A similar behavior is observed in Fig. ) for TBP at 2 M concentration, where no kink was seen for the range of 1-4 M HN O 3 . This data is consistent with a hypothesis that the critical acid contraction increases as the concentration of extractant is increased, similar to the shift of third phase formation with increases in concentration of extractant, as has been observed for TBP. The data for 0.1 M TEHDGA suggests a similar trend. While we lack robust statistical confirmation, data from a single reference (see Fig.