Bidimensional Dynamic Magnetic Levitation: Sequential Separation of Microplastics by Density and Size.

There is a current gap in sample preparation techniques integrating the separation of microplastics according to their different material types and particle sizes. We describe herein the Bidimensional Dynamic Magnetic Levitation (2D-MagLev) technique, enabling the resolution of mixtures of microplastics sorting them by plastic type and particle size. Separations are carried out in a bespoke flow cell sandwiched between two ring magnets and connected to programmable pumps for flow control. The first separation dimension is based on sequential increases in the concentration of a paramagnetic salt (MnCl2), enabling magnetic levitation of microplastics with determined densities. The second dimension is based on increasing flow rate gradients and maintaining constant MnCl2 concentrations. This fractionates the magnetically levitating microplastics according to their different particle sizes. Microplastics are therefore collected by their increasing density, and the particles corresponding to each density are fractionated from smaller to larger size. Using polyethylene microspheres with defined density (1.03-1.13 g cm-3) and size (98-390 µm) as microplastic mimicking materials, we investigated their optimum threshold velocities for their size fractionation, potential effects of medium viscosity and sample loading, and types of flow rate gradients (linear, step). Performing a separation using a combination of step gradients in both MnCl2 concentration and flow rate, mixtures comprising microplastics of two different densities and three different particle sizes were separated. 2D-MagLev is simple, fast, versatile, and robust, opening new avenues to facilitate the study of the environmental presence and impact of microplastics.

Sponge-nested polymer monoliths: Versatile materials for the solid-phase extraction of bisphenols.

Polymer monoliths are promising materials for sample preparation due to their high porosity, pH stability, and simple preparation. The use of melamine formaldehyde foams has been reported as an effective support to prepare highly robust silica and polymer monoliths. Herein, divinylbenzene monoliths based on a 50:50 (%, w/w) crosslinker/porogen ratio have been nested within a melamine-formaldehyde sponge, resulting in monoliths with a surface area higher than 400 m2 /g. The extraction performance of these monoliths was evaluated for the extraction of endocrine-disrupting bisphenols from aqueous solutions. We evaluated for the first time the versatility of sponge-nested polymer monoliths by comparing three different extraction modes (vortex mixing, magnetic stirring, and orbital shaking). Vortex mixing showed a comparable recovery of bisphenols (39%-81%) in a shorter extraction time (30 min, instead of 2 h). In addition, the robustness of the sponge-nested polymer monoliths was demonstrated for the first time by reshaping a larger monolithic cube (0.125 cm3 ) into four smaller pieces (4 × 0.03125 cm3 ) leading to a 16%-21% increase in extraction efficiency. This effect was attributed to an increase in the effective contact area with the sample, obtaining a higher analyte extraction capacity.

A miniaturized analytical system with packed epoxy-functionalized mesoporous organosilica for copper determination using a customized Android-based software.

A smartphone-assisted determination of copper ions is introduced by using a down-scaled microfluidic mixer. The system was coupled with a micro-column packed with a periodic mesoporous organosilica (PMO) material for preconcentration of copper ions. Copper ions were reduced to Cu(I) on-chip to selectively form an orange-colored complex with neocuproine. A novel Android-based software was made to determine the color change of the adsorbent by analyzing red-green-blue (RGB) components of images from the packed PMO material. Four porous framework materials with high porosity and chemical stability were synthesized and compared for the extraction of the Cu-neocuproine complex. The main parameters influencing the complex extraction efficiency were optimized. The analytical performance of the method showed limit of detection and quantification of 0.2 µg L-1 and 0.5 µg L-1, respectively. The accuracy and precision of the method were determined as recovery > 92% and relative standard deviations < 5.2% at medium concentration level (n = 5). Due to accumulation of the retained analyte in a single point and elimination of the stripping step, the RGB-based method showed sensitivity and precision higher than inductively coupled plasma-atomic emission spectrometry (ICP-AES) for determination of copper ions. To investigate the applicability of the method, six different water samples were analyzed. The t-test on the data showed that the method has no significant difference when compared with ICP-AES determination.

