Simple Pretreatments Research Articles

Determination of multiple analytes in urine using label-free SERS coupled with simple sample pretreatments

Determination of multiple analytes in urine using label-free SERS coupled with simple sample pretreatments

Fabrication of ternary hybrid composites of Co-MOFs/MoS2/PEDOTs for sensitive detection of dopamine and norepinephrine in biological samples

In this study, a simple and multifunctional application for Co-based organic frameworks (Co-MOFs) with molybdenum disulfide (MoS2) and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOTs:PSS) is presented. The Co-MOFs with MoS2 exhibit excellent peroxidase mimicking and catalytic activities, making them suitable for colorimetric dopamine sensors. From an electrochemical standpoint, fouling-free and selective sensing of dopamine (DA) and norepinephrine (NE) is highly challenging. However, the synergistic effect of morphological tunability of Co-MOFs with hybrid composites of MoS2 and PEDOTs:PSS offers a wide detection concentration range of 2 nM-350 µM for DA and 20 nM-1000 µM for NE, high sensitivity, excellent anti-fouling, facile kinetic rate reaction, and rapid signal response. A high selectivity rate was achieved in the presence of twenty times higher concentrations of a mixture of ascorbic acid, uric acid, and other bio-chemical co-interferents. Interestingly, ultrasensitive detection limits of 0.23 nM and 2.18 nM (S/N = 3) were achieved for DA and NE, enabling the real-time precise detection of cellular concentrations in PC12 living cells, and biological fluid samples with simple dilution pretreatments. Moreover, the sensor demonstrated satisfactory reproducibility and stability. Finally, the morphological and composite activity-based probes can detect neurotransmitter concentrations in real samples beyond the concentration limit, suggesting a potential clinical sensor tool.

Characterisation of Pea Milk Analogues Using Different Production Techniques.

Among legumes, peas are characterised by their high protein content, low glycaemic index and exceptional versatility. However, their potential as a food is often compromised by their undesirable off-flavour and taste. Hence, this study focuses on minimising off-flavours through simple pretreatments with the aim of improving the potential for the production of pea milk analogues. Pea milk analogues are a burgeoning type of plant-based milk alternatives in the growing plant-based market. Pea seeds were subjected to different pretreatments: (i) dry milling, (ii) blanching followed by soaking in alkaline solution and subsequent dehulling and (iii) vacuum. Typical physicochemical properties such as pH, viscosity, colour, titratable acidity and yield were measured to obtain a brief overview of the products. Consumer acceptance test, descriptive sensory analysis, gas chromatography-mass spectrometry and gas chromatography-olfactometry were used to map the complete sensory profile and appeal of the pea milk substitutes. The L* values of the pea milk analogues were significantly lower than those of cow's milk, while a*, b*, viscosity and pH were similar. In the descriptive sensory analysis, sweet, astringent, pea-like, cooked, hay-like, boiled corn and green notes received relatively higher scores. The vacuum-treated pea milk analogues received higher scores for flavour and overall acceptability in the consumer acceptance test. The pretreatments resulted in significant changes in the volatile profiles of the pea milk analogues. Some volatiles typically associated with off-flavour, such as hexanal, were found in higher concentrations in blanched pea milk analogues. Among the applied pretreatments, vacuum proved to be the most effective method to reduce the content of volatile off-flavour compounds. This study stands out as a rare investigation to characterise pea milk analogues and to evaluate the impact of simple pretreatments on the improvement of their sensory properties. The results of this study could contribute to the development of milk alternatives that offer both high nutritional value and strong appeal to consumers.

