Ion chromatography coupled with fluorescence/UV detector: A comprehensive review of its applications in pesticides and pharmaceutical drug analysis

A purine fluorescent derived probe assay for glyphosate and mesotrione via Schiff base cleavage

A fluorescent probe derived from purine with Schiff base moiety was developed for the recognization of glyphosate and mesotrione. The detected glyphosate and mesotrione can lead to the dissociation of the Schiff base probe to enhance the fluorescence via a turn-off PET process. Mechanism study revealed that the synergistic effect of the phosphoric acid and the secondary amine moieties in glyphosate results in the bond cleavage of the Schiff base probe. Quantitative measurements of glyphosate and mesotrione were achieved with the detection limits of 17.2 nM and 484.32 nM, respectively. Meanwhile, the detection of glyphosate pesticide in real samples and cells was also conducted, demonstrating the good practicality and cytocompatibility of the probe.

Analysis of cassine and spectaline in the Senna spectabilis ethanolic extracts by capillary zone electrophoresis with indirect UV detection

INTRODUCTION

2,6-Disubstituted piperidin-3-ols are an important group of piperidine alkaloids found in species such as Senna spectabilis, whose main constituents include cassine and spectaline, compounds with relevant pharmacological activity. The analysis of these compounds is challenging due to the complexity of plant extracts and the absence of chromophores capable of absorbing ultraviolet (UV) radiation.

OBJECTIVE

This paper presents a new analytical method to separate and quantify the non-UV-absorbing alkaloids present in ethanol extracts from S. spectabilis flowers using capillary zone electrophoresis (CZE) with indirect UV detection.

METHODOLOGY

The optimized CZE method employs a background electrolyte containing 60 mM histidine (His), 15 mM α-cyclodextrin, 20% acetonitrile (ACN), and pH-adjusted to 4.7 with acetic acid (AcOH).

RESULTS

The limit of detection (LOD) values was 10.2 and 13.9 mg L-1 for cassine and spectaline, respectively. For both analytes, the precision data were better than 2% of relative standard deviation (RSD) for migration times and peak areas. To evaluate the applicability of the developed method, ethanolic extracts from S. spectabilis flowers were prepared and analyzed.

CONCLUSIONS

Thereby, the method proved to be efficient and complementary to conventional techniques, offering a cost-effective alternative in the quantification of the non-UV-absorbing piperidine alkaloids present in plant extracts.

Association of urinary glyphosate levels with iron homeostasis among a representative sample of US adults: NHANES 2013-2018

PURPOSE

Glyphosate and glyphosate-based herbicides (GBH), widely used globally, were initially considered harmless to humans. Experimental studies have suggested that these substances can disrupt iron homeostasis by interfering with iron uptake or triggering inflammatory responses. However, their potential impact on human iron homeostasis remains underexplored.

APPROACH AND RESULTS

We analyzed data from 5812 participants aged three and older from the 2013 to 2018 NHANES. We investigated the relationships between urinary glyphosate levels, oral iron intake, and markers of iron homeostasis, including serum iron, unsaturated iron-binding capacity (UIBC), total iron-binding capacity (TIBC), transferrin saturation, ferritin, and transferrin receptor. Higher urinary glyphosate levels were positively associated with oral iron intake (β = 1.310, S.E. = 0.382, P = 0.001). A one-unit increase in the natural logarithm (ln)-glyphosate was associated with lower serum iron (β = - 4.236, 95 % CI = - 6.432 to - 2.039, P < 0.001) and ferritin (β = - 9.994, 95 % CI = - 17.342 to - 2.647, P = 0.009), and higher UIBC (β = 5.431, 95 % CI = 1.061-9.800, P = 0.018) and transferrin receptor levels (β = 0.139, 95 % CI = 0.015-0.263, P = 0.029). Increasing glyphosate exposure was associated with significant decreases in serum iron and ferritin across exposure quintiles (trend P-values = 0.003 and 0.018, respectively).

CONCLUSIONS

Higher glyphosate exposure is associated with reduced iron availability, suggesting potential disruptions in iron absorption. These findings underscore the need for further research into the health implications of glyphosate exposure on iron homeostasis.

Ozonation: Post-harvest processing of different fruits and vegetables enhancing and preserving the quality

Daily ingestion of fresh produce has increased tremendously due to a rise in awareness of its nutritional benefits that contribute to reducing health risks and disease. However, these commodities are highly perishable and prone to significant post-harvest losses. Conventional methods have been scrutinized in the production of undesirable by-products. Ozone technology has emerged as an efficient sterilization technique. Additionally, it stimulated the synthesis of bioactive and antioxidant compounds by activating secondary metabolic pathways. However, there are conflicting findings in the literature related to their impact on the quality and physiological processes of fruits and vegetables (F&V). This scientific literature review focuses on key studies examining the effects of ozonation on the growth of microorganisms and the quality preservation of different F&V. This review also enlarges our understanding of eco-friendly technologies which not only extend the shelf life of F&V but also uphold their quality without introducing harmful chemicals.

