Photoresponsive Hydrogen-Bonded Organic Frameworks-Enabled Organic Photoelectrochemical Transistors for Sensitive Bioanalysis.

A facile route for exponential magnification of transconductance (gm) in an organic photoelectrochemical transistor (OPECT) is still lacking. Herein, photoresponsive hydrogen-bonded organic frameworks (PR-HOFs) have been shown to be efficient for gm magnification in a typical poly(ethylene dioxythiophene):poly(styrenesulfonate) OPECT. Specifically, 450 nm light stimulation of 1,3,6,8-tetrakis (p-benzoic acid) pyrene (H4TBAPy)-based HOF could efficiently modulate the device characteristics, leading to the considerable gm magnification over 78 times from 0.114 to 8.96 mS at zero Vg. In linkage with a DNA nanomachine-assisted steric hindrance amplification strategy, the system was then interfaced with the microRNA-triggered structural DNA evolution toward the sensitive detection of a model target microRNA down to 0.1 fM. This study first reveals HOFs-enabled efficient gm magnification in organic electronics and its application for sensitive biomolecular detection.

Anisotropic Multitentacle Janus Particles Synthesized by Selective Asymmetric Growth.

Anisotropic colloidal particles with asymmetric morphology possess functionally rich heterogeneous structures, thus offering potential for intricate superstructures or nanodevices. However, it is a challenge to achieve controlled asymmetric surface partitioned growth. In this work, an innovative strategy is developed based on the selective adsorption and growth of emulsion droplets onto different regions of object which is controlled by wettability. It is found that the emulsion droplets can selectively adsorb on the hydrophilic surface but not the hydrophobic one, and further form asymmetric tentacle by the interfacial sol-gel process along its trajectory. Janus particles with an anisotropic shape and multitentacle structure are achieved via integration of emulsion droplet (soft) and seed (hard) templates. The size and number of tentacles exhibit tunability mediated by soft and hard templates, respectively. This general strategy can be expanded to a variety of planar substrates or curved particles, further confirming the correlation between tentacle growth and Brownian motion. Most interestingly, it can be employed to selectively modify one region of surface partitioned particles to achieve an ABC three-component Janus structure.

Magnetic targeting and pH-microwave dual responsive Janus mesoporous silica nanoparticles for drug encapsulation and delivery.

In this paper, a new Janus-structured nano drug delivery carrier Fe3O4@TiO2&mSiO2was designed and synthesized, which consisted of a spherical head and a closely connected rod. The head was a nanocomposite of core/shell structure with magnetic spinel ferric tetraoxide core and anatase titanium dioxide shell (Fe3O4@TiO2), and the rod was ordered mesoporous silica (mSiO2). The nanocarriers showed excellent magnetic targeting capability (saturation magnetization, 25.18 emu g-1). The core/shell heads endowed the carriers with fine microwave responsiveness. The pore volume of mesoporous nanocarriers was 0.101 cm3g-1, and the specific surface area was 489.0 m2g-1. Anticancer drug doxorubicin could be loaded in the mesoporous of the carriers to form Fe3O4@TiO2&mSiO2-DOX. The drug loading capacity was 10.4%. Fe3O4@TiO2&mSiO2-DOX exhibited acid-sensitive and microwave-sensitive release properties along with good bio-compatibility. Fe3O4@TiO2&mSiO2Janus nanoparticles are expected to be ideal drug carriers.

Analysis of ester-producing performance in high-yield ethyl hexanoate yeast and the effect on metabolites in bio- enhanced Daqu, the starter for Baijiu and other traditional fermented foods.

AIMS: Ethyl hexanoate, one of the key flavor compounds in strong-flavor Baijiu. To improve the content of ethyl hexanoate in strong-flavor Baijiu, a functional strain with high yield of ethyl hexanoate was screened and its ester-producing performance was studied. METHODS AND RESULTS: Upon identification, the strain was classified as Candida sp. and designated as ZY002. Under optimal fermentation conditions, the content of ethyl hexanoate synthesized by ZY002 can be as high as 170.56 mg L-1. A fermentation test was carried out using the ZY002 strain bioaugmented Daqu to verify the role of the strain applied to Baijiu brewing. It was found that strain ZY002 could not only improve the moisture and alcohol contents of fermented grains but also diminish the presence of reducing sugar and crude starch. Furthermore, it notably amplified the abundance of flavor compounds. CONCLUSION: In this study, Candida sp. ZY002 with a high yield of ethyl hexanoate provided high-quality strain resources for the actual industrial production of Baijiu.

