neded to the serial port of the printer is connected to a manual switchbox instead, so that the output can be of a micnlrouted either to the printer or to the serial computer. With communication software (we use ProC o d ) running on the microcomputer, the software's log mode is turned on before instructing the spectrophotometer to ~ r i nout t the table of data. This automaticallvresults in the'data normally sent to the printer being cadtured to disk instead in the form of a standard ASCII fie. Since the data transfer rates are low, even the simplest personal comnuter is adeauate for this task. Once the data are on disk, it is a quick k d easy process for the student to import the ASCII tile into a s~readsheet.delete the extraneous table headings, etc., an'd arrange the data in the form required by the nonlinear, least-squares program. Transcription errors are eliminated, and large quantities of data are handled readily. In the abovekxample, the motivation for the data transfer is the need to make use of the nonlinear, least-squares program. The same situation exists whenever any &alysis tool only available outside the instrument must be employed.-other reasons may arise even more frequently, such as the need to prepare puhlication-quality figures from experimental data.
An Efficient FTlR Setup for the Undergraduate Teaching Laboratory Scott Hammond and Daniel A. ~ t r a u s ' San Jose State Univeffilty San Jose. CA 95192 We recently replaced three aging dispersion IR spectrometers in our undergraduate organic teaching laboratories with a single FTIR instrument. Because spectrometer time has been a frequent bottleneck in completion of lab exneriments. it was essential to confirmre our svstem to midimize the' time required for the &dent to obtain spectral data. With essentially no teaching-assistant support available, we also sought to minimize the instructor supervision needed. We found that use of a laser printer in conjunction with a programmable FTIR fulfills both of these requirements.' The hardware and software combination described herein instructs students step-by-stepin acauirine and lott tine a s~ectrumand allows them. without ihstru&or supervision, obtain an IR spectrum on preprinted chart paper with a separate peak list in an average student time of three minutes. To the best of our knowledge this is the first use of a laser printer with a teaching
FTIR instrument. With the price of laser printers coming down rapidly, the cost is not much greater than that of a good plotter. We are using a Perkin-Elmer 1620 FTIR and a Hewletb Packard LaserJet I11 ~ r i n t e er a u i ~ ~ with e d a Pacific Data Products plotter-in-;-cartridge plotter emulation card. The program (or "method") we have ~ r i t t e nUGLAB, ,~ is copied easily from disk to FTIR memory and is initiated by the instructor or a student bv ~ r e s s i n ethe "UGLAB" method soft key. It is not necessary to ree&er the program after each svectrum since the proeram is constructed as a continuous ioop with only twd choices at any poinh'proceed" or "stop." While in the program loop the remainder of the keypad is locked automatically.Routine operation is as follows. The screen instructs the student that an IR sample and chart paper are required and to press the "proceed" soR kev if they are available. Next the student is asked to verify that the sample compartment is empty for a background scan and to press "proceed" to acquire one. The background spectrum is displayed for two seconds. The student is then prompted to place a piece of preprinted chart paper in the manual feed chute of the laser printer and a sample in the beam and to press "proceednagain. A snectrum is acauired. disvlaved for 10 s. and Drinted on the &rt paper," &en a list dfpiak frequenkes and intensities is ~ r i n t e dautomaticallv on a sheet of lain Dauer from the paper feed tray of the laser printer. ~he'student is reminded to wait for both codes and is instructed how to clean the salt plates. The next student is prompted to press "Droceed" to rcstan the Droeram. 1f"sto~" isselected at any ];oint in the program, h e program is k t e d with plot pirameters set for printing with axes on unlined paper. This enables students wishing to obtain expanded plots or to use other features of the instrument in the manual mode of operation to print their spectral data with axes by simply pressing "plot" on the keypad. The use of a laser printer instead of a plotter saves considerable time. The printing of both spectrum and peak table for polystyrene as described above requires only 70 s. The entire program is run by an experienced operator in 100 s. By contrast an HP Color Pro plotter requires 2 min to plot a polystyrene spectrum with axes on plain paper and an additional 4 min to plot a peak table. There is no need to press any keys on the laser printer; whereas, pen selector and paper positioning keys must be selected on the plotter. Use of the FTIR program described reduces the number of FTIR keys that must be pressed from several to just one, avoiding confusion and delay. A
Literature Cited 1. Douglss. J.E. J. Chern. Edvc. 19W, 67,424. 2. Bordass, W. T:Linnett, J. W J. Cham. Edue 1910,47,765-168. 3. J J Cham Edue 1913,49,61&611. 4. Streifweiser, A., JI: Owens, P. H. Orbital and E k l m n Donsily Diogmms: Maemil-
OlconR.
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'Indicates author to whom correspondence should be addressed. %me required to plot FTiR data is normally the rate-limitingfactor in this technique. Perkins, W. D. J. Chem. Educ. 1987, 64, A269. 3~vailableas "UGLAB" on disk PC-4104 from project SERAPHIM, Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, WI 53706. Also provided on disk is documentation of hardware and softwareand a synthetic spectrum to facilitate calibration of the spectral printout to the pre-printed chart paper. 4Reproducibilityof paper placement using the manual feed chute on the HP LaserJet I i I is excellent, less than + 3 cm-' for the 1601 cm-' band of polystyrene. A79
Journal of Chemical Education
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,072
5. Cooper, R;Casanova, J. J Chem. Educ 1991,GS. 4 8 1 4 8 .
6. Hanna, M . W Q u n t u m Mechoniesm Chamlstry; Benjamin: New Yark 1965, p200.
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