In the chlor-alkali and electrolysis industries, as well as many others, there is a need to analyze for TOC in samples containing high salt concentrations. These samples can range from sea water, which is typically 3% salt, up to brine solutions containing 28% salt. Shimadzu’s TOC-L with the high salt kit (P/N 638-93176-01 for N model & P/N 638-93176-02 for H model) is well suited for analyzing these types of samples.
To assess the capability of the TOC-L to analyze samples with high salt concentrations, the worst case scenario was chosen – brine water (28% NaCl). Calibration standards were prepared from KHP in brine. A calibration curve from 0 to 100 ppm was created as shown below. (calibration curve 1). Measurements were made using NPOC. 1:4 sulfuric acid was added to each sample by the instrument at a rate of 15%.