Portable particle sizing concept for beach sand identification for forensic purposes: a success case application of DLS/PCS

Abstract

A cheap and simple experimental setup for executing particle sizing in water disperion by means of dynamic light scattering (DLS) and consequently the necessary software to evaluate the calculations of photon correlation spectroscopy (PCS) are described here in order to characterize beach sand by its source location according to the mean beach sand grain hydrodynamic diameter. Despite the existence of similar commercial particle sizing equipments, the innovation presented here consists of a portable measurements able to be used in the field. It consists of an easy handling apparatus composed by a solid-state laser pointer as light source and a smartphone CCD camera as detector for video acquiring. Correlation calculus of light intensity variations were performed in a software developed by the authors. The performance test of the proposed protocol was evaluated to characterize beach sand particles on aqueous solution determining its hydrodynamic diameter. The limitations of the technique were explored and comparison with optical microscopy results and literature were performed.