Probing the toxic hypochlorous acid in natural waters and biosystem by a coumarin-based fluorescence probe

Since the onset of the SARS-CoV-2 pandemic in early 2020, there has been a notable rise in sodium hypochlorite disinfectants. Sodium hypochlorite undergoes hydrolysis to generate hypochlorous acid for virus eradication. This chlorine-based disinfectant is widely utilized for public disinfection due to its effectiveness. Although sodium hypochlorite disinfection is convenient, its excessive and indiscriminate use can harm the water environment and pose a risk to human health. Hypochlorous acid, a reactive oxygen species, plays a crucial role in the troposphere, stratospheric chemistry, and oxidizing capacity. Additionally, hypochlorous acid is vital as a reactive oxygen species in biological systems, and its irregular metabolism and level is associated with several illnesses. Thus, it is crucial to identify hypochlorous acid to comprehend its environmental and biological functions precisely. Here, we constructed a new fluorescent probe, utilizing the twisted intramolecular charge transfer mechanism to quickly and accurately detect hypochlorous acid in environmental water and biosystems. The probe showed a notable increase in fluorescence when exposed to hypochlorous acid, demonstrating its excellent selectivity, fast response time (less than 10 seconds), a large Stokes shift (∼ 102 nm), and a low detection limit of 15.5 nM.

Pompon mum-like ionic covalent organic framework nanocomposites for efficient solid-phase extraction of nonsteroidal anti-inflammatory drugs

Molecularly imprinted ionic covalent organic framework nanocomposites (MI-IC-COF@SnO2) were prepared as potential adsorbents for the enhanced adsorption of nonsteroidal anti-inflammatory drugs (NSAIDs) from aqueous solution. The resulting material exhibited a pompon mum-like structure, featuring a large surface area, and well-defined mesopores. The presence of uniform positive ions within the three-dimensional skeleton of MI-IC-COF@SnO2 facilitated a rapid adsorption rate and high adsorption capacity for target analytes. Thermodynamic fitting revealed the adsorption process of NSAIDs to be feasible, endothermic, and spontaneous. Additionally, the adsorbent material exhibited respectable selectivity, as evidenced by imprinting factor values ranging from 2.8 to 6.7. Utilizing MI-IC-COF@SnO2 as the sorbent, a solid-phase extraction method coupled with high-performance liquid chromatography-ultraviolet detection (SPE-HPLC-UV) was developed and optimized. The proposed method demonstrated good linear range with determination coefficients of 0.998-0.999, and low limit of detection (0.18-1.35 µg L-1). Recoveries of NSAIDs in urine and river water samples were 78.1 %-106.1 %, with relative standard deviations lower than 12.5 %. This rapid and sensitive method enables the determination of NSAIDs at trace levels in complex matrices, providing reliable and reproducible results.

Copper regulation of PtRhRuCu nanozyme targeted boosting peroxidase-like activity for ultrasensitive smartphone-assisted colorimetric sensing of glucose

Point-of-care testing (POCT) is promising for biodetection in home healthcare due to advantages of simplicity, rapidity, low cost, portability, high sensitivity and accuracy, and object-oriented POCT platform can be developed by nanozyme-based biosensing. However, designing high-performance nanozymes with targeted regulated catalytic activity remains challenging. Herein, advanced PtRhRuCu quaternary alloy nanozymes (QANs) were rationally designed and successfully synthesized. Cu atoms induced mechanisms of hydrogen peroxide (H2O2) activation and d-band center regulation, achieving high enhancement of peroxide (POD)-like activity and inhibition of oxidase (OXD)-like activity. Inspired by this, a smartphone-assisted colorimetric platform integrated with test strips was established for glucose detection of soft drinks, with a detection limit of 0.021 mM and a recovery rate of 97.87 to 103.36 %. This work not only provides a novel path for tuning specific enzyme-like activities of metal nanozymes, but also shows the potential feasibility for rational design of POCT sensors in actual samples.

Comparative evaluation of amino acid profiles, fatty acid compositions, and nutritional value of two varieties of head water Porphyra yezoensis: "Jianghaida No. 1" and "Sutong No.1"

Comparative nutritional analysis of Porphyra yezoensis strains "Jianghai No. 1" and "Sutong No.1" revealed significant differences in crude protein, crude fat, crude fiber, crude ash, and total sugar. Both strains contained 16 amino acids, with alanine as the highest and histidine the lowest content. Methionine was determined to be the first limiting amino acid for both strains in both amino acid score and chemical score assessment. They also featured 24 fatty acids, differing notably in four saturated fatty acids and five unsaturated fatty acids. All 12 mineral elements were present, notably differing in sodium, magnesium, potassium, calcium, iron, and zinc. The "Jianghai No. 1" strain stands out with its nutrient-rich profile, featuring high protein content, low fat, and abundant minerals, which could potentially command higher market prices and generate greater economic benefits due to its superior nutritional, and set a strong foundation for its future large-scale promotion and cultivation.

