| Popis: |
Glass electrodes are commonly used to measure the pH of natural waters over various, sometimes wide, ranges of salinity (S). For such applications, the electrodes must be calibrated against solutions of known pH and salinity identical to those of the sample solutions. Well-characterized buffer solutions may be used for these calibrations, but if a wide range of salinity is to be encountered in the samples (e.g., as in estuarine transects), this approach is quite laborious. Previous work has demonstrated that for 28.5 5, was reliably consistent with theoretical expectations, such that repeat verification needs to be conducted only occasionally. Electrode intercept potential (E0), in contrast, was found to depend substantially on salinity: approximately linearly for 5 ≤ S ≤ 36 and substantially nonlinearly for 0.5 ≤ S |
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