Determination of Metals in Natural Waters by Inductively Coupled Plasma Optical Emission Spectroscopy after Preconcentration on Silica Sequentially Coated with Layers of Polyhexamethylene Guanidinium and Sulphonated Nitrosonaphthols

Figure 4

Data on total (solid dark line, TG, %) and differential mass (solid light line, DTG, %/min) changes of SiO₂–PHMG–NNS obtained at heat rate 10 К/min at the air flow rate 50 mL/min. DSC profile is shown by dashed line. Similar dependences were observed during TGA-FTIR analysis of SiO₂–PHMG–NRS.