N-rich hypercrosslinked porous polymers for highly efficient preconcentration and sensitive detection of chlorophenols.

Three novel N-rich hypercrosslinked porous polymers (NHCP1, NHCP2, and NHCP3) were facilely developed using Friedel-Crafts alkylation. NHCP1 with a remarkably large surface area (2066 m2 g-1) showed the best adsorption performance for chlorophenol pollutants. A sensitive and simple method was developed by using NHCP1 as a sorbent for solid-phase extraction to preconcentrate several chlorophenols in honey, water, and peach beverage samples followed by determination using a high-performance liquid chromatography-ultraviolet detector. The detection wavelength was 280 nm. Under the optimized conditions, the linear ranges were 1.67-1000 ng g-1 for honey, 0.170-100 ng mL-1 for water, and 0.330-100 ng mL-1 for peach beverage samples. The detection limits (S/N = 3) were 0.500-2.00 ng g-1, 0.0500-0.100 ng mL-1, and 0.100-0.200 ng mL-1, respectively. Recovery values were 89.3-111% with relative standard deviations <9.4%. The proposed extraction/preconcentration and quantitative analysis method provides an affordable and effective alternative for the preconcentration and determination of low levels of chlorophenols in real samples.

Chronic stress inhibits testosterone synthesis in Leydig cells through mitochondrial damage via Atp5a1.

Stress is one of the leading causes of male infertility, but its exact function in testosterone synthesis has scarcely been reported. We found that adult male rats show a decrease in bodyweight, genital index and serum testosterone level after continual chronic stress for 21 days. Two-dimensional gel electrophoresis (2-DE) and MALDI-TOF-MS analysis identified 10 differentially expressed proteins in stressed rats compared with controls. A strong protein interaction network was found to be centred on Atp5a1 among these proteins. Atp5a1 expression significantly decreased in Leydig cells after chronic stress. Transfection of Atp5a1 siRNAs decreased StAR, CYP11A1, and 17ß-HSD expression by damaging the structure of mitochondria in TM3 cells. This study confirmed that chronic stress plays an important role in testosterone synthesis by regulating Atp5a1 expression in Leydig cells.

Sustainable synthesis of hydroxyl-functional porous organic framework as novel adsorbent for effective removal of organic micropollutants from water.

Organic micropollutants (OMPs) in water resources are a growing threat to aquatic ecosystems and human health. Efficient removal of polar OMPs is very challenging because of their high hydrophility. Synthesizing novel adsorbent capable of high-efficiently removing hydrophilic and hydrophobic micropollutants is highly desirable for water remediation. Here, using natural proanthocyanidin as building units, a novel hydroxyl-functional porous organic framework (denoted as PC-POF) with amphiphilic feature was synthesized through facile azo coupling reaction. Five sulfonamide antibiotics were selected as model OMPs for adsorption study. Adsorption experiments demonstrated a more rapid and efficient sulfonamides capture ability of the PC-POF than that of the most reported adsorbents due to strong hydrogen bonding, π stacking and electrostatic interactions. The PC-POF can be easily recovered and reused at least 5 times without obvious decline in adsorption performance. Moreover, experiments conducted at environmentally relevant concentrations (µg L-1) further confirmed a notable adsorption performance of the PC-POF even when the sulfonamides solution was rapidly passed through the PC-POF packed column. The PC-POF also showed good adsorption performance for other micropollutants like neonicotinoid insecticides, nitroimidazole antibiotics and triazine herbicides, indicating a promising prospect. This work provides a new strategy to construct amphiphilic adsorbent by using renewable resources for pollutants removal.

