Development of a green microwave assisted extraction method for triazine herbicides determination in soil samples

Abstract

Foi desenvolvido um método de extração limpo, assistido por microondas, para a determinação de herbicidas triazínicos em amostras de solos. A estratégia de extração foi baseada em ambiente micelar associado às microondas, seguido da determinação dos herbicidas por CLAE, de tal forma que o procedimento pudesse ser considerado limpo. Foram utilizadas duas porções (10 e 8 mL) da solução extratora de SDS (dodecil sulfato de sódio) 0,06% (m/v) associada a 0,500 g da amostra e da seguinte programação do forno de microondas: 540 W (6 min), 0 W (1 min), 630 W (2 min). As curvas analíticas apresentaram-se lineares na faixa de 0.05 até 10.0 mg L -1 para atrazina, ametrina e simazina. Os limites de detecção e quantificação foram estimados como 0,90, 0,57 e 0,235 µg g -1 e 3,1, 1,9 e 0,8 µg g -1 para atrazina, ametrina e simazina, respectivamente. O método proposto é preciso (RSD < 8%, n = 3) e os resultados obtidos concordam com aqueles do método clássico. Testes de recuperação dos herbicidas para amostras de solo forneceram valores entre 82,0 e 94,0%.It was developed a green microwave-assisted extraction method for determination of triazine herbicides in soil samples. The extraction strategy was based on micellar medium associated to microwaves followed by the herbicides determination by HPLC in such way that the procedure could be considered as green. Two portions (10 and 8 mL) of aqueous SDS (sodium dodecyl sulphate) 0.06% (m/v) were used as extracting solutions associated to 0.500 g of sample and the following microwave oven program: 540 W (6 min), 0 W (1 min), 630 W (2 min). The analytical curves were linear in the analytical range of 0.05 up to 10.0 mg L -1 for atrazine, ametryne and simazine. The limits of detection and quantification were estimated as 0.90, 0.57 and 0.235 µg g -1 and 3.1, 1.9 and 0.8 µg g -1 for atrazine, ametryne and simazine, respectively. The proposed method is precise (RSD < 8%, n = 3) and the obtained results are in agreement with the classical one. Recovery tests for soil samples indicated that the percentage of recuperation were between 82.0 e 94.0%.

Dynamic microwave-assisted extraction combined with continuous-flow microextraction for determination of pesticides in vegetables

“…Furthermore, high temperature was also beneficial to the diffusion and mass transfer during extraction, and the improvement of dissolving capacity of extraction solvent at the same time. However, too high microwave power was not useful to increase the recoveries of the OPPs and may result in the degradation of the analyte (Silva, Costa, Visentainer, Souza, & Oliveira, 2010;You et al, 2007). Thus, 250 W of microwave power was selected.…”

Microwave-assisted liquid–liquid microextraction based on solidification of floating organic droplet for the determination of triazines in honey samples

“…The effect of microwave power on the recoveries of triazines was studied by varying the power between 60 and 360 W when the irradiation time was 40 s. As observed in Fig. 29,30 The main decomposition reaction of triazines should be hydrolysis. The temperature can affect both the mass transfer rates of analytes and the contact area between 1-dodecanol and aqueous solution.…”

“…microwave irradiation time from 0 to 40 s, and then decrease when the time exceeds 40 s. Too high a temperature caused by long irradiation times may result in the degradation of the analytes 29,30. Most of the recoveries of triazines were the highest when the extraction time was 40 s. Thus, 40 s was considered as the appropriate extraction time.3.1.5 Effect of pH of sample solution.…”

Extraction method for the determination of atrazine, deethylatrazine, and deisopropylatrazine in agricultural soil using factorial design

“…For these reasons, high performance liquid chromatography (HPLC) has been the analytical technique most largely employed for triazines determination in soils. [1][2][3]5,8,11,[13][14][15][16][17] The quality of the analytical data is mostly dependent on the sample preparation, especially for the procedures of extraction and cleanup, 18 and as a result, this is a critical step for the determination of any contaminant in soil samples. For that reason, several different approaches have been proposed for the extraction and cleanup of triazines in soils.…”

“…A traditional and low cost method that can be used for triazine extraction from soils is soxhlet, that yields efficient extraction, but it is a time and solvent consuming method. 12,19 Because of this, green extraction methods have been proposed, including ultrasonic solvent extraction (USE), 14,19 microwave assisted extraction (MAE), 15,16 supercritical fluid extraction (SFE), 20 extraction of the analytes after the shaking of the sample in the presence of an appropriate solvent, followed by solid phase extraction (SPE), 17 headspace solid-phase microextraction (HS-SPME), 21 pressurized liquid extraction (PLE), 1,12,13,22 besides the development of other miniaturized methods as reported in the literature. 14 These methods usually present appropriate results, however some authors have used a less expensive extraction method, based on a simple shaking with solvents of adequate polarity like acetonitrile or methanol and water, providing acceptable recovery values for the extraction of triazine herbicides from soils; 5,8,19 nevertheless, the extraction time is often a drawback, for instance, Mahía et al, 5 and Delgado-Moreno et al, 19 employed 24 h as extraction time.…”