Porous Capsules Research Articles

One-year results of the first road surface with the addition of sunflower oil porous capsules

This paper presents findings from the first surface course in the UK employing sunflower oil-filled porous capsules as a self-healing additive. The capsules, designed to mitigate ravelling, were tested on a road constructed at an asphalt plant and subjected to a year of traffic in temperatures ranging from below 0°C to 35°C. Spherical in shape with a diameter of about 1.5 mm, the capsules possess a porous structure filled with sunflower oil. Each tonne of asphalt contained 5 kgs of capsules. The material used was Stone Mastic Asphalt (SMA), one of the UK's most utilised surface course materials. Eight sections were built, with four varying binder contents (6.4 %, 5.9 %, 5.5 % and 5.2 %), each with and without capsules. The road performance was evaluated by measuring two indicators: rut depth and surface macrotexture. Results show that the capsules delay fretting progression in wearing courses. Fretting could have resulted from the complex interaction between early life wearing and asphalt compaction by traffic that caused the mastic to move to the road surface. In addition, no considerable difference in rutting was observed between the different materials. Moreover, core samples were extracted from the road before and after traffic and age exposure for further laboratory analysis to assess the long-term performance. Results showed that stone loss resistance in asphalt-containing capsules was 30.02 % lower before ageing and 25.92 % lower after ageing. Furthermore, the stiffness ageing factor was 15–20 % lower in materials with capsules, while the fatigue life remained consistent across all materials.

Facile synthesis of Co3O4 with porous capsule–shaped structure and its lithium storage properties as anode materials for Li–ion batteries

In this work, a porous Co3O4 anode material with capsule–shaped morphology is prepared by a simple solvothermal method and subsequent heat treatment process in air. The as–synthesized CoCO3 precursor and Co3O4 sample are systematically studied and analyzed by a series of testing technologies, such as XRD, FTIR, FESEM, (HR)TEM, TGA, XPS and N2 adsorption/desorption measurement. As negative materials in Li–ion batteries, the Co3O4 active material exhibits high charge/discharge specific capacity, good rate performance and satisfactory cycle stability. The excellent electrochemical properties are inevitably related to the structural characteristics of the electrode material itself, including regular morphology, rich pore structure, large specific surface area, high crystallinity, nanoscale particle size, etc.

Micropores in Hollow Organic Cage Nanocapsule as a Size Exclusion Gate: Cage Entrapped Pd(II)-Catalyst for Efficient Cross-Coupling Reaction.

Hollow porous organic capsules (HPOCs) with an entrapped active catalyst have nanosized cavities, providing the benefits of a nanoreactor, as well as separation of the catalysts from the reaction medium via pores acting as a size-exclusion gate. Such purpose-built HPOCs with desired molecular weight cutoffs offer the advantages of semipermeable membrane separation and a sustainable chemical process that excludes energy-extensive separation. Here, we report a newly synthesized HPOC with an entrapped Pd(PPh3)2Cl2 as the catalyst for demonstrating a Suzuki-Miyaura coupling reaction as a proof of concept.

Dendrimer-induced synthesis of porous organosilica capsules for enzyme encapsulation

Dendrimer-induced synthesis of porous organosilica capsules for enzyme encapsulation

Structural Effects on ORR Performances of Carbon-Free Connected Platinum–Cobalt Catalysts with Chemically Ordered Superlattice Structures

