Four potential simulants for fentanyl analogues, Simili 1-3 and Benzylfentanyl, were created and investigated regarding detection and sampling characteristics for training purpose for CBRNE units e.g. the 1st CBRN-company. All four simulants showed a significantly lower potency than their toxic equivalent Fentanyl and did not show any toxic effects on living cells. Detection of simulants and fentanyl analogues by indicator paper 104/105 was investigated for solids, solutions and dried solutions on a surface. Results showed that all compounds, except simulant 3, could be detected for solids. Simulants and fentanyl analogues were applied at three different concentrations, on cotton fabric, wood surface and hard-burned brick. All compounds were detected from the materials at the two highest concentrations, with GC/MS and LC/MS. For detection at low concentrations, here 0.5 ng/mL, LC/MS analysis was required. Based on the combined results from indicator paper and GC/MS and LC/MS analysis, simulant 1 was identified as the most suitable simulant for Carfentanil while Bezylfentanyl performed well as a simulant for Fentanyl and simulant 3 was the best simulant for Remifentanil. If a sample gives a green colour change on indicator paper 104, the concentration is sufficient to continue with GC/MS analysis for identification. If there is no colour change but still a suspicion of toxic material, the concentration could be too low for indicator paper 104. At such scenario, swab sampling and analysis by GC/MS or LC/MS is necessary for detection. Results also show that cotton samples, like a curtain or clothes, is the best material of choice for sampling in a room potentially contaminated with a toxic gas or aerosol. Secondarily, a hard smooth surface, preferably a wood surface, is the best to sample.