Heavy metal salts

PM (CRM No. 28) was obtained from the National Institute for Environmental Studies (Ibaraki, Japan). Morphological and compositional analyses of PM were demonstrated in our previous study [15 (link)]. Heavy metal salts, potassium bromide, potassium permanganate, hydrogen peroxide, and nitric acid were purchased from Sigma-Aldrich (St Louis, MO, USA). Commercial sodium alginate was purchased from DaeJung chemicals metals Co., Ltd. (Siheung-si, Korea). Multi-element calibration standard for inductively coupled plasma optical emission spectroscopy (ICP-OES) was purchased from Perkin Elmer Inc. (Norwalk, CT, USA). ELISA kits were obtained from Thermo Fisher Scientific (Waltham, MA, USA) and Invitrogen (Carlsbad, CA, USA). Other chemicals were obtained from commercial and were of high analytical grade.

Fresh persimmon leaves were collected from Nainital, Uttarakhand, India. Silver nitrate (AgNO₃) and heavy metal salts were purchased from Sigma-Aldrich (India) and used unpurified. The aqua-regia and Milli-Q water were used to wash and rinsed the glassware before use. Milli-Q and deionized water were used throughout the experimental procedure.