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

Abstract

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. 10mL of water was filtered through a nylon filter (45 mpore size and 13mmof diameter), after the chlorophylls were dissolved by immersing the filter in 1mL 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 70cm in length (0.32mm i.d. coated with 5% diphenyl–95% polydimethylsiloxane, 3 m coating thickness) was used as the loop of the injection valve for preconcentration and a Zorbax SB C18 (SiO2-based) 150mm×0.5mm i.d., 5 m column (Agilent) was used as analytical column. The achieved detection limit was 0.05 gL−1 and the working range of concentrations was 0.1–1 gL−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.