Sensitive fluorescence detection of glyphosate and glufosinate ammonium pesticides by purine-hydrazone-Cu2+ complex

Organophosphorus pesticides play an important role as broad-spectrum inactivating herbicides in agriculture. Developing a method for rapid and efficient organophosphorus pesticides detection is still urgent due to the increasing concern on food safety. An organo-probe (ZDA), synthesized by purine hydrazone derivative and 2,2'-dipyridylamine derivative, was applied in sensitive recognition of Cu2+ with detection limit of 300 nM. Mechanism study via density functional theory (DFT) and job's plot experiment revealed that ZDA and Cu2+ ions form a 1:2 complex quenching the fluorescence emission. Moreover, this fluorescent complex ZDA-Cu2+ was applicable for detecting glyphosate and glufosinate ammonium following fluorescence enhancement mechanism, with detection limits of 11.26 nM and 11.5 nM, respectively. Meanwhile, ZDA-Cu2+ was effective and sensitive when it is used for pesticide detection, reaching the maximum value and stabilizing in 1 min. Finally, the ZDA-Cu2+ probe could also be tolerated in cell assay environment, implying potential bio-application.

Micro solid phase extraction of lead and cadmium using functionalized nanodiamonds@CuAl2O4@HKUST-1 nanocomposite for FAAS analysis in food and water samples

This study focuses on the development and application of a novel nanocomposite (functionalized nanodiamonds@CuAl2O4@HKUST-1)-based µ-SPE method for the sensitive and selective extraction of Pb and Cd from food and water samples. The technique offers high sensitivity and selectivity, allowing accurate measurement of these metals at trace levels. The detection limit is 0.031 µg kg-1 for Cd and 0.052 µg kg-1 for Pb, with a relative standard deviation of 1.7 % for Cd and 4.8 % for Pb. The method was successfully applied to real samples and efficiently quantified Pb and Cd in food and natural water samples. The highest concentrations were found in red lentils (0.274 µg kg-1 Pb) and fresh mint (0.197 µg kg-1Cd), but still below recommended limits set by FAO/WHO (300 µg kg-1 for Pb and 200 µg kg-1 for Cd). It promises to ensure food safety, monitor environmental contamination, and informs regulatory decisions to protect public health.

Rational design of a rapidly responsive and highly selective fluorescent probe for SO2 derivatives detection and imaging

Sulfur dioxide (SO2) is emerging as a double-edged molecule, while plays vital roles in food and biological system. However, the fast, highly sensitive, and versatile fluorescent probe still remains a tough challenge among current reports. Herein, we developed a novel aggregation-induced emission (AIE) fluorescent probe TPE-PN for specifically sensing SO2 derivatives with high sensitivity (150 nmol/L) and rapid response time (10 s) based on intramolecular charge transfer (ICT) mechanism. And the fluorescence at 575 nm decreased tremendously with 31-fold after the probe was treated with HSO3-. Employing the probe, the accurate analysis of HSO3- was successfully realized in food samples, cells, plant tissues, and zebrafishes. Furthermore, we successfully demonstrate the eruption of SO2 derivatives within plant during drought and salt stress processes. Therefore, probe TPE-PN illustrates significant potential for applications in food analysis and monitoring of SO2 derivatives levels in biological systems under stress conditions.

Universal ion chromatography method for anions in active pharmaceutical ingredients enabled by computer-assisted separation modeling

Ion Chromatography (IC) is one of the most widely used methods for analyzing ionic species in pharmaceutical samples. A universal IC method that can separate a wide range of different analytes is highly desired as it can save a lot of time for method development and validation processes. Herein we report the development of a universal method for anions in active pharmaceutical ingredients (APIs) using computer-assisted chromatography modeling tools. We have screened three different IC columns (Dionex IonPac AS28-Fast 4 µm, AS19 4 µm and AS11-HC 4 µm) to determine the best suitable column for universal IC method development. A universal IC method was then developed using an AS11-HC 4 µm column to separate 31 most common anionic substances in 36 mins. This method was optimized using LC Simulator and a model which precisely predicts the retention behavior of 31 anions was established. This model demonstrated an excellent match between predicted and experimental analyte retention time (R2 =0.999). To validate this universal IC method, we have studied the stability of sulfite and sulfide analytes in ambient conditions. The method was then validated for a subset of 29 anions using water and organic solvent/water binary solvents as diluents for commercial APIs. This universal IC method provides an efficient and simple way to separate and analyze common anions in APIs. In addition, the method development process combined with LC simulator modeling can be effectively used as a starting point during method development for other ions beyond those investigated in this study.