Early maternal deprivation impairs learning and memory and alters hippocampal gene expression in adult male rats.

Maternal deprivation (MD) in early life severely disrupts hippocampal development, leading to persistent cognitive and behavior deficits. The current study uncovered that early MD (P1-P21) impaired spatial learning and memory capacity detected by Morris water maze (MWM) tests from juvenile (P31) to adult (P81) rats compared to age-matched controls. And the protein expression in hippocampus were detected by two-dimensional gel electrophoresis (2-DE) before MWM, respectively. Protein changes in hippocampal were examined to identify the molecular pathways underlying MD-induced hippocampal dysfunction. There were 11 differentially expressed proteins analyzed between adult MD and control male rats, while the 8 proteins were then identified by UPLC-ESI-Q-TOF-MS. Gene Ontology (GO) annotations of the identified proteins were related to neuronal and glial cytoskeletal dynamics, membrane signaling, stress responses, biosynthesis, and metabolism. The different expression proteins spectrin alpha chain, non-erythrocytic 1 (Sptan1), ATP-citrate synthase (Acly), and heat shock protein 90-alpha (Hsp90aa1) have been verified by western blot analysis, and their expression levels showed consistent with 2-DE analysis. In addition, glial fibrillary acidic protein (GFAP) was also found reduced in adult hippocampus of MD rats. This study identifies candidate proteins encompassing a range of functional categories that may contribute to persistent learning and memory deficits due to early life MD.

Fabrication of carbonyl-functional hypercrosslinked polymers as solid-phase extraction sorbent for enrichment of chlorophenols from water, honey and beverage samples.

Three carbonyl-functional novel hypercrosslinked polymers (HCP-TPS, HCP-TPA, and HCP-TPP) were successfully fabricated through an one-step Friedel-Crafts acylation reaction by copolymerizing paraphthaloyl chloride with triphenylsilane, triphenylamine, and triphenylphosphine, respectively. The resultant HCPs contained plenty of carbonyl-functional groups. Among the series of such HCPs, HCP-TPS displayed the best adsorption capability to chlorophenols (CPs), and thus it was employed as solid-phase extraction (SPE) adsorbent for enrichment of chlorophenols from water, honey, and white peach beverage prior to determination by high-performance liquid chromatography. Under the optimal conditions, the detection limits of the method (S/N = 3) were 0.15-0.3 ng mL-1 for tap water and leak water, 2.5-6.0 ng g-1 for honey sample and 0.4-0.6 ng mL-1 for white peach beverage sample. The recoveries of CPs in the spiked water, honey samples, and white peach beverage were in the range of 89.0-108.4%, 81.4-118.2%, and 85.0-113.5%, respectively. This work provides a new strategy for constructing functionalized HCPs as efficient SPE adsorbents. In this work, three novel hypercrosslinked polymers (HCPs) were synthesized by the Friedel-Crafts alkylation reaction (paraphthaloyl chloride as the alkylating agent, triphenylsilane, triphenylamine, and triphenylphosphine as the aromatic units). Then, HCP-TPS was applied to soild-phase extraction sorbent for enrichment CPs from water, honey, and white peach beverage samples.

Comparison of the Whole-Genome Sequence of an Oka Varicella Vaccine from China with Other Oka Vaccine Strains Reveals Sites Putatively Critical for Vaccine Efficacy.

