Multiresidue method for pesticides in drinking water using a graphitized carbon black cartridge extraction and liquid chromatographic analysis

Abstract

A general liquid-solid extraction procedure for the isolation of pesticides from groundwater and drinking water for high-performance liquid chromatography (HPLC) is presented. This simple and rapid procedure involved passing a 2-L sample through a 250-mg graphitized carbon black (Carbopack B) cartridge at a flow rate of 150-160 mL/min. By taking advantage of the presence of positively charged active centers on the Carbopack B surface, a stepwise elution system allowed the complete separation of base-neutral pesticides from acidic ones. After partial solvent removal, the components in the two fractions were separated and quantified by gradient elution, reversed-phase HPLC with ultraviolet (UV) detection. The performance of the Carbopack cartridge was compared with that of a 500-mg C-18 bonded silica cartridge. With the Carbopack cartridge, the grand mean measurement accuracy of the 35 pesticides considered was 95%. With the C-18 cartridge, the grand mean measurement accuracy of the analytes was 76%. Compared to the C-18 cartridge, additional advantages of using a Carbopack cartridge are that the extraction procedure is about 7 times shorter, no pH adjustment of the environmental sample is necessary for trapping acidic compounds, and one cartridge instead of two suffices to extract base-neutral and acidic pesticides, making the Carbopack cartridge more adaptable than the C-18 one for field use. The detection limits by this method of all the pesticides considered were between 0.003 and 0.07 micrograms/L.

Gas chromatography/mass spectrometry applied for the analysis of triazine herbicides in environmental waters

“…Gas chromatography (GC) coupled with nitrogenphosphorus detector (Popl et al, 1983;Steinheimer and Brooks, 1984;Thurman et al, 1990) or mass spectrometer (MS) (Lopez-Avila et al, 1985;Thurman et al, 1990;Durand and Barcelo, 1991;Ahel et al, 1992;Cai et al, 1993;Cassada et al, 1994;Xiong et al, 1998), high performance liquid chromatography (HPLC) (Corcia et al, 1987;Battista et al, 1989;Steinheimer and Ondrus, 1990;Corcia and Marchetti, 1991) and enzyme-linked Chemosphere 52 (2003Chemosphere 52 ( ) 1627Chemosphere 52 ( -1632 www.elsevier.com/locate/chemosphere immunosorbent assay (Thurman et al, 1990;Xiong et al, 1998) have been developed for ATR determination in water. The most common sample preparation for trace analysis of ATR in water involves solid-phase-extraction (SPE).…”

Validation of UV Spectrophotometric and HPLC Methods for Quantitative Determination of Chlorpyrifos

“…Different chromatographic methods for the determination of chlorpyrifos in food and environmental samples [6][7]. For example, limits of detection (LOD) between 0.05 and 0.5 ng/ml were reached using thin layer chromatography (TLC) [8]; also high performance liquid chromatography (HPLC) with LOD [9]. In addition, gas chromatography (GC) coupled to nitrogen/phosphorous (NPD) [10][11], atomic emission (AED) [13], electron capture (ECD) [13] or flame photometric detectors (FPD) [14], have also been applied for the determination of chlorpyrifos.…”

Cloud Point Extraction of Pesticide Residues

“…The results obtained in this study indicate that the use of Genapol X-080 provides better results than POLE for the extraction of OPPs using CPE. One problem with the UV detection is that pesticides absorb appreciably at wavelengths below 250 nm (DiCorcia & Marchetti, 1991;Ellington et al,2001), the same spectral region where many reactives and matrix-derived interferences absorb. For this reason, LC-UV analysis is generally more applicable in high-concentration formulations (Cho et al, 1997) or very clean environmental substrates.…”