The current absence of well-established and standardized methods for characterizing submicrometer- and nano-sized particles in water samples presents a significant analytical challenge. With the increasing utilization of nanomaterials, the potential for unintended exposure escalates. The widespread and persistent pollution of water by micro- and nanoplastics globally is a concern that demands attention, not only to reduce pollution but also to develop methods for analyzing these pollutants. Additionally, the analysis of naturally occurring nano entities such as bubbles and colloidal matter poses challenges due to the lack of systematic and consistent methodologies. This study presents Asymmetric Flow Field-Flow Fractionation (AF4) separation coupled with a UV-VIS spectrometer followed by Multi-Angle Light Scattering (MALS) for detection and size characterization of nanometric entities. It is coupled with an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) for elemental analysis. Water samples from different sources, such as untreated mountain spring water, groundwater, and bottled drinking water, were analyzed. The system was calibrated using pure particle standards of different metallic compositions. Our study demonstrates the capability of AF4-UV-MALS-ICP-MS to detect metals such as Al, Ba, Cu, and Zn in particles of around 200 nm diameter and Mg associated with very small particles between 1.5 and 10 nm in different drinking water samples.

This paper deals with the repetitively pulsed spark discharges over the water surface by studying both the electrical and the spectroscopic aspects. Detailed discharge electrical parameters, vibrational and rotational temperatures, and electron density measurements for nine different conditions of input frequencies and voltages over the water surface have been reported. The objective of this paper was to find effective operating conditions and compile results for the future industrial applications. The spectroscopic characterizations such as temperatures and densities were gathered from the optical emission spectroscopy (OES). The N2 (C-B) second positive system (SPS) transition (370-382 nm) and the O triplet line (777 nm) obtained from plasma spectrum were analyzed by SpecAir software in order to get the vibrational/rotational temperatures and electron densities, respectively. The results of this work are concurred with our previous work on softening hard water using pulsed spark discharge, finding the most effective conditions practically.