MINIATURIZED LIQUID-LIQUID EXTRACTION WITH LOW-TEMPERATURE PARTITIONING TECHNIQUE (LLE/LTP) FOR PESTICIDE ANALYSIS IN A BIOLOGICAL MATRIX BY GAS CHROMATOGRAPHY

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.

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Measuring the Phthalates of Xiangjiang River Using Liquid-Liquid Extraction Gas Chromatography

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.301-303.752 ◽

2011 ◽

Vol 301-303 ◽

pp. 752-755 ◽

Cited By ~ 1

Author(s):

Xiao Juan Zhu ◽

Yin Yan Qiu

Keyword(s):

Gas Chromatography ◽

Water Environment ◽

Liquid Extraction ◽

Dioctyl Phthalate ◽

Optimum Conditions ◽

Xiangjiang River ◽

Chromatography Method ◽

Extraction Solvent ◽

Liquid Liquid Extraction ◽

Ethylhexyl Phthalate

Objective: To observe the phthalates pollution situation in water environment and design the liquid-liquid extraction gas chromatography method to measure phthalates in Xiangjiang River water. Methods: The water samples were collected from six monitor points of the Xiangjiang River’s Changsha period. After liquid-liquid extraction, gas chromatography was used to measure and analyze the phthalates pollution in this period of the river. Results: Dioctyl phthalate resin (DOP) and dibutyl phthalate (2- ethylhexyl) phthalate (DEHP) were detectable in all samples from six monitor points, the concentrations of DEHP were from 0.62-15.23μg/L, DOP were from 0.04-0.21μg/L. Conclusion: The optimum conditions for the extraction of phthalates are: 0.025ml dichloromethane as extraction solvent, centrifuge speed at 4000r/min, extraction time 20 minutes, and this method is appropriate for monitoring the phthalates pollution in water environment.

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Optimization and validation of the salting-out assisted liquid-liquid extraction method and analysis by gas chromatography to determine pesticides in water

Eclética Química Journal ◽

10.26850/1678-4618eqj.v43.1si.2018.p11-21 ◽

2018 ◽

Vol 43 (1SI) ◽

pp. 11

Author(s):

Alessandra Aparecida Zinato Rodrigues ◽

Antônio Augusto Neves ◽

Maria Eliana Lopes Ribeiro De Queiroz ◽

André Fernando De Oliveira ◽

Lucas Henrique Figueiredo Prates ◽

...

Keyword(s):

Gas Chromatography ◽

Single Phase ◽

Limit Of Detection ◽

Liquid Extraction ◽

Solvent Ratio ◽

Limit Of Quantification ◽

Salting Out ◽

Extraction Solvent ◽

Liquid Liquid Extraction ◽

Pesticides In Water

The salting-out assisted liquid-liquid extraction (SALLE) was developed for the analysis of four pesticides (cypermethrin, chlorpyrifos, deltamethrin, and thiamethoxam) in water samples. For its optimization, a 2³ factorial design was used to evaluate the simultaneous behavior of three factors: sample and extraction solvent ratio, saline concentration, and stirring mode. A 1.0 mL saline solution (NaCl) was added to the single-phase mixture of water and extraction solvent to separate the phases. The mixture was stirred, allowed to stand and the top organic phase containing the pesticides of interest was analyzed by gas chromatography coupled with electron capture detector (GC/ECD). The optimized method was validated for some merit figures. The limit of detection of the method ranged from 0.15 to 5.5 µg L-1 and the limit of quantification from 5.5 to 18.2 µg L-1. The method showed satisfactory results for the linearity (R2 ≥ 0,990), precision (CV < 9 %) and accuracy (72 % ≤ recovery ≤ 90 %) for all the assessed analytes. The method showed to be simple, efficient and inexpensive for the extraction of pesticide residues. The validated method was applied to ten samples of water collected in the Zona da Mata region of the state of Minas Gerais, Brazil.

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