Varicella-zoster virus (VZV) infection results in varicella mostly in children. Reactivation of the virus causes herpes zoster (HZ), mostly in adults. A live attenuated vaccine (vOka-Biken) was originally derived from the parental strain pOka. Several live attenuated vaccines based on the Oka strain are currently available worldwide. In China, varicella vaccines have been licensed by four manufacturers. In this study, we analyze the whole-genome sequence (WGS) of vOka-BK produced by Changchun BCHT Biotechnology also known as Baike. vOka-BK WGS was compared against the genomic sequences of four other Oka strains: pOka, vOka-Biken, vOka-Varilrix from GlaxoSmithKline, and vOka-Varivax from Merck & Co. A previous study identified 137 single nucleotide polymorphisms (SNPs) shared by all vOkas. The current analysis used these data as a reference to compare with vOka-BK WGS and focused on 54 SNPs located in the unique regions of the genome. Twenty-eight nonsynonymous substitutions were identified, ORF62 and ORF55 featuring the most amino acid changes with 9 and 3, respectively. Among the 54 SNPs, 10 had a different mutation profile in vOka-BK compared to the other three vaccines. A comparison with the clade 3 strain Ellen, known to be attenuated, identified three shared amino acid changes: *130R in ORF0 and R958G and S628G in ORF62. This analysis provides the first comparison of a Chinese varicella vaccine to the other vaccines available worldwide and identifies sites potentially critical for VZV vaccine efficacy.IMPORTANCE Varicella, also known as chickenpox, is a highly contagious disease, caused by varicella-zoster virus (VZV). Varicella is a common childhood disease that can be prevented by a live attenuated vaccine. The first available vaccine was derived from the parental Oka strain in Japan in 1974. Several live attenuated vaccines based on the Oka strain are currently available worldwide. Among the four vaccines produced in China, the vaccine manufactured by Changchun BCHT Biotechnology, also known as Baike, has been reported to be very efficacious. Comparative genomic analysis of the Baike vaccine with other Oka vaccine strains identified sites that might be involved in vaccine efficacy, as well as important for the biology of the virus.

Effects of aging on the quality of roasted sesame-like flavor Daqu.

BACKGROUND: Daqu, the saccharification, fermentation, and aroma-producing agents for Baijiu brewing, is prepared using a complex process. Aging is important for improving the quality of Daqu, but its impact has rarely been studied. This study investigated changes in the physicochemical properties, flavor compounds, and microbial communities during aging of Daqu with a roasted sesame-like flavor. RESULTS: The physicochemical properties changed continuously during aging to provide a high esterifying activity. Aging removed unpleasant flavor compounds and helped to stabilize the flavor compounds in mature Daqu. A high-throughput sequencing approach was used to analyze the changing composition of the microbial communities during aging. Aging helped to modify the microbial population to produce better Baijiu by eliminating low-abundance microbial communities and optimizing the proportion of predominant microbial communities. Nine genera of prokaryotic microbes formed the core microbiota in Daqu after aging. Regarding eukaryotic microbes, Zygomycota, the predominant community, increased in the first 2 months, then decreased in the third month of aging, while Ascomycota, the subdominant community, showed the opposite behavior. Absidia, Trichocomaceae_norank and Rhizopus were the predominant genera in the mature Daqu. CONCLUSIONS: Significant correlations between microbiota and physicochemical properties or flavor compounds were observed, indicating that optimizing microbial communities is essential for aging Daqu. This study provides detailed information on aging during Daqu preparation.

Fluorescent nanoprobe array based on carbon nanodots for qualitative and quantitative determination of biogenic polyamine.

A nanoprobe array based on fluorescent nitrogen-rich carbon dots (N-CDs) and Ag+ was constructed for simultaneous qualitative and quantitative determination of seven kinds of biogenic polyamines (BAs), including tryptamine (Try), histamine (His), putrescine (Put), cadaverine (Cad), spermine (Spm), spermidine (Spd), and agmatine (Agm). Ag+ can specifically bind to the N-CDs and quench the fluorescence of the N-CDs through a static mechanism. BAs further statically quench the fluorescence of the N-CD@Ag+ composite by bridging two Ag+ centers of the N-CD@Ag+. The nanoprobe array was constructed based on the differential fluorescence response arising from the differential binding affinity of various BAs. BAs can be differentiated and analyzed by the nanoprobe array within the concentration range 0.5-500 µM. The preliminary diluted and artificially spiked commercial human serum was utilized to simulate the serum environment for assessing the performance of the nanoprobe array in real samples. The N-CD@Ag+ system can recognize BAs with 100% accuracy in simulated human serum samples. The quantitative determination of BAs - no matter in a one-component system or a three-component system - was also realized by using the N-CD@Ag+ system even in the simulated serum environment. The recovery rates from spiked serum samples were higher 99%, and the relative standard deviation (RSD) was less than 3%. Based on the excellent multi-BA determination performance, a BA-related disease model about cerebral ischemia was constructed. Healthy cases as well as mild, moderate, and severe cerebral ischemia cases can be well identified from the disease model based on the N-CD@Ag+ nanoprobe array. Schematic representation of fluorescent nanoprobe array constructed by carbon nanodots (N-CDs) and Ag+ for qualitative and quantitative analyses of biogenic polyamines (BAs) and diagnosis of cerebral ischemia (CI) through linear discriminant analysis (LDA) and support vector machine (SVM).

