The residual amounts of detergent that remains on medical instruments after insufficient rinsing not only causes discoloration and corrosion, but it can also have some adverse effects on the human body. In this study, we measured amounts of chemical elements included in the detergent with inductivity coupled plasma (ICP) optical emission spectrometry in addition to the commonly used washer-disinfector (WD) rinsing evaluation method. We also attempted to identify the factors that could influence rinsing. Furthermore, cytotoxicity tests were performed to determine the concentration on how much the detergent was toxic to cells.
As a result of the tests, the method of elemental analysis could detect the detergent component with the highest sensitivity. The number of cleaning devices and the concentration of detergent had the most significant effect on the amount of detergent remaining. The cytotoxicity tests showed that the effluent was no longer toxic to cells after three or more wash cycles.
These findings were implied that the factors that influence the amount of residual detergent in the wastewater were the number of cleaning devices and the concentration of detergent used. Therefore, to perform three or more rinse cycles would be preferable when using a WD.
