By E. Michael Thurman and Imma Ferrer Center for Environmental Mass Spectrometry Department of Environmental Engineering University of Colorado Boulder, CO, USA
This application note presents examples of the use of UHPLC (ultrahigh performance liquid chromatography) for environmental applications using the new Agilent 1290 Infinity LC. The examples include wastewater analysis of pharmaceuticals with focus on EPA Method 1694 and the way that UHPLC makes this analysis more efficient and reliable. The second example will show that complex mixtures of pesticides may be analyzed with fast chromatography, opening the door for many types of UHPLC analyses for environmental applications. Finally, an example will show a 60-sec analysis of pharmaceuticals in wastewater using UHPLC and a ballistic gradient, which is one of the first examples in environmental analysis. The insights of efficient UHPLC analysis are discussed and illustrated.
The advent of UHPLC has brought two important innovations to liquid chromatography/mass spectrometry (LC/MS) analysis. First is the use of 1.8-µm columns, which gives an increase in plate number from the 5-µm columns of about a factor of two. This is important for environmental applications where complex matrices are encountered, such as pharmaceuticals in wastewater analysis. However, the use of 1.8-µm columns requires higher pressure pumps operating at pressures that exceed 600 bar on a routine basis, which is the range commonly used for UHPLC. Secondly, the 1.8-µm column allows the use of rapid resolution chromatography and even ultrafast chromatography, where runs may be less than 1 min in length. The high flow rates required for these analyses create pressures on the order of 800 to 1000 bar, or more, and are clearly in the range of UHPLC.