Polymer electrolyte fuel cells (PEFCs) have been considered as the promising next-generation energy-conversion technology, owing to their high energy efficiency and clean emissions. However, a sluggish oxygen reduction reaction (ORR) rate and the low durability of conventional catalysts in PEFCs limit the wider commercialization. To address these issues, our group has developed a carbon-free, connected Pt1–Fe1 catalyst with a porous hollow capsule structure. This catalyst comprises the nano-sized network formed by the connection of Pt1–Fe1 nanoparticles and exhibits an enhanced ORR specific activity (9 times higher than a commercial Pt/C) as well as excellent durability against start-stop operations due to the carbon-free structure.[1,2] However, during the load cycle operation, iron is dissolved from the catalyst, leading to the loss of ORR activity and the degradation of polymer electrolytes caused by the Fenton reaction.In this work, carbon-free and iron-free connected Ptx-Co1 catalysts with chemically ordered superlattice structures have been developed for the first time, as shown in Fig. 1(a). In addition, the metal compositions and chemically ordered (superlattice) degrees in the catalysts were controlled to investigate the structural effects on ORR activity and durability of the connected Ptx-Co1 catalysts.Herein, we employed the silica-coating method for the catalyst synthesis, which involves the combination of silica coating and high-temperature annealing. As shown in Fig. 1(b), the surface of the Ptx-Co1 nanoparticles/SiO2 sample was coated with thin silica layers to prevent the detachment of Ptx–Co1 nanoparticles from the SiO2 template as well as the large catalyst agglomeration and coalescence during the annealing process. We controlled the chemically ordered degrees of the connected Pt1–Co1 and Pt3–Co1 catalysts by using different annealing temperatures. The XRD patterns of the catalysts showed the peaks corresponding to L10 type and L12 type chemically ordered structures for the connected Pt1–Co1 and Pt3–Co1 catalysts annealed at 600°C, respectively. These two catalysts possessed ordered degrees (S) of ca. 50–60%. The TEM images of the connected Ptx–Co1 catalysts showed the formation of connected Ptx–Co1 nanonetwork and porous hollow capsule structures.The electrochemical measurements of ORR activity and durability were conducted in a 0.1 M HClO4 electrolyte solution. The connected Pt1–Co1 and Pt3–Co1 catalysts achieved 6- and 10-times higher ORR specific activities than that of Pt/C, respectively. Subsequently, the ORR activity and load cycle durability (0.6 V for 3 s Û 1.0 V for 3 s at 60 °C) of the connected Pt3–Co1 catalyst with different ordered degrees (S = 0%, 28%, and 58%) were evaluated. As the ordered degrees in the connected Pt3–Co1 catalysts were higher, the ORR specific activity was increased. Also, the retention of the specific activity of the ordered catalyst (S = 58%) was higher than that of the disordered catalyst (S = 0%) after 10,000 load cycles. The STEM-EDX line mapping results showed that 83% of the alloyed Co retained in the catalyst with a higher ordered degree even after 10000 load cycles, whereas the disordered and lower ordered catalysts retained lower Co ratios after the test, indicating the suppression effect of an ordered structure on metal dissolution. In addition, the L12 ordered Pt3–Co1 structure remained in the connected catalyst (S = 58%) after load cycle test, confirmed by the TEM diffraction analysis.In summary, we successfully developed the connected Ptx-Co1 catalysts with chemically ordered superlattice structures. In addition, we clarified the structural effects of metal composition and ordered degree in connected Ptx-Co1 catalysts on ORR activity and load cycle durability. These results provide useful guidelines for the design of advanced ORR catalysts towards high-performance PEFCs. Acknowledgement The part of this presentation is based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

Metal-Doped ZIF-8 Derived Hollow Carbon for High-Performance Lithium-Sulfur Batteries