Chemical surface modifications for highly reflective glass/vinyl ester composites with improved silver film adhesion

Silvered glass/vinyl ester composite was developed in this study as a novel approach, to achieve highly reflective surfaces with improved adhesion. As a prerequisite, surface properties of vinyl ester and the changes occurring after the required modifications need to be well understood, but have not been investigated so far. Therefore, one-step and simple pretreatments -alkali or tin-, were applied to modify the composites in short durations. Atomic force microscopy revealed that tin treatment did not change the surface roughness considerably, but increase in O/C ratio was determined by x-ray photoelectron spectroscopy. This led to higher adhesion strength (∼5B) at the silver/polymer interface and a smooth silver film having a reflectance of 95.4% at 550 nm. Alkaline treatment caused more micro holes and layered etchings on the surfaces and thus the resultant silver film was less smooth. The reflectance could reach 94.5% but after 4-folds of duration. No significant change in the composite interlaminar mechanical properties was determined. Fourier transform infrared spectroscopy, scanning electron microscopy, and contact angle measurements were also performed to further characterize the polymer surfaces. The results indicate the potential of these composites for highly reflective and conductive materials to be used in solar energy and aeronautics applications.

Advances in thin layer chromatography coupled with mass spectrometry technology

Thin layer chromatography (TLC) is a very useful liquid chromatography approach. The simple device, convenient operation, versatility, high throughput capabilities, low cost, and simple sample pretreatments make it widely employed in various fields. In recent years, TLC-MS has become one of the most prominent trends for this technology as developments of modern analytical technology and comprehensive application of different approaches. With the development and upgrading of medicine, food, and scientific instrument industries, it is believed that TLC-MS technology should play a better role and obtain an opportunity for development. This study reviewed TLC-MS interface technologies (most of which are in recent 10 years) based on more than 150 studies and classified these TLC-MS technologies as three strategies. The first is indirect coupling using commercially available interface instruments. The second is TLC-in-site detection directly with special MS ion source devices like fast-atom-bombardment desorption ionization, matrix-assisted laser desorption ionization, surface-assisted laser desorption ionization, electrospray-assisted laser desorption ionization, laser-induced acoustic desorption/electrospray ionization, electrostatic-spray ionization, easy ambient sonic-spray ionization, desorption sonic spray ionization, ionization using "desorption/ionization resource", ionization using "molecular ionization-desorption analysis source", multiwavelength laser desorption ionization, ionization using flowing afterglow-atmospheric pressure glow discharge, ionization low-temperature plasma probe, desorption/ionization induced using neutral clusters, ionization using inductively coupled plasma and so on. These MS analyses are performed after TLC development, thus, the relative position of the chromatographic bands on TLCs is invariable, and this analysis can be regarded as static detection, though flexible travel stages or conveyor belts can be introduced to move TLC plates. The third strategy is to monitor TLC run using MS in real-time just as the monitor employed in HPLC, in which the chromatographic bands are still moving. This strategy is generally run on forced-flow TLC techniques and is less examined. The typical coupling technologies (especially appeared in recent ten years) are summarized and briefly described in this study. TLC-MS has greatly enhanced the research efficiency of bioactive substances for food and drugs due to the widespread usage of TLC-bioautography technology. Nowadays, the main bottleneck in the development of TLC-MS is the design and commercialization of "plug and play" components. The high-throughput and real-time monitoring TLC-MS technology with flexible scanning functions is also expected. Furthermore, the comparative studies of different kinds of desorbing-ionizing technologies are also application problems for further discussion.

The Effect of Short Term Alkalinity on Photosynthesis Apparatus in Soil Cyanobacterium Fischerella sp. FS 18 - Ecophysiological Approach

