Multiphase electroextraction of malachite green from surface water and its determination using digital imaging and chemometric tools.

This study introduces a novel method for the quantification of malachite green (MG), a pervasive cationic dye, in surface water by synergizing multiphase electroextraction (MPEE) with digital image analysis (DIA) and partial least square discriminant analysis. Aimed at addressing the limitations of conventional DIA methods in terms of quantitation limits and selectivity, this study achieves a significant breakthrough in the preconcentration of MG using magnesium silicate as a novel sorbent. Demonstrating exceptional processing efficiency, the method allows for the analysis of 10 samples within 20 min, exhibiting remarkable sensitivity and specificity (over 0.95 and 0.90, respectively) across 156 samples in both training and test sets. Notably, the method detects MG at low concentrations (0.2 µg L-1) in complex matrices, highlighting its potential for broader application in environmental monitoring. This approach not only underscores the method's cost-effectiveness and simplicity but also its precision, making it a valuable tool for the preliminary testing of MG in surface waters. This study underscores the synergy among MPEE, DIA, and chemometric tools, presenting a cost-efficient and reliable alternative for the sensitive detection of water contaminants.

Enhancing Analytical Sensitivity and Selectivity for Methylene Blue Determination in Water Samples by Using Multiphase Electroextraction Coupled with Optical Absorption Spectroscopy and Surface-Enhanced Raman Scattering.

While optical analysis spectroscopy offers operational ease and low cost, it suffers from limitations regarding sensitivity when it comes to analyzing analytes at low concentrations. On the other hand, surface-enhanced Raman spectroscopy (SERS) offers high sensitivity but low selectivity in complex matrices. In this study, we have effectively addressed these challenges by integrating multiphase electroextraction (MPEE) as a sample preparation technique with these two spectroscopic methods for determining methylene blue (MB) dye in tap water samples. A Box-Behnken design was utilized for optimizing electroextraction parameters such as extraction time, pH, and acetonitrile percentage in the donor phase. After optimization, optical absorption spectroscopy results in a linear analytical curve within the range of 30 to 375 mg L-1 of MB, with method validation demonstrating high precision (relative standard deviation between 3.0 and 9.9%), recovery (99-105%), and detection and quantification limits of 1.3 and 4.0 µg L-1, respectively. On the other hand, using SERS, it was possible to detect MB in concentrations as low as 0.05 µg L-1. The extremely low concentrations of MB detected (in the range of a few ppb and ppt) and the acceptable validation performance parameters obtained highlight the potential of MPEE to enhance the applicability of spectroscopic techniques in routine analyses, especially when dealing with complex and challenging samples.

Multiphase electroextraction as a simple and fast sample preparation alternative for the digital image determination of doxorubicin in saliva.

Monitoring chemotherapeutic drugs in biological fluids is, in many cases, extremely important for dose adjustment, the maintenance of therapies, and the control of side effects. In this work, a method for determining the doxorubicin in saliva by digital image analysis (DIA) was optimised and validated. Images from a paper point were obtained using a conventional and cheap flatbed scanner at a 600 ppp resolution. The RGB data channels were obtained from the images in a region of 15 × 15 pixels around the sorbent vertex. The paper point was used as sorbent material in sample preparation using a multiphase electroextraction system. Following optimisation using a Doehlert experimental design, the method was able to simultaneously extract 66 samples in 20 min. The high selectivity of the electric field associated with the sorption capacity of the cellulosic material allowed the chemotherapy drug to be pre-concentrated and quantified in a range between 50 and 500 µg L-1 (R2 > 0.98). The method also exhibited adequate parameters (limits of detection and quantification, recovery, and precision) indicating its potential application in the monitoring of doxorubicin and similar drugs in saliva.

Efficient and easily scaled-up biosorbent based on natural and chemically modified macauba (Acrocomia aculeata) to remove Al3+, Mn2+ and Fe3+ from surface water contaminated with iron mining tailings.

The ruptures of tailings mine dams in the cities of Mariana and Brumadinho contaminated local Brazilian Rivers with toxic metals. Herein, we describe a scaled-up biosorbent based on natural macauba endocarp (NTE) and macauba endocarp chemically treated (TE) to remove Al3+, Mn2+ and Fe3+ from aqueous solutions. For the TE material: the variation of pH and temperature of water did not cause significant sorption interferences; the kinetics studies suggest a pseudo-second-order model; the adsorption isotherms revealed that the Langmuir equation was the best fit for Al3+ and Mn2+, while the Freundlich equation best described the Fe3+; and the maximum adsorption capacities were between 0.268 mg g-1 and 1.379 mg g-1. A scaled-up was carried out using an adsorption column to remove the metals from Rio Paraopeba River water samples and the results showed that both NTE and TE are potentially low cost biosorbents for removing Al3+, Mn2+ and Fe3+.

Large-volume electric field-assisted multiphase extraction of malachite green from water samples: A multisample device and method validation.

