Determination and Modeling of Peptide p K a by Capillary Zone

Since in the pH zone corresponding to the first (with respect to the second) ... the pKa,i. ∞ terms in eqs 25, 28, and 29 should be replaced with pK...
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Anal. Chem. 2007, 79, 3020

Correction

A typographical error was found in equation (11). This equation should be replaced with

Determination and Modeling of Peptide pKa by Capillary Zone Electrophoresis

pKa ) pH - log

Raphae 1 l Plasson and Herve´ Cottet*

(

[Az-1 ]

[AHz]

xI)/(1+1.6405xI)

10[(z-1) -z ](-0.5085 2

2

) (11)

(Anal. Chem. 2006, 78, 5394-5402).

Equation 7 in the original manuscript should be replaced with

(

µ ) µ0

1+

1 Ka,1 [H+]

+

Ka,1Ka,2

-

[H+]2

)

1 [H ] [H+]2 1+ + Ka,2 Ka,1Ka,2 +

(7)

For a better understanding of the temperature dependence of ∞ ∞ , the pKa,i terms in eqs 25, 28, and 29 should be replaced pKa,i ∞ with pKa,i (0 °C). Thus, eqs 25, 28, and 29 should be replaced by the following

∞ pKa,i ) pKa,i (0 °C) -

This equation can also be written as

µ ) µ0

3.64(n - 1) + βi

+ Θi(T - 273.15) (25)

(

1 1 + 10pH-pKa,1 + 102pH-pKa,1-pKa,2 1 (7bis) pKa,2-pH 1 + 10 + 10pKa,1+pKa,2-2pH

)

Since in the pH zone corresponding to the first (with respect to the second) acidity, the 102pH-pKa,1-pKa,2 term (with respect to 10pKa,1+pKa,2-2pH term) can be neglected, as compared to the 10pH-pKa,1 term (with respect to 10pKa,2-pH term), eq 7bis leads to eq 8, given in the original paper:

(

Ci

)

1 1 µ ) µ0 pH-pKa,1 1 + 10 1 + 10pKa,2-pH

pK∞a,1 (0 °C) ) pKa,1Cterm + 1.00

(28)

pK∞a,2 (0 °C) ) pKa,2Nterm - 1.56

(29)

A typographical error of sign appeared in eq 31 that should be replaced with

pK′a,2 ) pKa,2Nterm - 1.56 - 0.019(T - 273.15) + 2.24 0.5085xI (31) 3.65(n - 1) + 1.1 1 + 1.6405xI

(8)

Equation 9 in the original manuscript should be replaced with AC062219N

pKa ) -log

(

)

( )

aAz-1aH+ aAz-1 ) pH - log aAHz aAHz

3020 Analytical Chemistry, Vol. 79, No. 7, April 1, 2007

(9)

10.1021/ac062219n Published on Web 02/28/2007

10.1021/ac062219n CCC: $37.00

© 2007 American Chemical Society Published on Web 02/28/2007