The possibility of change in the phycobilisome status, photosynthetic pigments, ratios and light parameters of soil cyanobacteria <i>Fischerella</i> sp. FS 18 has been investigated by two pre-treatment factors, with neutral and extreme alkaline pH (7 and 9) over a short period. After purification, cyanobacteria were subjected to extreme alkaline treatment for under one hour at 20 min intervals (20, 40 and 60 min). A sample was selected as a control without pre-treatment. Colorimetric assays (phycocyanin, alophycocyanin, phycoerythrin, chlorophyll) and a comparison of the combined effect of time and alkalinity on photosystemic ratios were performed through photophysiology. The photosynthesis - light curves were compared with direct measurements. The results showed that the combination of time and alkalinity after 20 min of inoculation significantly increased the performance of the photosystem and stability of the phycobilin system. The 40 min time interval, under both neutral and alkaline conditions, significantly increased the yield of photosystem II, increased the production of the first photosystem compared to the second system, increased the linear fraction of the photosynthesis-light curve, and reduced the energy needed to achieve maximum photosynthesis. Maximal photosynthesis was entirely different at 40 min pretreatment conditions versus without pretreatment. Concerning the 20 and 60 min time intervals, the results show no specific regularity or trend. Production of light collecting antennas is influenced by both time and alkalinity. Two important conclusions from this study include: applying pre-treatment times, even at 60 min or less, cause a significant change in the structure and performance of the photosynthetic apparatus; as well as,-using simple alkaline pretreatments in a very short time period, saving energy whilst, photosynthesis and cyanobacterial materialization can be significantly increased.

Design of corn straw/paraffin wax shape-stabilized phase change materials with excellent thermal buffering performance

The introduction of 3D structured supporting materials is reckoned as an effective way to relieve the liquid leakage and improve the shape stabilization of phase change materials (PCMs). However, the complicated preparation process and high cost restrict their large-scale application. Herein, shape-stabilized composite PCMs are designed with cheap corn straw (CS) as 3D porous framework via simple pre-treatments. The loading efficiency of paraffin wax (PW) is up to 99.7%, resulting in superior thermal storage and release performance of CS/PW (CP) composite PCMs with phase change enthalpy above 185 J/g. The shape stability temperature of CP rises to 95 °C due to the capillary force. Excellent thermal buffering effect is proved by five highly consistent thermal cycles and only a little loss appears after 200 cycles. Moreover, CP mat with a diameter of 8 cm shows superior thermal buffering performance to retard the cooling of water and avoid the high temperature of table. As compared to rubber mat, 5.6 °C rise on water temperature and 14.5 °C reduction on table temperature are accomplished by CP mat, demonstrating the great application prospect in the field of thermal buffering materials and laying a foundation for the large-scale application of PCMs.

Cost‐effective approaches for acrylamide mitigation in high‐temperature‐processed tuber snacks

Acrylamide is a potential carcinogen produced at higher temperatures while frying, roasting and baking. Starch-rich foods like potatoes are known to produce acrylamide in increasing concentrations than other kinds of foods. This study focuses on mitigation of acrylamide in sweet potato, taro and cassava samples subjected to various heat-treatment processes like oil frying, air frying and baking. Dipping of tuber slices in solutions of garlic, green tea, sodium chloride, yeast, distilled water, whey and blanching prior to frying the tubers were found to be effective pre-treatment methods. However, the effect of the treatments depended on the sample and mode of processing. Yeast was found to produce a significant reduction in the acrylamide production in taro (98.64%) and garlic pretreatment reduced acrylamide in deep fat fried cassava samples up to 95.62%. Similarly, air fried taro samples dipped in distilled water was found to significantly reduce the browning reaction up to 96.51%; primarily due to the fact that distilled water was found to block the reaction between precursors like asparagine and reducing sugars, thereby preventing the formation of acrylamide. Influence of reducing sugar on the formation of acrylamide, when fried at different temperatures was analyzed using Response Surface Methodology (RSM), clearly indicating that the amount of reducing sugars decreased at higher temperatures with increase in acrylamide content. The attempts in the study clearly shows that simple and cost effective pretreatments can be successful applied to produce healthy tuber products with reduced concentration of acrylamide. Practical applications Fried foods are popular among all age groups. However, the acrylamide produced during its processing is a carcinogen of serious concern. Mitigation of this component is an urgent need. The tested simple and cost-effective pre-treatment methods can be applied for acrylamide mitigation in ready-to-eat food processing sector. Moreover these can be practically used by street-food vendors to prepare healthier and safer processed snack foods.

