Detecting trace levels of contaminants in water samples requires an optimized set of methods for sample preparation, liquid chromatography (LC), and mass spectrometry (MS). For advice about these methods, LCGC talked to Damià Barceló, a leading researcher in water and environmental analysis. Barceló is a research professor with the Scientific Research Council (CSIC) of the government of Spain, at the Institute of Environmental Assessment and Water Research (IDAEA) in Barcelona. He is also the director of the Catalan Institute for Water Research (ICRA) in Girona. He has published more than 775 peer-reviewed papers on water and environmental research.

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Optimizing Analytical Methods for Water Analysis

Effluents from wastewater treatment plants (WWTPs) are a major source of contamination by pharmaceuticals and personal care products (PPCPs) in the environment. The presence of low levels of PPCPs in surface and drinking water sources raises public concern because of the potential detrimental ecological effects of these contaminants. Because of these concerns, scientists and engineers have been interested in detecting PPCPs in water to evaluate their fate and transport in the environment, as well as monitor their transformation and degradation at WWTPs. Liquid chromatography coupled with mass spectrometry (LC–MS) has been the method of choice for separation and detection of PPCPs, because PPCPs are highly soluble in water and have low volatility. The majority of LC–MS methods use electrospray ionization either in positive or negative mode, with an acidic or basic mobile phase, respectively. As an alternative, this article presents the use of “wrong-way-round ionization” in electrospray mass spectrometry, where protonation of neutral or weakly basic molecules occurs in a strongly basic mobile phase in LC–MS. When “wrong-way-round ionization” was employed in LC–MS for the analysis of PPCPs in wastewater samples, increased signal intensities, by at least an order of magnitude, were observed in PPCPs with diverse polarity and acidic properties.

When the Wrong Way is Better: Using Wrong-Way-Round Ionization for the Targeted Analysis of Pharmaceuticals in Wastewater

Ethylenediamine, the preservative specified in EPA Method 300.1, can introduce a chromatographic artifact when analyzing samples containing elevated carbonate concentrations as a result of the formation of ethylenediamine carbamate. This artifact can compromise the ability to measure low levels of bromate in drinking water. The use of ammonia as an alternative preservative was investigated and found to produce improved bromate chromatography under challenging conditions. The improvement was seen on two different stationary phases, demonstrating that the benefit of this alternative preservative is independent of the column chemistry.

Spectroscopy E-Books-10-01-2014

Optimizing Analytical Methods for Water Analysis

When the Wrong Way is Better: Using Wrong-Way-Round Ionization for the Targeted Analysis of Pharmaceuticals in Wastewater

Ion Chromatography Analysis of Bromate in Natural Water Samples Using Ammonia as a Preservative