Screening and evaluation of bamboo shoots: Comparing the content of trace elements from 100 species

Hundreds of bamboo shoots have been reported to be edible, but the accumulation of trace elements and hazardous elements in bamboo shoots is poorly understood. Here, 100 bamboo species have been evaluated by screening elements including B, Fe, Mn, Cu, Zn, Cd, Pb and As in bamboo shoots using different assessment systems. Bamboo shoots displayed different morphological characteristics, and large differences were found in the concentration of elements. Most bamboo shoots were rich in Fe and Zn and low concentrations of hazardous elements, but the concentration of Cd and Pb exceeded the maximum permissible limits of tuber vegetables in some bamboo species. Different bamboo shoots were ranked differently in the four assessment systems, and the comprehensive evaluation assigned final scores to all 100 bamboo shoots. This study provides valuable recommendations for selecting high-quality bamboo shoots that are rich in trace elements nutrition while minimizing the potential for hazardous element accumulation.

Structure characterization and antioxidant activity of abalone visceral peptides-selenium in vitro

Peptide-selenium chelate is widely regarded as one of the best selenium supplements for relieving selenium deficiency. In this study, abalone visceral peptides (AVP) was used to prepare a new type of peptides-selenium chelate to develop an organic selenium supplement with antioxidant activity. AVP prepared by alcalase exhibited the highest selenium-chelating ability. UV-visible spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy and other structural analysis showed that selenium was mainly bound to the functional groups of -NH, -OH, -CH, CC, CO, and CN bonds on AVP. The formation of AVP-selenium chelate enhanced thermal stability and generated a new crystal structure. The ABTS•+ and •OH scavenging activities of AVP-selenium chelate were increased after in vitro digestion than that of AVP. Conclusively, this study analyzed the chelating mechanism of AVP and selenium from a structural perspective, which would provide a theoretical basis for the development of new selenium supplements.

Effects of electron beam irradiation on protein oxidation and textural properties of shrimp (Litopenaeus vannamei) during refrigerated storage

Protein oxidation leads to changes in shrimp texture, which affects sensory profile and consumer acceptability. This study aimed to evaluate the impact of electron beam irradiation (EBI) on protein oxidation and textural properties of Litopenaeus vannamei during refrigerated storage. Results revealed that EBI treatment and storage increased the protein oxidation level of shrimps. Shrimps irradiated with ≥ 7 kGy exhibited remarkably higher (P < 0.05) reactive oxygen species, turbidity, and carbonyl contents, and remarkably lower (P < 0.05) Ca2+-ATPase activity, surface hydrophobicity, solubility, and total sulfhydryl contents compared to the control group (0 kGy) on the 7th day of storage. Shrimps irradiated with 3 and 5 kGy exhibited remarkably higher (P < 0.05) hardness, springiness, and chewiness compared to the control group (14.99 N, 1.26 mm, and 3.19 mJ). Collectively, suitable EBI doses of 3-5 kGy were recommended in shrimp preservation to inhibit texture softening by inducing moderate protein oxidation.

Prioritization of control factors for heavy metals in groundwater based on a source-oriented health risk assessment model

Heavy metals (HMs) in groundwater seriously threaten ecological safety and human health. To facilitate the effective management of groundwater contamination, priority control factors of HMs in groundwater need to be categorized. A total of 86 groundwater samples were collected from the Huangpi district of Wuhan city, China, during the dry and wet seasons. To determine priority control factors, a source-oriented health risk assessment model was applied to compare the pollution sources and health risks of seven HMs (Cu, Pb, Zn, Cr, Ni, As, and Fe). The results showed that the groundwater had higher As and Fe contents. The sources of HM pollution during the wet period were mainly industrial and agricultural activities and natural sources. During the dry period, origins were more complex due to the addition of domestic discharges, such as sewage wastewater. Industrial activities (74.10% during the wet period), agricultural activities (53.84% during the dry period), and As were identified as the priority control factors for groundwater HMs. The results provide valuable insights for policymakers to coordinate targeted management of HM pollution in groundwater and reduce the cost of HM pollution mitigation.

