Promoting capillary microextraction of six organic nitrogen pesticides in water samples using versatile ZIF-8 hybrid monolithic column.

Because of rapid industrialization and agriculturalization, solving the pressing problems of environment pollution, especially water and food quality, requires innovative solutions. In this paper, a novel and versatile metal-organic framework (ZIF-8)-hybrid monolithic column (ZIF-HMC) was prepared for in-tube solid-phase microextraction (IT-SPME) of organic nitrogen pesticides (ONPs). The prepared monolithic columns had superior adsorption sites, high porosity, excellent permeability, and ideal specific surface area based on Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Thermal Field Emission Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), X-ray Photoelectron Spectroscopy (XPS), and N2 adsorption-desorption. The ZIF-HMC contained a large number of nitrogen and oxygen atoms, benzene rings and ZIF-8, which could synergistically promote the adsorption efficiency of ONPs through multiple interactions, such as hydrogen bonding, π-π accumulation, hydrophobic interactions, cation-π interactions, and pore adsorption by MOFs. Under the optimal conditions, a simple, efficient, and sensitive method for the analysis of six organic pesticides in environmental water samples was developed by using the ZIF-HMC as the extraction medium coupled with high performance liquid chromatography-ultraviolet (HPLC-UV). The method had a wide linear range (0.63-1000 µg L-1), a low detection limit (0.19-1.91 µg L-1) and satisfactory recoveries (87.4 %-110.2 %), the linear correlation coefficient was (R2) 0.9972-0.9995 and the relative standard deviation (RSD) was less than 2.64 %. The study had demonstrated the potential application of the developed method for the enrichment and analysis of organic pesticides in complex matrices of environmental samples, as well as the feasibility of MOFs materials for IT-SPME sample preparation.

Preparation of a multiple interacting magnetic fluid for rapid and sensitive simultaneous extraction of ß-nicotinamide mononucleotide metabolites in biological samples.

BACKGROUND: ß-nicotinamide mononucleotide stands out as an essential breakthrough in "anti-aging" and consistently leads the list of top-selling nutritional supplements in terms of quantity. As the metabolites of ß-nicotinamide mononucleotide, the detection of nicotinamide and N1-methylnicotinamide is of great significance for evaluating the nutritional effect of dietary supplements of ß-nicotinamide mononucleotide. However, due to the extremely low concentration of nicotinamide and N1-methylnicotinamide in vivo and the serious matrix interference in biological samples, there is an increasing demand for materials and methods of pre-treatment. RESULTS: In this study, Fe3O4@hydroxypropyl methyl cellulose@dodecylbenzenesulfonic acid magnetic fluid was synthesized for the first time, and it was used as pretreatment material to detect nicotinamide and N1- methylnicotinamide in urine samples by high performance liquid chromatography. Compared with other adsorption materials, Fe3O4@hydroxypropyl methyl cellulose@dodecylbenzenesulfonic acid nanoparticles are a kind of uniform magnetic fluid. Furthermore, they have more types and quantities of interaction sites (electrostatic interactions, hydrophobic interactions, hydrogen bonding interactions, and π-π interactions), so they own greater adsorption capacity. When the pH of the solution is 4, they can be adsorbed quickly within 10 s. The method successfully detected trace nicotinamide and N1-methylnicotinamide in urine samples in the linear range of 0.1-80 µg mL-1, the low detection limits were 0.30 ng mL-1 and 1.5 ng mL-1 respectively, and the quantification limits were 1.0 ng mL-1 and 5.0 ng mL-1, respectively. At the same time, the standard urine samples of nicotinamide and N1-methylnicotinamide showed satisfactory recovery rate 94.50-109.1 %. The results indicated that the established method can accurately and quantitatively determine trace nicotinamide and N1-methylnicotinamide in urine samples. SIGNIFICANCE: Consequently, low concentration of ß-nicotinamide mononucleotide metabolites can be detected simultaneously, and the interference can be eliminated during the detection process, which provides an efficient and convenient pretreatment method and a rapid and sensitive detection method for the analysis of ß-nicotinamide mononucleotide metabolites. What's more, it has a wide application prospect in the analysis of other similar metabolites in biological samples.

