Multiclass determination of endocrine disruptors in urine by hollow fiber microporous membrane and liquid chromatography.

A simple and rapid methodology was developed using hollow fiber membrane microporous and a 96-well plate system for a high throughput multiclass determination of endocrine disruptors in human urine (diclofenac, diazepam, carbamazepine, ibuprofen, naproxen, carbofuran, methyl parathion, 17-α-ethynyl estradiol, bisphenol A and benzophenone). The quantification and detection of the chemicals were carried out by an HPLC-diode array detector. The fixed conditions for carrying out the method optimization were 1.5 mL of sample and 300 µL of solvent desorption. Multivariate and univariate models were applied to optimize the parameters of the method, achieving the following conditions: 20% diluted urine, 1-octanol of extraction solvent impregnated in the microporous membrane, 70 min extraction in pH 3.0 and 30 min with a mixture of 75% methanol and 25% acetonitrile (v/v) for the desorption. The R2 were ≤ 0.9973 for ibuprofen. The LOD ranged from 3.3 to 16.7 ng mL-1 and the LOQ from 10 to 50 ng mL-1. Relative recoveries ranged from 71% to 126%. The repeatability (n = 3) ranged from 0.22% to 12.01%, and the intermediate precision (n = 9) ranged from 0.13% to 17.76%. The method presents a good alternative for the determination of different classes of compounds in human urine.

Sustainable green solvents for microextraction techniques: Recent developments and applications.

The development and application of alternative green solvents in analytical techniques consist of trends in sample preparation, since this subject represents an important step toward sustainability in experimental procedures. This review is focused on the main theoretical aspects related to deep eutectic solvents (DES), switchable hydrophilicity solvents (SHS) and supramolecular solvents (SUPRAS). Recent applications are highlighted, particularly for the extraction of different analytes from environmental, biological and food matrices. Moreover, novel configurations are emphasized, aiming for efficient, automated and high-throughput procedures. This review also provides some critical points regarding the use of these solvents and their green aspects.

A green approach to DDT degradation and metabolite monitoring in water comparing the hydrodechlorination efficiency of Pd, Au-on-Pd and Cu-on-Pd nanoparticle catalysis.

DDT (1,1,1-trichloro-2,2-bi(p-chlorophenyl)-ethane) and its metabolites (DDD, 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethane, and DDE, 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethylene) are persistent organic pollutants that can be catalytically degraded into a less toxic and less persistent compound. In this work, ecofriendly methodologies for catalyst synthesis, catalytic degradation of DDT and reaction monitoring have been proposed. Three types of Pd-based nanoparticles, NPs, (Pd, Au-on-Pd and Cu-on-Pd) were synthesized and used for catalytic hydrodechlorination of DDT and its metabolites. The structural and electronic properties of NPs were investigated using TEM and XAS spectroscopy. Au-on-Pd showed the highest hydrodechlorination efficiency within 1 h of reaction. To obtain the best reaction conditions, the effects of H2 flow and base addition Au-on-Pd NPs activity were investigated. To study the effectiveness of the different NPs, a solvent-free analytical method was optimized to detect and measure DDT and its by-products. The SPME-GC-MS method provided low detection limits (0.03 µg L-1) and high recovery (≥88.75%) and was a valuable tool for the NP degradation study. In this way, a green method for degradation and monitoring of DDT and its by-products in water was achieved.

Miniaturized QuEChERS method for determination of 97 pesticide residues in wine by ultra-high performance liquid chromatography coupled with tandem mass spectrometry.

A miniaturized sample preparation method was developed and validated for the multiresidue determination of 97 pesticides in wine samples. The proposed extraction procedure is based on the QuEChERS acetate method with dispersive solid phase extraction (d-SPE) for the clean-up step. Ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) was used for determination. The extraction and clean-up steps were evaluated to obtain the best conditions for the selected pesticides. Miniaturization of the sample preparation step provided a reduction in the consumption of samples and chemicals. The method limit of quantification was between 10 and 20 µg L-1. Trueness results, obtained by recovery assays at the spike levels 10, 20, 50 and 100 µg L-1, ranged from 70 to 120% with precision in terms of relative standard deviations (RSD) ≤ 20%. The method was successfully applied for the analysis of wine samples and different pesticides were found at concentrations from 14 to 55 µg L-1.

A green - high throughput -extraction method based on hydrophobic natural deep eutectic solvent for the determination of emerging contaminants in water by high performance liquid chromatography - diode array detection.

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%.

Expanding the applicability of magnetic ionic liquids for multiclass determination in biological matrices based on dispersive liquid-liquid microextraction and HPLC with diode array detector analysis.