Effect of cellulose on gel properties of heat-induced low-salt surimi gels: Physicochemical characteristics, water distribution and microstructure

The processing of surimi products requires the addition of high levels of salt, which makes it a high-salt food that poses a risk to human health. The search for exogenous additives to reduce the salt content of surimi products while ensuring their quality characteristics is crucial. Therefore, the effect of different species of cellulose on enhancing the quality characteristics of low-salt surimi gels was investigated and the best-modified cellulose was identified. Carboxymethyl cellulose (CMC), hydroxypropyl methylcellulose (HPMC), and microcrystalline cellulose (MCC) were selected for this study to compare with high-salt control and low-salt control. The results showed that cellulose could induce conformational transitions of proteins and promote the formation of an ordered and dense surimi gel network and the minimum porosity of 15.935% was obtained in the MCC-treated group. The cellulose-treated group conferred good textural properties to the surimi gels, significantly improved gel strength and water retention capacity (p < 0.05), and reduced the amount of water lost after cooking treatment (p < 0.05). Low-field NMR results showed that cellulose reduced the release of water, converting more free water to immobile water, thus increasing the water proton density. The higher energy storage modulus G' in the presence of cellulose indicated a more stable surimi gel system dominated by springiness. In summary, cellulose could confer better quality characteristics to low-salt surimi gels and MCC performance was superior to other cellulose species. This study helps the understanding of the mechanism of cellulose-surimi action on the development of high-quality low-salt surimi gels.

Mannan oligosaccharides selenium ameliorates intestinal mucosal barrier, and regulate intestinal microbiota to prevent Enterotoxigenic Escherichia coli -induced diarrhea in weaned piglets

Enterotoxigenic Escherichia coli (ETEC) is a common diarrheal pathogen in humans and animals. To prevent and treat ETEC induced diarrhea, we synthesized mannan oligosaccharide selenium (MOSS) and studied its beneficial effect on ETEC-induced diarrhea. A total of 32 healthy weaned piglets (6.69 ± 0.01 kg) were randomly divided into four groups: NC group (Basal diet), MOSS group (0.4 mg/kg MOSS supplemented diet), MOET group (0.4 mg/kg MOSS supplemented diet + ETEC treatment), ETEC group (ETEC treatment). NC and ETEC group fed with basal diet, MOSS and MOET group fed with the MOSS supplemented diet. On the 8th and 15th day of the experiment, MOET and ETEC group were gavaged with ETEC, and NC and MOSS group were gavaged with stroke-physiological saline solution. Our data showed that dietary MOSS supplementation increased average daily gain (ADG) and average daily feed intake (ADFI) and significantly decreased diarrhea index and frequency in ETEC-treated piglets. MOSS did not affect the α diversity and β diversity of ileal microbial community, but it significantly decreased the proportion of lipopolysaccharide biosynthesis in ileal microbial community. MOSS supplementation regulated colonic microbiota community composition, which significantly increased carbohydrate metabolism, and inhibited lipopolysaccharide biosynthesis pathway in colonic microbial community. Moreover, MOSS significantly decreased inflammatory stress, and oxidative stress in ETEC treated piglets. Furthermore, dietary MOSS supplementation significantly decreased intestinal barrier permeability, and alleviated ETEC induced intestinal mucosa barrier irritation. In conclusion, our study showed that dietary MOSS supplementation ameliorated intestinal mucosa barrier, and regulated intestinal microbiota to prevent ETEC induced diarrhea in weaned piglets.

Development and validation of an effective and sensitive technique for nitrate determination in fruits and vegetables using HPLC/PDA

This study aims to develop an effective and sensitive HPLC (High Performance Liquid Chromatography) method to determine the nitrate concentration in fruits and vegetables (F & V) using a C18 column (ZORBAX Eclipse XDB-C18, 80Å, 250 × 4.6 mm, 5 μm (Agilent Technologies)) maintained at 40 0 C, a mobile phase made up of methanol and buffer (pentane sulfonic acid sodium salt solution), and a Photo Diode Array Detector (PDA) at 225 nm. The developed method is validated in terms of selectivity, linearity, accuracy, precision, suitability, the limit of detection (LOD), and the limit of quantification (LOQ) according to the European Union Decision 2002/657/EC. The result revealed that a ratio of 30: 70 of the organic modifier methanol and buffer with pH 2.8 shows the highest efficiency. The calibration curve shows linearity with a correlation coefficient (r) of 0.9985. The LOD and LOQ were found to be 2.26 mg/kg and 7.46 mg/kg. The recovery was in the range of 98.96-100.21%. Moreover, the greenness assessment scores of different approaches (eco-scale score of 76, AGREE score of 0.71, and few red shades in GAPI portray) were at a very excellent level. Thus, our developed method is fully validated and can determine the nitrate content in F & V.

