Evaluation of various liquid chromatography-quadrupole-linear ion trap-mass spectrometry operation modes applied to the analysis of organic pollutants in wastewaters

The LC-MS/MS analysis of a group of 14 organic pollutants in wastewater – including pharmaceuticals (analgesics/anti-inflammatories, lipid regulators and diuretics), pesticides (diuron) and disinfectants (chlorophene) – has been carried out using a hybrid triple quadrupole-linear ion trap-mass spectrometer (QqLIT). In order to take advantage of the capabilities of the QqLIT system, two methods have been developed and compared, based on the application of different operation modes. One of them uses selected reaction monitoring (SRM), which is the standard mode for quantitative LC-MS/MS analysis. The other is based on the use of an information dependent acquisition scan function (IDA), which allows the combination of a SRM acting as the survey scan and an enhanced product ion scan (EPI) as dependent scan within the same analysis. Performance of both methods was compared, especially in terms of their limits of detection and identification capability. The advantages and limitations of both techniques are discussed. Finally, the two methodologies developed were applied to real samples for evaluation of effluent wastewater in a treatment plant on the south-eastern Mediterranean coast of Spain. The presence of most of the target compounds was detected at mean concentrations ranging from 50 ng/L (mefenamic acid) to 3373 ng/L (hydrochlorothiazide).