Robert F. Comte, Arthur M. Norregaard,
I Automated Continuous Flow Analysis
Technicon Corporation Tarrytown, New York 10591
in the Undergraduate Curriculum
and Hans Veening
Bucknell universitv Lewisburg, Pennsylvania 17837
I
During the past ten years, automated analysis has become more and more widespread in industrial, biochemical, aqd medical applications. I n addition, automated analysis has also been introduced into government research agencies and, to a limited extent, in the curricula of the graduate schools. At present, automated analysis has not been formally introduced into undergraduate curricula a t universities. This situation is unfortunate, for there is a genuine need to introduce this technique to undergraduate chemistry and biology students, and certainly to premedical students. Accordingly, the Department of Chemistry a t Bucknell University, in collaboration with Technicon Corporation, Tarrytown, N. Y., undertook a program a t the University for teaching a one-week course in automated analysis to undergraduates as part of Bucknell's recently adopted January program, which was inaugurated in 1970. The January program was flexible and voluntary for students and provided students with an opportunity to pursue independent studies or to take special short courses. Although no formal academic credit was given, a notation of "successful completion" was entered on the student's record. It was felt that the January program was especially well suited to introduce interested students to a course in practical automated analysis using the Technicon AutoAnalyzermsystem.
Figure 1 .
Boric AutoAnolyzer
The AutoAnalyzer (Fig. 1) is a train of interconnected modules that automate the time consuming, step-bystep procedures of manual analysis. The system analyzes samples to determine their concentration levels for specific substances, such as glucose, carbon dioxide, nitrogen, and amino acids. The AutoAnalyzer has also beensuccessfully employed in such applications as the anion exchange separation and determination of carboxylic acids ( 1 ) ; Iijeldahl nitrogen determinations (2, 3) ; and air and water pollution analysis (4,5). Presented in part a t the Technicon International Congress '70, New York, N. Y., November 1970.
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Journal of Chemkol Educotion
The operation of the instrument is based upon a continuous flow concept, in which chemical reactions take place in continuously flowing, air-segmented streams. The flow of the stream (or streams) is directed through plastic tubing from module to module, each of which automatically carries out a different analytical function-such as sampling of unknowns and standards (reference controls); metering of reagents; purification and filtration; heating and incubation; detection and recording. Briefly, operation is as follows: After the samples are loaded into the cups on the sampler, a multiplechannel peristaltic proportioning pump, operating continuously, moves the samples, one following another, and a number of streams of reagents, into the system. Sample and reagents are brought together under controlled conditions to cause a chemical reaction and color development. Color intensity of the analytical stream is measured in a calorimeter, and the results appear as a series of peaks on slowly moving chart paper. Air bubbles continuously segment the flowing streams of samples and reagents to maintain sample integrity and to eliminate cross-mixing of samples. Fundamental to AutoAnalyzer techniques is the exposure of known standards to exactly the same reaction steps as the unknown samples. The concentrations of the unknowns are continuously plotted against the known concentrations. For this reason, reactions need not he carried to completion as in conventional manual chemistry procedures. Since unknown and standard samples are treated repetitively and identically in every respect, the AutoAnalyzer system attains a degree of analytical speed and reproducibility once considered unattainable in the working laboratory. The AutoAnalyzer course was taught on campus, a t no cost to the student, by Technicon teaching personnel using the University's laboratory and classroom facilities. Four AutoAnalyzer units, as well as the necessary reagents, standards, and unknowns, were provided by the Company for experimental work. The class consisted of 13 students of sophomores, juniors, and seniors majoring in biology, chemistry, premedicine, and chemical engineering. There were no prerequisite courses for this class enrollment, although a student's completion of sophomore analytical chemistry was recommended. The course was structured for both lecture and laboratory sessions, an arrangement that allowed each student to receive approximately twenty hours of operational theory and use of the AutoAnalyzer system. A detailed outline of the one-week schedule is shown in the table. Teaching time for an average class period was fifty minutes; laboratory periods lasted about three hours.
