In Situ Quantification of Silver Nanoparticle Dissolution Kinetics in Simulated Sweat Using Linear Sweep Stripping...

Linear sweep stripping voltammetry (LSSV) is demonstrated as a sensitive, rapid, and cost-efficient analytical technique for the quantification of silver nanoparticle (AgNP) dissolution rates in simulated sweat. LSSV does not require the extensive sample preparation (e.g., ultrafiltration or centrifugation) needed by more commonly employed techniques, such as atomic spectroscopy. The limit of detection (LOD) of Ag(I)(aq) was 14 ± 6 μg L^-1, and measured dissolution rate constants, k_dissolution, varied from 0.0168-0.1524 h^-1, depending on solution conditions. These values are comparable and agree well with those determined by others in the literature using atomic spectroscopy. Importantly, LSSV had the necessary sensitivity to distinguish the effects of SSW solution conditions on AgNP dissolution rates. Specifically, enhanced dissolution rates were observed with decreased pH and with increased NaCl concentration. The colloidal stability of AgNPs in SSW solutions was also characterized using dynamic light scattering (DLS), ζ potential, and quantitative UV-vis spectroscopy measurements. An increase in AgNP aggregation rate was observed with increased NaCl concentration in SSW, suggesting that the enhancement in AgNP dissolution is driven by the large Cl/Ag ratio, even as the AgNPs undergo significant aggregation.