ZIF-8@Rhodamine B as a Self-Reporting Material for Pollutant Extraction Applications.

Herein, we have evaluated the potential of dye-encapsulation as a simple mechanism to self-report the stability of MOFs for pollutant extraction applications. This enabled the visual detection of material stability issues during the selected applications. As proof-of-concept, the zeolitic imidazolate framework (ZIF-8) material was prepared in aqueous medium and at room temperature in the presence of the dye rhodamine B. The total amount of loaded rhodamine B was determined using UV-vis spectrophotometry. The prepared dye-encapsulated ZIF-8 showed a comparable extraction performance with bare ZIF-8 for the removal of hydrophobic endocrine-disrupting phenols, such as 4-tert-octylphenol and 4-nonylphenol, and improved the extraction performance of more hydrophilic endocrine disruptors, such as bisphenol A and 4-tert-butylphenol.

Sponge-nested polymer monolith sorptive extraction.

Polymer monoliths are an alternative to traditional particle-packed supports used in solid-phase extraction because of their ease of preparation, high porosity, and pH stability. They often required the attachment of monoliths to a support, such as the internal walls of a column to enable their use for sample preparation. Applications of free-standing polymer monoliths are rarely found because of their limited mechanical stability. Herein, divinylbenzene monoliths were polymerised within a commercial melamine-formaldehyde sponge using different polymerisation times. The sponge-nested polymer monoliths are highly robust, and their size and shape can be easily adjusted for desired applications. The prepared sponge-nested polymer monoliths had surface areas in the range of 237 m2 g-1 to 369 m2 g-1. A melamine-formaldehyde sponge cut into 1 cm3 cubes were used to template the polymer monoliths. Miniaturized monoliths with a size of 0.125 cm3 were directly cut from the larger cubes without compromising the integrity of the porous monolith structure. The resulting nested monolith sorptive extraction (NMSE) supports were applied for the extraction of the endocrine disruptors bisphenol A, 4-tert-butylphenol, and 4-tert-octylphenol. The prepared sponge-nested monoliths are low-cost (40 monoliths/AU$). NMSE was carried out by the direct immersion of the monoliths in the aqueous standards/samples, requiring only an orbital shaker for the extraction procedure. Best performance was obtained for polymer monoliths polymerized for 6 h, enabling limits of detection of 5.6 to 6.5 µg L-1 for the selected analysis using HPLC-UV.

Magnetism-Assisted Density Gradient Separation of Microplastics.

A versatile method for the efficient separation of different types of microplastics from particle mixtures is presented. Magnetism-assisted density gradient separation (Mag-DG-Sep) relies on a bespoke separation cell connected to a gradient pump and located between two like-pole-facing neodymium magnets. In Mag-DG-Sep, particle mixtures initially sunk in water are subjected to a gradient of increasing concentration of MnCl2, enabling the sequential suspension and collection of particles with different densities. The suspension process is assisted by the paramagnetism of the MnCl2 solution placed between the two magnets, which contributes to focusing the ascending particles from the bottom of the separation cell to the outlet, thus enhancing the resolution of the separation process. To demonstrate the concept, a mixture of polyethylene (PE) polymer particles with a similar size range (180-212 µm) but different densities (ca. 0.98, 1.025, 1.08, and 1.35 g cm-3) was selectively separated in a single Mag-DG-Sep run. These particles were also efficiently separated when mixed with other types of particles, such as glass or soil. A generic linear MnCl2 gradient can be directly applied for sample screening covering a broad range of densities (0.98-2.20 g cm-3), while steps can be introduced in the gradient, increasing the separation resolution of particles with close densities (1.025-1.08 g cm-3). As a proof-of-concept application, Mag-DG-Sep facilitated sample preparation of microplastics present in a soil sample prior to their examination by attenuated total reflection Fourier-transform infrared spectroscopy.

