This is not to say that optimization software has not been useful at Stan dard Oil and other laboratories, how ever. According to Kosman, the pri mary utility of the optimization pro gram used at Standard Oil is "not that it finds the optimum, but that it does enough separations that I can go back through them and pick out something that is close to what I would call the optimum. I've talked to a lot of people who use optimization packages in in dustrial settings, and they have told me the same thing: that the packages they were using didn't necessarily con verge on the optimum, but ran enough
CAN TEMPERATURE CONTROL ENHANCE LC PRECISION? If you are using anything other than the BAS 200 Problem Solver™, you may not know the answer. With the BAS 200 you would have an advanced temperature control system which can accommodate both electrochemical and UV detector cells, most column formats, and the injection valve. The result? Enhanced precision, lower baseline drift, improved symmetry and results beyond anything you could expect from a modular LC system. This unique approach to temperature control is only one of 20 great ideas incorporated into the hot, new Problem Solver™ from BAS.
2701 Kent Ave West Lafayette Indiana 47906 Β iο a n a I y t c a I I n c S y s t e m s ,
Telex: 276141 (317) 463-4527
CIRCLE 17 ON READER SERVICE CARD 1198 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 12, OCTOBER 1986
separations that they could pick one out as a usable optimum. The main advantage is that it runs the instru ment by itself and performs a lot of separations." Ed Kikta, manager of analytical ser vices at FMC Corporation, affirms that the commercial optimization pro grams fail on occasion. "We've seen them diverge instead of converge," says Kikta. "That can happen very easily. However, there are also cases where they come up with the same conclusions a good methods develop ment chemist would come up with, and we've seen them come up with better conclusions. Still, if you put one up against the other, the top-notch analytical chemist is still going to do a better job." Where will it all lead? "One idea we have for an expert sys tem," explains Joseph Kosman, "is one where a client could come into the laboratory with a sample and be prompted by a computer to answer questions about it. Based on those re sponses the computer would choose a column and starting solvents. This in formation would be fed to an LC opti mization system, which would opti-
ι80° C
S8°C 5S°C