Analysis of environmental pollutants using ion chromatography coupled with mass spectrometry: A review

The rise of emerging pollutants in the current environment and requirements of trace analysis in complex substrates pose challenges to modern analytical techniques. Ion chromatography coupled with mass spectrometry (IC-MS) is the preferred tool for analyzing emerging pollutants due to its excellent separation ability for polar and ionic compounds with small molecular weight and high detection sensitivity and selectivity. This paper reviews the progress of sample preparation and ion-exchange IC-MS methods in the analysis of several major categories of environmental polar and ionic pollutants including perchlorate, inorganic and organic phosphorus compounds, metalloids and heavy metals, polar pesticides, and disinfection by-products in past two decades. The comparison of various methods to reduce the influence of matrix effect and improve the accuracy and sensitivity of analysis are emphasized throughout the process from sample preparation to instrumental analysis. Furthermore, the human health risks of these pollutants in the environment with natural concentration levels in different environmental medias are also briefly discussed to raise public attention. Finally, the future challenges of IC-MS for analysis of environmental pollutants are briefly discussed.

Bioactive properties and organosulfur compounds profiling of newly developed garlic varieties of Bangladesh

Studies are being carried out on achieving the maximum quality of garlic through various approaches. In Bangladesh, new garlic varieties (BARI 1-4, BAU-1, BAU-2, BAU-5) have been recently developed by artificial selection to enhance their quality. The present study aimed to evaluate their potency in terms of bioactive properties and organosulfur compounds content using different bioassay and GC-MS techniques while comparing them with other accessible varieties (Chinese, Indian, Local). The new variety, BARI-3 showed the highest antioxidant activity and total phenolic content. It was also found with the highest level of a potent blood pressure-lowering agent, 2-vinyl-4H-1,3-dithiine (78.15 %), which is never reported in any garlic at this percentage. However, the local variety exhibited greater inhibitory properties against the tested organisms including multidrug-resistant pathogens compared to other varieties. This study primarily shows the potential of these two kinds of garlic for their further utilization and development.

Exploring the mechanism of high hydrostatic pressure on the chemical activity of starch based on its structure and properties changes

High hydrostatic pressure (HHP) could induce changes in the structure and properties of starch. Native corn starch was treated and octenyl succinic anhydride (OSA)-modified corn starch was prepared under different pressures (200, 350, 500 and 600 MPa) at 40℃ for 20 min. The mechanism of HHP on the chemical activity of starch was elucidated by analyzing the relationship between the changes of native starch structure and properties and the quality of OSA-modified starch. Results showed that HHP not only helped water and OSA to penetrate the starch granules but also made the structure of starch granules undergone three changes similar to mechanochemical effects. The starch granules treated by 200 MPa were in the stress stage, and the starch granules treated by 500 MPa were in the transition stage from aggregation to agglomeration. Proper pressure treatment could significantly improve chemical activity of starch and quality of OSA-modified starch.

Isocratic ion pair chromatography for estimation of novel combined inhalation therapy that blocks coronavirus replication in chronic asthmatic patients

A rapid and sensitive isocratic ion-pair chromatographic method was developed for the accurate analysis of ternary mixtures of formoterol, tiotropium, and ciclesonide in their novel combined inhalation that is widely used for the symptomatic treatment of patients with chronic obstructive disease. Analytical separation was performed using a C8 column and ion pair mobile phase composed of acetonitrile: acidified deionized water (55: 45% v/v) containing 0.025% sodium dodecyl sulfate. The pH was adjusted to 3.0 using orthophosphoric acid and eluted isocratically at 2.0 mL/min and 40 °C applying UV detection at 237 nm. The calibration ranges were found to be 0.3-9.0 µg/mL for formoterol, 0.45-13.5 µg/mL for tiotropium, and 10.0-300.0 µg/mL concerning ciclesonide. The proposed method exhibited good repeatability, accuracy, and sensitivity (R.S.D. < 2.0%). The approach is rapid (run time does not exceed 15 min) and achieves satisfactory resolution (resolution factors = 7.45 and 5.3 between formoterol and tiotropium and tiotropium and ciclesonide respectively). The sensitivity and the efficiency of the proposed method permit their successful estimation with a recovery percentage ± SD of 99.33% ± 0.43 for formoterol, 99.15% ± 0.60 for tiotropium, and 99.90% ± 0.41 for ciclesonide.

Exploration of emerging environmental pollutants 6PPD and 6PPDQ in honey and fish samples

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPDQ) can pose a threat to human health through the food chain because of their ubiquitous presence in the environment and the biotoxicity on organisms. In this work, we developed modified QuEChERS methods coupled with high performance liquid chromatography tandem mass spectrometry (HPLC/MS-MS) to explore whether 6PPD and 6PPDQ are present in fish and honey. The proposed methods showed acceptable limits of quantification (0.00043-0.001 mg/kg), linearity (R2 > 0.99), recovery (73.3%-108.3%), matrix effect (70.4%-95.6%) and repeatability (RSD < 8.4%). Accordingly, 6PPD and 6PPDQ have been discovered in snakehead, weever and Spanish mackerel fish, while none of which have been detected in the honey samples. The results of our work contributed to increasing public attention to 6PPD and 6PPDQ in agricultural products and provided important reference for the analysis of them.

