Table 1 The computed pKa values of MTB by the MLA and those reported previously using stability quotients from absorbance data (SQUAD) program62.

From: Study of interaction of metal ions with methylthymol blue by chemometrics and quantum chemical calculations

pKa

MLA

SQUAD

pKa1

–

–

pKa2

–

–

pKa3

–

–

pKa4

2.35 (± 0.048)

–

pKa5

3.54 (± 0.039)

3.47 (± 0.058)

pKa6

5.66 (± 0.089)

6.31 (± 0.081)

pKa7

8.39 (± 0.065)

8.47 (± 0.081)

pKa8

10.08 (± 0.113)

10.81 (± 0.073)

pKa9

12.59 (± 0.142)

12.97 (± 0.045)

  1. Numbers in parentheses indicate the standard error (σP) values on acidity constants.
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