Lithium-ion (Li-ion) batteries have been ubiquitously utilized in the modernized world in portable electronic, electrical vehicles, and grid-scale energy storage. However, demand satisfaction for traditional Li-ion batteries is becoming difficult due to their limited capacity and energy density. Moreover, there are challenges related to the availability of non-renewable critical materials for Li-ion batteries such as Co, Ni, and graphite, and environmental pollution during battery creation and recycling. Further neglect of these problems will lead to dramatic consequences at which batteries will become a part of the environmental problems but not a solution to these problems as they should be. Therefore, it is highly imperative to explore novel battery systems that show high energy density, low production cost and low environmental pollution during production, use and recycling. One of the most promising candidates is the lithium-sulphur (LiS) battery, which offers various advantages such as high energy density, high theoretical specific capacity, and affordable cost, because of the high availability of elemental sulphur and carbon used in this type of battery. The theoretical gravimetric energy density of LiS batteries is 2567 Wh/kg which is 4.5 times higher than the energy density of conventional Li-ion batteries. Despite the richness of sulphur in the Earth’s crust and its prominent merits in energy density and cost, several problems have restricted the development of LiS batteries for commercialization. The most notorious and intractable problem is the high solubility of the sulphur species (Li2Sx, 3≤x≤8) in common Li-ion battery electrolytes that leads to the so-called lithium polysulfide (LiPS) shuttle effect and loss of battery capacity, Li metal anode corrosion, and low coulombic efficiency during interaction of the LiPS with Li metal anode. The most prospective solution to address the above drawbacks is sulphur incorporation with a porous, high-conductive carbon host that will tolerate sulphur volume expansion, improve the conductivity of the electrode, prevent the shuttle effect, and allow reversible lithium-ion migration during charging and discharging.However, to achieve the excellent operation performances of the porous carbon host its properties should be carefully tuned and the LiPS absorption ability of the carbon host should be improved for example by metal oxide doping. Many different strategies for the creation of the required material were proposed in recent years. Unfortunately, many proposed synthetic methods require a hard template to provide fine control of the pore distribution in the materials, which is a significant drawback as in this case harsh conditions are required for template removal. In addition, the formation of doped carbons with good electrical conductivity often demands high temperatures, simultaneously causing the undesirable reduction of metal cations to their metallic state followed by the aggregation to form nanoparticles, together with the collapse of the carbon matrices. Therefore, it still urgently needs to find a new strategy to produce a porous carbon host for the sulfur with fine porosity and good lithium polysulfide absorption ability, which purpose to accelerate the successful commercialization of this battery technology on the market.In our current work, we are investigating the possibility to synthesize finely dispersed metal oxide catalysts on hollow N-doped porous carbon capsules produced from zeolitic imidazolate framework (ZIF-8). The coating of the ZIF-8 with metal–tannic acid coordination polymer allows to uniformly dispersed metal oxide nanoparticles, such as Fe2O3, MnO, CoO etc., on hollow carbon capsules after the pyrolysis process. Moreover, the carbon produced by ZIF-8 pyrolysis is expected to be both doped with nitrogen and highly porous, which should have a positive effect on the maximum sulfur loading possibility in the carbon host and lithium polysulfide absorption ability. In addition, the used approach for the synthesis of the hollow N-doped porous carbon allows the distribution of multicomponent metal oxide nanoparticles on the surface of the hollow carbon capsules, which may have a synergetic effect and improve the lithium polysulfide absorption ability of the produced materials. The structural, compositional, and morphological properties of the created material are investigated using SEM, EDS, XPS, Raman spectroscopy, FTIR and TGA techniques. The effect of the different metal oxide nanoparticles and their combinations on the lithium polysulfide absorption ability of the synthesized materials are investigated by analysis of the electrochemical performances of the Li-S batteries, where synthesized material was used as the sulfur host during the creation of the Li-S battery cathode.

Porous Starch-Based Capsule as an Effective Colon-Targeting Carrier for Oral Paclitaxel Delivery

Porous Starch-Based Capsule as an Effective Colon-Targeting Carrier for Oral Paclitaxel Delivery

Functional Carbon Capsules Supporting Ruthenium Nanoclusters for Efficient Electrocatalytic 99 TcO4 - /ReO4 - Removal from Acidic and Alkaline Nuclear Wastes.

The selective removal of the β-emitting pertechnetate ion (99 TcO4 - ) from nuclear waste streams is technically challenging. Herein, a practical approach is proposed for the selective removal of 99 TcO4 - (or its surrogate ReO4 - ) under extreme conditions of high acidity, alkalinity, ionic strength, and radiation field. Hollow porous N-doped carbon capsules loaded with ruthenium clusters (Ru@HNCC) are first prepared, then modified with a cationic polymeric network (R) containing imidazolium-N+ units (Ru@HNCC-R) for selective 99 TcO4 - and ReO4 - binding. The Ru@HNCC-R capsules offer high binding affinities for 99 TcO4 - /ReO4 - under wide-ranging conditions. An electrochemical redox process then transformsadsorbed ReO4 - to bulk ReO3 , delivering record-high removal capacities, fast kinetics, and excellent long-term durability for removing ReO4 - (as a proxy for 99 TcO4 - ) in a 3m HNO3 , simulated nuclear waste-Hanford melter recycle streamand an alkaline high-level waste stream (HLW) at the U.S. Savannah River Site (SRS). In situ Raman and X-ray absorption spectroscopy (XAS) analyses showed that adsorbed Re(VII) is electrocatalytically reduced on Ru sites to a Re(IV)O2 intermediate, which can then be re-oxidized to insoluble Re(VI)O3 for facile collection. This approach overcomes many of the challenges associated with the selective separation and removal of 99 TcO4 - /ReO4 - under extreme conditions, offering new vistas for nuclear waste management and environmental remediation.

