A preliminary study determined that the saturation of NaCl in a
20 mL sample of soft drink was 6.2 g at 30 C. The range of the NaCl
added in this study was 0–6 g (0–30% w/v). A similar improvement
in the THM extraction efficiency occurs with the addition of NaCl.
Taking experimental errors into consideration, there is no significant
difference with the addition of 4, 5 or 6 g of NaCl. Chloroform
was the analyte that was less affected by the addition of NaCl,
probably because it is the most volatile among the THMs studied.
Thus, 4 g of NaCl was fixed as the optimum value.