Miniaturized Liquid-Liquid Extraction With Low-Temperature Partitioning Technique (Lle/Ltp) for Pesticide Analysis in a Biological Matrix by Gas Chromatography

Abstract

The liquid-liquid extraction with low-temperature partitioning technique (LLE/LTP) was miniaturized to determine the pesticides chlorpyrifos, bifenthrin, λ-cyhalothrin, and deltamethrin in a biological matrix, by gas chromatography. The method was proposed for fetal-bovine serum samples (500 μL), by using a full factorial design (23) with one center point. The evaluated factors included the volume of water added to the sample (1000 μL), volume of extraction solvent (500 μL) and stirring time (60 s) – a cleanup step was not necessary. The method was validated for the main figures of merit. The results indicated that the LLE/LTP/GC/ECD miniaturized method was efficient in extracting pesticides from blood-serum samples (75 to 115%). It showed both selectivity and sensitiveness, with limits of quantification (LOQ) ranging from 8 at 17 μg L-1. Once validated, the method was applied to blood-serum samples of rural workers from a city in the Brazilian state of Minas Gerais. In that case, the presence of chlorpyrifos was detected in two of the samples.

Optimization and Validation of the Miniaturized Solid-Liquid Extraction with Low Temperature Purification (SLE-LTP) Method for Determining Fluopyram in Sandy, Clayey and Medium-Textured Soil

“…In addition to reducing the signal intensity of the analyte studied, the use of ethyl acetate in the extractor phase also intensified the matrix effect, as evidenced by the high recovery percentages, as shown in Table 1. These results are in agreement with those found by Silva et al 17 who achieved high recovery rates using acetonitrile in the miniaturized version of liquid-liquid extraction with low temperature partition to determine pesticides in biological matrices; and Mesquita et al, 14 who used acetonitrile in SLE-LTP to study various pesticides in soil samples.…”

“…The extraction methodology used in this study was the one that obtained the best experimental results and is in agreement with the study by Silva et al 17 who miniaturized liquid-liquid extraction with low temperature partition (LLE-LTP) for pesticide determination in biological samples. Thus, 1 mL of distilled water was added to a 5 mL vial containing 1 g of soil and vortexed for 30 s. Then, 2 mL of acetonitrile were added and homogenized again for 30 s. After 15 min of rest, the samples were frozen at -20 ºC for 1 h. Next, 1.1 mL of the supernatant organic phase was transferred to a 15 mL Falcon tube containing 130 mg of anhydrous sodium sulfate and vortexed for 30 s. The anhydrous sodium sulfate was dried in a muffle oven for two hours at 300 ºC to remove water and possible interferences.…”

“…High analyte recovery rates were observed using less reagents and samples in this study, in addition to maintaining the main advantage of this methodology, which is extracting and cleaning extracts in a single step. 17 In a previous study, 18 the Empresa Brasileira de Agropecuária (Embrapa) defined that there are at least 13 types of soil classes in Brazil which differ in their chemical, physical and morphological characteristics. This complexity of the soil matrix can influence the recovery rate of chemical contaminants, as verified in a previous work by Đurović et al 19 Therefore, we chose three soil types with different textures and organic matter contents in this study in order to ensure the applicability of the extraction method.…”

Antibiotic Residues in UK Foods: Exploring the Exposure Pathways and Associated Health Risks

“…The LTPE method was performed to extract potential antibiotic residues from samples in a cost-effective manner. Additionally, the cold environment during the extraction process minimizes the thermal degradation of target compounds [ 22 ].…”