Water consumption of three ornamental species with the suction irrigation system

Objective: To evaluate water consumption in ornamental plants (geranium, gazania and petunia) in two substrates with different particle sizes (fine and coarse) of tezontle and peat moss, through a suction irrigation system, which uses porous capsules as irrigation emitters. Design/methodology/approach: The experimental design was in complete randomized blocks, with six treatments (three ornamental species and two substrates) with four repetitions (24 experimental units). The first mixture contains fine substrate (composed of tezontle with particle size less than 0.4 mm) and peat moss, in a 1:2 v/v ratio; the second mixture presents coarse substrate (composed of tezontle with particle size between 0.4-0.6 mm) and peat moss, 1:1 in v/v. Results: In water consumption, there are significant differences by ornamental species and type of substrate, where the irrigation system has the ability to self-regulate. The highest water consumption was in petunia in the coarse substrate (which has a higher proportion of peat moss in its composition). Limitations on study/implications: With use in protected agriculture, rural and urban orchards, gardens, walls and green roofs and research purposes. Findings/Conclusions: The suction irrigation system through porous capsules has the capacity to continuously supply the water demanded by the plant-substrate-atmosphere system.

The Combination of Progesteron Sponge, PMSG and Minimal Dose PGf2 Alfa toward Sheep Pregnantion

Background: The goal of this study was to confirm the effects of the engineering design of the vaginal progesterone implant capsule, which had a 2 cm sponge with a diameter of 5 cm, a 2 cm porous capsule with a dose of 50 mg MAP in the centre and 13 cm nylon cord for keeping the sponge in position. Methods: A full concentrate total protein 17% consumed at 0.05 kg/day/head was previously administered to as many as 30 overweight ewes with a body score of at least 3 and those who were positively identified as having ever given birth to help them improve their body score condition. It was found that T0 consisted of 10 obese female sheep that underwent a normal oestrous cycle without oestrus synchronization therapy and waited for natural oestrus, while T1 and T2 consisted of 10 sheep that received progesterone implant capsule vaginal sponges with a dose of 50 mg MPA on day 0 getting 100 IU sc PMSG folligon intervet Holland in addition. Result: On day 35, the oestrous response was 100% and the pregnancy rates were 70%, 80% and 80% in T0, T1 and T2 groups, respectively (p greater than 0.05). Progesterone levels in the groups non pregnant are 1,66±0.8; 1,23±0.78 and 1,60 ± 0.90 ng/ml (p greater than 0.05).

Encapsulation of polyethylene glycol in cellulose-based porous capsules for latent heat storage and light-to-thermal conversion

Encapsulation of polyethylene glycol in cellulose-based porous capsules for latent heat storage and light-to-thermal conversion

Mezankimal Kök Hücre Enkapsülasyonu için 3B Baskı ile Makro Kapsül Üretimi

Purpose: Cell transplantation is a widely used method to induce cell-mediated immune reactions inside the body. However, possible immune responses to the transplanted cells decrease the efficiency of applied cell therapy. This issue can be addressed by the transplantation of cells via 3D-printed polymeric capsules which encapsulate cells and protect them from immune system attacks. Cell-loaded capsules (macro or micro) have emerged as potential carriers for more efficacious cellular therapies. In this study, 3D-printed porous capsules were prepared from biodegradable and biocompatible polyester “polycaprolactone (PCL)” and this macro-capsule was evaluated as a carrier for its cell encapsulation effectiveness.
 
