In this communication, the use of multimedia guides in electronic format is proposed as a support to the teaching and learning of practical procedures in the analytical laboratory. These guides integrate video, audio, tutorials and fixed images.
There is a group of operations that are usually carried out in an analytical laboratory such as the weighting of a solid reagent, the preparation of a solution, the realization of a titration analysis and the calibration curves preparation and subsequent measurement in an analytical instrument. The aim of all this laboratory work is to get information about the concentration of a certain compound in a sample of interest, and these results are used for the decision making in multiple situations. However, these results have an associated experimental error and bias whose magnitude should be minimized and evaluated. The only way to minimize the experimental errors and bias, to obtain trustworthy results, is to be very careful during the realization of the laboratory work and, moreover, to evaluate the bias by means of the adequate statistical treatment.

So, the students must learn the suitable form to carry out the operations and calculus above mentioned, and for that not only is it essential to dominate the basic laboratory operations and the skills acquired at the basic courses of chemistry, but also it is necessary to know about the quality control in the laboratory, topics that are treated in superior or specialization courses.
We founded that the traditional teaching-learning methodologies have certain limitations with so practical character competences. Although the learning of this type of subjects requires practical work in a laboratory, it seems to be also necessary to do some previous and posterior activities in order to get longer term learning.

Therefore, since the employment of the new technologies in the university education constitutes a complementary tool to facilitate the student process of learning, we have developed two multimedia guides in electronic format as a resource of support to the education task realized in the laboratory. This type of tutorials allow, on one hand, the reduction of the lecture hall lessons in the teaching-learning process and, on the other hand, they have the audio-visual component that a conventional book lacks, which makes them more attractive to students. Thus, for example, some videos allow the students to observe the correct way to carry out the major basic operations in laboratory as many times as needed to the complete learning.

The “Guide of basic operations in chemical, pharmaceutical and environmental analysis” focus on the basic skills of the analytical laboratory for students who start in a chemistry laboratory. On the other hand, the “Guide for the validation, quality control and expression of the uncertainty related to the chemical volumetric methods” focus on the concepts related to the quality in the analysis laboratories. The included quality criteria (validation of methods, quality control, and estimation of uncertainty) are, at the same time, realistic and useful for the educational laboratories. And the developed technical documents harmonize the academic and enterprise points of view and can be used as a model to develop new guides in the future.