Evaluation of direct sample injection as a fast, no-sample handling, approach for the LC-MS/MS monitoring of pharmaceuticals in different water matrices

•DI, an alternative to SPE for the LC-MS/MS determination of pharmaceuticals in water.•Matrix effects led to ion suppression in SPE but to signal enhancement in DI.•Matrix effects did not decrease after SPE pre-concentration of water samples.•The use of analyte-ILIS allowed to improve the performance of DI procedure.•Recoveries of QCs analyzed by DI-LC-MS/MS were satisfactory for most compounds.