Multiresidue analysis of quinolones and fluoroquinolones in soil by ultrasonic-assisted extraction in small columns and HPLC-UV

In this work, a new and simple analytical methodology for the simultaneous analysis of several quinolones (cinoxacin, oxolinic acid, nalidixic acid and flumequine) and fluoroquinolones (norfloxacin, enrofloxacin, enoxacin, ciprofloxacin and danofloxacin) in soil samples is presented. The method is based on the extraction of these analytes by an ultrasonic-assisted extraction in small columns and their subsequent quantification by HPLC using UV detection. The observed strong sorption of quinolones and fluoroquinlones to soil together their different acid-base properties made necessary an exhaustive optimisation of the extraction step. The optimum extraction procedure, based on the formation of antibiotic-Mg(II) complexes, allowed to desorb and quantitatively extract both groups of antibiotics in a single step, which was not possible by using conventional organic solvents. The proposed method was validated and the limits of detection achieved were in the low μg g⁻¹ concentration range proving its suitability for the determination of quinolones and fluoroquinolones in soil samples at realistic environmental concentration level.     

Analysis of Steroid Hormones in Water Using Palmitate-Coated Magnetite Nanoparticles Solid-Phase Extraction and Gas Chromatography–Tandem Mass Spectrometry

A new extractive method based on magnetic solid–phase extraction using palmitate-coated magnetite nanoparticles coupled with gas chromatography-tandem mass spectrometry was developed for the extraction of estrone, androstenedione and progesterone hormones from water. The amount of nanoparticles and extraction time were optimized applying an experimental design to estimate simultaneously their influence on the recoveries. Results showed that the extraction efficiency was highly affected by the addition of salt and acetonitrile was the solvent used to elute the analytes from the nanoparticles. Derivatization via enolization of ketone group was carried out in the extract for the simultaneous derivatization of hydroxyl and ketone groups of steroid hormones previously to their chromatographic analysis. The extraction efficiencies of the nanoparticles were studied spiking at four concentration levels and recoveries from 94.6 to 109.7 % were obtained. The limits of detection ranged from 4 to 8 ng L^?1. The developed method provided a preconcentration factor of 100. The present work shows that palmitate-coated magnetite nanoparticles have good applicability for the extraction of natural estrogenic hormones that could be pollutants in real water samples.     

Rapid determination of natural and synthetic hormones in biosolids and poultry manure by isotope dilution GC–MS/MS

The release of hormones into the environment due to land application of biosolids and manure is a cause of concern for their potential impacts. This paper presents the development of a rapid and sensitive method, based on extraction, for the analysis of 13 hormones in biosolids and poultry manure. A simultaneous derivatization of hydroxyl and ketone groups was carried out for the determination of hormones by GC–MS/MS. The method was validated in three matrices (sewage sludge, manure, and broiler litter). Recoveries from spiked samples at three concentration levels (50, 25, and 10 ng/g) ranged from 76 to 124% with relative SDs ≤ 16%. Method detection limits for the three matrices were in the range of 0.5–3.0 ng/g dry weight. The optimized method was applied to biosolid and poultry manure samples collected in Spain. Only seven of the 13 studied hormones were detected in the different samples. trans‐Androsterone was detected at high levels (up to 3.1 μg/g in biosolid samples). Estrone and estradiol were the two hormones detected at higher levels in layer manure, whereas estrone and 4‐androstene‐3,17‐dione presented the highest levels in broiler litter.     

Determination of endosulfan isomers and endosulfan sulfate in tomato juice by matrix solid-phase dispersion and gas chromatography

A rapid method based on matrix solid-phase dispersion was developed for the determination of endosulfan isomers and endosulfan sulfate in commercial tomato juice. After the optimisation of different parameters such as the type of adsorbent, the extraction solvent, and the extraction assistance by sonication, the recoveries obtained ranged from 81 to 100% with relative standard deviations equal to or lower than 10%. The analysis of samples was accomplished using gas chromatography with electron-capture detection and the identity of endosulfan residues was confirmed by gas chromatography-mass spectrometry with selected ion monitoring. The detection limit for these compounds, calculated as three times the background noise, was 1 microg/kg. The proposed method was applied to the analysis of these compounds in commercial juice samples and levels of endosulfan between 1 and 5 microg/kg were detected in some samples.     

Analysis of Steroid Hormones in Water Using Palmitate-Coated Magnetite Nanoparticles Solid-Phase Extraction and Gas Chromatography–Tandem Mass Spectrometry

A new extractive method based on magnetic solid–phase extraction using palmitate-coated magnetite nanoparticles coupled with gas chromatography-tandem mass spectrometry was developed for the extraction of estrone, androstenedione and progesterone hormones from water. The amount of nanoparticles and extraction time were optimized applying an experimental design to estimate simultaneously their influence on the recoveries. Results showed that the extraction efficiency was highly affected by the addition of salt and acetonitrile was the solvent used to elute the analytes from the nanoparticles. Derivatization via enolization of ketone group was carried out in the extract for the simultaneous derivatization of hydroxyl and ketone groups of steroid hormones previously to their chromatographic analysis. The extraction efficiencies of the nanoparticles were studied spiking at four concentration levels and recoveries from 94.6 to 109.7 % were obtained. The limits of detection ranged from 4 to 8 ng L⁻¹. The developed method provided a preconcentration factor of 100. The present work shows that palmitate-coated magnetite nanoparticles have good applicability for the extraction of natural estrogenic hormones that could be pollutants in real water samples.