Layered porous organic frameworks as a novel adsorbent for the solid phase extraction of chlorophenols prior to their determination by HPLC-DAD.

A layered porous organic framework (L-POF) with high surface area and porous volume was used as a novel adsorbent for adsorption of chlorophenols (CPs). The L-POF showed much higher adsorption capacity for four CPs (2-CP, 3-CP, 2,3-CP, 2,4-CP) compared with corresponding amorphous POF and some commercial adsorbents. Then, an L-POF-based solid-phase extraction method combined with high-performance liquid chromatography for analyzing CPs at the wavelength of 280 nm in water and honey samples was established. Under the optimum conditions, four CPs exhibited good linearity in the range 0.10-80.0 ng mL-1 for water and 2-400 ng g-1 for honey samples with determination coefficient r2 > 0.996. The method has low limits of detection of 0.03-0.10 ng mL-1 for water and 0.5-1.0 ng g-1 for honey samples. The method presented satisfactory precision and accuracy with relative standard deviations ≤ 7.8% and recoveries of 80-115%. High enrichment factors of 123-190 for water and 63-97 for honey were obtained. The validated method was successfully used to determine CPs in water and honey samples. The L-POF also displayed prominent adsorption performance for many other dyes and organic contaminants. This suggests that it can be an ideal candidate as adsorbent for wide application in separation and analysis. Graphical Abstract.

Graphene intercalated with carbon nanosphere: a novel solid-phase extraction sorbent for five carbamate pesticides.

Graphene-carbon nanosphere composite (G@CNS) was prepared via a simple hydrothermal method. The G@CNS nanocomposite was characterized by X-ray diffraction, scanning electron microscope, surface area, and porosity analysis. The G@CNS was applied as a new sorbent for solid-phase extraction of five carbamate pesticides (tsumacide, carbaryl, isoprocarb, bassa, diethofencarb) prior to quantitative determination by high-performance liquid chromatography with ultraviolet detection at 208 nm. Some experimental parameters including desorption conditions, sample pH, sample volume, and loading rate were studied carefully. Under the optimized condition, the method provided good linearity ranging from 0.3 to 100.0 ng mL-1 with low limits of detection of 0.10-0.20 ng mL-1 for grape juice, 0.10-0.30 ng mL-1 for blend fruit juice, and 0.10-0.20 ng mL-1 for water sample. Good method recoveries (80.2-110%) with relative standard deviations less than 7.2% and high enrichment factors (167-293) were achieved. Results demonstrated that this novel G@CNS can serve as a promising alternative sorbent for more applications. In this work, a graphene-carbon nanosphere (G@CNS) composite was synthesized via a simple hydrothermal method. Then, the G@CNS was served as a novel sorbent for solid-phase extraction of five carbamate pesticides (tsumacide, carbaryl, isoprocarb, bassa, diethofencarb) in juice and environmental water samples, followed by their quantitative analysis with high-performance liquid chromatography-ultraviolet detection.

Rational integration of porous organic polymer and multiwall carbon nanotube for the microextraction of polycyclic aromatic hydrocarbons.

