Research Article
Masking Ability of Various Metal Complexing Ligands at 1.0 mM Concentrations on the Potentiometric Determination of Fluoride in Aqueous Samples
Table 1
Fluoride content of 60 water samples measured by F-ISE with different masking agents.
| Sample ID | Mean fluoride concentration (mg L−1) | EC (μS/cm) | Ref. | CDTA | EDTA | HE-EDTA | TEA | Citrate | Tartrate | Phosphate | Acetate | Photometer |
| 1 | 1.842 | 1.730 | 1.689 | 1.645 | 1.595 | 1.475 | 1.493 | 1.556 | 1.469 | N/A | 126.4 | 2 | 1.619 | 1.614 | 1.603 | 1.558 | 1.524 | 1.467 | 1.317 | 1.364 | 1.098 | 1.30 | 177.8 | 3 | 1.868 | 1.703 | 1.542 | 1.669 | 1.620 | 1.193 | 1.506 | 1.548 | 1.321 | N/A | 149.1 | 4 | 1.543 | 1.503 | 1.456 | 1.492 | 1.422 | 0.975 | 1.218 | 1.266 | 0.969 | 1.03 | 165.1 | 5 | 1.734 | 1.625 | 1.592 | 1.556 | 1.526 | 1.332 | 1.518 | 1.530 | 1.221 | N/A | 127.5 | 6 | 1.563 | 1.503 | 1.486 | 1.426 | 1.403 | 1.083 | 1.153 | 1.259 | 0.974 | 1.15 | 288.0 | 7 | 1.486 | 1.450 | 1.455 | 1.388 | 1.317 | 0.863 | 1.052 | 1.240 | 0.784 | 0.91 | 181.2 | 8 | 1.854 | 1.763 | 1.715 | 1.703 | 1.593 | 1.485 | 1.662 | 1.598 | 1.475 | N/A | 221.0 | 9 | 1.916 | 1.892 | 1.889 | 1.809 | 1.762 | 1.440 | 1.545 | 1.672 | 1.360 | N/A | 156.3 | 10 | 1.476 | 1.390 | 1.383 | 1.323 | 1.104 | 0.522 | 0.962 | 1.067 | 0.486 | 0.96 | 231.0 | 11 | 0.864 | 0.758 | 0.753 | 0.645 | 0.542 | 0.188 | 0.238 | 0.352 | 0.186 | 0.24 | 117.9 | 12 | 0.796 | 0.764 | 0.743 | 0.559 | 0.544 | 0.408 | 0.456 | 0.486 | 0.419 | 0.40 | 78.9 | 13 | 0.686 | 0.659 | 0.611 | 0.598 | 0.487 | 0.415 | 0.648 | 0.467 | 0.420 | 0.42 | 53.3 | 14 | 0.693 | 0.637 | 0.522 | 0.486 | 0.496 | 0.403 | 0.445 | 0.458 | 0.374 | 0.42 | 92.6 | 15 | 1.352 | 1.260 | 1.334 | 0.959 | 0.921 | 0.800 | 0.817 | 0.837 | 0.808 | 0.82 | 79.9 | 16 | 0.749 | 0.641 | 0.627 | 0.605 | 0.577 | 0.512 | 0.545 | 0.571 | 0.513 | 0.53 | 97.0 | 17 | 0.695 | 0.457 | 0.437 | 0.392 | 0.355 | 0.319 | 0.338 | 0.359 | 0.309 | 0.34 | 115.2 | 18 | 1.261 | 0.885 | 0.859 | 0.801 | 0.797 | 0.593 | 0.717 | 0.775 | 0.720 | 0.73 | 134.6 | 19 | 1.344 | 1.179 | 1.154 | 1.121 | 1.114 | 0.876 | 0.983 | 1.055 | 0.862 | 0.94 | 194.5 | 20 | 1.652 | 1.478 | 1.413 | 1.391 | 1.618 | 1.147 | 1.294 | 1.354 | 1.137 | 1.29 | 191.2 | 21 | 0.722 | 0.607 | 0.604 | 0.582 | 0.566 | 0.206 | 0.521 | 0.494 | 0.196 | 0.49 | 282.0 | 22 | 0.679 | 0.504 | 0.524 | 0.469 | 0.441 | 0.142 | 0.194 | 0.244 | 0.149 | 0.16 | 339.0 | 23 | 1.476 | 1.291 | 1.225 | 1.230 | 1.039 | 0.889 | 0.409 | 0.977 | 0.912 | 0.91 | 128.6 | 24 | 1.455 | 1.390 | 1.314 | 1.187 | 1.065 | 0.916 | 1.018 | 1.069 | 0.831 | 1.00 | 261.0 | 25 | 0.636 | 0.628 | 0.569 | 0.424 | 0.333 | 0.206 | 0.318 | 0.269 | 0.111 | 0.26 | 188.5 | 26 | 0.696 | 0.642 | 0.633 | 0.576 | 0.420 | 0.132 | 0.297 | 0.307 | 0.209 | 0.29 | 342.0 | 27 | 1.098 | 1.019 | 1.029 | 0.986 | 0.720 | 0.528 | 0.601 | 0.976 | 0.495 | 0.52 | 296.0 | 28 | 0.986 | 0.767 | 0.773 | 0.640 | 0.561 | 0.220 | 0.352 | 0.448 | 0.115 | 0.30 | 154.7 | 29 | 0.954 | 0.739 | 0.716 | 0.820 | 0.702 | 0.533 | 0.680 | 0.686 | 0.529 | 0.58 | 79.0 | 30 | 1.956 | 1.706 | 1.651 | 1.596 | 1.587 | 1.503 | 1.521 | 1.548 | 1.489 | N/A | 196.6 | 31 | 0.611 | 0.578 | 0.535 | 0.519 | 0.482 | 0.282 | 0.320 | 0.467 | 0.239 | 0.39 | 382 | 32 | 0.636 | 0.632 | 0.576 | 0.518 | 0.482 | 0.244 | 0.299 | 0.437 | 0.237 | 0.25 | 87.8 | 33 | 0.654 | 0.457 | 0.375 | 0.319 | 0.282 | 0.169 | 0.241 | 0.260 | 0.161 | 0.13 | 65.1 | 34 | 0.924 | 0.756 | 0.893 | 0.712 | 0.672 | 0.431 | 0.518 | 0.678 | 0.315 | 0.44 | 179.4 | 35 | 0.701 | 0.592 | 0.533 | 0.527 | 0.493 | 0.237 | 0.425 | 0.511 | 0.210 | 0.39 | 83.1 | 36 | 0.694 | 0.675 | 0.583 | 0.565 | 0.329 | 0.280 | 0.422 | 0.453 | 0.289 | 0.33 | 88.8 | 37 | 0.671 | 0.686 | 0.475 | 0.437 | 0.396 | 0.221 | 0.311 | 0.376 | 0.208 | 0.24 | 97.2 | 38 | 0.682 | 0.552 | 0.483 | 0.387 | 0.447 | 0.264 | 0.358 | 0.387 | 0.225 | 0.30 | 116.0 | 39 | 0.679 | 0.542 | 0.475 | 0.401 | 0.376 | 0.253 | 0.318 | 0.370 | 0.369 | 0.30 | 111.1 | 40 | 0.659 | 0.436 | 0.562 | 0.588 | 0.648 | 0.415 | 0.472 | 0.516 | 0.142 | 0.44 | 55.6 | 41 | 0.671 | 0.550 | 0.521 | 0.456 | 0.377 | 0.224 | 0.360 | 0.389 | 0.219 | 0.23 | 276.0 | 42 | 0.678 | 0.583 | 0.521 | 0.433 | 0.378 | 0.204 | 0.298 | 0.336 | 0.192 | 0.27 | 70.3 | 43 | 1.046 | 0.924 | 0.873 | 0.745 | 0.820 | 0.535 | 0.679 | 0.753 | 0.547 | 0.59 | 72.0 | 44 | 1.076 | 0.889 | 0.859 | 0.848 | 0.720 | 0.547 | 0.652 | 0.677 | 0.498 | 0.61 | 73.6 | 45 | 0.709 | 0.683 | 0.657 | 0.646 | 0.618 | 0.410 | 0.453 | 0.583 | 0.383 | 0.43 | 62.4 | 46 | 0.884 | 0.793 | 0.778 | 0.760 | 0.723 | 0.521 | 0.685 | 0.697 | 0.400 | 0.67 | 401.0 | 47 | 0.784 | 0.687 | 0.642 | 0.596 | 0.566 | 0.439 | 0.518 | 0.555 | 0.410 | 0.49 | 353.0 | 48 | 1.083 | 0.880 | 0.863 | 0.757 | 0.548 | 0.583 | 0.679 | 0.694 | 0.586 | 0.67 | 84.9 | 49 | 0.771 | 0.650 | 0.441 | 0.456 | 0.408 | 0.284 | 0.355 | 0.385 | 0.281 | 0.28 | 132.4 | 50 | 0.821 | 0.777 | 0.753 | 0.706 | 0.672 | 0.357 | 0.561 | 0.587 | 0.288 | 0.54 | 318.0 | 51 | 0.864 | 0.719 | 0.656 | 0.420 | 0.620 | 0.424 | 0.547 | 0.589 | 0.409 | 0.52 | 481.0 | 52 | 0.933 | 0.820 | 0.779 | 0.765 | 0.718 | 0.544 | 0.686 | 0.699 | 0.457 | 0.62 | 382.0 | 53 | 0.822 | 0.727 | 0.722 | 0.698 | 0.633 | 0.464 | 0.577 | 0.629 | 0.357 | 0.57 | 252.0 | 54 | 1.095 | 0.866 | 0.821 | 0.739 | 0.721 | 0.453 | 0.690 | 0.701 | 0.457 | 0.61 | 231.0 | 55 | 1.412 | 1.294 | 1.276 | 1.187 | 1.133 | 0.944 | 1.003 | 1.160 | 0.819 | 0.95 | 149.3 | 56 | 0.835 | 0.817 | 0.718 | 0.826 | 0.626 | 0.453 | 0.556 | 0.578 | 0.408 | 0.54 | 153.2 | 57 | 1.094 | 0.836 | 0.865 | 0.833 | 0.812 | 0.617 | 0.718 | 0.783 | 0.549 | 0.68 | 251.0 | 58 | 0.828 | 0.752 | 0.781 | 0.679 | 0.634 | 0.326 | 0.552 | 0.627 | 0.223 | 0.34 | 263.0 | 59 | 0.892 | 0.870 | 0.726 | 0.648 | 0.638 | 0.421 | 0.446 | 0.439 | 0.395 | 0.38 | 116.0 | 60 | 0.868 | 0.745 | 0.666 | 0.626 | 0.596 | 0.337 | 0.518 | 0.518 | 0.422 | 0.40 | 57.6 |
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N/A = not analyzed; Ref. = WTW TISAB solution; TEA = triethanolamine; EC = electrical conductivity.
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