An in-tube SPME device for the selective determination of chlorophyll a in aquatic systems

We report a new device for the estimation of the content of chlorophyll a pigment in water samples as an indicator of water quality. The extraction of the pigment from water was also optimized. 10 mL of water was filtered through a nylon filter (45 mu m pore size and 13 mm of diameter), after the chlorophylls were dissolved by immersing the filter in 1 mL of a low non-hazardous solvent as ethanol. An in-valve in-tube SPME device coupled to capillary liquid chromatography with diode array detection was designed. A capillary column of 70 cm in length (0.32 mm id. coated with 5% dipheny1-95% polydimethylsiloxane, 3 mu m coating thickness) was used as the loop of the injection valve for preconcentration and a Zorbax SB C-18 (SiO2-based) 150 mm x 0.5 mm i.d., 5 mu m column (Agilent) was used as analytical column. The achieved detection limit was 0.05 mu g L-1 and the working range of concentrations was 0.1-1 mu g L-1. % RSD values between 2 and 11 were obtained. Chlorophyll a in several water matrices was determined with good results in presence of other pigments such as chlorophyll b, pheophytin a and pheophytin b. (C) 2010 Elsevier B.V. All rights reserved.