Magnetic solid phase extraction coupled with high-performance liquid chromatography-diode array detection based on assembled magnetic covalent organic frameworks for selective extraction and detection of microcystins in aquatic foods

It is crucially important to develop simple, selective, and rapid extraction pretreatments and analytical methods to detect microcystins (MCs) in food samples with complex matrices. In this study, a magnetic self-assembled covalent organic framework (COF) adsorbent was synthesized via a facile approach by using a one-pot reaction of 1,6-bis(4-formylphenyl)-3,8-bis(4-aminophenyl)pyrene (BFBAPy) as precursors to assemble amino-functionalized magnetic Fe3O4-NH2 nanoparticles (Fe3O4@Py-COF, simplified as mCOF). The superparamagnetic mCOF is found to exhibit a high specific surface area, abundant nanopores and good stability. In particular, adsorption experiments demonstrate that mCOF exhibits a good adsorption capability, efficiency and some specificity to MCs. The mCOF was applied for magnetic solid phase extraction (MSPE) of two kinds of MCs (MC-LR and MC-RR) from aquatic samples followed by high-performance liquid chromatography-diode array detection (HPLC-DAD). Under the optimized conditions, good linearity is obtained in the range of 10-1000 µg/kg (R2≥0.9989), the limits of detection are 3.0-4.5 µg/kg, and the relative standard deviations (RSDs) are lower than 4.9% (n=5). The extraction recoveries are also satisfactory (84.2%-105%). These results demonstrate that the developed method can be used as a good alternative method for the selective determination of MCs in complex aquatic foods.

MALDI-TOF/MS Analysis of Non-Invasive Human Urine and Saliva Samples for the Identification of New Cancer Biomarkers

Cancer represents a group of heterogeneous diseases that are a leading global cause of death. Even though mortality has decreased in the past thirty years for different reasons, most patients are still diagnosed at the advanced stage, with limited therapeutic choices and poor outcomes. Moreover, the majority of cancers are detected using invasive painful methods, such as endoscopic biopsy, making the development of non-invasive or minimally invasive methods for the discovery and fast detection of specific biomarkers a crucial need. Among body fluids, a valuable non-invasive alternative to tissue biopsy, the most accessible and least invasive are undoubtedly urine and saliva. They are easily retrievable complex fluids containing a large variety of endogenous compounds that may provide information on the physiological condition of the body. The combined analysis of these fluids with matrix-assisted laser desorption ionization–time-of-flight mass spectrometry (MALDI-TOF/MS), a reliable and easy-to-use instrumentation that provides information with relatively simple sample pretreatments, could represent the ideal option to rapidly achieve fast early stage diagnosis of tumors and their real-time monitoring. On this basis, the present review summarizes the recently reported applications relevant to the MALDI analysis of human urine and saliva samples.

Fractionation Analysis of Iron in Coastal Rivers to Yantai Sishili Bay with a Bismuth Microrods-Based Electrochemical Sensor

As an essential metal micronutrient, Fe plays an important role in the marine biogeochemical cycling process, and the bioavailability of Fe has a direct relationship with its fractions in water. The fractionation analysis of iron in main coastal rivers to Yantai Sishili Bay was achieved with an electrochemical sensor based on bismuth microrods (BiMRs). The sensor was characterized by scanning electron microscope and electrochemical methods, and the reliability of the sensor was verified by the determination of the standard samples. Different fractions of iron in coastal river waters, including total iron (TFe), total dissolved iron (TDFe) and particulate iron (PFe), have been determined by combining simple sample pretreatments and cathodic stripping voltammetry with the BiMRs-based sensor. The average concentrations of TFe in Guangdang River, Xin’an River and Yuniao River were 4.02, 3.66 and 4.42 μmol L−1, respectively. The main fractionation of iron in three rivers was PFe, which accounts for 84.46%, 87.56% and 92.34%, respectively. Furthermore, the relationships between iron concentration and tidal action, salinity, dissolved oxygen and other factors were also investigated.

