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In this study, a biosorbent material with characteristics for the adsorption of organic compounds was used for a cork pellet-based bar adsorptive microextraction technique, as a new greener alternative for the determination of organochlorine compounds. Aldrin, chlordane, dieldrin, endrin, lindane, 4,4-DDD, 4,4-DDE, 4,4-DDT, α-endosulfan and β-endosulfan were analyzed in water samples (drinking water, stream water and river water) with separation/detection by gas chromatography and electron capture detection (GC/ECD). The parameters that can affect the sample preparation efficiency such as desorption solvent and time as well as extraction time and ionic strength were evaluated by multivariate and univariate designs. Cork pellets (10 × O 3 mm) were used for the extraction of 15 mL of sample in the optimal conditions: 60 min of agitation with no salt added to the sample, followed by desorption of the cork pellet with 120 µL of ethyl acetate for 30 min. The bar-to-bar RSD out with five different bars showed good results with RSD ≤ 15.6%, allowing the use of simultaneous extractions. LOD and LOQ values ranged from 3 to 15 ng L−1 and 10 to 50 ng L−1 respectively, and the determination coefficients were greater than 0.9869. The target analytes were not detected in the three analyzed samples. Therefore, the recovery study was performed fortifying the water samples. Analyte recovery ranged from 48.7 – 138.2% for drinking water, 40.2 – 128.2% for stream water and 67.5 – 128.7% for river water.

Brazil is among the ten largest rice producers in the world, concentrating its production in the southern region. Anthropic activities, such as the disposal of chemicals in the ecosystem and consequently in the aquatic environment, end up harming the availability and quality of the water. Here, we developed an analytical method based on BAµE with WAX as an extraction phase for the determination of 5 pesticides and 2 emerging contaminants in water samples used in rice cultivation by HPLC–DAD. The method was fully optimized through univariate and multivariate approaches. The optimized condition was obtained with 145 min of extraction time, without salt addition and 35 min of desorption time using 250 μL of MeOH:AcEt (60:40, v/v). A reduced mass of extraction phase (around 4 mg) and sample and solvent volumes (15 mL and 300 µL, respectively) were used. The bars have a low cost and can be used up to 20 times without loss of extraction efficiency. Furthermore, the developed method presented high-throughput, because it uses a Voltage Regulator Variac system that allows the coupling of six magnetic stirrers simultaneously. The LODs ranged from 1.67 to 2.50 µg L−1 and the LOQs ranged from 5.00 to 7.50 µg L−1; both were below the VMP established by Ordinance 2.914/2011/MS for drinking water. Relative recoveries applied to the sample ranged from 80 to 121%. The intra-day and inter-day precision were up to 14% and 19%, respectively. The results were satisfactory, in accordance with the validation guidelines of the AOAC. Twenty-four samples collected in the Camboriu River Basin, which is influenced by rhiziculture, were analyzed and the analytes were not detected, as they are below the limits obtained in this method.

In this study, a new analytical methodology was proposed for the simultaneous determination of 16 polycyclic aromatic hydrocarbons (PAH) in leached extracts. This approach consisted of a new configuration based on hollow fiber-microporous membrane liquid–liquid extraction (HF-MMLLE) with palladium nanoparticles (Pd-NPs) impregnated in the pores of the membrane as part of the extraction phase. The analytes were separated and identified by gas chromatography coupled to mass spectrometry (GC–MS). The optimizations of the main extraction and desorption parameters were evaluated using univariate and multivariate strategies. The optimized extraction conditions were achieved with the use of 1-octanol solvent with the Pd-NPs as extraction phase, salt concentration adjusted to 5% (w/v of NaCl), 150 µL of acetonitrile as solvent of desorption, 70 and 30 min of extraction and desorption time, respectively. Satisfactory analytical performance was obtained with correlation coefficients greater than 0.9818, detection and quantification limits of 1.5 and 5.0 ng mL−1, respectively, for all analytes. Relative recoveries varied from 62 to 117%, intra-day precision from 0.3 to 18.3% and inter-day precision from 1.3 to 20.8%. The proposed method was successfully applied to three samples of leached extracts of residues provided by the petrochemical oil industry. The composers phenanthranene (5.6 ng mL−1 ± 8.8%) in leachate extract 1 and anthracene (6.1 ng mL−1 ± 4.8%) in leachate extract 2 were quantified. Leachate extract 3 did not present quantifiable analytes by the proposed method. The results of this approach can provide a simple, easy to prepare and economic strategy (in terms of solvent and sample consumption) for the determination of PAH in aqueous samples.

