Density tunable dispersive solid phase extraction of four organochlorine pesticides from edible oil sample using rhodamine B as a sorbent prior to GC-MS analysis.

In this study, a new method was used to evaluate the levels of four organochlorine pesticides in edible samples. In this method, a density tunable dispersive solid phase extraction procedure was coupled with gas chromatography-mass spectrometry. Rhodamine B was used as a sorbent, which was distributed throughout the oil matrix with the aid of evaporation of methanol. This process enabled the possibility of effective extraction and preconcentration of the target analytes. To achieve this goal, several factors affecting the extraction efficiency, including the type and volume of diluent, the amount of rhodamine B, the volume of methanol, and the temperature of the ultrasonic bath were carefully evaluated. This method provided low detection limits (from 0.21 to 0.36 ng g-1), wide linear range (1.1-100 ng g-1) and acceptable extraction recoveries (64-72%) and enrichment factors (102-115). The precision of the method was evaluated by calculating the relative standard deviation, which ranged from 3.6 to 6.8% for intra- and 3.1 to 8.8% for inter-day precisions. The investigated method reduced the interference of the matrix and provided the possibility of quantitative determination of the studied organochlorine pesticides in various oil samples (canola, corn, sunflower, and olive). This method introduced a reliable analytical tool for the monitoring of the pesticide residues in different oil samples by providing capabilities such as simplicity, sensitivity, and compatibility with the environment.