By integration of benzene-constructed porous organic polymer (KBF) and multiwalled carbon nanotube (MWCNT), a MWCNT-KBF hybrid material was constructed through in situ knitting benzene with formaldehyde dimethyl acetal in the presence of MWCNTs to form a network. MWCNT-KBF was then adopted as a novel solid-phase microextraction (SPME) fiber coating. Coupled to gas chromatography-flame ionization detection, the MWCNT-KBF-assisted SPME method showed large enhancement factors (483-2066), low limits of detection (0.04-0.12 µg L-1), good linearity (0.13-50 µg L-1), and acceptable reproducibility (4.2-10.2%) for the determination of polycyclic aromatic hydrocarbons (PAHs). The method recoveries of seven PAHs were in the range 80.1-116.3%, with relative standard deviations (RSDs) ranging from 3.5 to 11.9%. The SPME method was successfully applied to the determination of PAHs in river, pond, rain, and waste water, providing a good alternative for monitoring trace level of PAHs in environmental water. Graphical abstract Schematic representation of the rational integration of porous organic polymer (KBF) and multiwalled carbon nanotube (MWCNT) to form a MWCNT-KBF hybrid material through in situ knitting benzene with formaldehyde dimethyl acetal at the presence of MWCNT.

A magnetic covalent aromatic polymer as an efficient and recyclable adsorbent for phenylurea herbicides.

A magnetic covalent aromatic polymer (Fe3O4-NH2-CAP) was synthesized by grinding a covalent aromatic polymer (CAP) and amino-functionalized magnetic nanoparticles (Fe3O4-NH2 NPs). The CAP was prepared by a Friedel-Crafts reaction between biphenyl and 1,3,5-benzenetricarbonyl trichloride. The interaction in the Fe3O4-NH2-CAP is based on hydrogen bond formation between the carbonyl groups in the CAP and the amino groups in the Fe3O4-NH2 NPs. The adsorbent inherits the advantages of the CAP and also has the superior magnetic property of the Fe3O4 NPs. The adsorbent was applied to magnetic solid-phase extraction of six phenylurea herbicides (metoxuron, monuron, chlortoluron, isoproturon, monolinuron, buturon) from soil and water samples. Following elution with 600 µL methanol, the herbicides were quantified by HPLC. The calibration plots are linear in the 1.00-100 ng g-1 herbicide concentration ranges in case of spiked soil samples, and in the 0.10-40 ng mL-1 concentration range for spiked water samples. The limits of detection range from 0.3 to 0.5 ng g-1 (soil) and from 0.01 to 0.03 ng mL-1 (water), with relative standard deviations of <8.0% and < 6.9%, respectively. Graphical abstract Schematic presentation for the preparation of the magnetic covalent aromatic polymer (Fe3O4-NH2-CAP) and of magnetic solid-phase extraction.

p-Phenylenediamine-modified graphene oxide as a sorbent for solid-phase extraction of phenylurea herbicides, nitroimidazoles, chlorophenols, phenylurea insecticides and phthalates.

Graphene oxide was covalently modified with p-phenylenediamine via a diazonium reaction. The resulting material was employed as a sorbent for the solid-phase extraction of six phenylurea herbicides (metoxuron, monuron, chlortoluron, isoproturon, monolinuron, and buturon) from environmental water and lettuce leafs. Some key factors that influence the extraction efficiency were studied, including sample loading rate, sample pH, and desorption conditions. Following desorption with acetonitrile, the analytes were quantified by HPLC with UV detection. Under optimized conditions, response to phenylurea herbicides is linear in the 2.0-100 ng mL-1 concentration range for water samples, and 5.0-100 ng g-1 for leaf lettuces. The limits of detection are 0.10-0.25 ng mL-1 for water samples, and 1.5-2.5 ng g-1 for leaf lettuces. The sorbent was also applied to the preconcentration of organic compounds including nitroimidazoles, chlorophenols, phenylurea insecticides and phthalates. This shows that this sorbent has a large potential for the enrichment of organic pollutants. Graphical abstract A graphene oxide/p-phenylenediamine (GO@PA) composite was prepared via a simple and environmentally-friendly diazonium reaction between p-phenylenediamine diazonium salt and graphene oxide. It was used as the solid phase extraction (SPE) adsorbent to extract phenylurea herbicides with the extraction efficiency higher than that of commercial C18, multi-walled carbon nanotube and polystyrene polymer. The SPE method was combined with HPLC for simultaneous determination of six phenylurea herbicides in environment water and vegetable samples.

