The stability of target CECs in river samples at room temperature over 24 hours was investigated. This was achieved by spiking triplicate samples of river water (50 mL) with analytes at initial concentrations of 100 ng L-1 and 500 ng /L before being left covered for 24 hours. Samples were then spiked with 50 ng of IS solution before being processed via the iMME sampler.