Instrumental analysis experimental course teaching discussion paper

Instrumental Analysis Experiment course is one of the main basic courses in chemistry and related majors, the content of the course mainly includes electrochemical analysis, UV-visible absorption spectroscopy, infrared absorption spectroscopy, chromatography, atomic absorption spectroscopy, fluorescence spectrometry, and fluorescence spectrometry. Absorption Spectrometry, Infrared Absorption Spectrometry, Chromatography, Atomic Absorption Spectrometry, Fluorescence Spectrometry, etc. Through the study of this course, students can deepen their understanding of the basic principles of instrumental analytical methods, master the basic structure and use of the instrument, reasonable selection of experimental conditions, the correct processing of experimental data and the expression of experimental results, for the study of subsequent courses and future vocational positions to lay a certain foundation.

1 instrumental analysis of the main problems of experimental teaching

1.1 insufficient hardware resources, students lack of hands-on training

Instrumental analysis of the experiments used in the large-scale instrumentation prices of less than a few thousand dollars, more than tens of thousands of dollars, or even hundreds of thousands of dollars. Many colleges and universities are subject to financial and site constraints, unable to configure all the equipment required for the course, or only 1 to 2 units for all teachers and students. Therefore, the lack of hardware resources, resulting in instrumental analysis experimental teaching can not be as basic experiments, the use of independent operation, so that each student is involved in the experiment, can only rely on the teacher to demonstrate or let the students do some auxiliary operations to complete the teaching task. For example: in the infrared spectroscopy experiment, students can be operated mostly solid samples of the press; in the liquid chromatography experiment, the main task of the students is to configure the solution, ultrasound to remove the gas, filtration with a microporous filter membrane and so on. And the instrument parameters of the settings, sample injection and other parts of the instrument operation by the teacher demonstration, the students have little opportunity to operate the instrument.

1.2 The special characteristics of precision instruments make the use of students restricted

The operation of precision instruments requires a high level of technical requirements, the use of personnel only in familiar with the performance of the instrument and master the premise of the operating procedures, in order to carry out the actual operation. Once used improperly, not only will cause damage to the instrument, but also relatively high maintenance costs and relatively long maintenance time will bring serious impact on daily teaching. Therefore, in the instrumental analysis experimental teaching, the teaching is usually organized in a large cycle. Most of the teachers in order to ensure that the equipment is in good operating condition, to avoid or reduce the occurrence of failures, in the class is only a personal demonstration, do not allow students to arbitrarily turn on and off the instrument, arbitrarily rotate the instrument buttons, and arbitrarily change the working parameters of the instrument. In this case, students can only walk around to see the demonstration, to achieve the desired learning effect.

1.3 focus on cultivating the ability to operate, ignoring the introduction of the internal structure

Instrumental analysis of the teaching objectives of the experiment for the mastery of the experimental principles, to understand the structure of the instrument, the function of the various parts of the instrument, as well as the use of the instrument, maintenance and repair. Most schools in the existing conditions, the harvest of the more ideal teaching effect is only the students can master the mechanical operation of the instrument at the end of the course, while the students on the internal structure of the instrument and the principle of little understanding, but also do not understand the routine maintenance and repair, the ability to natural can not be fully exercise. This is obviously not enough to help the future work, it is difficult to meet the actual needs of vocational education and training of skilled personnel.

1.4 Auxiliary teaching tools are not strong

With the advent of the information age, in the case of insufficient hardware resources, the teacher can use the Internet teaching video to assist in teaching, on the students to master the experimental principles, instrumentation can also play a certain effect. However, due to the different models of instruments and equipment, software, hardware operating procedures vary greatly, students watch the video on the Internet, the face of the school's experimental equipment may still not be able to start. For example: the use of Baidu search to the UV-visible spectrophotometer teaching video mostly 721, 722, 752, UV756MC models; gas chromatography teaching video is mainly GC120M, AGILENT6890N type; and liquid chromatography, atomic absorption spectrophotometer, atomic fluorescence photometer, gas chromatography and other instruments of the network teaching resources are very limited. In view of the above problems, according to the actual conditions, choose, develop suitable for the school's auxiliary means of teaching, used to make up for the lack of teaching resources, is not a feasible way.