Auranofin is lethal against feline Tritrichomonas foetus in vitro but ineffective in cats with naturally occurring infection.

Protozoal diarrhea caused by Tritrichomonas foetus (blagburni) is a prevalent, lifelong, and globally distributed burden in domestic cats. Treatment is limited to the use of 5-nitroimidazoles and treatment failure is common. The repurposed gold salt compound auranofin has killing activity against diverse protozoa in vitro but evidence of efficacy in naturally occurring protozoal infections is lacking. This exploratory study investigated the efficacy and safety of auranofin for treatment of cats with naturally occurring, 5-nitroimidazole-resistant, T. foetus infection. The minimum lethal concentration (MLC) of auranofin against 5 isolates of feline T. foetus was determined under aerobic conditions in vitro. Healthy cats and cats with T. foetus infection were treated with immediate release auranofin (range, 0.5-3 mg/cat for 7 days) or guar gum-coated auranofin capsules (0.5 or 3 mg/cat for 7 days). Adverse effects were monitored by clinical signs and clinicopathologic testing. Efficacy was determined by fecal consistency score, bowel movement frequency, and single-tube nested PCR of feces for T. foetus rDNA. Fecal samples were assayed for concentrations of auranofin, known and predicted metabolites of auranofin, gold containing molecules, and total gold content using HPLC, LC-MS, ion mobility-MS, and ICP-MS, respectively. Auranofin was effective at killing isolates of feline T. foetus at MLC ≥ 1 µg/ml. Treatment of cats with T. foetus infection with either immediate release auranofin or a colon-targeted guar gum-coated tablet of auranofin did not eradicate infection. Treatment failure occurred despite fecal concentrations of gold that met or exceeded the equivalent MLC of auranofin. Neither auranofin, known or predicted metabolites of auranofin, nor any gold-containing molecules >100 Da could be detected in fecal samples of treated cats. Adverse effects associated with auranofin treatment were common but minor. These studies identify that in vitro susceptibility test results of auranofin may not translate to treatment effectiveness in vivo even when achieving gold concentrations equivalent to the MLC of auranofin in the target environment. These studies further establish the absence of any predicted or unpredicted gold containing metabolites in feces after oral administration of auranofin.

Development of a pre-column derivatization ultra-high-performance liquid chromatography method for polysaccharide and monosaccharide quantification in Lycium barbarum.

Given the limited specificity and accuracy observed in the current official colorimetric quantification of polysaccharide in Lycium barbarum, our study aims to establish a novel, specific, accurate, and economic pre-column derivatization ultra-high-performance liquid chromatography (UHPLC) method for determining the monosaccharide and polysaccharide content in L. barbarum. The optimization of extraction, hydrolysis, and derivatization (using 1-phenyl-3-methyl-5-pyrazolone) processes for polysaccharide from L. barbarum was conducted initially, followed by separation of nine monosaccharides within 20 min using UHPLC with a C18 column. Subsequently, a novel method known as quantitative analysis of multiple components by single marker was developed, utilizing either additive 2-deoxy-D-ribose or any monosaccharide present in the sample as a single reference standard to simultaneously detect the contents of polysaccharide and nine monosaccharides in L. barbarum. To validate the accuracy of the established method, the quantitative results of our approach were compared to both external and internal standard method methods. The minimal relative errors in the quantitative determination of monosaccharides among the three methods confirmed the dependability of the method. By analyzing 20 batches of L. barbarum samples, D-galacturonic acid exhibited the highest content and the polysaccharide levels ranged from 3.02 to 13.04 mg/g. All data implied the specificity and accuracy of the method.

Content of Primary and Secondary Carotenoids in the Cells of Cryotolerant Microalgae Chloromonas reticulata.