Miniaturized 3D printed solid-phase extraction cartridges with integrated porous frits.

Here we have studied the effect of the thickness and printing orientation using PolyJet 3D printing to fabricate single-material cartridges with built-in porous frits enabling solid-phase extraction (SPE) by packing commercial sorbents. This is achieved by tuning the degree of interpenetration of the building material and the water-soluble support material used in PolyJet 3D printing by modifying the orientation of the print head respective to the frit. SPE cartridges printed at an orientation of 30° with a 150 µm thick integrated frit were selected for the SPE experiments in a compromise between frit permeability to flow and stability to retain commercial sorbents for SPE. The performance of the 3D printed cartridges was evaluated for the SPE of the endocrine-disrupting phenols 4-tert-octylphenol (4-tOP) and 4-nonylphenol (4-NP), comparing three commercial SPE sorbents (Evolute Express ABN, Bond Elut PPL, and Silica-C18). The best overall extraction performance was obtained using Silica-C18, and the main extraction parameters were optimized. Detection limits of 0.3 µg L-1 for 4-tOP and 1.1 µg L-1 for 4-NP were achieved using HPLC-DAD for analyte separation and quantification. Enrichment factors of 30.1 (4-tOP) and 16.2 (4-NP) were obtained under the selected conditions. The developed method was applied to water and milk powder samples obtaining satisfactory recoveries ranging from 97% to 103%. These results demonstrate the suitability of PolyJet 3D printing for the fabrication of miniaturized cartridges with integrated frits for SPE applications.

Flow-based determination of lead exploiting in-syringe dispersive liquid-liquid micro-extraction in xylene and integrated spectrophotometric detection.

A lab-in-syringe flow system exploiting dispersive liquid-liquid micro-extraction in a solvent lighter than water is proposed for the spectrophotometric determination of lead in industrial residual waters. The steps inherent to both liquid-liquid extraction and monitoring of the formed compound are in-syringe carried out. The classical carbon tetrachloride is not used as the extracting solvent, as it does not present the friendly characteristics inherent to the Green Analytical Chemistry. Aiming at a cleaner alternative for this determination, xylene is selected. Enrichment factor, linear dynamic range, detection limit, sample throughput and residue volume inherent to the proposed procedure were estimated as 36, 50.0-250 µg L-1, 9.0 µg L-1, 13 h-1, and 2.0 mL, respectively.

Biphasic Magnetic Levitation to Detect Organic Pollutants on Microplastics.

Microplastics have the potential to adsorb organic pollutants due to their lipophilic nature. Evaluating the distribution of multiple organic pollutants in different types of microplastics coexisting in a sample is a strenuous and challenging analytical task. Here, we report position-dependent microplastic trapping in a biphasic medium comprising a paramagnetic aqueous donor phase containing the mixed microplastics and a diamagnetic organic acceptor phase. Depending on the relative height of the sample container positioned in a magnetic field, the selective density-dependent trapping of microplastics is achieved. Concurrently, the organic pollutants adsorbed on the microplastics are desorbed in the organic acceptor phase, which is easily solidified, separated, and transferred for organic pollutant determination by high-performance liquid chromatography. This facilitates analytical studies involving multiple organic pollutants distributed in solid heterogeneous mixtures.

Recent trends on the implementation of reticular materials in column-centered separations.

Advances in the development of column-based analytical separations are strongly linked to the development of novel materials. Stationary phases for chromatographic separation are usually based on silica and polymer materials. Nevertheless, recent advances have been made using porous crystalline reticular materials, such as metal-organic frameworks and covalent organic frameworks. However, the direct packing of these materials is often limited due to their small crystal size and nonspherical shape. In this review, recent strategies to incorporate porous crystalline materials as stationary phases for liquid-phase separations are covered. Moreover, we discuss the potential future directions in their development and integration into suitable supports for analytical applications. Finally, we discuss the main challenges to be solved to take full advantage of these materials as stationary phases for analytical separations.