2 auxiliary means of teaching in the instrumental analysis of the use of experimental teaching

2.1 will be introduced into the teaching of simulation technology

analytical instrumentation simulation technology is the use of computer technology, network technology, simulation technology and information technology, the establishment of a set of computer and the real analytical instrumentation is identical to a set of virtual analytical system [ 1]. 1]. It can use images, animation to describe the characteristics of the equipment, show the real action of the entity, imitating the real operation process. Domestic large-scale analytical instrument simulation technology is now mature, developed by the Beijing Oriental Simulation Software Technology Co., Ltd. of large-scale analytical instrument simulation operating system software series, for example, which covers the ultraviolet spectrometer, infrared spectrometer, gas chromatography device, atomic absorption spectrometry, high-performance liquid chromatography, color and mass spectrometry analyzers simulation and other content. The system adopts computer virtual simulation technology for development. The software has a mechanism model, high fidelity of the virtual scene, and the real experimental database as a support, can automatically simulate the corresponding experimental phenomena, and get the experimental results similar to the real experiments. The operation mode is flexible and real, and the simulation operation process is extremely similar to the operation process of real instruments. Students can complete the simulation of expensive analytical instruments and equipment through the virtual experimental operation platform established on the computer through simulation technology, just as in the operation of real analytical instruments. It can not only meet the needs of daily training, routine assessment and skills competition, but also provide great convenience for analyzing the internal structure and principle of the instrument. The establishment of the simulation training room can be expanded by using the existing computer room in the school and purchasing the corresponding operating software. This is compared with the acquisition of equipment, simulation technology, less investment, low consumption, long service life, easy maintenance. The introduction of large-scale analytical instrument simulation software, compared with the traditional teaching methods, not only to meet the huge gap between the number of equipment and the number of students to make up for the contradiction between the number of hardware resources to make up for the lack of schooling, but also on the internal structure of the equipment, experimental principles and other related knowledge of the image analysis and three-dimensional explanation. Repeated operation of the simulation instrument will not only not increase the cost of experiments, encounter improper operation, incorrect parameter settings, but also will not damage the instrument, safety issues, can help students as soon as possible, comprehensive mastery of the operation of the instrument and equipment skills.

2.2 Reasonable use of microclasses

In response to the problem of insufficient hardware resources for instrumental analysis experiments, how to integrate the limited practical training resources into the traditional teaching environment to maximize the role of teachers need to be taken seriously. From a technical point of view, microclasses, a flexible, subject-oriented new teaching mode is an effective method. Microcourse is an organic combination of various teaching resources with teaching video as the main carrier, reflecting the teacher's teaching and learning in the process of teaching activities for a certain knowledge point or teaching link. The development of instrumental analysis experiments related to microcourse, with the help of network and video technology, through the video, pictures, PPT and other forms, can visualize the image of the training project operating skills visualization for students to watch repeatedly, more conducive to students' understanding and mastery of professional skills [2]. It can also extend classroom teaching to outside the classroom, students are able to use electronic devices to browse the teaching content of practical training courses before and after class, targeted learning. Teaching video is the core component of microcourse, the length is generally 5 to 8 minutes, the theme is prominent, after the post-production of the video and supporting the total capacity of auxiliary resources is generally dozens of megabytes, the video format must be to support the network online playback of the streaming media format (eg, rm, wmv, flv) and so on [3]. Instrumental analysis experiments microclass production can be used to "video method", the instrument parts, knobs, operating methods, practical training content of a complete show. Such as infrared spectroscopy experiments in the solid sample compression process, the use of spectrophotometer, can be recorded throughout. For large-scale equipment, such as gas chromatography, high-performance liquid chromatography, atomic absorption spectrophotometer, etc., a complete experiment is time-consuming, the production of microclasses can be made according to the action nodes of the operating steps fragmented into different units, for the fragmented knowledge points to be recorded. The steps should be coherent and cannot be easily skipped. In the post-production of the video, key words are added to supplement the part that it is not suitable to speak clearly in the form of subtitles. Take the operation of G5 gas chromatograph as an example, it can be fragmented into the following parts to record: First, the instrument structure, mainly introducing the gas control system, instrument control panel, injector, column box, detector (including the control circuit), etc.; Second, the method of powering on, introducing the order of powering on the operating order and the adjustment of the carrier gas flow rate; Third, the sample determination, mainly introducing the main menu function, the method of setting the temperature and the bridge current, as the Temperature rise time is longer, the process is omitted; four is the operation of the sampling feed; five is the shutdown method, introducing how to return to the main menu, set the bridge current, how to turn off the constant current source cooling, and finally shut down the host; six is the operation of the software part of the software operation, you can use the "Camtasia" video recording software, the software will be a complete recording of the operation process. Instrument operation of the recording process, both the overall picture of the equipment, but also focus on the details, so that students can accurately find the relevant keys or knobs in the whole set of equipment, but also to see the operation method.

