Determination of pKa values of acid components in atmospheric condensates by linearization of segmented titration curves

Dissociation of weak acids during Gran plot free acidity titrations

“…However, because individual line segments for specific weak acids are often difficult to resolve (Seymour et al, 1977), it is still useful to obtain the estimation of total acidity from the Gran plot line segment associated with the excess base plateau (point B in Fig. 1).…”

“…Determination of the individual pK, values of the weak acids in the sample may be attempted using a coulometric procedure (Liberti et al, 1972) or by detailed linearization of the titration curve (Seymour et al, 1977). However, because individual line segments for specific weak acids are often difficult to resolve (Seymour et al, 1977), it is still useful to obtain the estimation of total acidity from the Gran plot line segment associated with the excess base plateau (point B in Fig. 1).…”

“…plot techniques are widely used to determine the acid content of natural water samples. The pKa values of particular weak acids have also been determined using these methods (Lee and Brosset, 1978;Seymour et al, 1977). Precautions involved in using these techniques have appeared in the literature (e.g., Burden and Euler, 1975) and have been discussed in particular detail by Brosset and Ferm (1978), Lee and Brosset (1978), and Keene et al (1983).…”

Simultaneous Estimation of the Dissociation Constant and Concentration by a Linear Least-Squares Method with Non-Negative Constraint

“…These are important aspects of an acid's properties. The Gran function, 1 modified Gran function, [2][3][4][5][6] and the non-linear least-squares method 7 have been used to solve titration curves. However, prior to calculations, these methods require additional information, such as the approximate value of the dissociation constants of acids in a solution.…”

Estudo voltamétrico da adsorção de Cd(II) e Zn(II) na microalga marinha Tetraselmis gracilis

“…A Tabela 4 apresenta os dados experimentais de uma dessas titulações. O tratamento dos dados de titulação potenciométrica ácido base foi feito pelo método de linearização com funções de Gran modificadas para determinação de misturas de ácidos fracos na presença ou não de ácido forte (equações 3.10 e 3.11 do capítulo Material e Métodos) (Seymour, Clayton et al 1977). Quando se adota esse método para tratar dados de titulações potenciométricas de polieletrólitos ou suspensões assume-se o modelo de distribuição discreta de sítios ionizáveis, no qual a influência da acumulação de cargas sobre a macromolécula ou superfície é refletida no pKa aparente determinado para cada sítio, bem como na abundância de sítios ionizáveis com esse pKa (Godinho, Masini et al 1992;Masini 1993;Masini, Abate et al 1998).…”