Sensor array based on single carbon quantum dot for fluorometric differentiation of all natural amino acids.

A sensor array is described that consists of a carbon quantum dot (CQD) and metal ions, including Hg2+, Cu2+, Fe3+, Ag+, Cd2+, and Pb2+. The CQDs display blue fluorescence with excitation/emission maxima at 370/440 nm. It is shown that the array can be applied to the determination of all natural amino acids (NAAs). Metal ions can quench the fluorescence of the CQDs, while NAAs can take metal ions away or co-bind to the CQD@metal-ion complex, which enhances or depresses the fluorescence of the CQDs. Based on the differential fluorescence variation, the CQD@metal-ion@NAA array exhibits a unique pattern for NAAs. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were carried out to generate visualized datagrams for NAA discrimination. The design and construction of the sensor array is convenient and economical. The sensor array can distinguish NAAs at a concentration of as low as 30 µM, and can distinguish NAAs into acidic, neutral and basic NAAs. Semi-quantitative assay of alanine and threonine was also realized. Based on the low limit of detection and multi-NAA detection capability, the array can differentiate healthy cases from acute leukemia, chronic leukemia and lymphoma by analyzing the NAA status of serum samples. Graphical abstractSchematic representation of a fluorometric (FL) sensor array based on single CQD (carbon quantum dot) interacting with metal ions for differentiating all NAAs (natural amino acids) into acidic, neutral and basic NAAs (ANs, NNs and BNs) through PCA (principle component analysis).

Magnetic solid-phase extraction of benzoylurea insecticides by Fe3 O4 nanoparticles decorated with a hyper-cross-linked porous organic polymer.

A magnetic polytriphenylamine porous organic polymer was prepared through simple self-polycondensation of triphenylamine followed by coprecipitation with Fe2+ and Fe3+ . It was applied as a magnetic adsorbent for the extraction of six benzoylurea insecticides from tomato, cucumber, and watermelon samples before their high-performance liquid chromatography and mass spectral detection. Under the optimized experimental conditions, the established method gave a low limit of detection ranging from 0.05 to 0.1 ng/g and a good linear response ranging from 0.2 to 40 ng/g with coefficients of determination >0.99. The method recoveries for spiked analytes at the concentrations of 3 and 15 ng/g in real samples were in the range of 87.7-106.7% with the relative standard deviations <6.4%. The results indicated that it had a good adsorption capability toward the target analytes due to the π-stacking and hydrogen bonding interactions. The polymer material showed great potential in the efficient extraction of organic compounds from real samples with complex matrixes.

ß-Cyclodextrin polymer@Fe3 O4 based magnetic solid-phase extraction coupled with HPLC for the determination of benzoylurea insecticides from honey, tomato, and environmental water samples.

In this work, a magnetic ß-cyclodextrin polymer was successfully prepared and used as an adsorbent for the magnetic solid-phase extraction of six benzoylurea insecticides (diflubenzuron, triflumuron, hexaflumuron, teflubenzuron, flufenoxuron, and chlorfluazuron) from honey, tomato, and environmental water samples. The influence of the main experimental conditions on the extraction was studied. Under the optimized conditions, the ß-cyclodextrin polymer@Fe3 O4 showed an excellent extraction performance for the benzoylurea insecticides. A good linearity was obtained for the analytes in the range of 3.0-800 ng/g for honey samples, 0.3-160 ng/g for tomato samples, and 0.1-80.0 ng/mL for water samples, with the correlation coefficients above 0.9998. Satisfactory repeatabilities were achieved, with the relative standard deviations less than 5.7%. The limits of detection (S/N = 3) of the method for the benzoylurea insecticides were 0.2-0.8 ng/g for honey samples, 0.04-0.10 ng/g for tomato samples, and 0.02-0.05 ng /mL for water samples. The method was successfully used for the determination of the six benzoylurea insecticides residues in honey, tomato, and environmental water samples with a satisfactory result.