2.3 Construction of a network teaching platform

The National Medium- and Long-term Education Reform and Development Plan (2010-2020) proposes to "strengthen the construction of the network teaching resources system, the development of e-learning courses, and the innovation of the network teaching mode". Network teaching platform is an important way to realize the innovation of education and teaching methods, and promote the popularization of high-quality educational resources **** enjoyment and basic protection [4]. Network teaching support platform refers to the general name of the software system established on the basis of the Internet to provide comprehensive support services for network teaching, including hardware facilities to support network teaching and software systems to support network teaching. Network teaching platform mainly has on-demand teaching platform and interactive network teaching platform. On-demand teaching platform can realize the rapid transmission of teaching resources, students can always on-demand audio, video courseware, access to electronic lesson plans and other teaching content. The interactive teaching platform enables teachers and students to communicate through the network, and teachers can also use the teaching platform to track students' learning and selectively release course content according to students' learning. The construction of network teaching platform includes hardware construction and software construction. Hardware facilities mainly include an all-round campus broadband network, a well-functioning network multimedia classroom, servers, storage equipment for multimedia teaching materials and software. The software aspect is mainly the teaching system platform. Teachers can upload the courseware, lesson plans, professional materials, and microcourses on the use of instruments of instrumental analysis courses to the platform for students' independent learning. Students can first watch the micro-courses of instrument operation through the network platform to familiarize themselves with the instrument structure and operation essentials, and then operate on the machine, which makes the teaching more targeted. At present, many domestic colleges and universities or companies have developed and developed a network teaching platform products suitable for their own needs, such as Beijing Normal University developed Vcalss, Shanghai Jiaotong University Answer teaching system platform, can be introduced and used.

2.4 The use of other aids

According to the characteristics of the instrumental analysis laboratory courses, teachers can also choose simple and easy to implement aids, such as: the production of large-scale instrumentation operation flow charts, and will be printed, laminated plastic sealing on the side of the instrument, the students need to read carefully before use, in accordance with the instructions for the operation; for the current situation of the college students almost all have smart phones!

3 Conclusion

Instrumental analysis experimental course is a highly practical course, the demand for analytical instruments is high. In the case of limited teaching resources, we should actively explore the use of auxiliary teaching tools to help students y and intuitively understand and master the knowledge they have learned, improve their hands-on ability and ability to operate independently, and lay a good foundation for students to independently debug and use the instrumentation, so as to achieve the purpose of improving the quality of teaching.

Author: Liu Yi Unit: Jinzhou Normal College

References:

[1] Tian Wende, Ding Hui, Yao Fei. Computer simulation of analytical instruments [J]. Modern Scientific Instruments, 2001(3):41-49.

［2］ Hu Haixing, Zhang Chunxia, Zhang Chunyan. Research on the application of microclasses in higher vocational practical training teaching [J]. Journal of Changsha University, 2015(3):125-126.

［3］ Liu Yi. Application of microclass in practical training of environmental engineering technology [J]. Journal of Harbin Institute of Vocational Technology, 2016(2):42-44.

［4］ Xu Xusong. Development and Application of ActRes Interactive Network Teaching Platform［J］. Journal of Jiangsu Polytechnic Institute, 2015(4):82-86.