Snow (cryotolerant) algae often form red (pink) spots in mountain ecosystems on snowfields around the world, but little is known about their physiology and chemical composition. Content and composition of pigments in the cells of the cryotolerant green microalgae Chloromonas reticulata have been studied. Analysis of carotenoids content in the green (vegetative) cells grown under laboratory conditions and in the red resting cells collected from the snow surface in the Subpolar Urals was carried out. Carotenoids such as neoxanthin, violaxanthin, anteraxanthin, zeaxanthin, lutein, and ß-carotene were detected. Among the carotenoids, the ketocarotenoid astaxanthin with high biological activity was also found. It was established that cultivation of the algae at low positive temperature (6°C) and moderate illumination (250 µmol quanta/(m2⋅s) contributed to accumulation of all identified carotenoids, including extraplastidic astaxanthin. In addition to the pigments, fatty acids accumulated in the algae cells. The data obtained allow us to consider the studied microalgae as a potentially promising species for production of carotenoids.

A pilot study on post-mortem determination of drug abuse on dental tissues.

BACKGROUND: Post-mortem toxicology constantly deals with the research of reliable alternative matrices to be applied in case of highly damaged corpses (such us carbonized, skeletonized, human remains, etc.). Teeth represent a promising alternative matrix since dental tissues are endowed by different features, resistance and stability after death. SCOPE: Since scant literature reported on the pharmacokinetics and mechanism of incorporation of xenobiotics into dental tissues, this pilot research aims to investigate whether in the pulp can be detected the same substances found in blood in drug related death cases. Secondly, the study is addressed to disclose the possible deposit of drugs in dental hard tissues (dentine and/or enamel), thus contributing to reconstruct the drug abuse history (timing, e.g.). MATERIALS AND METHODS: The study experimented with a novel method to separately analyse dental enamel, dentin, and pulp, applied to 10 teeth collected during autopsies of drug-related deaths along with blood and hair samples for classic toxicological analyses. Each tooth was prepared by "pulverization technique" and then analysed by gas chromatography paired with mass spectrometry (GC-MS) and ultra high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC/HR-MS) for searching cocaine, opiates, and metabolites. The results were then compared with those obtained from blood and hair samples. RESULTS: Preliminary results demonstrated that teeth differ from any other classic matrix (blood and hairs) since the qualitative correspondence of the detected substances between pulp and blood as well as dental hard tissues and hair suggests that they can be useful in post-mortem evaluation as a unique matrix for both acute and chronic assumptions of drugs. The mechanism of accumulation of substances in mineralized dental tissues emerged the most significant result, being influenced by the type of molecule and the method of assumption. The main limitation of this study is the limited availability of the sample and the absence of anamnestic information of the time, rates and method of drug assumption during life. Further research is necessary to systematically investigate the distribution of different substances within the different tissues of the tooth.

[Zirconium-based metal-organic framework composites for solid phase extraction of brevetoxin-A from seawater].

Red tides are a type of natural marine disaster caused by harmful algae characterized by a high toxicity, wide distribution, and long duration. Since the concentration of algal toxins in seawater increases with the occurrence of red tides, algal toxins detected in seawater could be used to predict the occurrence and evolution of red tides. Brevetoxin-A (BTX-A) is a secondary metabolite produced by the harmful algae Karenia brevis, whose detection in seawater could form the basis of an accurate warning system for incoming red tides. However, due to the inherent complexity of the seawater matrix and the extremely low levels of BTX-A in seawater, the use of instruments for its direct detection is difficult. Therefore, there is an urgent need to develop a sample pretreatment method for the efficient enrichment of BTX-A in seawater. In this study, a metal-organic backbone material (UiO-66) and its composite with silica microspheres (SiO2@UiO-66) were successfully synthesized using the solvothermal method. The prepared SiO2@UiO-66 exhibited good hydrophilicity, water stability, and large specific surface area. Furthermore, it also exhibited hydrogen bonding and electrostatic interactions with BTX-A, had a strong affinity for BTX-A, and was able to efficiently adsorb BTX-A in complex matrices. Therefore, SiO2@UiO-66 showed potential as a novel packing material for the extraction of BTX-A from solid phase extraction columns. Combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), a highly sensitive detection method for the determination of BTX-A in marine water was established. The established analytical method had a low detection limit (3.0 pg/mL), a wide linear range (10.0 -200.0 pg/mL), and a good linear relationship (R=0.9992). Combined with the Fujian Province Red Tide Monitoring and Early Warning Information 2021 issued by the Fujian Provincial Oceanic and Fisheries Bureau, the analytical method established herein was successfully applied to analyze and monitor the content of BTX-A in actual seawater samples. This highlights the proposed system's potential for use as an early warning factor in the monitoring of red tides, representing a simple and fast pretreatment methodology for the detection of BTX-A in seawater.

