In-column micro-high-performance liquid chromatographic concentration-separation prior to ultraviolet detection for the determination of chlorophenols in water samples

Two methods for the determination of all chlorophenols (CPs) plus phenol have been developed, both based on multiple sample injection – 2 or 12 injections – for in-column concentration prior to total content determination (TCD) of CPs and individual separation-quantification (ISQ) of each CP in drinking-water by micro-liquid chromatography–ultraviolet absorption spectrometry (μLC–UV). A Zorbax SB C18 capillary column (150 mm × 0.5 mm; 5 μm particle size) and a monitoring wavelength of 210 nm were used in both methods. The limits of detection (LODs) and quantification (LOQs) are 9 and 36 ng/l, respectively, for the TCD method, and range between 3–13 ng/l and 8–21 ng/l, respectively, for the ISQ method, with linear dynamic ranges from LOQs to 2.00 μg/l. The precision, expressed as relative standard deviation (RSD), ranges between 2.25 and 6.91% for repeatability and between 3.08 and 8.06% for within laboratory reproducibility for both methods, and the errors, also expressed as RSD for all compounds, range between 0.57 and 9.35%. The time necessary for the TCD and the ISQ methods are 20 and 92 min, respectively. The accuracy of the methods and potential matrix effects were studied by using spiked water samples and recoveries between 90.9 and 111.1% were obtained. Then, the ISQ method was applied to different samples including tap, mineral and spring water.