Characterization and application of a lanthanide-based metal-organic framework in the development and validation of a matrix solid-phase dispersion procedure for pesticide extraction on peppers (Capsicum annuum L.) with gas chromatography-mass spectrometry.

The metal-organic framework [(La0.9 Sm0.1 )2 (DPA)3 (H2 O)3 ]∞ was synthetized and characterized by X-ray diffractometry, differential thermogravimetric analysis, and infrared spectroscopy. The material was tested for the development and validation of a matrix solid-phase dispersion procedure for extraction of atrazine, bifenthrin, bromuconazole, clofentezine, fenbuconazole, flumetralin, procymidone, and pirimicarb, from peppers, with analysis using gas chromatography with mass spectrometry in the selected ion monitoring mode. The method developed was linear over the range tested (50.0-1000.0 μg/kg for procymidone and 200.0-1000.0 μg/kg for all other pesticides), with correlation coefficients ranging from 0.9930 to 0.9992. Experiments were carried out at 250.0, 500.0, and 1000.0 μg/kg fortification levels, and resulted in recoveries in the range of 52.7-135.0%, with coefficient of variation values between 5.2 and 5.4%, respectively, for [(La0.9 Sm0.1 )2 (DPA)3 (H2 O)3 ]∞ sorbent. Detection and quantification limits ranged from 16.0 to 67.0 μg/kg and from 50.0 to 200.0 μg/kg, respectively, for the different pesticides studied. The results were compared with literature data. The developed and validated method was applied to real samples. The analysis detected the presence of residues of pesticides procymidone, fenbuconazole, flumetralin, clofentezine, atrazine, and bifenthrin.