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

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.

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

Química Nova ◽  
2021 ◽  
Author(s):  
Thaís Silva ◽  
Maria Eliana Queiroz ◽  
Antônio Neves ◽  
Patrícia Vieira ◽  
André Oliveira ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Low Temperature ◽  
Blood Serum ◽  
Liquid Extraction ◽  
Serum Samples ◽  
Biological Matrix ◽  
Rural Workers ◽  
Extraction Solvent ◽  
Liquid Liquid Extraction ◽  
Partitioning Technique

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.

scholarly journals Complex Formation in a Liquid-Liquid Extraction System Containing Cobalt(II), 4-(2-Pyridylazo)resorcinol, and Nitron

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Petya Vassileva Racheva ◽  
Kiril Blazhev Gavazov ◽  
Vanya Dimitrova Lekova ◽  
Atanas Nikolov Dimitrov
Keyword(s):  
Complex Formation ◽  
Limit Of Detection ◽  
Equilibrium Constants ◽  
Ion Association ◽  
Molar Absorptivity ◽  
Liquid Extraction ◽  
Optimum Conditions ◽  
Limit Of Quantification ◽  
Liquid Liquid Extraction ◽  
Experimental Parameters

Complex formation and liquid-liquid extraction were studied in a system containing cobalt(II), 4-(2-pyridylazo)resorcinol (PAR), 1,4-diphenyl-3-(phenylamino)-1H-1,2,4-triazole (Nitron, Nt), water, and chloroform. The effect of some experimental parameters (pH, shaking time, concentration of PAR, and concentration of Nt) was systematically investigated, and the optimum conditions for cobalt extraction as an ion-association complex, (NtH+)[Co3+(PAR)2], were found. The following key equilibrium constants were calculated: constant of association (Log β=4.77±0.06), constant of distribution (LogKD=1.34±0.01), and constant of extraction (LogKex=6.11±0.07). Beer’s law was obeyed for Co concentrations up to 1.7 μg mL−1 with a molar absorptivity of 6.0×104 L mol−1 cm−1 at λmax=520 nm. Some additional characteristics, such as limit of detection, limit of quantification, and Sandell’s sensitivity, were estimated as well.

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

2011 ◽  
Vol 301-303 ◽  
pp. 752-755 ◽  
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.

scholarly journals A fast, low-cost and eco-friendly method for routine determination of Bisphenol-A in landfill leachate employing vortex assisted liquid-liquid extraction

2021 ◽  
Vol 4 (03) ◽  
pp. 59-67
Author(s):  
Gustavo Fehrenbach ◽  
Daniel Ricardo Arsand ◽  
Sergiane Caldas Barbosa ◽  
Kátia Castagno ◽  
Pedro Filho ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Low Cost ◽  
Liquid Extraction ◽  
Effluent Treatment ◽  
Limit Of Quantification ◽  
Synthetic Compound ◽  
Simple Method ◽  
Extraction Solvent ◽  
Liquid Liquid Extraction ◽  
Relative Standard

Landfills are sites designed to receive and final disposal of a broad variety of urban solid wastes (USW). The decomposition and biodegradation processes generate a leachate of high complexity and toxicity, containing persistent and recalcitrant contaminants that are not usually monitored. Bisphenol-A (BPA) is a synthetic compound applied mostly on the production of polycarbonate plastics, epoxy resins, and is an endocrine disruptor. The presence of BPA in USW urges the development of feasible analytical methods to support the effluent treatment plants and reduce the risks of contamination. The main goal of this work was to develop an efficient, eco-friendly, fast and simple method for routine analysis of BPA in the leachate from landfill. A vortex assisted liquid-liquid extraction (VALLME) using 1-octanol as solvent was performed. BPA recoveries at spiking levels of 2.5, 6.5 and 12.5 µg L-1 were between 60 to 104% with relative standard deviation (RSD) lower than 26%. The linearity of the method was evaluated and the correlation coefficient was (r) 0.9985. The limit of quantification (LOQ) was 2.5 µg L-1 with a pre-concentration factor of 20. The method has advantages such as low consumption of extraction solvent (150 µL), low cost, easy and fast determination.

scholarly journals Salting-out assisted liquid-liquid extraction method coupled to gas chromatography for the simultaneous determination of thujones and pulegone in beverages

2017 ◽  
Vol 20 (sup3) ◽  
pp. S2776-S2785 ◽  
Author(s):  
Anas Adib Alshishani ◽  
Bahruddin Saad ◽  
Nadhiratul Farhin Semail ◽  
Salizawati Mohamad Salhimi ◽  
Mohd Khairuddin Mohd Talib
Keyword(s):  
Gas Chromatography ◽  
Simultaneous Determination ◽  
Extraction Method ◽  
Liquid Extraction ◽  
Salting Out ◽  
Liquid Liquid Extraction

scholarly journals Optimization of Sample Preparation for Detection of 10 Phthalates in Non-Alcoholic Beverages in Northern Vietnam

Toxics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 69 ◽  
Author(s):  
Thanh-Thien Tran-Lam ◽  
Yen Dao ◽  
Duong Nguyen ◽  
Hoi Ma ◽  
Trung Pham ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Liquid Extraction ◽  
Alcoholic Beverages ◽  
Method Performance ◽  
Extraction Solvent ◽  
Liquid Liquid Extraction ◽  
Chromatography Tandem Mass Spectrometry ◽  
Limit Of Quantitation ◽  
Novel Method ◽  
Central Composite

A novel method was developed for the sensitive, cheap and fast quantitation of 10 phthalates in non-alcoholic beverages by liquid–liquid extraction (LLE) combined with gas chromatography tandem mass spectrometry (GC-MS/MS). The best results were obtained when n-hexane was used as extraction solvent. A central composite design (CCD) was applied to select the most appreciated operating condition. The method performance was evaluated according to the SANTE/11945/2015 guidelines and was linear in the 0.1 to 200 µg/L range for 10 phthalate compounds, with r2 > 0.996 and individual residuals <15%. Repeatability (RSDr), within-laboratory reproducibility (RSDwr), and the trueness range were from 2.7 to 9.1%, from 3.4 to 14.3% and from 91.5 to 118.1%, respectively. The limit of detection (LOD) was between 0.5 to 1.0 ng/L and the limit of quantitation (LOQ) was between 1.5 to 3.0 ng/L for all 10 compounds. The developed method was successfully applied to the analysis of non-alcoholic beverages.

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