Advances in Hemoglobinopathies and Thalassemia Evaluation.

Hemoglobin (Hb) disorders are among the most prevalent inherited diseases. Despite a limited number of involved genes, these conditions represent a broad clinical and prognostic spectrum. The menu of laboratory tests is extensive. From widely available modalities, for example, complete blood count to rather sophisticated molecular technologies, the investigation of Hb disorders recapitulates an increasing complexity of laboratory workup in other medical fields. This review highlights a current state of biochemical and molecular investigation of Hb disorders and offers a glimpse on technologies that are yet to be fully embraced in clinical practice.

Ultrasound-assisted matrix solid-phase extraction based on deep eutectic solvents and zinc oxide: Extraction and determination of six active ingredients in Ligustri Lucidi Fructus.

In this study, we propose a novel strategy utilizing deep eutectic solvents (DESs) as both the extraction solvent and dispersing liquid, with nanometer zinc oxide (ZnO) serving as the adsorbent. This method incorporates ultrasound-assisted matrix solid phase dispersion (UA-MSPD) for the extraction of six active components (salidroside, echinacoside, acteoside, specnuezhenide, nuezhenoside G13, and oleanolic acid) from Ligustri Lucidi Fructus samples. The extracts were then analyzed using high-performance liquid chromatography equipped with a diode array detector. The effects of various parameters such as dispersant dosage, DESs volume, grinding time, ultrasonication duration, and eluent volume on extraction recovery were investigated and optimized using a central composite design under response surface methodology. The optimized conditions yielded detection limits ranging from 0.003 to 0.01 mg/g and relative standard deviations of 8.7% or lower. Extraction recoveries varied between 93% and 98%. The method demonstrated excellent linearity for the analytes (R2 ≥ 0.9997). The simple, green, and efficient DESs/ZnO-UA-MSPD technique proved to be rapid, accurate, and reliable for extracting and analyzing the six active ingredients in Ligustri Lucidi Fructus samples.

[Study on the difference and clinical value of serum amino acids in patients with laryngeal squamous cell carcinoma].

