Determination of Rinsing Effectiveness in Washing Machines

This technical report outlines the evaluation of rinsing effectiveness for household and commercial washing machines, specifically washer-dryer combos, as per the technical specification PD CLC/TS 50677:2019. The report details the methodology for determining the concentration of residual surfactants, particularly linear alkylbenzene sulfonate (LAS), using UV/Vis measurements with the SPECORD 210 PLUS spectrophotometer. The process involves creating a calibration curve based on absorbance values at specific wavelengths, which is essential for accurate measurement due to the low concentration of LAS remaining after washing. The report also discusses the preparation of stock solutions and working standards, along with the instrumentation settings required for the measurements. Additionally, preliminary studies were conducted to ensure the purity of cuvettes and the accuracy of measurements. The findings indicate that the SPECORD 210 PLUS provides reliable results, achieving high precision in determining the concentration of surfactants in compliance with the specified standards.