The percentage increase in A that occurred during the first 25 s is
presented in Table S2. At NaCl concentrations higher than 58 mM for
AgNP-ALG and 50 mM for 109AgNP-ALG, there was no observable
increase in A, so contributions from the formation of new AgNPs from
the silver ions are not expected. Usually, the time required for the
collection of a full spectrum using a standard bench-top laboratory
spectrophotometer is ≥25 s, and therefore important information,
such as the possible formation of new NPs from the silver ions present
in solution, is missed. In this study, we obtained a full spectrum from
the first second of a NP aggregation process, which facilitated our interpretation
of AgNP behaviour at the early stages of aggregation.