Data
A selection of pHabsH2O values of some mobile phases for liquid chromatography and other solutions is given in the tables below.
Mobile phases
Organic phase | Water phase | Volume ratio organic/ water | Water phase pH | Salt bridge | pHabsH2O | uRW | uc | Ref |
MeCN | 1 mM NH3 | 80/20 | 9,75 | 0.05 M Et4NClO4 in MeCN | 10,47 | 0,06 | 0,15 | 1 |
MeCN | 1 mM NH3 | 50/50 | 9,75 | 0.05 M Et4NClO4 in MeCN | 10,07 | 0,06 | 0,15 | 1 |
MeCN | 5 mM CH3COONH4 titrated with NH3 | 80/20 | 9,01 | 0.05 M Et4NClO4 in MeCN | 9,69 | 0,00 | 0,14 | 1 |
MeCN | 5 mM CH3COONH4 titrated with NH3 | 80/20 | 7,03 | 0.05 M Et4NClO4 in MeCN | 9,41 | 0,01 | 0,14 | 1 |
MeCN | 5 mM CH3COONH4 titrated with NH3 | 80/20 | 7,82 | 0.05 M Et4NClO4 in MeCN | 9,39 | 0,01 | 0,14 | 1 |
MeCN | 5 mM CH3COONH4 | 80/20 | 6,50 | 0.05 M Et4NClO4 in MeCN | 9,39 | 0,00 | 0,14 | 1 |
MeCN | 5 mM CH3COONH4 titrated with HCOOH | 80/20 | 5,48 | 0.05 M Et4NClO4 in MeCN | 9,22 | 0,00 | 0,14 | 1 |
MeCN | 5 mM CH3COONH4 titrated with HCOOH | 80/20 | 6,05 | 0.05 M Et4NClO4 in MeCN | 9,16 | 0,01 | 0,14 | 1 |
MeCN | 5 mM CH3COONH4 titrated with HCOOH | 80/20 | 5,03 | 0.05 M Et4NClO4 in MeCN | 8,99 | 0,00 | 0,14 | 1 |
MeCN | 5 mM CH3COONH4 titrated with HCOOH | 80/20 | 5,00 | 0.05 M Et4NClO4 in MeCN | 8,92 | 0,07 | 0,15 | 1 |
MeCN | 5 mM CH3COONH4 titrated with HCOOH | 80/20 | 4,66 | 0.05 M Et4NClO4 in MeCN | 8,65 | 0,01 | 0,14 | 1 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 80/20 | 5,50 | 0.05 M Et4NClO4 in MeCN | 8,59 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 80/20 | 5,00 | 0.05 M Et4NClO4 in MeCN | 8,43 | 0,01 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 75/25 | 5,50 | 0.05 M Et4NClO4 in MeCN | 8,41 | 0,01 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 70/30 | 5,50 | 0.05 M Et4NClO4 in MeCN | 8,23 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 75/25 | 5,00 | 0.05 M Et4NClO4 in MeCN | 8,18 | 0,01 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 80/20 | 4,50 | 0.05 M Et4NClO4 in MeCN | 8,10 | 0,01 | 0,14 | 2 |
MeCN | 5 mM CH3COONH4 titrated with HCOOH | 80/20 | 4,02 | 0.05 M Et4NClO4 in MeCN | 7,95 | 0,00 | 0,14 | 1 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 70/30 | 5,00 | 0.05 M Et4NClO4 in MeCN | 7,94 | 0,01 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 75/25 | 4,50 | 0.05 M Et4NClO4 in MeCN | 7,80 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 80/20 | 4,00 | 0.05 M Et4NClO4 in MeCN | 7,64 | 0,01 | 0,14 | 2 |
MeCN | 5 mM CH3COONH4 titrated with HCOOH | 80/20 | 3,77 | 0.05 M Et4NClO4 in MeCN | 7,52 | 0,06 | 0,15 | 1 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 70/30 | 4,50 | 0.05 M Et4NClO4 in MeCN | 7,50 | 0,01 | 0,14 | 2 |
MeCN | 5 mM CH3COONH4 titrated with HCOOH | 50/50 | 5,00 | 0.05 M Et4NClO4 in MeCN | 7,50 | 0,07 | 0,15 | 1 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 50/50 | 5,50 | 0.05 M Et4NClO4 in MeCN | 7,49 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 75/25 | 4,00 | 0.05 M Et4NClO4 in MeCN | 7,32 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 45/55 | 5,50 | 0.05 M Et4NClO4 in MeCN | 7,30 | 0,01 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 80/20 | 3,50 | 0.05 M Et4NClO4 in MeCN | 7,18 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 40/60 | 5,50 | 0.05 M Et4NClO4 in MeCN | 7,11 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 50/50 | 5,00 | 0.05 M Et4NClO4 in MeCN | 7,05 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 70/30 | 4,00 | 0.05 M Et4NClO4 in MeCN | 7,03 | 0,01 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 75/25 | 3,50 | 0.05 M Et4NClO4 in MeCN | 6,86 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 45/55 | 5,00 | 0.05 M Et4NClO4 in MeCN | 6,85 | 0,01 | 0,14 | 2 |