Practice-Changing Use of the 21-Gene Test for the Management of Patients With Early-Stage Breast Cancer in Latin America.

PURPOSE: We present a physician survey of the impact of 21-gene Breast Recurrence Score test results on treatment decisions in clinical practice in Latin America. METHODS: This prospective survey enrolled consecutive patients at 14 sites in Argentina, Colombia, Mexico, and Peru who had routine 21-gene testing. Physician surveys captured patient and tumor characteristics and treatment decisions before and after 21-gene test results. The survey spanned the period before and after Trial Assigning Individualized Options for Treatment (TAILORx) results reported (June 2018). Overall net percent change in adjuvant chemotherapy recommendations was estimated, and asymptotic 95% CIs with continuity correction were calculated. The proportion with a change between pretest treatment recommendation and actual treatment received was calculated overall and by Recurrence Score groups per TAILORx. RESULTS: Between March 2015 and December 2019, the survey was completed for 647 patients; 20% were node-positive. The mean patient age was 54 years (24-85 years); 55% were postmenopausal; 17%, 63%, and 20% had grade 1, 2, and 3 tumors, respectively; and 30% had tumors > 2 cm. Recurrence Score (RS) results were as follows: 20% RS 0-10, 56% RS 11-25, and 24% RS 26-100. Overall, chemotherapy recommendations fell by a relative proportion of 39% (95% CI, 33.4 to 44.3) after 21-gene testing (33% decrease in node-negative and 55% decrease in node-positive). Among node-negative patients, the relative decrease in chemotherapy recommendations was 28% (95% CI, 18.9 to 39.5) before TAILORx and 36% (95% CI, 28.4 to 43.7) after. CONCLUSION: To our knowledge, this large survey of 21-gene test practice patterns was the first conducted in Latin America and showed the relevance of 21-gene testing in low- and medium-resource countries to minimize chemotherapy overuse and underuse in breast cancer. The results showed substantial reductions in chemotherapy use overall-especially after TAILORx reported-indicating the practice-changing potential of that study.

Scalable 3D printing method for the manufacture of single-material fluidic devices with integrated filter for point of collection colourimetric analysis.

Assembly and bonding are major obstacles in manufacturing of functionally integrated fluidic devices. Here we demonstrate a single-material 3D printed device with an integrated porous structure capable of filtering particulate matter for the colourimetric detection of iron from soil and natural waters. Selecting a PolyJet 3D printer for its throughput, integrated filters were created exploiting a phenomenon occurring at the interface between the commercially available build material (Veroclear-RGD810) and water-soluble support material (SUP707). The porous properties were tuneable by varying the orientation of the print head relative to the channel and by varying the width of the build material. Porous structures ranging from 100 to 200 µm in thickness separated the sample and reagent chambers, filtering particles larger than 15 µm in diameter. Maintaining the manufacturing throughput of the Polyjet printer, 221 devices could be printed in 1.5 h (∼25 s per device). Including the 12 h post-processing soak in sodium hydroxide to remove the solid support material, the total time to print and process 221 devices was 13.5 h (3.6 min per device), with a material cost of $2.50 each. The applicability of the fluidic device for point of collection analysis was evaluated using colourimetric determination of iron from soil slurry and environmental samples. Following the reduction of Fe3+ to Fe2+ using hydroxylammonium chloride, samples were introduced to the fluidic device where particulate matter was retained by the filter, allowing for particulate-free imaging of the red complex formed with 1,10-phenanthroline using a smartphone camera. The calibration curve ranged from of 1-100 mg L-1 Fe2+ and good agreement (95%) was obtained between the point of collection device and Sector Field ICP-MS.

Mutations in the VP2 gene of rotavirus associated with benzimidazole sensitivity.

