Yokogawa EXAxt PH450 4-Wire Analyzer for pH and ORP - Manual (Page 59)

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APPENDICES
APPENDICES
Appendix 1, Buffer tables
NIST (IEC 60746-2)/DIN 19266
°C 0 5 10 15 20 25 30 35 38 40 45 50 55 60 70 80 90 95
1,68 pH 1.668 1.670 1.672 1.675 1.679 1.683 1.688 1.691 1.694 1.700 1.707 1.715 1.723 1.743 1.766 1.792 1.806
4,01 pH 4.003 3.999 3.998 3.999 4.002 4.008 4.015 4.024 4.030 4.035 4.047 4.060 4.075 4.091 4.126 4.164 4.205 4.227
6,87 pH 6.984 6.951 6.923 6.900 6.881 6.865 6.853 6.844 6.840 6.838 6.834 6.833 6.834 6.836 6.845 6.859 6.877 6.886
9,18 pH 9.464 9.395 9.332 9.276 9.225 9.180 9.139 9.102 9.081 9.068 9.038 9.011 8.985 8.962 8.921 8.885 8.850 8.833
DIN 19267 (German buffers) so called: technical buffer solutions
°C 0 10 20 25 30 40 50 60 70 80 90
4,65 pH DIN 4.670 4.660 4.650 4.650 4.650 4.660 4.680 4.700 4.720 4.750 4.790
6,79 pH DIN 6.890 6.840 6.800 6.790 6.780 6.760 6.760 6.760 6.760 6.780 6.800
9,23 pH DIN 9.480 9.370 9.270 9.230 9.180 9.090 9.000 8.920 8.880 8.850 8.820
US technical buffers
°C 0 5 10 15 20 25 30 35 40 45 50 55 60
4.0 pH US 4.000 3.998 3.997 3.998 4.001 4.005 4.001 4.018 4.027 4.038 4.050 4.064 4.080
7.0 pH US 7.120 7.090 7.060 7.040 7.020 7.000 6.990 6.980 6.988 6.978 6.970 6.890 6.980
10.0 pH US 10.317 10.245 10.179 10.118 10.062 10.012 9.966 9.926 9.889 9.856 9.828 9.828 9.828
FREE PROGRAMMABLE (Default settings based on rounded NIST values).
°C 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
buffer 4 4.00 4.00 4.00 4.00 4.00 4.01 4.02 4.02 4.04 4.05 4.06 4.08 4.09 4.11 4.13 4.15 4.16
buffer 7 6.98 6.95 6.92 6.90 6.88 6.87 6.85 6.84 6.84 6.83 6.83 6.83 6.84 6.84 6.85 6.85 6.86
buffer 9 9.46 9.40 9.33 9.28 9.23 9.18 9.14 9.10 9.07 9.04 9.01 8.99 8.96 8.94 8.92 8.90 8.89
The freely programmable table is populated with a basic set of data to provide a start for the
user configuration. This table is intended for the user to be able to choose his buffer solutions to
suit his own preference. The data concerning the pH temperature characteristic will need to be
obtained from the supplier of the buffers.
Note: Yokogawa recommend the use of NIST (primary buffer standards) rather than buffers which
have been adjusted by the addition of acid or alkaline materials to the buffer composition. In this
way the customer gets a recognized standard, as well as the best buffer capacity (the ability to
resist pH change with contamination).
Defaults for matrix temperature compensation
Tref T1 T2 T3 T4 T5
25 ºC 5.0 ºC 25.0 ºC 45.0 ºC 65.0 ºC 85.0 ºC
Solution 1 6.40 pH 6.42 pH 6.40 pH 6.34 pH 6.23 pH 6.11 pH
Solution 2 7.00 pH 7.38 pH 7.00 pH 6.70 pH 6.45 pH 6.25 pH
Solution 3 7.30 pH 7.94 pH 7.30 pH 6.86 pH 6.54 pH 6.31 pH
Solution 4 7.60 pH 8.31 pH 7.60 pH 7.06 pH 6.67 pH 6.40 pH
Solution 5 9.00 pH 9.74 pH 9.00 pH 8.40 pH 7.91 pH 7.51 pH
Defaults for mA-output table
% 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
pH 0.0 0.7 1.4 2.1 2.8 3.5 4.2 4.9 5.6 6.3 7.0 7.7 8.4 9.1 9.8 10.5 11.2 11.9 12.6 13.3 14.0