 Method: The macro-capsule was designed to have dimensions of 2x5x10 mm and drawn in Autodesk Fusion 360 program. PCL was utilized for its 3D bio-printing via Axolotl Bioprinter Dual Print Head System. Leakage on the closed form of the macro-capsule was visually controlled by surface electron microscopy (SEM). Permeability of the macro-capsule was tested with trypan blue dye and human serum albumin (HSA) protein. Sterilization of the obtained macro-capsule was achieved via UV light and the cytotoxicity of the polycaprolactone capsule was tested for 24 and 72 hour incubation time periods.
 
 Results: The semi-permeable macro-capsule was successfully obtained as closed and hollow form. Its porous structure was demonstrated using trypan blue dye. To evaluate the porosity of the macrocapsule, human serum albumin (HSA) protein release was performed from the macrocapsule. It has been shown that 98% of HSA was released from the macrocapsule within 24 hours. The polycaprolactone (PCL) macrocapsule was sterilized using UV light and was reported to show no in vitro cytotoxicity. In addition, it was shown that the cells in the macro-capsule consumed at least 10% glucose from the outside medium during 12 days of incubation, compared to 2D cell culture conditions, and were able to release at least 8% of the lactic acid molecules outside.
 
 Conclusion: In conclusion, reproducible fabrication of polymer macro-capsule, high viability of encapsulated cells inside, and their metabolic assessment results have obviously indicated the potential of these capsules as effective carriers for living cells with transplantation-dependent cellular therapies.

In situ synthesis of integrated dodecahedron NiO/NiCo2O4 coupled with N-doped porous hollow carbon capsule for high-performance supercapacitors

NiO and NiCo2O4 exhibit excellent synergistic effects and broad application prospects in electrochemical applications. However, the apparent interfacial instability between NiO and NiCo2O4 limits ion transport kinetics, charge/ion transfer, and electrochemical stability. In response, we developed and designed an integrated dodecahedron NiO/NiCo2O4 by a facile in-situ calcination method. Moreover, by utilizing the porous hollow structure of nitrogen-doped carbon capsules (N-Cc) as a conductive network, the N-Ccx@NiO/NiCo2O4 heterostructures with stable interface structure, excellent electrolyte adsorption, and electron transfer pathways were carefully designed. The N-Cc1.0@NiO/NiCo2O4 heterostructures are found to deliver an outstanding specific capacitance of 658.8 F g−1, and a high energy density of 101.40 Wh kg−1 at a power density of 775.03 W kg−1, along with capacitance retention of more than 93.5% after 8000 cycles. Based on the DFT calculations and electrochemical experimental results, this work provides an effective in situ route for the construction of high-performance metal oxide heterostructure electrode materials for new energy storage devices.

Construction of Covalent Organic Framework Capsule-Based Nanoreactor for Sensitive Glucose Detection.

Enzyme immobilization is critical to boosting its application in various areas. Covalent organic frameworks (COFs) are ideal hosts for enzyme immobilization due to their porous and predesignable structures. Nevertheless, the construction of COFs-based enzyme immobilization systems with high activity via existing immobilization methods (including covalent linkages and channel entrapment) remains a considerable challenge. Herein, a versatile approach was introduced to encapsulate enzymes within hollow COF capsule (named enzyme@COF) using metal-organic frameworks (including ZPF-1(C8H11N4O4.5Zn), ZIF-8(C8H10N4Zn), and ZIF-90(C8H6N4O2Zn)) as sacrificial templates. The obtained porous COF capsule could not only facilitate the efficient mass transfer of enzymatic reactions but also protect enzymes against the incompatible conditions, resulting in enhanced activity and stability of the encapsulated enzymes. Moreover, this approach offered an opportunity to spatially organize multienzymes in COF capsule to construct enzyme cascade system. For instance, glucose oxidase (GOx) and cytochrome c (Cyt c) were coencapsulated within COF capsule to construct GOx-Cyt c cascade. The integration of GOx and Cyt c within COF capsule achieved ∼1.6-fold improvement in catalytic activity than that of free enzymes and the resultant GOx-Cyt c@COF was successfully adopted as a nanoreactor for the sensitive determination of glucose in serum. This work provided a new insight into the design of COFs-based enzyme immobilization systems.

