. 2022 May 27;94(23):8115–8119. doi: 10.1021/acs.analchem.2c00200

Table 2. pK_a in DMSO (pK_a^det), Indicators and Acids Used, and the Difference from Literature Values (ΔpK_a) for the Analytes.

analyte	pK_a^det ± 0.1	ΔpK_a^lit	indicators	acid
1-methylimidazole	6.16	+0.01²⁶	^a, ^b	ⁱ
morpholine	9.01	+0.07²⁷	^c, ^d	^j
benzylamine	9.78	–0.03²⁸	^e, ^f	^k
diethylamine	10.42	+0.02²⁹	^g, ^f	^k
2,4-dinitrobenzoic acid	6.51	–0.01³⁰	^h, ^d	^l
salicylic acid	6.78	–0.02³¹	^h, ^b or ^b, ^d	^l
aspirin	8.68		^d, ^c	^l
niacin	8.60		^d, ^c or ^c, ^g	^l
imidazole	6.46	–0.53 to +1.36,^32,26,33,34	^a, ^h	ⁱ

2,6-Lutidine.³⁵

Imidazole.

Triethylamine.³¹

Dimethylbenzylamine.³⁶

Diethylamine.²⁹

Pyrrolidine.³³

Benzylamine.²⁸

1-Methylimidazole.²⁶

ⁱ

Saccharin.

Meldrum’s acid.

Barbituric acid.

The analyte was used as the diffusing acid.

Table 2. pKa in DMSO (pKadet), Indicators and Acids Used, and the Difference from Literature Values (ΔpKa) for the Analytes.