The optimised vDMS conditions were combined with a short column trap-elute LC method. Analytes were trapped on a 1 cm C18 column for 15 seconds using 10% acetonitrile and eluted in back-flush mode using 20% acetonitrile, for a total run time of 1 minute as described in Figure . Compared to flow injection analysis the trap-elute method reduces ionisation suppression by separating compounds based on physicochemical properties (pKa, Log P) in the condensed phase, while the vDMS dimension provides separation of target species based on gas phase interactions. The advantage compared to LC- isomers BZE-NCOC (RS=12.14) and ODT-NDT (RS=11.52) and increase the analysis throughput by a factor of 5 compared to the LC-MS/MRM method. vDMS also substantially reduces the chemical noise observed in blank urine samples (Figure ). By this method, the presence of cannabinoids was identified but quantification of THC and CBD was not possible as these isomers were not resolved. A second method was developed to confirm the presence of isomeric THC/CBD and quantification of five cannabinoids in selected ion monitoring mode.