MeCN | 5 mM CH3COONH4 titrated with HCOOH | 80/20 | 3,07 | 0.05 M Et4NClO4 in MeCN | 6,82 | 0,01 | 0,14 | 1 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 40/60 | 5,00 | 0.05 M Et4NClO4 in MeCN | 6,62 | 0,01 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 70/30 | 3,50 | 0.05 M Et4NClO4 in MeCN | 6,57 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 50/50 | 4,50 | 0.05 M Et4NClO4 in MeCN | 6,56 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 45/55 | 4,50 | 0.05 M Et4NClO4 in MeCN | 6,36 | 0,00 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH titrated vith NH3 | 40/60 | 4,50 | 0.05 M Et4NClO4 in MeCN | 6,14 | 0,01 | 0,14 | 2 |
MeCN | 0.1 vol% HCOOH | 80/20 | 2,68 | 0.05 M Et4NClO4 in MeCN | 5,37 | 0,07 | 0,15 | 1 |
MeCN | 0.1 vol% HCOOH | 50/50 | 2,68 | 0.05 M Et4NClO4 in MeCN | 4,39 | 0,05 | 0,15 | 1 |
MeCN | 0.1 vol% TFA | 80/20 | - | 0.05 M Et4NClO4 in MeCN | 3,63 | 0,00 | 0,14 | 1 |
MeCN | 0.1 vol% HCOOH | 20/80 | 2,68 | 0.05 M Et4NClO4 in MeCN | 3,27 | 0,04 | 0,14 | 1 |
MeOH | 1 mM NH3 | 80/20 | 9,75 | 0.05 M Et4NClO4 in MeCN | 8,89 | 0,05 | 0,15 | 1 |
MeOH | 1 mM NH3 | 50/50 | 9,75 | 0.05 M Et4NClO4 in MeCN | 8,70 | 0,05 | 0,15 | 1 |
MeOH | 5 mM CH3COONH4 titrated with HCOOH | 80/20 | 5,00 | 0.05 M Et4NClO4 in MeCN | 7,49 | 0,06 | 0,15 | 1 |
MeOH | 5 mM CH3COONH4 titrated with HCOOH | 50/50 | 5,00 | 0.05 M Et4NClO4 in MeCN | 6,47 | 0,06 | 0,15 | 1 |
MeOH | 0.1 vol% HCOOH | 80/20 | 2,68 | 0.05 M Et4NClO4 in MeCN | 4,79 | 0,05 | 0,15 | 1 |
MeOH | 0.1 vol% HCOOH | 50/50 | 2,68 | 0.05 M Et4NClO4 in MeCN | 3,89 | 0,04 | 0,14 | 1 |
uRW within-lab reproducibility uc combined standard uncertainty
1 Suu, A. et al. (2015), Analytical Chemistry, 87(5), pp. 2623–2630. doi.org/10.1021/ac504692m
2 Liigand, P. et al. (2017), Journal of The American Society for Mass Spectrometry, 28(10), pp. 2124–2131. doi.org/10.1007/s13361-017-1737-5
Formate buffers
Solution | pHabsH2O | SD of 4 values from ladders with different electrodes | Salt bridge |
10 mM NH4HCO2 in EtOH | 7,45 | 0,03 | [N2225][NTf2] |
10 mM NH4HCO2 in 80 wt% EtOH | 8,21 | 0,02 | [N2225][NTf2] |
10 mM NH4HCO2 in 50 wt% EtOH | 8,90 | 0,02 | [N2225][NTf2] |
From: Heering, A., Bastkowski, F. and Seitz, S. (2020), Journal of Sensors and Sensor Systems, 9(2), pp. 383–389. doi.org/10.5194/jsss-9-383-2020
Water-organic mixtures without additives
Weight percentage | Solvent | pHabsH2O range min … max | Number of results | Salt bridge |
100 | MeCN | 6.40 … 9.78 | 4 | [N2225][NTf2] |
76 | MeCN | 7.46 … 9.36 | 5 | [N2225][NTf2] |
44 | MeCN | 6.20 … 7.24 | 4 | [N2225][NTf2] |
25 | MeCN | 6,30 | 1 | [N2225][NTf2] |
17 | MeCN | 5.99 … 6.33 | 4 | [N2225][NTf2] |
100 | MeOH | 6.70 … 8.96 | 5 | [N2225][NTf2] |
80 | MeOH | 9,14 | 1 | [N2225][NTf2] |
76 | MeOH | 6.35 … 8.71 | 5 | [N2225][NTf2] |
75 | MeOH | 6,49 | 1 | [N2225][NTf2] |
50 | MeOH | 6.91 … 7.87 | 2 | [N2225][NTf2] |
44 | MeOH | 6.78 … 7.94 | 3 | [N2225][NTf2] |
25 | MeOH | 6.23 … 6.43 | 2 | [N2225][NTf2] |
20 | MeOH | 6,79 | 1 | [N2225][NTf2] |
17 | MeOH | 5.83 … 6.20 | 2 | [N2225][NTf2] |
100 | EtOH | 7.83 … 9.41 | 3 | [N2225][NTf2] |
90 | EtOH | 9,57 | 1 | [N2225][NTf2] |
80 | EtOH | 7.84 … 9.12 | 5 | [N2225][NTf2] |
70 | EtOH | 7.81 … 8.48 | 3 | [N2225][NTf2] |
50 | EtOH | 6.82 … 8.12 | 7 | [N2225][NTf2] |
40 | EtOH | 6,74 | 1 | [N2225][NTf2] |
30 | EtOH | 6,57 | 1 | [N2225][NTf2] |
20 | EtOH | 6.29 … 6.43 | 2 | [N2225][NTf2] |
10 | EtOH | 6.00 … 6.03 | 2 | [N2225][NTf2] |
From: Deleebeeck, L. et al. (2021), Sensors, 21(11), 3935. doi.org/10.3390/s21113935