Figure 11.
Distribution of neutral, acid, basic, and zwitterionic SCEs in period A (2000–2011: N = 1038) and period B (2012–2021: N = 980). * To define the acid/base properties of the SCEs, their ionization state at pH 7.4 was considered.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.