Determination of common organophosphorus pesticides in the blood of children with acute leukaemia using a double-solvent system as a novel extractant for dispersive liquid-liquid microextraction.

In this research, a new mode of dispersive liquid-liquid microextraction based on a double-solvent system (DLLME-DSS) was developed for the extraction and preconcentration of organophosphorus pesticides (OPPs) in the blood of children with acute leukaemia prior to determination by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). In the present method, two long normal chain alcohols are mixed in a particular ratio, and then injected into the sample solution, which is magnetically stirred. In this case, the mixture of the two alcohols changes to a new aggregate extractant. This new double-solvent is used as an extractant, which has a higher extraction power than any of its components alone. Under the optimum conditions, the calibration graph was linear in the rage of 3-600 µg L-1 with detection limits of 1 to 2 µg L-1. Relative standard deviations (RSDs) including intra-day and inter-day of the method based on 7 replicate determinations of 100.0 µg L-1 for each analyte were in the range of 2.9-4.7% and 3.8-6.1%, respectively. The results proved that DLLME-DSS is a sensitive, very simple, inexpensive, environmentally friendly, rapid and efficient method for the preconcentration of trace amounts of OPPs in blood samples.