Rotavirus species A (RVA) is the etiological agent of acute gastroenteritis in young individuals of various animal species, including humans. Vaccination has helped to reduce the impact of these viruses on humans and some species of domestic mammals, but they do not confer complete immunity, so antirotavirus agents are another important control option. In this study, millimolar concentrations of benzimidazole inhibited the replication of the Rhesus rotavirus (RRV) strain of RVA. Two mutants partially resistant to the inhibitory effect of benzimidazole were independently selected, and their genomes and those of their parental strains were fully sequenced. Most (7/11) mutations occurred in the gene that encodes the VP2 protein, and similarly most of the missense mutations (5/9), including the only one shared by the two mutants (G2,414 → R[G/A], D800 N), occurred in the VP2 gene. Our results identify the VP2 gene as the primary target affected by benzimidazole.

Zeolitic imidazolate frameworks in analytical sample preparation.

Zeolitic imidazolate frameworks are a class of metal-organic frameworks that are topologically isomorphic with zeolites. Zeolitic imidazolate frameworks are composed of tetrahedrally coordinated metal ions connected by imidazolate linkers and have a high porosity and chemical stability. Here, we summarize the progress made in the application of zeolitic imidazolate frameworks in sample preparation for analytical purposes. This review is focused on analytical methods based on liquid chromatography, gas chromatography, or capillary electrophoresis, where the use of zeolitic imidazolate frameworks has contributed to increasing the sensitivity and selectivity of the method. While bulk zeolitic imidazolate frameworks have been directly used in analytical sample preparation protocols, a variety of strategies for their magnetization or their incorporation into sorbent particles, monoliths, fibers, stir bars, or thin films, have been developed. These modifications have facilitated the handling and application of zeolitic imidazolate frameworks for a number of analytical sample treatments including magnetic solid-phase extraction, solid-phase microextraction, stir bar sorptive extraction, or thin film microextraction, among other techniques.

Recomendaciones para el diagnóstico, tratamiento y seguimiento del cáncer de mama durante la pandemia de SARS-Cov-2/COVID-19 en Colombia / Recommendations for the diagnosis, treatment and monitoring of breast cancer during the SARS-Cov-2/COVID-19 pandemic in Colombia

Resumen Bajo las nuevas condiciones generadas por la pandemia de COVID-19, los tratamientos para el cáncer de mama requieren algunas reorientaciones y cuidados que se exponen en este artículo. Se consideran aquí las tres fases de gravedad de la pandemia y los respectivos tratamientos que demandan en función de los lineamientos dictados por el Ministerio de Salud y Protección Social de Colombia. Se trata de un conjunto de referencias para orientar las terapias y tratamientos, inspiradas en las políticas de salud regionales, nacionales e institucionales.

Abstract Under the new conditions generated by the COVID-19 pandemic, breast cancer treatments requires some reorientations and cares that are discussed in this article. The three phases of severity of the pandemic and the respective treatments they require -based on the guidelines issued by the Ministry of Health and Social Protection of Colombia- are considered here. It is a set of references to guide therapies and treatments, inspired by regional, national and institutional health policies.

3D Printing in analytical sample preparation.

In the last 5 years, additive manufacturing (three-dimensional printing) has emerged as a highly valuable technology to advance the field of analytical sample preparation. Three-dimensional printing enabled the cost-effective and rapid fabrication of devices for sample preparation, especially in flow-based mode, opening new possibilities for the development of automated analytical methods. Recent advances involve membrane-based three-dimensional printed separation devices fabricated by print-pause-print and multi-material three-dimensional printing, or improved three-dimensional printed holders for solid-phase extraction containing sorbent bead packings, extraction disks, fibers, and magnetic particles. Other recent developments rely on the direct three-dimensional printing of extraction sorbents, the functionalization of commercial three-dimensional printable resins, or the coating of three-dimensional printed devices with functional micro/nanomaterials. In addition, improved devices for liquid-liquid extraction such as extraction chambers, or phase separators are opening new possibilities for analytical method development combined with high-performance liquid chromatography. The present review outlines the current state-of-the-art of three-dimensional printing in analytical sample preparation.

Rapid Additive Manufacturing of 3D Geometric Structures via Dual-Wavelength Polymerization.

