Fluoride in sea water: intercalibration study based on electrometric and spectrophotometric methods

Fluoride was shown to be a conservative constituent of sea water. Samples from the eastern tropical North Pacific, the Caribbean, the Labrador Basin, and the Reykjanes Ridge region indicated that the most probable $\text{F}\text{Cl}$ ratio in sea water is 6.71·10^-5 with an overall uncertainty of ±0.07·10^-5 based on 99% confidence limits of ±0.02·10^-5 and an allowance of ±0.05· 10^-5 for systematic error. Double-blind measurements from laboratories using electrometric and spectrophotometric methods agreed closely. Mean $\text{F}\text{Cl}$ ratios found were all within 0.7% of the most probable value.