The Characteristics and Potential Risks of Neonicotinoid Residues in Soils of Different Types of Land Use in Hangzhou

Due to the wide existence of neonicotinoid insecticides (neonics) and their potential impact on ecosystems and human health, they have received special attention in recent years. Soil is not only a sink of neonics but also a source of neonics, so it plays a key role in the ubiquity of neonics in the environment. The purpose of this research was to compare neonics residues in soils of different types of land use and estimate their exposure to different populations via ingestion. A total of 130 soil samples from six different types were collected. The concentrations of seven neonics in soil were simultaneous determined using isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry. The results showed that at least one neonic was analyzed in all samples. The highest average concentration was 3.42 ng/g (clothianidin), followed by 3.39 ng/g (thiamethoxam), 3.06 ng/g (acetamiprid), 2.84 ng/g (imidacloprid), 2.66 ng/g (nitenpyram), 2.43 ng/g (thiacloprid), and 1.89 ng/g (dinotefuran). IMI and ACE were the most commonly found neonics in soil. The neonic levels in different soils varied significantly. The integrated neonic residue in cropland was much higher than that in other types of land. The risk assessment revealed that the average daily dose (ADD) through ingestion contact with soil was acceptable to children and adults. With the increasing evidence that neonics could cause a variety of toxic effects on mammals and humans, ingestion exposure caused by neonics in soil should also receive continuous attention in future studies.

Low-dose florfenicol and copper combined exposure during early life induced health risks by affecting gut microbiota and metabolome in SD rats

The potential health risks associated with simultaneous presence of residues of heavy metals and antibiotics in the environment and food have been of wide concern. However, the adverse health effects of combined heavy metal and antibiotic exposure at low doses remain unclear. In this study, the effects of combined exposure to florfenicol and copper at low doses during early life on toxicity, gut microbiota, drug resistance genes, and the fecal metabolome were investigated in Sprague-Dawley (SD) rats. The results showed that combined exposure induced inflammatory responses and visceral injury as well as faster weight gain compared with florfenicol or copper exposure alone. Alpha and beta diversity indices indicated that the composition of the gut microbiota and the abundance of bacteria related to energy intake and disease in the combined exposure group were significantly altered. The increase in resistance genes (floR, fexA) induced by florfenicol exposure was suppressed under combined exposure to florfenicol and copper. The fecal metabolome also demonstrated that metabolic pathways related to energy intake and liver injury were significantly affected in the combined exposure group. In conclusion, this study shows that combined exposure to florfenicol and copper during early life can pose a nonnegligible health risk even if the exposure concentration of florfenicol or copper is below the safe limit.

Synthesis of natural proanthocyanidin based novel magnetic nanoporous organic polymer as advanced sorbent for neonicotinoid insecticides

In this work, a natural proanthocyanidin (PA) based magnetic nanoporous organic polymer (named as PA-MOP) was successfully synthesized for the first time. The PA-MOP possessed high hydrophilic-surface, good magnetic responsiveness and high affinity for neonicotinoid insecticides. It was applied as an advanced magnetic sorbent for extraction of four neonicotinoids (thiamethoxam, imidacloprid, acetamiprid and thiacloprid) from environmental water, peach juice and honey samples prior to HPLC analysis. Under optimal conditions, the limits of detection for the analytes at S/N = 3 were 0.02-0.08 ng mL^-1 for water, 0.03-0.10 ng mL^-1 for peach juice and 0.05-0.16 ng g^-1 for honey sample. The method recoveries were 80.0%-114.8%, with the relative standard deviations below 6.8%. The values of matrix effect were from -1.5% to -9.3%. Based on theory calculation, the extraction mechanism can be attributed to multiple interactions between the PA-MOP and the neonicotinoids, in which hydrogen bonding, π-π stacking and electrostatic interactions are the major interactions.

An overview of poly (amide-amine) dendrimers functionalized chromatographic separation materials

Chromatography is one of the most important separation techniques in analytical chemistry. In which, the separation materials are the core for good separation results. Poly (amide-amine) dendrimers with regular three-dimensional structure, abundant terminal groups, controllable molecule chains, and unique cavities appear to have a positive impact on chromatographic separation materials. In the past decades, poly (amide-amine) grafted adsorbents and stationary phases have presented high grafting efficiency, controllable surface structure, good dispersion, and wide practical applications. In this review, the prepared poly (amide-amine) functionalized separation materials and their applications are systematically summarized. Functions, significance, structure-actvity relationships and benefits of poly (amide-amine) dendrimers in the proposed separation materials are discussed in detail. And we hope to provide a useful reference for the future development of chromatographic separation materials and inspire new discoveries in the study of poly (amide-amine) functionalized materials.

