This study aims to describe the history and development of e-commerce in Brazil and the world associated with its milestones. In addition to describing the positive and negative points and a parallel to physical trade, highlighting the differences between the two and which are complementary and not competing. Digital commerce has emerged with technological advances, the spread of Internet access, and the need to simplify the purchasing process. The CO-VID-19 pandemic forced several companies to invest in online commerce because restrictive measures shut down physical commerce and made e-commerce a valuable alternative. In this way, e-commerce achieved significant development in a short period. Several analyses describe that e-commerce was already a trend and with the health crisis, there was a need for investment for trade to survive and develop the economy. As a trend for the coming years, there is research that maps the consumption pattern of each region to contribute to and explain the next step of e-commerce in post-covid reality. Additionally, this study aims to implement bibliometric resources to search for data at Scopus based on the terms "e-commerce", "Covid-19" and "pandemic" enabling the measurement and quantification of scientific production on the subject in question.

Biosensors are a class of sensors aimed at carrying out measurements involving organic substances. These sensors have many advantages for use, ranging from miniaturization to portability of the equipment, thus enabling their use in an easy way and in a very wide range of locations. This work has the focus of evaluating the functioning of a monolayer enzymatic amperometric biosensor through a process of mathematical modeling of its working principle from Partial Differential Equations (PDEs) and the boundary/initial conditions that govern and characterize this type of equipment, the systems of equations created were solved based on the Finite Difference Method (FDM) techniques and with the aid of a computer code to provide the solution for the evaluated system. Finally, tests were simulated to evaluate the impacts that each factor plays on the system response, sensitivity tests were performed for each of its parameters, by means of a monolayer enzymatic amperometric biosensor. With the results, it was possible to observe the great impacts that factors such as the maximum enzymatic rate (VMAX), the enzymatic layer thickness (d) and the initial concentration of the substrate (S0) have on the system response, which are considered crucial in a project of biosensors.