Monitoring biological samples at trace levels of chemicals from anthropogenic actions such as pesticides, pharmaceuticals, and hormones has become a very important subject. This work describes a method for the determination of eight compounds of different chemical classes in human urine samples. Dispersive liquid-liquid microextraction based on magnetic ionic liquids was used as the sample preparation procedure. The main parameters of the method, such as sample dilution, type, and volume of disperser solvent, amount of magnetic ionic liquids, extraction time, and pH were optimized by univariate and multivariate procedures. Validation was performed using a urine sample of a male volunteer in order to obtain a calibration curve and the main analytical parameters of merit such as limits of detection and quantification. Values varied from 3.0 to 7.5 µg/L and from 10 to 25 µg/L, respectively. Satisfactory precisions of 21% for intraday (n = 3) and 16% for interday (n = 9) were achieved. Accuracy was evaluated by relative recovery assays using different urine samples and ranged from 75 to 130%. Robustness was assured by the Lenth method. The validated procedure was applied to five urine samples from different volunteers and the hormone estrone was found in one sample.

Balls-in-tube matrix solid phase dispersion (BiT-MSPD): An innovative and simplified technique for multiresidue determination of pesticides in fruit samples.

Sample preparation of complex matrices, like food samples, continues to be a challenge demanding great effort for improvements. In this study, a new technique named balls-in-tube matrix solid-phase dispersion (BiT-MSPD) is proposed based on a simplification of the conventional MSPD technique being all sample preparation performed directly in a closed extraction tube with the assistance of steel balls. An innovative method using BiT-MSPD was successfully established for the determination of 133 pesticide residues in apple, peach, pear and plum by ultra-high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS). Several sorbents were evaluated as solid support in different proportions with the sample. The homogenization step using mortar, glass rod or steel balls, with methanol and acetonitrile as extraction solvent, was evaluated. Vortex and ultrasound assisted extractions were also tested. Best results were obtained with C18, homogenization with steel balls, acetonitrile as solvent and ultrasound assisted extraction. Validation presented adequate trueness and precision results for the evaluated pesticides with recovery results ranging from 72 to 113% and RSD ≤ 17%. Practical limit of detection (LOD) and quantification (LOQ) for the compounds were 3 and 10 µg kg-1, respectively. The developed method proved to be easier and faster to perform than the MSPD, considering that extraction and clean-up are performed in the same tube without the need to transfer to cartridges, recipients or to use a separate clean-up step. The proposed BiT-MSPD technique was successfully applied to fruit samples and has great potential to be applied in other matrices, like cereals and meat, since the steel balls promote an efficient sample dispersion and extraction of pesticides. The BiT-MSPD permit a fully automation of the entire sample preparation step.

Histamine functionalized magnetic nanoparticles (HIS-MNP) as a sorbent for thin film microextraction of endocrine disrupting compounds in aqueous samples and determination by high performance liquid chromatography-fluorescence detection.

This paper describes the development of a new method in which histamine-functionalized magnetic nanoparticles (HIS-MNP) are used as the extraction phase associated with thin-film microextraction and a 96-well plate system. This approach was applied to the determination of estrone, estriol, 17-ß-estradiol, 17α-ethynylestradiol, 4-octylphenol and 4-nonylphenol in aqueous samples by HPLC-FLD. Extraction and liquid desorption steps were optimized employing multivariate and univariate procedures. The optimum extraction conditions were 50 min of extraction time, no salt addition and sample pH 5. Liquid desorption was carried out for 30 min with 300 µL of acetonitrile:methanol (50:50 v/v). The quantification limits varied between 0.5 and 20 µg L-1. The method showed recovery values between 82 and 120%, and relative standard deviations varied from 0.1 to 13.6%.

Natural sparkling guava wine: volatile and physicochemical characterization / Espumante natural de goiaba: caracterização volátil e físico-química

ABSTRACT: Although different tropical fruit species have been used in the development of fermented beverages, there are only few references in the literature to the production of natural sparkling wines from fruits other than grapes. In this sense, the objective of the present research was the development and physicochemical and volatile characterization of a natural sparkling guava wine produced by the champenoise method. Volatile compounds were identified by gas chromatography coupled to mass spectrometry using the headspace solid-phase microextraction (HS-SPME) technique on samples. Eighty-nine volatile compounds were detected, of which 51 were identified. Esters were the predominant class of volatile compounds (a total of 26), followed by alcohols (10), terpenes (9), ketones (3), and acids (3). Volatile compounds with possible odoriferous activity were reported in the beverage, including ethyl octanoate, ethyl 5-hexenoate, phenethyl acetate, (E)-β-damascenone, (E)-ethyl cinnamate, 2-methyl butyl acetate, 3-methylbutanol, ethyl 3-(E)-hexenoate, and methyl 5-hexenoate. Natural sparkling guava wine produced showed a complex composition of fruity and floral aromas. Furthermore, the use of the champenoise method, traditionally applied to grapes, enabled the manufacture of a natural sparkling guava wine with physicochemical characteristics equivalent to those of sparkling wines made from grapes.

