Improved single-drop microextraction for high sensitive analysis

This paper described a simple approach to prepare a small bell-mouthed extraction device for single-drop microextraction (SDME). Analytical sensitivity was improved by increasing the suspended acceptor volume. Because of the increased contact area and the rough inner surface of the extraction device, the stability of drop was markedly increased. The merits of the proposed method were demonstrated by using I-octanol as extractant and with cyanazine, simazine and atrazine as model compounds. The related parameters and the effect of humic acid were systematically investigated. Under the optimized extraction conditions, the linear range, detection limit (S/N = 3) and precision (RSD, it = 6) were 0.2-50, 0.06 mu g-L-1, 5.7% for cyanazine, 0.1-25, 0.03 mu g L-1, 6.7% for simazine, and 0.15-37.5, 0.04 mu g L-1, 5.0% for atrazine, respectively. The established method was applied to determine the target compounds in four real water samples, and the satisfactory spiked recoveries at two concentration levels were obtained. Moreover, the comparison of the proposed SDME with the traditional SDME was performed. These results indicated that the proposed improvement made SDME be a competitive analytical tool and an alternative of the traditional methods for the analysis of organic pollutants at trace level. (c) 2006 Elsevier B.V. All rights reserved.