Fabrication of NiPS3 coupled with hollow porous nitrogen-doped carbon capsules for high-performance asymmetric supercapacitor

NiPS3 electrodes usually suffer from aggregation large volume changes, low electrical conductivity, and huge volume changes in bulk phase. These significantly decrease the electron transport efficiency, resulting in the sluggish reaction kinetics of supercapacitors during cycling. Herein, we designed and produced hollow porous nitrogen-doped carbon capsules (N-Cc), which are used as a conductive matrix and dispersed growing substrate for NiPS3. Finally, NiPS3 nanosheets were successfully grown in situ on N-Cc by chemical vapor deposition method. The specific capacitance of the highly integrated N-Cc@NiPS3-1.0 electrode structure is notable, at 590 C g−1. The assembled N-Cc@NiPS3-1.0//AC asymmetric supercapacitor (ASC) delivers an energy density of 55.42 Wh kg−1 at power density of 750.05 W kg−1 and an outstanding stability with 89.9 % of retention rate for 8000 cycles. It should be noted that the performance of the N-Cc@NiPS3-1.0 here surpasses most of previously reported similar materials.

Monolithic capsule phase microextraction prior to gas chromatography-mass spectrometry for the determination of organochlorine pesticides in environmental water samples

In this study, a capsule phase microextraction (CPME) protocol followed by gas chromatography-mass spectrometry is proposed for the accurate and sensitive monitoring of organochlorine pesticides (OCPs) in environmental water samples. Different monolithic sol–gel encapsulated sorbents were compared and monolithic sol–gel poly(ethylene glycol)-based sorbent incorporated into porous microextraction capsules resulted in the highest extraction efficiency. Following the selection of the microextraction device, the CPME conditions were optimized, while linearity, limits detection (LODs), limits of quantification (LOQs), accuracy, and precision were the figures-of-merit measured. Under optimum conditions the LODs for the OCPs ranged between 0.01 ng mL−1 and 0.03 ng mL−1. The relative standard deviations were better than 5.3 % and 9.2 % for intra-day and inter-day study, respectively. The relative recoveries ranged between 90.5 and 105.2 % (intra-day) and 93.0–105.0 % (inter-day), demonstrating good method trueness. Finally, the proposed protocol was implemented for the monitoring of OCPs in tap, river, pond, and lake water. The developed method presents better analytical features than existing methods.

Green capsule phase microextraction employing hydrophobic monolithic sol-gel octadecyl siloxane platforms for the monitoring of organophosphorus pesticides in environmental water samples

In this study, a novel, facile and green capsule phase microextraction (CPME) method is presented for the extraction and preconcentration of organophosphorus pesticides (i.e., chlorpyrifos, disulfoton, ethoprophos, fenchlorphos, prothiofos, and parathion-methyl) from environmental water samples. Monolithic sol-gel octadecyl siloxane (sol-gel C18) sorbent encapsulated within porous polypropylene capsules was synthesized, characterized, and evaluated for its efficiency towards the adsorption of the target organophosphorus pesticides. CPME was combined with gas chromatography-mass spectrometry (GC-MS) for the monitoring of the target analytes. The method was optimized to ensure high method sensitivity and it was fully validated. The limits of detection of the CPME-GC-MS method for the OPPs were 0.02–0.15 ng mL−1. The relative standard deviations were 1.5–8.7% for intra-day study and 5.4–9.6% for inter-day study, demonstrating satisfactory precision. Moreover, good method accuracy was obtained, since the relative recoveries were within the range 92.6–107.0% and 90.8–107.6% for intra-day and inter-day (c = 5.00 and 20.0 ng mL−1), respectively. The absence of interferences in the blank samples demonstrates that the proposed method is selective. The sol-gel C18 sorbent encapsulated CPME media could be reused for at least 25 adsorption/desorption cycles. In addition, the methodology presents advantageous features in comparison to existing methods. The final protocol was used for analyzing four different water sample types (i.e., lake water, river water, pond water and tap water sample).