Impact strength of surface treated SS316L wires reinforced PMMA**

Abstract Stainless steel 316L (SS316L) as a significant bio-material, their wires were used to support the PMMA matrix. Two simple and low-cost surface pretreatments for SS316L wires were performed to enhance denture impact strength: mechanical scratching (treating SS316L wires with SiC powder inside a rotating container) and electrochemical anodizing. Three mechanical scratching samples for different periods of 60, 90 and 120min were prepared. Anodizing technique conditions were: Ethylene glycol with perchloric acid as an anodizing solution, 15V supplying and graphite rod as an anode. Anodizing process involved three pretreating periods of 15, 20, and 30min. All the prepared samples had dimensions of 65 × 10 × 3 mm. SEM technique showed different morphology nature involved holes, scratches and pores with a density of 104/μm2 and a crack length of 60μm. The PMMA reinforced with scratched stainless steel 316L wire surface for 120 min presented the highest impact strength value (42 kJ/m2) with (450.91%) increment. Anodizing samples showed a fluctuating behavior of samples with enhancing in the impact strength of anodizing wire for 20min of about 26.99 kJ/m2, which is still lower than that for scratched samples in average.

Towards new routes to increase the electrocatalytic activity for oxygen reduction reaction of n-doped graphene nanofibers

A facile preparation of nitrogen doped graphene nanofibers (GNF) is required in order to promote an easy scalable method for the production of batteries using this material as catalyst support. In this work, two simple oxygen pretreatments were developed in order to maximize the nitrogen amount on the structure of the carbon nanomaterial. In that sense, a mild-term oxidation with acid and a high oxidative procedure using potassium permanganate were developed. After that, the two oxidized fibers and the raw ones were doped using a hydrothermal method which use 2-chlorethyl amine as nitrogen donor. All the materials have been deeply studied by SEM, RAMAN, FTIR, CHNS, Zeta potential, XRD, N2 adsorption-desorption and, TGA analysis. The characterization of the material showed that its structure after the treatments was more defective, significantly varying the surface area of the final material. After the hydrothermal treatment different amounts of N atoms (1.2–5.5%) were introduced in the structure depending on the oxidative treatment. The introduction of the nitrogen atoms increases the activity on oxygen reduction reaction (ORR) in almost all the cases, increasing further in the case of the GNF pretreated with acids which increase the electrochemical activity considerably.

Reduction of Internal Phosphorus Load in New Lakes by Pretreatment of the Former Agricultural Soil—Methods, Ecological Results and Costs

New lakes are established or reestablished to provide ecosystem services such as limiting floods and nutrient discharge and to improve biodiversity. New lakes are often established on fertilized land formerly used for agricultural purposes, thereby posing a risk of issues such as phosphorus (P) release when inundated. Release of P from agricultural soil affects both the developing ecosystem of the new lake and may increase downstream eutrophication. To decrease P release following inundation, three simple and cost-effective soil pretreatments were tested through laboratory soil–water fluxes from the test sites in the new Lake Roennebaek and the fluxes of P, nitrogen (N), and iron (Fe) were compared. The pretreatments compared were sand-capping, depth-plowing, and addition of the commercial iron product CFH-12® (Kemira). Untreated agricultural soil incubated under laboratory conditions released 687 ± 88 mg P·m−2 over 207 days and 85% was released within 60 days from inundation followed by low soil–water P exchange during the remaining incubation period. However, P was still released from the untreated soil 180 days after inundation within the lake. The cumulated P flux of the three pretreatment methods was in comparison negative, between −12 ± 3 and −17 ± 4 mg P·m−2 over 207 days incubation and showed negative P fluxes from cores collected within the lake 180 days after inundation. This study showed that the release of P when establishing new lakes on former agricultural land could be minimized using these simple and cost-effective methods, which may improve the ecological status of future lakes and enable the establishment of new lakes without threatening vulnerable downstream ecosystems.

