Chemometric analysis of targeted 3DLC-DAD data for accurate and precise quantification of phenytoin in wastewater samples.

A variety of pharmaceuticals have been found in various water systems, including wastewater treatment effluent. Due to the possible environmental and human health implications, it is important to be able to quickly and reliably quantify the amount of pharmaceuticals and personal care products that may be present in such samples. To this end, a new chromatographic analysis technique involving three dimensions of liquid chromatography, including selective comprehensive separations in the second and third dimensions, was applied to the analysis of a wastewater treatment plant effluent (WWTPE) sample using both standard addition and external calibrations. Iterative key set factor analysis alternating least squares with the application of both sample and spectral selectivity constraints was used to resolve the phenytoin peak at a concentration corresponding to about 40 parts-per-trillion using UV absorbance detection. Both the precision and accuracy of the method are investigated. We determined that the concentration of phenytoin in WWTPE using selective three dimensional liquid chromatography with diode array detection was 42 ± 1 ng/L, after resolution from an unknown interferent. The estimated concentration was not significantly different from that obtained by the reference 2DLC/MS/MS method, but was four and a half times more precise.