Widening the Analytical Perspective: Polarity Extended Separation for Monitoring of Trace Organic Compounds in Surface Water Matrices

Today monitoring trace organic compounds in water bodies is part of many strategies aiming to protect environmental health or drinking water quality. The occurrence of hazardous compounds in water bodies can be assessed using different analytical screening strategies. Reversed phase chromatography (RPLC) coupled to mass spectrometric detection is a commonly used technique. RPLC is well suited for the separation and detection of medium to non-polar compounds, but can hardly be used for the detection of polar compounds. To cover the entire range from non-polar to very polar compounds in water bodies, a serial coupling of RPLC and hydrophilic interaction liquid chromatography (HILIC) or a supercritical fluid chromatography (SFC) system, both coupled to a time-of-flight mass spectrometer (TOF-MS) pose a new separation and detection technique. Both novel techniques were applied for target and suspect target screening. The polarity range of the two techniques was comparable and covered the full range from non-polar (log DpH 7 = +7.67) to very polar (log DpH 7 = -7.86) properties. In addition to the extension of accessible polarity space for separations, the application of RPLC-HILIC/TOF-MS and SFC/TOF-MS in parallel improves the level of confidence in compound verification. For the verification of suspect compounds in water samples, the comparison of RPLC-HILIC/TOF-MS and SFC/TOF-MS data could substitute tandem-mass spectrometric data.