Modification of Cellulose Nanocrystals With 2-Carboxyethyl Acrylate in the Presence of Epoxy Resin for Enhancing its Adhesive Properties

Cellulose nanocrystals (CNCs) have unparalleled advantages in the preparation of nanocomposites for various applications. However, a major challenge associated with CNCs in nanocomposite preparation is the lack of compatibility with hydrophobic polymers. The hydrophobic modification of CNCs has attracted increasing interest in the modern era standing with long challenges and being environmentally friendly. Here, we synthesized CNCs by using cotton as raw material and then modified them with 2-carboxyethyl acrylate to improve their corresponding mechanical, adhesive, contact angle, and thermal properties. Different concentrations (1-5 wt%) of CNCs were used as modifiers to improve the interfacial adhesion between the reinforced CNCs and E-51 (Bisphenol A diglycidyl ether) epoxy resin system. CNCs offered a better modulus of elasticity, a lower coefficient of energy, and thermal expansion. Compared with the standard sample, the modified CNCs (MCNCs) showed high shear stress, high toughness, efficient degradation, thermal stability, and recycling due to the combined effect of the hyperbranched topological structure of epoxy with good compatibility. The native CNCs lost their hydrophilicity after modification with epoxy, and MCNCs showed good hydrophobic behavior (CA = 105 ± 2°). The findings of this study indicate that modification of CNCs with 2-carboxyethyl acrylate in the presence of epoxy resin and the enhancement of the features would further expand their applications to different sectors.

Analytical Methods for Determination of Antiviral Drugs in Different Matrices: Recent Advances and Trends

Viruses are the main pathogenic substances that cause severe diseases in humans and other living things. They are among the most common microorganisms, and consequently, antiviral drugs have emerged to prevent and treat viral infections. Antiviral drugs are an essential drug group considering their prescription and consumption rates for different diseases and indications. Therefore, it is crucial to develop accurate and precise analytical methods to detect antiviral drugs in various matrices. Chromatographic techniques are used frequently for the quantification purpose since they allow simultaneous determination of antivirals. Electrochemical methods have also gained importance since the analysis can be performed quickly without the need for pretreatment. Spectrophotometric and spectrofluorimetric methods are used because they are simple, inexpensive, and less time-consuming methods. The purpose of this review is to present an overview of the analysis of currently used antiviral drugs from 2010 to 2021. Since studies on antiviral drugs are numerous, selected publications were reviewed in this article. The analysis of antiviral drugs was divided into three main groups: chromatographic, spectrometric, and electrochemical methods which were applied to different matrices, including pharmaceutical, biological, and environmental samples.

Comparative Analysis of Ethylene/Diene Copolymerization and Ethylene/Propylene/Diene Terpolymerization Using Ansa-Zirconocene Catalyst with Alkylaluminum/Borate Activator: The Effect of Conjugated and Nonconjugated Dienes on Catalytic Behavior and Polymer Microstructure

The copolymerization of ethylene‒diene conjugates (butadiene (BD), isoprene (IP) and nonconjugates (5-ethylidene-2-norbornene (ENB), vinyl norbornene VNB, 4-vinylcyclohexene (VCH) and 1, 4-hexadiene (HD)), and terpolymerization of ethylene-propylene-diene conjugates (BD, IP) and nonconjugates (ENB, VNB, VCH and HD) using two traditional catalysts of C₂-symmetric metallocene—silylene-bridged rac-Me₂Si(2-Me-4-Ph-Ind)₂ZrCl₂ (complex A) and ethylene-bridged rac-Et(Ind)₂ZrCl₂ (complex B)—with a [Ph₃C][B(C₆F₅)₄] borate/TIBA co-catalyst, were intensively studied. Compared to that in the copolymerization of ethylene diene, the catalytic activity was more significant in E/P/diene terpolymerization. We obtained a maximum yield of both metallocene catalysts with conjugated diene between 3.00 × 10⁶ g/mol_Mt·h and 5.00 × 10⁶ g/mol_Mt·h. ENB had the highest deactivation impact on complex A, and HD had the most substantial deactivation effect on complex B. A ¹H NMR study suggests that dienes were incorporated into the co/ter polymers’ backbone through regioselectivity. ENB and VNB, inserted by the edo double bond, left the ethylidene double bond intact, so VCH had an exo double bond. Complex A’s methyl and phenyl groups rendered it structurally stable and exhibited a dihedral angle greater than that of complex B, resulting in 1, 2 isoprene insertion higher than 1, 4 isoprene that is usually incapable of polymerization coordination. High efficiency in terms of co- and ter- monomer incorporation with higher molecular weight was found for complex 1. The rate of incorporation of ethylene and propylene in the terpolymer backbone structure may also be altered by the conjugated and nonconjugated dienes. ¹³C-NMR, ¹H-NMR, and GPC techniques were used to characterize the polymers obtained.