Optimization of orange peel waste ensiling for sustainable anaerobic digestion

Today, orange peel waste (OPW) is mainly used as cattle feed, often after ensiling. This storage phase can increase the efficiency of anaerobic digestion, since it allows both a better management of possible co-digestion and a reduction in the high content of essential oils (mainly composed of d-Limonene a well-known inhibitor of anaerobic digestion). The effects of ensiling on the methane potential of OPW have been little studied, particularly its microbiological profile. This study has simulated, at laboratory scale, OPW ensiling under three different conditions. Ensiled OPW samples were then either directly anaeobically digested or subjected to simple pretreatments aiming at the further removal of d-Limonene. The microbiota evolution during ensiling and the species of microorganisms present during the aforementioned process were also identified. After ensiling, up to over 70% of the initial d-Limonene content of OPW was removed and biomethane yield was preserved up to about 90%.

Exploration advantages of data combination and partition: First chemometric analysis of liquid chromatography–mass spectrometry data in full scan mode with quadruple fragmentor voltages

A novel soft strategy for combination and partition of mass spectra data recorded at different fragmentor voltages in full scan mode of a mass spectrometer was developed to generate abundant multi-way data. It is the first time that non-linear four-way and combined three-way LC-MS data have been obtained simultaneously in a single chromatographic run. This strategy ensures that each analyte can be ionized and detected at the most appropriate MS conditions (ionization modes, fragmentor voltages) and avoids a hard chromatographic segmentation in subsequent chemometric analysis. Two different experimental datasets were analyzed to validate the feasibility and applicability of this strategy. Some simple pretreatments were carried out before LC-MS analysis to prevent potential matrix effects. Proper chemometric tools were used to resolve three-way (partitioned data) and enhanced three-way LC-MS (combined data) data, respectively. The method was assessed by comparing the analytical results obtained from the same chemometric algorithm with both combined and partitioned datasets: (1) the combined data provided the best global overall resolution, higher sensitivity and more reliable results, (2) the partitioned data provided higher selectivity for some specific analytes. The results showed that the developed method could be a soft and ingenious tool to handle the unordered but information-rich raw LC-MS data. Moreover, the proposed strategy could take extra analytical advantages in terms of higher sensitivity and more reliable quantitative results when compared with LC-MS (with single fragmentor voltage) strategy and showed nearly the same capability in analytical quality as classic LC-MS/MS method.

Unraveling human adult hippocampal neurogenesis.

Adult neurogenesis occurs in a few selected regions of the mammalian brain. One such region is the hippocampus, the so-called gateway to memory, where adult hippocampal neurogenesis (AHN) occurs. Here, we provide a comprehensive description of the methods used in our laboratory to unambiguously detect a population of immature neurons in the human hippocampus until the 10th decade of life. The criteria used to refine and develop the current protocol include obtaining post-mortem human samples of remarkable quality and under tightly controlled conditions for immunohistochemistry (IHC) studies, optimizing tissue processing and histological procedures, establishing criteria to reliably validate antibody signal and performing unbiased stereological cell counts. Moreover, we provide a detailed description of the parameters that, in our view, should be reported in human AHN studies. The opposing results obtained by introducing slight variations in the methodological conditions should be considered by future studies that seek to increase our knowledge of this fascinating process. By applying simple and inexpensive tissue pre-treatments, this protocol, which can be completed in 7 days, might be applicable to a variety of IHC studies performed on other tissues of human (or animal) origin.

