Abstract
An analytical scheme for the determination of several organochlorine pesticides like hexachlorocyclohexanes (HCHs) and DDX compounds (p,p′-DDE, p,p′-DDD, and p,p′-DDT) as well as chlorobenzenes in strawberries has been developed. The procedure is based on aqueous accelerated solvent extraction (ASE) followed by solidphase microextraction (SPME) or stir bar sorptive extraction (SBSE) and subsequent thermodesorption–gas chromatography/mass spectrometry analysis. A 65 μm polydimethylsiloxane/divinylbenzene fiber was chosen for the SPME experiments. Significant SPME and ASE parameters were optimized using spiked water and strawberry samples. For the ASE of the organochlorine compounds, a water–acetone mixture (90 + 10, v/v) as the extraction solvent, an extraction temperature of 120°C, and 2 cycles of 10 min extraction proved optimal. The developed method was evaluated with respect to precision and limits of detection (LOD). The relative standard deviations of replicate ASE–SPME determinations (n = 5) were in the range of 4–24%. LOD values between 1 and 10 μ g/kg were achieved with the exception of DDT and DDE (40 μg/kg). Using SBSE, the LOD of these compounds could be improved (2 and 5 μg/kg). The main advantages of this method are the avoidance of cleanup and concentration procedures as well as the significant reduction of the required volume of organic solvents. The described method was applied to the determination of the pollutants in strawberry samples collected from different allotment gardens in a potentially polluted area, the Bitterfeld-Wolfen region (Germany).
Determination of Eight Volatile Nitrosamines in Meat Products by Ultrasonic Solvent Extraction and Gas Chromatography-Mass Spectrometry Method