A dual-wavelength photopolymerization process is presented, allowing for the volumetric fabrication of complex geometries using a multistep process. The methacrylate-based resin contained 0.1 wt % camphorquinone/0.1 wt % ethyl 4-(dimethylamino) benzoate and 0.2 wt % bis[2-(ochlorophenyl)-4,5-diphenylimidazole] as photoinitiator (473 nm) and photoinhibitor (365 nm), respectively. The photoinitiator and photoinhibitor concentrations were optimized to allow for photocuring to full depth (4.6 mm) following an exposure time of 2 min solely by 473 nm light, but no curing occurred when 365 nm light was present due to photoinhibition. This resin was validated using one-step volumetric fabrication of two objects containing voids defined by the 365 nm irradiation region. Two more complex structures were printed in a step-by-step manner, relying on the dynamic control of the projection patterns of both 365 and 473 nm projectors, decreasing the print time from 20 min using a commercially available single wavelength resin printer to 2 min.

Porogens and porogen selection in the preparation of porous polymer monoliths.

Porogens are key components required for the preparation of porous polymer monoliths for application in separation science. Porogens determine the stability, selectivity, and permeability of polymer monoliths. This review summarizes the role of porogens in the preparation of porous polymer monoliths with a focus on clear understanding of effect of porogens on morphological properties, porosity, surface area, mechanical stability, and permeability of monoliths, particularly targeting the field of separation science. This review also includes the use of different types of porogens with the focus on various approaches used to set criteria for their systematic selection, including porogen-free techniques recently used for synthesis of porous monoliths. It discusses the current state-of-the-art applications of porogens in column preparation as well as where the future developments in this field may be directed.

Ordered macro/micro-porous metal-organic framework of type ZIF-8 in a steel fiber as a sorbent for solid-phase microextraction of BTEX.

An ordered array of macropores on microporous metal-organic framework crystals was developed. This array facilitates analyte diffusion in microextraction applications. A prototypical zeolitic imidazolate framework (ZIF-8) was synthesized in the interstitial voids of a polystyrene bead packing of sub-µm polystyrene beads. After removal of polystyrene by dimethylformamide, a single-crystal ordered macroporous ZIF-8 material (SOM-ZIF-8) was obtained. The resulting µm-sized SOM-ZIF-8 crystals are based on a fully-microporous structure containing a macroporous network. The SOM-ZIF-8 crystals were placed in a stainless-steel fiber and applied as a sorbent for the extraction of benzene, toluene, ethylbenzene, and xylenes (BTEX) by headspace solid-phase microextraction (HS-SPME). The fiber was applied to the HS-SPME of BTEX from wastewater samples followed by GC with flame ionization detection. A Plackett-Burman design and Box-Behnken design were carried out to evaluate the variables affecting the method. Figures of merit include (a) limits of detection of 1.0-12 ng·L-1, (b) linear ranges of 0.004-50 µg·L-1, (c) relative standard deviations of 4.6-6.7%, and (d) excellent fiber-to-fiber reproducibility (5.6-6.7% for n = 3). Spiking recoveries between 92 and 106% were obtained for BTEX analysis in wastewater samples. The introduction of an ordered macroporous network on microporous ZIF-8 crystals enhanced analyte uptake. This increases the extraction performance by a factor of 2.5-3.1 when compared to analogous ZIF-8 crystals that lack templated macropores. Graphical abstract BTEX extraction is enhanced by templating an ordered macroporous network in microporous crystals as exemplified with the single-crystal ordered macropore zeolitic imidazolate framework-8 (SOM-ZIF-8). Graphical Abstract contains poor quality of image inside the artwork. Please do not re-use the file that we have rejected or attempt to increase its resolution and re-save. It is originally poor, therefore, increasing the resolution will not solve the quality problem. We suggest that you provide us the original format. We prefer replacement figures containing vector/editable objects rather than embedded images. Preferred file formats are eps, ai, tiff and pdf.The file in original format has been attached.