Large-Volume Direct Injection for Determining Naphthalene Derivative Pesticides in Water Using a Restricted-Access Medium Column in RPLC-LC with Fluorescence Detection

A simple multidimensional system for direct injection of large volumes has been developed for the determination of three naphthalene-derivative pesticides [2-(1-naphthyl) acetamide (NAD), 1-naphthyl methylcarbamate (carbaryl) and 1-naphthol] in water using fluorescence detection. The capability of restricted-access medium (RAM), pre-columns for eliminating large interfering molecules, combined with an optimised, coupled-column separation procedure, large volume injection (LVI) and fluorescence detection, gave excellent sensitivity for target analytes. The maximum admissible concentration levels established by the European Union (EU) for individual pesticides and their related compounds in drinking water (0.1 μg L^?1) were easily reached. Detection limits were lower than, or equal to, 0.003 μg L^?1. Average recoveries ranged: 81–104% (n=3) with relative standard deviation (RSD) values: 2–7%. Application of the coupled-column liquid chromatography (LC-LC) method was by determining target analytes in ground water samples from five agricultural zones of Almería, (Spain) over three months.