Technicon-Bucknell Course in Automated Analysis
Day Monday
Tuesday
Wednesday
Thursday
Friday
Activity
Morning: Color film on AutoAnaly~er. Lecture on continuous How analysis. Afternoon: Reading of Chapters 1 and 2 of programmed instruetmn hook (6). Demonstration of the sampler module in operation. Morning: Reading of Chapter 3 ( B ) . Demonstration of proportioning pump. Interpretation of flow diagram?. Afternoon: Demonstration of tubing, connections, and detector Howcell preparation. Assembly of flowcell by students. Morning: Reading of Chapters 4 and 5 (Heating Bath) (8). Lecture on interconnecting modules for system opertttion. Afternon: L)emonstrat,ion on Dialyzer preparation. Assembly of Dialyzer by students. connection of modules; pumping of di6tilled water through system. Morning: Reading of Chapters 6 and 7 (6). Review of week's work. Review of methods to be used in next laboratory period. Afternoon: Analysis for either glucose or urea using the AutoAnalyzer. Interpretation of AutoAnalyser raw data. Morning: Discussion of AutoAndyzer maintenance and troubleshooting. Discussion of other AutoAndyeer systems and applications. Afternoon: Individual student analyses and - ademonstration on converting s-manual procedure to an automated one.
During the lectures, several chapters of the Technicon Programmed Instruction Book (6) were read and discussed, while supplementary slides and overlays were shown. Typical examples of programmed-instruction "teaching frames" are shown in Figure 2. During the laboratory periods, every student had an opportunity to assemble the AutoAnalyzer and to perform the various operations and manipulations necessary to make the system functional. One task, for example, required that the detector flowcell (cuvet) be assembled with the proper tubing and connectors (Figure 3). The use of a continuous photometric flow cuvet, in combination with the appropriate filters, was instructional for students in that i t represented a very practical application of filter photometry. Another task which students performed was the preparation and incorporation of a membrane into the Dialyzer unit. The partial and reproducible separation of the desired constituent (glucose or urea) from a donor to a recipient stream by means of dialysis was illustrative of the practical application of this method of separation. Each student had an opportunity to study a color-producing (urea) and a color-reducing (glucose) determination, and to interpret the recorder tracings. The AutoAnalyzer method for the determination of urea nitrogen in whole blood, serum, plasma, or other body fluids is based on the direct color producing reaction of urea and diacetyl monoxime (2,3-butanedione-2-oxime) in the presence of thiosemicarbazide under acid conditions. The colored reaction product is measured a t 520 nm in a 15 mm flowcell. This procedure has been described in detail by Marsh, Fingerhut, and Miller (7). Glucose can be determined in the AutoAnalyzer stream by using potassium ferricyanide as the oxidant. The latter is reduced to the colorless ferrocyanide, and measurements are made a t 420 nm. This procedure was first proposed by Hoffman (8).
Figure 2.
Typic01 page of pmgrommed instruction.
The course was enthusiastically received by students and it was felt by the staff that this initial experimental program was very successful in that students were exVolume 48, Number 2, February 7 977
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~ o s e dto the evervdav ~racticalutilitv which is inherent, although noi aiways obvious, & many manual analytical procedures. Formal instruction in automated analysis as part of undergraduate chemistry courses is presently planned. It was also felt that a teaching venture between and an industrial company is of immense value to all concerned. It is hoped that similar programs involving industrial companies and academic institutions become more frequent in the future.
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Journal o f Chemical Education
Literature Cited (1) Z E R P T N ~R. . C., AND V=END*O,H., Anal. Chsm.,38,1312 (1966). ( 2 ) TuresnAN, J. H.. Hofib. W. W., M x c n ~ m ~T. a , P.. *NO SINOTTD, L. P.,
am. N. Y . A ~ ~ ~ . S iCa o~, .6 .z i ( 1 ~ 6 6 ) . (3) W H ~ H E * DE. . C.. P ~ o t i d e ~ B i oFluids. l. 9.70 (1962). (4) YON(IH*NB, R. S., MUNRO., W. A,, AND L n ~ 1 8 N. , J., Technicon Symp. 1966. "Automation in Anal. Chem.:' VOI. I. ~ d a dhc., -.. N ~ W YO?~. a'o (LYO,,. (5) GAneen. W.. NAWNO.J., A N D WAD*, F., Technicon Symp.. 1965 "Automationin Anal. Chem.." Mediad Ino.. New York, 280 (1906). (6) D'Onofrio, E. A., "Progrsmmed Instruction for the Basic AutoAnalyzer," Technioon Corporation. Tarrytorin. N. Y., 1969. (7) MARBX, W. H.,FIN~ERXUT, B.,A N D MILLER,H. Clinical Chem.. 11,624 (1965). (8) H O P F ~ N W. , s.,J . B ~ IChem., . 120.51 (19.37).
