MULTIVARIATE OPTIMIZATION OF HEADSPACE IONIC LIQUID SINGLE DROP MICROWXTRACTION OF CHLOROBENZENES FROM WATER SAMPLES

L. VIDAL; E. PSILLAKI; C. DOMINI; N. GRANÉ; F. MARKEN; AN. CANALS

Zaragoza

Congreso; 12 th SYMPOSIUM ON SAMPLE HANDLING FOR ENVIRONMENTAL AND BIOLOGICAL ANALYSIS; 2006

PÓSTER (PREMIADO)

Room temperature ionic liquids (ILS) are a group of new organic salts consisting of a combination of organic cations and varios anions that are liquids at room temperature. Important features of ILs include their immeasurably low vapour pressure, high stability, large viscosity, moderate dissolvability of organic compounds as well as adjustable miscibility and polarity. The main advantages of ILs when ised for single-drop microextraction (SDME) are the possibility of using longer sampling time as well as larger droplet volume. In this study the possibility of using 1-butyl-3-methylimidazolium hexaflurophosphate, an ionic liquid, as the acceptor phase for headspace SDME coupled to HPLC for the analysis of chlorobenzenes in environmentl water samples is evaluated. Experimental design is used to obtain the optimun conditions fo the main experimental paramenters (i.e., extraction solvent, droplet volume, aqueous sample volume. stirring speed. ionic strength, extraction time and temperature). Exposing a few microlitres of ionic liquid drop to the headspace of an aqueous sample contaminated with 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,3-dichlorobenzene, 1,2,3,-trichlorbenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,4,5-tetrechlorobenzene, compounds proved to be an excellent preconcentration method for headspace analysis by HPLC equipped with a Photodiode Array Detector (DPA).The optimum experimental conditions found from this statistical evaluation are: a 5 ul microdrop of 1-butyl-3-metrylimidazolium hexaflurophosphate, exposed for 37 min to the headspace of a 10 ml acueous sample placed in a 15 ml vial, stirred at 1580 rpm at room temperature and containing 30% w/v NaCl. The method linearity is confirmed for all analytes from 5 up to 320 ppb, except for 1,2,4,5- TeCB which lineariy range is from 5 up to 160 ppb, with correlation coefficients ranging betwen 0.9992 and 0.9998. The repeatability of the method, expressed as relatie standard deviation, varies between 1.6 and 5.1 % (n=5)and the limit of detection values are ranged between 0.102 and 0.203 ug l-1. Matrix effects upon extraction are evaluated by analysing spiked tap and river water as well as effluent water samples from a municipal wastewater treatment plant.