Long-Term Antibody Release Polycaprolactone Capsule and the Release Kinetics in Natural and Accelerated Degradation.

Although therapy using monoclonal antibodies (mAbs) has been steadily successful over the last 20 years, the means of delivery of mAbs has not been optimized, especially for long-term delivery. Frequent injections or infusions have been the current standard of care. In this study, we have developed a long-term antibody biodegradable implant using a porous polycaprolactone (PCL) capsule. It released bevacizumab (Bev) slowly for 8 months to date. The Bev release kinetics fit a drug release model with experimental data of the diffusion coefficient and partition coefficient through the polymer capsule. Since screening drug release profiles for the long term (>6 months) is time consuming, an accelerated degradation method was used after validating the characteristics of the PCL capsule in natural and accelerated degradation conditions. The correlation of the time period between natural and accelerated degradation was determined. Overall, the study suggests that mAbs can be released from a porous PCL capsule without an effect of the polymer degradation over a long period (∼6 months) and the long-term release kinetics can be determined by the accelerated degradation within 14 days.

Comparison of solution extraction methods for estimating electrical conductivity in soils with contrasting mineralogical assemblages and textures

Characterization of the soil solution is of fundamental importance for monitoring plant nutrient availability, environmental contamination, and evaluation of salt-affected soils. Due to the diversity of methodologies adopted in various parts of the world, comparison of the most common extraction methods in different types of soils is warranted. This study compared the efficiency of five soil solution extraction methods for five soils with different mineralogical assemblages and textures with the most commonly used saturated paste extract method. The extraction methods compared were: centrifugation, porous extractor capsules, and soil–water extracts (soil:water ratio of 1:2, 1:5, or 1:10). The soil types evaluated were: Regosol, Luvisol, Gleysol, Nitisol and Ferrosol in the soil surface and subsurface horizons. Linear regression equations were developed that allowed accurate estimation of electrical conductivity of the saturated paste extract (ECse). Ten equations were developed for the porous capsule method, eight were developed for the centrifugation method (with the exception of the Regosol with 900 g k−1 of total sand, which was not suitable for this method due to the high sand content), and 30 equations were developed for the soil–water extract method (at each of the soil:water ratios tested). The diversity of equations developed for soils with different mineralogical assemblages and textures should assist growers and extension workers who need to know the soil electrical conductivity for making soil management decisions.

Designing an “all-in-one” microextraction capsule device for the liquid chromatographic-fluorescence determination of doxorubicin and its metabolites in rat plasma

In this study, an “all-in-one” microextraction device was designed and fabricated for the extraction of doxorubicin and its two metabolites from rat plasma prior to their determination by high performance liquid chromatography coupled to fluorescence detector. A sol-gel-based sorbent was synthesized in situ and incorporated within two conjoined porous polypropylene tubes together with a cylindrical magnetic bar in order to avoid the need of an external stirring bar. Among other sorbents investigated, the moderately polar sol-gel poly(tetrahydrofuran) was found to be advantageous due to its high affinity toward the target analytes. Systematic investigation of the critical parameters affecting the adsorption and the desorption step was carried out. Due to the “built-in” filtration mechanism of the porous microextraction capsules, the isolation of the analytes was performed directly in the plasma matrix without any previous sample pretreatment (i.e., protein precipitation, centrifugation, etc.). The proposed method was validated in terms of linearity, accuracy, precision, specificity, sensitivity, and stability according to the FDA guidelines. The limits of detection ranged between 1 – 2 ng mL−1 while the lower limits of quantitation of the analytes were calculated as 10 ng mL−1. The accuracy (% relative error) was found within -9.7 – 15.3% under both intra- and inter-day conditions. The precision was better than 13.4% in all cases. ComplexGAPI index was employed to present the green attributes of the developed protocol from the preparation of the microextraction device to the final determination of the analytes. Finally, the applicability of the fabricated stand-alone extraction device was demonstrated in the analysis of the target analytes in rat plasma after intravenous administration of doxorubicin in order to assess its pharmacokinetic profile.