Instrumentation in Chemical Analysis' A Technical Training Course RAYMOND H . LAMBERT Rochester Institute of Technology, Rochester, New York
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HE number and variety of instruments used in chemical analysis have become so great that demands are being made on educational institutions for a course or courses of training to cover as many of these instruments as possible. Problems of find'mg sufficient classroom and laboratory space, of acquiring a minimum number of instruments for a general and fundamental study, and of selecting the proper students immediately confront the school that decides to initiate a course of instruction of this kind. It is obvious that the organization and teaching of such a course will tax the ingenuity of any instructor who attempts to do so, since it would be surprising if he should be thoroughly familiar with all the many instruments and the uses to which they may be applied in the field of chemical analysis. Pedagogical methods may, in many cases, have to be altered from the orthodox, since i t seems plausible that training should be based more directly on what the student is expected to encounter in the industrial laboratory than on his general knowledge of the subject. Thus an experiment should be designed in such a manner that the student must rely to a great extent on his own resources. The chemist in industry often meets a particular problem in which a new instrument may appear to be desirable. He must buy or make it himself. Having the instrument, he may find the problem necessitates alterations in the instrument or the way in which i t is to be manipulated. .The purpose of this course should be to give the student jamiliarity with the applications and limitations of the instruments studied, so that the correct choice may be made, and so that the needed alterations in the instrument or its application can be carried out. In the industrial laboratory distinction should be made between the attendant, who is merely an automaton on a particular instrument, and one who has a knowledge of its fundamental action and thus is able to appreciate the results of his efforts. The analytical chemist need not be an instrument maker, but it would be extremely to his advantage to understand the construction as well as the functioning of instruments. Ralph Muller in the May number of the Analytical Edition of Industrial and Engineering Chemistry points out that our analytical needs in industry are deviating considerably from present academic training. He points out that automatic analysis is becoming so
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Presented before the Division of Chemical Education at the 110th meeting of the American Chemical Society in Chicago, September 9-13, 1946.
popular that data collection and its treatment intrigues the analyst far more than the mechanics involved, and the latter should be left to a mechanical engineer or an electronics expert. I t appears, however, that the separation he makes is too distinct, a t least for research purposes, since a knowledge of the limits or versatility of a new instrument may easily lead to new fields for its use if they are realized by the manipulator. It is obvious then that in conducting a course on the use of instruments in chemical analysis, many problems arise to confront the instructor. Such a course was started in the fall of 1944 a t the Rochester Institute of Technology and was considerably improved last year. Although many difficulties have been overcome in making this an effective course, others still confront the instructor, and it is hoped that through our own experiences, and with information obtained from others conducting similar courses in schools throughout the country, it can beimproved further. The number desiring this course in Rochester is so great that a means of selecting students and instruments had to be found. A plan was worked out whereby candidates were selected from those employed regularly in local industries during the day. These students attend the course in the evening. A committee of chemists representing the many industries in Rochester serves in an advisory capacity to the Institute staff. This committee meets irregularly to discuss improvements, suggest added instrument's, arrange for likely students, and give advice. An annual report is submitted by the instructor through the head of the Chemistry Department to.tbe members of this committee on the achievements of the year. The class of 1945-46 was conducted as follows: Eighteen students were chosen from the applicants, and six units were studied. A unit was considered a specific phase of instrumentation in chemical analysis. Three students were assigned to each unit. They were expected to cover their assignment in three sessions of two and one-half hours per session. Then they shifted to a second unit for three sessions, and so on until each group had covered all the units furnished. The six units chosen were spectrophotometry, conductometry, potentiometry, amperometry, polarographic analysis, and spectrographic analysis. Spectrophotometry includes colorimetry and turbidimetry and ranges from 200 p to 2500 p. Amperometry and polarographic analysis were separated so that the former could include the dead-stop end-point experiments. The Bausch and Lomb large Littrow quartz
spectrograph with auxiliary equipment gave enough range for a single unit. Typewritten instructions were given each student a t the outset to cover the entire course. The several experiments for each unit were on separate sheets so that they might be revised or other experiments substituted conveniently. An introduction of an explanatory nature was given for each experiment which included the objective of the experiment. Detail of instruction was varied. In some cases it was of the cook-book type to speed the student. Often the instruction was left incomplete and much was left to the ingenuity of the individual. For example, in the spectrophotometric determination of iron each step of the procedure was given and the experiment was completed rapidly. For analysis of nickel with the same instrument, the student was given a reference to instruction in the literature and told to proceed accordingly. At the beginning of a new shift the instructor held a classroom session of not more than