     

Analysis of emerging organic contaminants in environmental solid samples

Spreading sewage sludge on agricultural lands has been actively promoted by national authorities as an economic way of recycling. However, as by-product of wastewater treatment, sewage sludge may contain toxic substances, which could be incorporated into agricultural products or be distributed in the environment. Moreover, sediments can be contaminated by the discharge of wastewater effluents into rivers. This article reviews the determination of emerging contaminants (surfactants, flame retardants, pharmaceuticals and personal care products) in environmental solid samples (sludge, soil and sediment). Sample preparation, including extraction and clean-up, as well as the subsequent instrumental determination of contaminants are discussed. Recent applications of extraction techniques, such as Soxhlet extraction, ultrasound assisted extraction, pressurised liquid extraction, microwave assisted extraction and matrix solid-phase dispersion to the analysis of emerging contaminants in environmental solid samples are reviewed. Determination of these contaminants, generally carried out by gas chromatography and liquid chromatography coupled with different detectors, especially mass spectrometry for the identification and quantification of residues, is also summarised and discussed.      

Application of ultrasound-assisted extraction to the determination of contaminants in food and soil samples

The application of ultrasound-assisted extraction (UAE) to the sample preparation of environmental and food samples has increased in the last years. This technique has been used in the development of methods for the analysis of numerous contaminants, including organic compounds (pesticides, pharmaceuticals, polycyclic aromatic hydrocarbons, polyhalogenated flame retardants, etc.) and heavy metals. The aim of this work is to review the application of this extraction procedure to the analysis of contaminants in food and soil and the comparison of its use with other well-established extraction procedures. The advantages and disadvantages of this technique together with the possibility of coupling UAE with other analytical techniques will be also discussed.     

Molecularly imprinted polymer for the extraction of parabens from environmental solid samples prior to their determination by high performance liquid chromatography-ultraviolet detection

An analytical methodology incorporating a molecularly imprinted solid-phase extraction procedure (MISPE) has been developed for the determination of parabens in environmental solid samples. Four different polymers were prepared combining the use of acetonitrile or toluene as porogen, and 4-vinylpyridine (VP) or methacrylic acid (MAA) as monomer, using benzylparaben (BzP) as a template molecule. Although all the polymers were able to recognize the template in rebinding experiments, the MIP prepared in toluene using MAA showed better performance. This polymer was also capable of recognizing other parabens (methyl, ethyl, isopropyl, propyl, isobutyl, butyl and benzylparaben) allowing to develop an appropriated MISPE procedure for this family of compounds. The extraction of the parabens from environmental solid samples was performed by ultrasonic assisted extraction in small columns (SAESC), and this procedure next to MISPE as clean-up step followed by HPLC-UV determination was successfully used for the determination of parabens in soil and sediment samples of different locations. Recoveries ranging from 80% to 90% have been achieved depending on the compound and the samples, and limits of detection (LODs) were under 1 ng g⁻¹ for all the compounds, making this method suitable for the determination of parabens in environmental solid matrices. The method was further applied to the determination of paraben contents in real samples, founding levels up to 11.5 ng g⁻¹ in sea sediments.     

Determination of cyclic and linear siloxanes in soil samples by ultrasonic-assisted extraction and gas chromatography-mass spectrometry

A rapid method, based on sonication-assisted extraction in small columns (SAESC) and subsequent quantification and identification by gas chromatography-mass spectrometry (GC-MS), was developed for the determination of cyclic and linear siloxanes in soil. In the experiments with spiked samples (10-50 ng g(-1)), the recovery of cyclic and linear siloxanes ranged from 87.7 to 108.0% and from 84.9 to 107.6%, respectively. The validated method was used to determine the levels of these compounds in various types of soil samples collected from different locations in Spain. The cyclic siloxanes, decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) were detected in all the soil samples analyzed at concentrations from 9.2 to 56.9 ng g(-1) for D5 and from 5.8 to 27.1 ng g(-1) for D6 in agricultural soils and from 22 to 184 ng g(-1) for D5 and from 28 to 483 ng g(-1) for D6 in industrial soils. The total linear siloxanes concentrations (L5-L14) (sum of the 10 congeners) ranged from 191 to 292 ng g(-1) in agricultural soils and from 1411 to 8532 ng g(-1) in industrial soils.     

Fully conjugated push–pull dendrons with high dipole moments in excited state; synthesis and theoretical rationalization

Novel fully conjugated push–pull dendrons were synthesized by a divergent approach to evaluate the performance of non‐conventional architectures like dendritic one in charge separation processes associated with photovoltaic events. The dipole moments in excited state were estimated by the solvatochromic method, to be related to the charge separation efficiency. A 1:2 ratio of donor–acceptor groups (methoxy and nitro groups respectively) promotes the largest dipole moment in both ground and excited state (up to 17 D), due to the efficient electron density transfer over the entire molecule, through the π‐electron system. The synthesized dendrons induce charge transfer on excitation as follows from UV–vis absorption–emission analysis and theoretical calculations. Copyright © 2015 John Wiley & Sons, Ltd.