In this study, a new method was developed in which a biosorbent material is used as the extractor phase in conjunction with a recently described sample preparation technique called thin-film microextraction and a 96-well plate system. The method was applied to the determination of emerging contaminants, such as 3-(4-methylbenzylidene) camphor, ethylparaben, triclocarban and bisphenol A, in water samples. The separation and detection of the analytes were performed by high-performance liquid chromatography with diode array detection. These contaminants are considered hazardous to human health and other living beings. Thus, the development of an analytical method to determine these compounds is of great interest. The extraction parameters were evaluated using multivariate and univariate optimization techniques. The optimum conditions for the method were 3 h of extraction time, 20 min of desorption with 300 μL of acetonitrile and methanol (50:50, v/v) and the addition of 5% w/v sodium chloride to the sample. The analytical figures of merit showed good results with linear correlation coefficients higher than 0.99, relative recoveries of 72–125%, inter-day precision (n = 3) of 4–18% and intra-day precision (n = 9) of 1–21%. The limit of detection was 0.3–5.5 μg L−1, and the limit of quantification was 0.8–15 μg L−1. This article is protected by copyright. All rights reserved

In this paper, a remodeling of the bar adsorptive microextraction (BAμE) technique is proposed with impregnation of the derivatization reagent on the surface of the adsorptive bar containing a biosorbent material. The derivatization reagent was 2,4-dinitrophenylhydrazine (DNPH), which was adsorbed on the surface of the bar containing cork powder as the extractor phase for the determination of two aldehydes (hexanal and heptanal) which are known as lung cancer biomarkers in human urine samples. The derivatization reaction and the extraction occurred simultaneously on the surface of the bar (length 7.5 mm) under acidic conditions. The method optimization was carried out by univariate and multivariate analysis. The optimal conditions for the method were a DNPH to aldehydes ratio of 40:1, buffer solution of pH 4.0, extraction time of 60 min and liquid desorption of 10 min in 100 μL of acetonitrile. The aldehydes were analyzed by HPLC-DAD with a simple and fast (6 min) chromatographic run. The limits of detection (LODs) for hexanal and heptanal were 1.00 and 0.73 μmol L−1, respectively. The relative recoveries in urine samples ranged from 88 to 111% with relative standard deviations (RSDs) being less than 7%. The method developed is of low cost and can be successfully used for the quantification of these two lung cancer biomarkers in human urine samples, potentially providing an early diagnosis of lung cancer.

The compound 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) consists of the major metabolite of tetrahydrocannabinol (THC) in human urine. Analysis of this compound exhibits an important role in forensic scenario; therefore, several analytical methods have been developed for this purpose. In this study, for the first time, a biosorbent-based disposable pipette extraction was developed for the determination of THC-COOH, using a simple and high-throughput sample preparation technique. In addition, a rapid instrumental analysis was achieved by fast-gas chromatography coupled with flame ionization detection (fast-GC-FID). Different biosorbents were examined, including cork, moringa and bract. The method was optimized through univariate and multivariate designs with the conditions comprised of 15 mg of cork as the extraction phase, pH maintained at 2.5 with 8 cycles of extraction of 60 s each, and 1 cycle of 5 s for the desorption step with a mixture of acetonitrile:methanol (ACN/MeOH). Limit of detection was 0.21 ng mL−1 and the limit of quantification was 0.73 ng mL−1, with a linear range from 5 to 100 ng mL−1 and coefficient of determination (R2) 0.9905. The relative recoveries ranged from 96 to 108%, intraday and interday precisions were lower than 13%. Different samples were subjected to the extractions using the method developed with four positive samples for the analyte.