RESUMO: Diferentes frutos tropicais vêm sendo utilizados para o desenvolvimento de bebidas fermentadas, porém na bibliografia consultada há poucas referências sobre a produção de espumantes naturais de outras frutas diferentes da uva. Nesta perspectiva, o objetivo deste trabalho foi o desenvolvimento e a caracterização físico-química e volátil de um espumante natural de goiaba produzido pelo método champenoise. A determinação dos compostos voláteis foi realizada por cromatografia em fase gasosa acoplada a espectrometria de massas utilizando a técnica de microextração em fase sólida no headspace (HS-SPME) das amostras. Foram detectados 89 compostos voláteis, dos quais 51 foram identificados. Os ésteres foram os compostos voláteis predominantes em número, totalizando 26 compostos, seguido pelos álcoois (10), terpenos (9), cetonas (3) e ácidos (3). Compostos voláteis com possível atividade odorífera foram encontrados na bebida, dentre eles os ésteres octanoato de etila, 5-hexenoato de etila, acetato de fenetila, (E)-β-damascenona, (E)-cinamato de etila, acetato de 2-metil butila, 3-metil butanol, 3-(E)-hexenoato de etila e o 5-hexenoato de metila. O espumante natural produzido apresentou uma composição complexa de aroma frutado e floral. Além disso, a utilização do método tradicionalmente aplicado a uvas, o champenoise, proporcionou a fabricação de um espumante natural de goiaba com características físico-químicas equivalentes aos espumantes elaborados a partir de vinho.

An effective method for pesticide residues determination in tobacco by GC-MS/MS and UHPLC-MS/MS employing acetonitrile extraction with low-temperature precipitation and d-SPE clean-up.

An effective method has been developed and validated for the determination of residues of 55 pesticides in tobacco. The proposed sample preparation method is based on acetonitrile extraction, low-temperature precipitation (LTP) and dispersive solid phase extraction (d-SPE) clean-up. Gas chromatography and ultra-high performance liquid chromatography analysis, both coupled to tandem mass spectrometry (GC-MS/MS and UHPLC-MS/MS), were used for determination. LTP is easy to perform and was crucial to obtain a clean extract. Method quantification limit for the pesticides were between 25 and 75µgkg-1. Extraction recoveries obtained for blank samples spiked at 25, 75, 125 and 250µgkg-1 levels ranged from 63 to 161% with relative standard deviations (RSD)≤20%. The method was successfully applied to the analysis of thirteen different tobacco samples, providing to be a robust procedure for routine analysis. The compounds pirimiphos methyl and isofenphos presented residues in the range of 35-51µgkg-1.

A simple and efficient method for imidazolinone herbicides determination in soil by ultra-high performance liquid chromatography-tandem mass spectrometry.

The use of pesticides in agriculture has generated numerous consequences to the environment, requiring analysis of the persistent residues in soil, water and air. The variability of soil properties interferes in the extraction of pesticide residues with robustness and accuracy. The group of imidazolinones herbicides, widely used for weed control, becomes an additional task in multiresidue extraction procedures because of their low pKa values. In order to determine these compounds in soil samples, different methods have been proposed, however they can be very laborious and require more time and well trained analysts. Thus, this study aimed to develop a simple and efficient method for determination of imidazolinones (imazamox, imazapic, imazapyr, imazaquin and imazethapyr) residues in soil, using an extraction with aqueous ammonium acetate solution (0.5 M) and clean-up with dispersive solid phase extraction employing PSA, followed by UHPLC-MS/MS analysis. Satisfactory values of accuracy (70-93%) and RSD (≤17%) were achieved, as well as lower limit of quantification (5.0 µg kg(-1)). Considering the matrix and compounds complexity, the developed and validated method proved to be an excellent tool for rapid analysis (20 min), with reliability for application in real samples with wide pH range. In the analysis of 22 real samples, the method allowed the quantification of imazapic (5.84 and 12.1 µg kg(-1)), imazapyr (5.3 µg kg(-1)) and imazethapyr (24.0 and 37.7 µg kg(-1)) in three samples.