The complex fingerprint of vancomycin using electrochemical methods and mass spectrometry

Vancomycin (VAN) is a glycopeptide antibiotic, active against Gram-positive bacteria resistant to other antibiotics. VAN therefore needs to be monitored for maximum efficacy and minimum toxicity. Electrochemical sensors can be used for this purpose, using the direct electrochemical signal of VAN. Due to its molecular complexity and the need for analysis from complex matrices, the electrochemical detection of VAN requires the development of a complex electrochemical fingerprint (CEF), which covers a large variety of possible combinations of samples and interferents at concentrations of interest.The objective of this study was to develop a CEF for VAN, involving a battery of tests and the elucidation of the mechanism of anodic oxidation of VAN, using high-performance liquid chromatography coupled with mass-spectrometric analysis of the products obtained after small-scale electrolysis.A CEF for VAN was obtained, describing the electrochemical behavior of VAN at different commercially available screen-printed electrodes, with several electrolytes, considering successive analyses, after simple pretreatments, and examining both anodic and cathodic peaks. The concept was successfully applied to analysis of VAN in real samples and in the presence of some common interferents. Furthermore, a two-step combined electrochemical–chemical mechanism was proposed for the electrooxidation of VAN.

A headspace sorptive extraction method with magnetic mesoporous titanium dioxide@covalent organic frameworks composite coating for selective determination of trace polychlorinated biphenyls in soils

It’s crucial to develop some simple, selective and rapid extraction pretreatments for detection of trace polychlorinated biphenyls (PCBs) residues in soils. Herein, a new magnetic mesoporous titanium dioxide@covalent organic frameworks (Fe3O4@mTiO2@COFs) composite coating was fabricated and adsorbed onto a Nd-Fe-B magnet for headspace sorptive extraction (HSSE) of seven indicative PCBs (PCB28, PCB52, PCB101, PCB118, PCB138, PCB153 and PCB180) in soils. The coating was assembled layer by layer using hydrothermal method. After being extracted by the magnetic stir bar, the adsorbed PCBs can be desorbed in thermal desorption unit (TDU) and measured by gas chromatography-mass spectrometry (GCMS). Under the optimal conditions, the limit of detection (S/N = 3) was measured less than 0.06 ng/g and the linear range was from 0.01 to 100 ng/g. The new coating exhibited good extraction capacity (its saturated adsorption amount was found to be 35 mg/g), selectivity and can be reused for at least 80 times with a recovery above 90%. The HSSE assay showed the following distinctive advantages: Firstly, the outer COFs coating has a uniform size of cavities (about 3.9 nm), thus PCBs (less than 2 nm) can freely pass through them, while the larger macromolecules can be effectively excluded. Secondly, the inner flower-like mTiO2 coating has good affinity towards chlorine-containing organic compounds, which further improves the selectivity for PCBs. Thirdly, both mTiO2 and COFs have large specific surface area. The synergistic effects of the composite coating make the HSSE assay exhibit high capacity, selectivity and prominent sensitivity towards PCBs detection coupling with TDGCMS. Finally, it is an environmentally friendly pretreatment method that does not require any organic solvents.

Simple pretreatment processes for successful reclamation and remanufacturing of crystalline silicon solar cells

AbstractThis study presents an effective method for recovering unbroken solar cells from photovoltaic (PV) modules. The combustion process is effective at removing ethylene vinyl acetate (EVA) in PV modules. However, the solar cell tends to break during the combustion process. We verify that the breakage mechanisms of the solar cell in the module are related to the thermal changes of EVA during the heat treatment process, that is, generated gases form bubbles behind the glass, and the thermal deformation of the rear EVA applies stress to the solar cell. This study investigates the simple pretreatments of glass cracking and EVA patterning to prevent the breakage behavior. An unbroken solar cell was successfully recovered from the module after complete EVA removal using the combustion process. The recovered solar cell was immersed in a mixed acid solution of HNO3 and HF to reclaim the crystalline silicon wafer, which subsequently underwent the solar cell manufacturing process. The PV performances of the solar cells based on the reclaimed wafer and a commercial wafer were evaluated and compared. The PV performance of the solar cell manufactured from the reclaimed wafer was measured at 18.5%, whereas that from the commercial wafer‐based solar cell was measured at 18.7%. Consequently, the considered pretreatment processes yielded solar cells acceptable for use in the PV industry.