ABB AX400 Series User Manual

Single and dual input analyzers for pH/Redox (ORP)
AX416, AX436, AX460, AX466 & AX468 Appendix A – Buffer Solutions
IM/AX4PH Rev. P 67
Appendix A – Buffer Solutions
The pH value of buffer solutions is influenced considerably by
temperature variations. Thus, when significant temperature
fluctuations occur, it is general practice to correct automatically
the measured, prevailing pH to the value that would apply if the
solution temperature were 25 ºC (77 ºF), the internationally
accepted standard.
Tables A1 to A5 include the pH values for ABB, DIN, Merck,
NIST, and US Technical buffer solutions. Standards are for 4, 7
and 9 pH values, from 0 to 95 ºC (32 to 203 ºF).
Tem p ABB Buffers
ºC ºF 4.01 pH 7pH 9.18 pH
0 32 4.000 7.110 9.475
5 41 3.998 9.409
10 50 3.997 7.060 9.347
15 59 3.998 9.288
20 68 4.001 7.010 9.233
25 77 4.005 7.000 9.182
30 86 4.011 6.980 9.134
35 95 4.018 9.091
40 104 4.027 6.970 9.051
45 113 4.038 9.015
50 122 4.050 6.970 8.983
55 131 4.064 8.956
60 140 4.080 6.970 8.932
65 149 4.097 8.913
70 158 4.116 6.990 8.898
75 167 4.137 8.888
80 176 4.159 7.030 8.882
85 185 4.183 8.880
90 194 4.208 7.080 8.884
95 203 4.235 8.892
Table A.1 ABB Buffer Solutions
Tem p DIN 19266 Buffers
ºC ºF 1.68 pH 4.01 pH 6.86 pH 9.18 pH
0 32 1.666 4.003 6.984 9.464
5 41 1.668 3.999 6.951 9.395
10 50 1.670 3.998 6.923 9.332
15 59 1.672 3.999 6.900 9.276
20 68 1.675 4.002 6.881 9.225
25 77 1.679 4.008 6.865 9.180
30 86 1.683 4.015 6.853 9.139
35 95 1.688 4.024 6.844 9.102
40 104 1.694 4.035 6.838 9.068
45 113 1.700 4.047 6.834 9.038
50 122 1.707 4.060 6.833 9.011
55 131 1.715 4.075 6.834 8.985
60 140 1.723 4.091 6.836 8.962
65 149
70 158 1.743 4.126 6.845 8.921
75 167
80 176 1.766 4.164 6.859 8.885
85 185
90 194 1.792 4.205 6.877 8.850
95 203 1.806 4.227 6.886 8.833
Table A.2 DIN Buffer Solutions
Tem p Merck Buffers
ºC ºF 4pH 7pH 9pH 10 pH
0 32 4.05 7.13 9.24 10.26
5 41 4.04 7.07 9.16 10.17
10 50 4.02 7.05 9.11 10.11
15 59 4.01 7.02 9.05 10.05
20 68 4.00 7.00 9.00 10.00
25 77 4.01 6.98 8.95 8.95
30 86 4.01 6.98 8.91 9.89
35 95 4.01 6.96 8.88 9.84
40 104 4.01 6.95 8.85 9.82
45 113 4.01 6.95 8.82
50 122 4.00 6.95 8.79 9.74
55 131 4.00 6.95 8.76
60 140 4.00 6.96 8.73 9.67
65 149 4.00 6.96 8.72
70 158 4.00 6.96 8.70 9.62
75 167 4.00 6.96 8.68
80 176 4.00 6.97 8.66 9.55
85 185 4.00 6.98 8.65
90 194 4.00 7.00 8.64 9.49
95 203 4.00 7.02 8.64 8.833
Table A.3 Merck Buffer Solutions

ABB AX400 Series Specifications

General

Display	LCD with backlight
Output	4 to 20 mA, HART
Process connection	Flanged
Lining material	PTFE, PFA
Electrode material	Stainless steel, titanium
Communication	HART