On-line immunoaffinity column-liquid chromatography–tandem mass spectrometry method for trace analysis of diuron in wastewater treatment plant effluent sample

An on-line immunoaffinity column with liquid chromatography/tandem mass spectrometry (IAC-LC–MS/MS) method for the determination of diuron in water matrices was described. This method used a sol–gel immunoaffinity column (20 mm × 4 mm I.D.) for on-line sample cleanup and enrichment, a monolithic analytical column (100 mm × 4.6 mm I.D.) for separation, and a triple quadrupole mass spectrometer for quantitation. The major challenges for the on-line set-up were discussed. The optimized on-line protocol was emphasized by the fact that low limit of quantitation (LOQ) of 1.0 ng/L was achieved with only 2.5-mL sample. In addition, a satisfactory accuracy (∼90% of recovery) and precision (<6% of relative standard deviation) at 50 ng/L concentration were also obtained. Due to the ability of the sol–gel immunoaffinity column to eliminate matrix effect, the on-line IAC-LC–MS/MS analysis method can reliably determine diuron in wastewater treatment plant effluent sample.