In this work, a new large-volume multiphase, multi-sample electroextraction device was developed and applied to selectively extract malachite green (MG) from water samples. This device was easily constructed with ordinary materials and capable of extracting ten samples simultaneously, obtaining MG preconcentrated on a solid support, to fit into a pipette tip. A multi-well plate was applied to extract MG from aquaculture water samples, and the extracts containing the desorbed MG were analysed by LC-DAD and LC-MS/MS. The signals from both detectors were used in two independent validation procedures. Linearity, matrix effect, selectivity, precision, trueness, and limits of detection and quantification were all evaluated. For both detectors, linearity was demonstrated in the range of 0.5-5 µg L-1 (R2 > 0.98). Matrix effect was insignificant for LC-DAD only, and the average preconcentration factor was about 60 times. Recoveries ranged from 94 to 113% for LC-DAD and 95-115% for LC-MS/MS analysis. ANOVA was applied to estimate the standard deviation under repeatability (6.96-8.61% for LC-DAD and 5.98-7.41% for LC-MS/MS) and within-reproducibility (6.96-8.61% for LC-DAD and 6.56-7.41% for LC-MS/MS) conditions. The limits of detection and quantification for LC-MS/MS analysis were 4.29 and 28.74 ng L-1, respectively, while, for LC-DAD, these limits were 14.29 and 95.81 ng L-1, respectively. The results demonstrated that the developed method was suitable for determining MG in water samples, and the large-volume multiphase, multi-sample electroextraction device proved to be a powerful sample preparation technique to obtain high clean-up and large preconcentration levels, which are of paramount importance for environmental applications.

Application of aqueous two-phase system for selective extraction and clean-up of emerging contaminants from aqueous matrices.

This review approaches how aqueous two-phase systems (ATPS), in their various compositions (e.g., polymer + salt, copolymer + salt, ionic liquid + salt, acetonitrile + salt), can be efficiently used for extraction, preconcentration, and clean-up of analytes in aqueous samples to determine the compounds classified as emerging contaminants (ECs). In the literature, there are some studies using ATPS applied to ECs, like pesticides, pharmaceuticals, illicit drugs, personal care products, alkaloids, and hormones, even when in trace concentrations. The ATPS is an alternative to the conventional liquid-liquid extraction technique. However, it is predominantly composed of water and do not generally use organic solvents and, therefore, is based on the principles of green chemistry. An ATPS approach has a unique advantage because it can extract neutral, anionic, cationic, polar, and nonpolar compounds, even when present simultaneously in the same sample. This review covers how this simple and low environmental impact technique has been employed for the analysis of different classes of emerging contaminants.

Cellulose cone tip as a sorbent material for multiphase electrical field-assisted extraction of cocaine from saliva and determination by LC-MS/MS.

A porous and hydrophilic sorbent material was used in an extraction system, assisted by electric fields, for the extraction of cocaine in saliva and subsequent determination by ultra-high-performance liquid chromatography associated with sequential triple quadrupole mass spectrometry (UHPLC-MS/MS). The cellulose-based material was characterized by scanning electron microscopy, infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. The time and voltage variables applied in the extraction process were investigated through a Doehlert experimental design, and with the best conditions found (35min and 300 V) some validation parameters were evaluated. The established working range was 1-100 µg L-1 (R2 > 0.99), and the detection and quantification limits determined were 0.3 and 0.8 µg L-1, respectively. Recoveries from 80 to 115% and coefficient of variation ≤15 and 16% for intra-day and inter-day assays, respectively, were obtained for sample concentrations of LOQ, 5, 25, and 75 µg L-1, indicating satisfactory accuracy and precision for the proposed method. In addition, the method presented no matrix effect, and the extraction efficiency was between 56 and 70%. The results showed that the material used has adequate physicochemical characteristics and can be applied as a sorbent and electrolyte support in multiphase extractions using electric fields.

Comparative effects of the ω3 polyunsaturated fatty acid derivatives resolvins E1 and D1 and protectin DX in models of inflammation and pain.

PURPOSE: Specialized pro-resolving lipid mediators (SPMs), also known as lipoxins, resolvins (Rvs), protectins and maresins, have been implicated in the resolution of the inflammatory process. However, a systematic comparison of their activity in the relief of inflammation and pain models is still lacking. MATERIALS AND METHODS: The effects of Rvs E1 and D1 and protectin DX (PDX) were assessed in rat paws inflamed by the standard proinflammatory stimulus carrageenan or by histamine, 5-hydroxytryptamine, substance P or prostaglandin E2. The experimental outcomes were the mechanical nociceptive threshold and increase in paw volume as a measure of pain and edema formation, respectively. The analgesic and anti-inflammatory activities of the indicated SPMs were also compared with nonsteroidal (indomethacin and celecoxib) and steroidal (dexamethasone) anti-inflammatory drugs. RESULTS: Only RvE1 and RvD1 presented analgesic and anti-inflammatory activities in the carrageenan model, and RvE1 was twice as potent as RvD1. Both substances tended to be better analgesics than anti-inflammatory agents, with a modeling profile similar to steroidal anti-inflammatory drugs. However, proinflammatory effects (edema formation) were also detected when the mediators histamine, 5-hydroxytryptamine or substance P replaced carrageenan as the proinflammatory stimuli. The analgesic and anti-inflammatory effects of resolvins were specifically prevented by an antagonist of the leukotriene B4 receptor 1 (BLT1). CONCLUSION: Rvs, as analgesic agents, may be better therapeutic agents than nonsteroidal anti-inflammatory drugs, the current choice in the relief of pain of an inflammatory origin. However, the possibility of developing adverse effects cannot be overlooked.