one hour for purposes of introduction and for questions concerning the previous shift. No attempt was made to cover theoretical considerations through classroom presentation. Such instruction was given to the individual group either by the instructor or his assistants. This arrangement is to be altered in the next class as will be outlined below. Equipment for each unit was set up on a table of such size and shape as could conveniently be arranged about the room. Each table has a cabinet wherein all equipment not permanently attached and chemicals pertinent to that particular unit can be stored. The nature of the apparatus used in the several units varied considerably and ranged from the most modern to some of the most simple, constructed of parts which could easily be obtained. This was considered good instructional technique, since the student could experience the distinction and could learn a great deal about the construction as Gel1 as the handling of instruments. For example, in place af an automatic recording polarograph, a simply wired apparatus mounted on a panel with an open back was constructed. The wires connecting galvanometer, voltmeter, rheostats, Ayrton shunt, etc., were fitted with patent clips for attachment. The student was given a diagram of the electrical connections and told to wire i t himself; however, it is planned to have one automatic recording instrument in the course since the student should come to know that not all analytical procedures need be drudgery and also to show the advantages in some cases of securing permanent data independent of the analyst. The course was conducted previously by an instructor and two assistants, one giving his entire time to the spectrograph unit. The course for the next class is to be extended considerably. The one criticism voiced most often was that the course was too superficial and that the student in general was still too little trained to carry on independent analytical procedures in the plant where he was employed. With this in mind the course
this year will consist of two sessions a week for 25 weeks. One session will consist of lectures, demonstrations, visits to industrial plants, and attendance a t pertinent scientific meetings. In general this session will be of one and one-half hours' duration. The second session of two and one-half hours will be conducted as before but with a minimum of fundamental instruction on the theory underlying instrumentation. The rotational procedure in the laboratory will continue with six units and three students per unit, but with added sessions. The first session will be an organization meeting. It is expected an instructor and one assistant will be adequate for the laboratory. The classroom work necessarily cannot parallel work in the laboratory, for students are covering all phases of the course a t any one time. This may be the most serious problem to contend with in this arrangement. An attempt will be made to add a t least one new unit each year. This year we propose to give chromatography as a new feature. The committee from industry referred to above recommended that in addition to the units now being taught, others, including density determination, viscosimetry, analysis by electrodeposition, refradometry, polarimetry, the microscope, and use of Geiger counten, be included eventually. Recent instruments which are very important also being considered are the electron microscope, the mass spectrograph, instruments for dielectric constant measurements, for electron diffraction, and for infrared spectroscopy. An attempt was made this spring to secure information on how courses of this nature were being conducted by other educational institutiotis. A poll on instrumentation in general had been made by Mr. J. F. Sullivan, editor of Instrumentation, who kindly furnished us with a copy of his tabulation. This poll covered 88 schools. Thirty of these schools were selected as stating they were teaching courses in industrial instruments and the questionnaire was sent to them. Questions were asked concerning when the course was initiated, whether it is specifically on instruments for chemical analysis, in what student year i t is offered, whether it is offered in the regular curriculum or in evening school, the number a n d qualification of students, the length of the course, and, in particular, what instruments were being used. A question on the desirability of having the instructor from the industrial field rather than an educator familiar with the industrial field was also submitted. Only about one-third of the schools returning the questionnaire stated they were conducting a course specifically for instrumental methods of chemical analysis. Others, however, stated the need for such a course. Where such courses were given, in general, only about ten students were being accommodated in a given class. The number of hours in classroom and laboratory was about the same as a t the Rochester Institute of Technology. The type of instruments either recommended for such a course or actually being
used also did not d&er greatly from those used or contemplated in this course. In fact the only novel feature of the course a t Rochester Institute of Technology seemed to be the rotational method of instruction in the laboratory whereby nearly double the number of students can be handled with the same teaching staff. As previously stated, this procedure in the laboratory is at variance with the lecture and demonstration procedure. This may not turn out to be a problem when put into actual practice. One question submitted in the questionnaire concerned the treatment of data with respect to its interpretation. Not one answer was received to this ques-.
tion. Considerable stress is given to this phase of instrumentation in this course, and more time will be devoted to it in the more extended course. From the returned questionnaires, it would appear that very few schools conduct a course specifically on instruments in chemical analysis; however, in some cases the query did not reach the proper individual in a given school and it is likely that other schools were overlooked. A follow-up of this venture would, it is believed, yield further worthwhile information, as it is certain that the demand for instruction on instruments in chemical analysis in educational institutions will greatly increase.