This study reports the use ofa natural deep eutectic solvent (NADES) with hollow fiber-microporous membrane liquid-liquid microextraction (HF-MMLLE) for the multiclass determination of 11 compounds classified as emerging contaminantsin water. Different deep eutectic solvents were synthetized and Thymol: Camphor (1:1 molar fraction) wasused as extraction solvent. The Thymol:Camphor was impregnated into the polypropylene membrane porous for 10 min, replacing commonly used solvents (ex. hexane and octanol). The optimized parameters were obtained by multi and univariate models. Extractions were carried out for 50 min using 1.5 mL of water sample at pH 6 and without addition of salt while desorption was made in a mixture of acetone: methanol (3:1, v/v) for 15 min. Separation/quantification was conducted by HPLC with a diode array detection (DAD)and calibration curves were obtained for each analyte. Determination coefficients higher than 0.9906 and limits of detection ranged from 0.3 to 6.1 µg L−1. Intraday precision (n = 3) ranged from 1.6 to 18.4% and inter day from 5.0 to 21.3%. Relative recoveries were performed in tap and stream water and ranged from 64 to 123%.

This study proposes an efficient analytical methodology using a biosorbent (cork) as an extraction phase in disposable pipette extraction technique for the rapid determination of the emerging contaminants methyl paraben, ethyl paraben, benzophenone, 3-(4-methylbenzylidene) camphor and 2-(ethylhexyl)-4-(dimethylamino) benzoate in lake water samples using high-performance liquid chromatography with diode array detection. The optimized conditions were comprised of 800 μL of sample, three cycles of 30 s each for the extraction, pH 6, addition of 30% w/v of NaCl. For the desorption step, the optimized desorption conditions were achieved with 100 μL of a mixture comprised of 50% methanol and 50% acetonitrile v/v, using one cycle of 30 s. Excellent analytical performance was achieved with limits of detection of 0.6 μg/L for methyl paraben to 1.4 μg/L for 3-(4-methylbenzylidene) camphor, and the limit of quantitation varied from 2 μg/L for methyl paraben to 4.3 μg/L 3-(4-methylbenzylidene) camphor, respectively. The correlation coefficients ranged from 0.9962 for ethyl paraben to 0.9980 for methyl paraben. The method accuracy varied from 71-132%, and the intraday precision ranged from 3 to 23% (n = 3) and interday from 9 to 23% (n = 9). The robustness was evaluated through Youden and Lenth's methods and indicated no significant variations in the results.

This paper describes the application of the solid-phase microextraction (SPME) technique for the determination and monitoring of the volatile profile of minimally-processed pineapple fruit stored at various temperatures (-12 °C, 4 °C and 25 °C) for different periods (1, 4 and 10 days). The SPME fiber coating composed of Car/PDMS presented the best performance. The optimal extraction conditions obtained through a Doehlert design were 60 min at 35 °C. The profiles for the volatile compounds content of the fruit at each stage of storage were determined by gas chromatography-mass spectrometry (GC-MS). The variation in the volatile profile over time was greater when the fruit samples were stored at 25 °C and at -12 °C compared to 4 °C. Thus, according to the volatile profiles associated with the storage conditions evaluated in this study, packaged pineapple retains best its fresh fruit aroma when stored at 4 °C.

In this study, for the first time, an analytical methodology comprised of disposable pipette extraction technique (DPX) based on a conductive polymer (polypyrrole - PPy) was developed for the simultaneous extraction/determination of 14 compounds including two hormones and twelve polycyclic aromatic hydrocarbons in river water samples. Pipette tips of 1 mL were filled with the extraction material, named PPy.CTAB, and the separation/detection was performed HPLC-DAD. The extraction material was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The optimized extraction conditions were comprised of 700 μL of sample using 2 cycles of 15 seconds each, and pH adjusted at 6.00. Regarding the desorption step, a mixture of 200 μL of acetonitrile and methanol (50:50, v/v) was used with 6 cycles of 15 seconds each. The calibration curves were performed in the sample matrix and LODs and LOQs ranged from 1.5 to 6.1 μg L-1 and from 5.0 to 20.0 μg L-1, respectively, with r ≥ 0.9901. The accuracy ranged from 44-139% and intraday precision with values ≤ 8% and interday ≤ 26%. The methodology was applied in three samples collected from Tubarao River located in the city of Orleans - SC and the analytes were not detected in these samples.