BUFFERING FUNCTION: A GENERAL APPROACH FOR BUFFER BEHAVIOR

André Fernando De Oliveira

doi:10.18540/jcecvl6iss3pp0387-0396

Abstract

Sistemas tampão são amplamente usados em diversas áreas da ciência que envolvem soluções aquosas, tais como química farmacêutica, ambiental e analítica. Entretanto, há várias propostas e parâmetros que tentam explicar o comportamento tampão, tais como poder tamponante de Van Slyke, capacidade tamponante de Kolthoff, acidez, alcalinidade and outros, mas todos são incapazes de apresentar uma explicação global para esse comportamento. Neste artigo, propomos a Função Tamponante, que é uma equação fundamental que permite explicar todos os tipos comportamento tampão e os parâmetros já proposto, sem usar a Equação de Henderson-Hasselbach.

Highlights

Buffer systems are very useful in many areas of chemistry, including biochemistry and medicinal, pharmaceutical, industrial, forensic, environmental, and organic chemistry
Some buffer solutions include more than one system, such as McIlvaine’s buffer; BrittonRobinson; or universal buffer
There are five associated factors that influence the pH behavior of a buffer solution: (i) the type of Brønsted acid-base system in solution; (ii) the concentration of the system; (iii) the initial pH of the solution; (iv) the quantity of Brønsted acid or base added to the solution, which the buffer solution must “resist”; (v) the acceptable pH change of the buffer solution after its action, which depends on the application. (Oliveira, 2009; 2013, 2020)

Summary

INTRODUCTION

Buffer systems are very useful in many areas of chemistry, including biochemistry and medicinal, pharmaceutical, industrial, forensic, environmental, and organic chemistry. Oliveira (2009, 2020a) presented a simple calculation procedure for this parameter that could be applied to buffer solutions formed by one or several Brønsted acid-base monoor polyprotic systems This parameter is more practical than the buffer value (or capacity) but is still defined in terms of substances external to the solution studied. It can be seen from careful analysis of the charge balance that the terms Wat and the contributions of the Brønsted acid-base system are responsible for the buffering effect. The parameters associated with the evaluation or use of the buffers discussed previously will be defined based on the Buffering Function, demonstrating its fundamental importance

REDEFINITION OF BUFFER’s PARAMETERS

CONCLUSION