A rapid, efficient, and new solvent terminated dispersive liquid-liquid microextraction technique coupled with HPLC was developed for selective extraction and analysis of s-triazine herbicides from environmental water samples. Important parameters influencing the extraction process including type and volume of extraction and disperser solvent, extraction time, sample pH, ionic strength, and extraction temperature were successfully optimized. Under the optimal conditions, there are excellent linear relationships between the analytical results and concentration in the range of 10-400 mg/L for atrazine, propazine, prometryn, and terbutryn. LOD and LOQ ranged from 0.60 to 2.33 μg/L and 2.0 to 7.7 μg/L, respectively. Performance of the analytical technique was evaluated by carrying out the repeatability and reproducibility analyses that were ranged from 2.86 to 5.66% and 4.64 to 5.89% for 100 μg/L of each target analyte, respectively. The proposed method has been successfully applied to the analysis of real water samples and acceptable relative recoveries over the range of 65.93-101.46%, with RSDs ≤ 8.80%, were obtained. The overall results have been compared with the literature values. Thus, the method developed could efficiently be used for selective extraction of the target analytes from complex matrices, particularly environmental waters.
In this study, salting-out assisted liquid-liquid extraction combined with high performance liquid chromatography diode array detector (SALLE-HPLC-DAD) method was developed and validated for simultaneous analysis of carbaryl, atrazine, propazine, chlorothalonil, dimethametryn and terbutryn in environmental water samples. Parameters affecting the extraction efficiency such as type and volume of extraction solvent, sample volume, salt type and amount, centrifugation speed and time, and sample pH were optimized. Under the optimum extraction conditions the method was linear over the range of 10 -100 μg/L (carbaryl), 8 -100 μg/L (atarzine), 7 -100 μg/L (propazine) and 9 -100 μg/L (chlorothalonil, terbutryn and dimethametryn) with correlation coefficients (R 2 ) between 0.99 and 0.999. Limits of detection and quantification ranged from 2.0 to 2.8 μg/L and 6.7 to 9.5 μg/L, respectively. The extraction recoveries obtained for ground, lake and river waters were in a range of 75.5% to 106.6%, with the intra-day and inter-day relative standard deviation lower than 3.4% for all the target analytes. All of the target analytes were not detected in these samples. Therefore, the proposed SALLE-HPLC-DAD method is simple, rapid, cheap and environmentally friendly for the determination of the aforementioned herbicides, insecticide and fungicide residues in environmental water samples.
In this work, we developed a roll‐to‐roll printed poly(3,4‐ethylenedioxythiophene)/polystyrene sulphoanate without graphene oxide (GO) (PEDOT/PSS) and with graphene oxide (PEDOT/PSS/GO) plastic films for the electrochemical determination of carbofuran. Both the PEDOT/PSS and PEDOT/PSS/GO plastic films showed electroactivity towards the oxidation of carbofuran. Incorporation of graphene oxide (GO) improves the electrochemical activity of carbofuran and increased its sensitivity. The printed plastic films were characterized by cyclic voltammetry (CV), linear sweep voltammetry (LSV), surface profilometer, four point probe and atomic force microscopy (AFM). The effects of pH, deposition time, deposition potential and film thickness on the oxidation peak current of carbofuran were investigated. Under the optimized conditions, a dynamic linear range of 1 μM–90 μM with a detection limit of 1.0×10−7 M (S/N=3) were obtained. The printed PEDOT/PSS/GO plastic electrode was applied for the determination of carbofuran in vegetable and fruit samples with recoveries between 94.4 and 101.8 %.
The excessive use of pesticides is a serious health problem due to their toxicity and bioaccumulation through the food chain. Due to the complexity of foods, the analysis of pesticides is challenging often giving large matrix effects and co-extracted compounds. To overcome this problem, a selective and “green” supercritical fluid extraction method was developed, using neat carbon dioxide as a solvent at pressures of up to 800 bars. A Box–Behnken response surface experimental design was used, with the independent variables of density (0.70−1.0 g mL−1), temperature (40−70 °C), and volume (10−40 mL) of solvent, and the dependent variable of extracted amount of pesticides. The optimum extraction condition was found at the use of 29 mL of supercritical CO2 at 0.90 g mL−1 and 53 °C (corresponding to 372 bars of pressure). It was observed that increasing the density of CO2 significantly increased the extraction recovery of endrin and 2,4′-dichlorodiphenyldichloroethane. Matrix-matched calibration curves showed satisfactory linearity (R2 ≥ 0.994), and LODs ranged from 0.2 to 2.0 ng g−1. Precision was lower than 11% and recoveries between 80%–103%. Thus, the developed method could efficiently be used for trace analysis of pesticides in complex food matrices without the use of organic solvents.
In this study, a miniaturized analytical technique based on high density solvent based dispersive liquid-liquid microextraction (HD-DLLME) was developed for extraction of trace residues of multiclass pesticides including three s-triazine herbicides, two organophosphate insecticides and two organochlorine fungicides from environmental water and sugarcane juice samples. The analytical method was validated and found to offer good linearity: R 2 ≥ 0.991; repeatability varied from 0.73% -5.28%; reproducibility varied from 1.14% -8.74% and limit of detection ranged from 0.005 to 0.02 µg/L. Moreover, accuracy of the optimized method was evaluated and the recovery was varied from 80.39% -114.05%. Analytical applications of this method to environmental waters and sugarcane juice samples indicate the presence of trace residues of ametryn in the lake water and sugarcane juice samples. Atrazine and ametryn were also detected in irrigation water.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.