Objective:To detect the differences in types and levels of amino acids in the peripheral serum of patients with laryngeal squamous cell carcinoma and non-tumor patients, and explore their relationship with clinical parameters of laryngeal squamous cell carcinoma as well as their clinical value in diagnosis. Methods:High-performance liquid chromatography-tandem mass spectrometry（HPLC-MS） was employed to detect the serum amino acid contents and levels of 62 patients diagnosed with laryngeal carcinoma and 141 non-tumor patients at the First Affiliated Hospital of Jinzhou Medical University between September 2018 and February 2021. The study compared the differences in 22 non-essential and essential amino acids found in the serum between the experimental group and the control group. An ROC curve and risk scoring formula of multivariate linear logic regression model was utilized to evaluate the efficiency of serum amino acids in the early diagnosis of laryngeal carcinoma. Results:There were significant differences in the contents of fourteen types of amino acids between the experimental and control groups, with thirteen amino acids showing higher levels in the experimental group（P<0.05）. Seven of these amino acids were essential, including phenylalanine, threonine, leucine, valine, histidine, tyrosine, and citrulline. The other six amino acids were non-essential, including arginine, asparagine, cysteine, glycine, ornithine, and proline. Interestingly, the content of homocysteine in the experimental group was lower than that in the control group（P=0.024）. Further analysis showed that patients with laryngeal squamous cell carcinoma in TNM stage Ⅰ and Ⅱ had higher serum methionine levels compared to those in stages Ⅲ and Ⅳ（P=0.026）. In addition, the content of serum histidine was higher in patients with poorly differentiated squamous cell carcinoma compared to those with well-differentiated squamous cell carcinoma（P=0.041）. The level of asparagine in the serum of patients with laryngeal squamous cell carcinoma older than 64 years old was lower than that in patients younger than 64 years old（P=0.033）. The level of tryptophan in the serum of patients with a smoking history was lower than that in patients without a smoking history（P=0.033）. The level of citrulline in the serum of patients with a history of alcohol consumption was higher than that in patients with no history of alcohol consumption（P=0.003）. ROC curve analysis showed that out of the 14 different amino acids between the experimental and control groups, citrulline and cysteine were relatively effective as independent factors in the diagnosis of laryngeal squamous cell carcinoma, with an AUC of 0.856 and 0.850, respectively. Arginine was the most sensitive factor in the diagnosis of laryngeal squamous cell carcinoma（AUC=0.855）. However, citrulline alone had the highest specificity（0.830） in the diagnosis of laryngeal squamous cell carcinoma, and the combination of 12 amino acids significantly improved the diagnostic efficiency of laryngeal squamous cell carcinoma, with an AUC of 0.946, sensitivity of 0.887, and specificity of 0.894. A risk score formula for a multivariate logistic regression model was established based on the differential amino acid content in the serum. The risk score of laryngeal squamous cell carcinoma group was higher than that of the non-tumor group（P<0.001）. The AUC of risk score in the diagnosis of laryngeal squamous cell carcinoma was 0.953 with sensitivity and specificity of 0.957 and 0.855. Conclusion:This study found that there are differences in the contents of 14 amino acids among which 13 amino acids were increased in serum of patients with laryngeal squamous cell carcinoma, and were associated with age, clinical stage, pathological differentiation, smoking, and drinking. Combined detection of 12 amino acids can improve the diagnostic efficiency of laryngeal squamous cell carcinoma and serve as potential markers for the auxiliary diagnosis of laryngeal squamous cell carcinoma using peripheral blood samples. Additionally, the established risk score model was found to be more effective in the diagnosis of laryngeal squamous cell carcinoma, indicating its important potential value as an auxiliary diagnostic tool.

[Determination of 13 perfluorinated and polyfluoroalkyl substances in fishes by QuEChERS-ultra-high performance liquid chromatography-tandem mass spectrometry].

Perfluorinated and polyfluoroalkyl substances (PFASs) are compounds characterized by at least one perfluorinated carbon atom in an alkyl chain linked to side-chain groups. Owing to their unique chemical properties, these compounds are widely used in industrial production and daily life. However, owing to anthropogenic activities, sewage discharge, surface runoff, and atmospheric deposition, PFASs have gradually infiltrated the environment and aquatic resources. With their gradual accumulation in environmental waters, PFASs have been detected in fishes and several fish-feeding species, suggesting that they are bioconcentrated and even amplified in aquatic organisms. PFASs exhibit high intestinal absorption efficiencies, and they bioaccumulate at higher trophic levels in the food chain. They can be bioconcentrated in the human body via food (e. g., fish) and thus threaten human health. Therefore, establishing an efficient analytical technique for use in analyzing PFASs in typical fish samples and providing technical support for the safety regulation and risk assessment of fish products is necessary. In this study, by combining solvent extraction and magnetic dispersion-solid phase extraction (d-SPE), an improved QuEChERS method with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed for the determination of 13 PFASs in fish samples. Fe3O4-TiO2 can be used as an ideal adsorbent in the removal of sample matrix interference and a separation medium for the rapid encapsulation of other solids to be isolated from the solution. Based on the matrix characteristics of the fish products and structural properties of the target PFASs, Fe3O4-TiO2 and N-propyl ethylenediamine (PSA) were employed as adsorbents in dispersive purification. The internal standard method was used in the quantitative analyses of the PFASs. To optimize the sample pretreatment conditions of analyzing PFASs, the selection of the extraction solvent and amounts of Fe3O4-TiO2 and PSA were optimized. Several PFASs contain acidic groups that are non-dissociated in acidic environments, thus favoring their entry into the organic phase. In addition, acidified acetonitrile can denature and precipitate the proteins within the sample matrix, facilitating their removal. Finally, 2% formic acid acetonitrile was used as the extraction solvent, and 20 mg Fe3O4-TiO2, 20 mg PSA and 120 mg anhydrous MgSO4 were used as purification adsorbents. Under the optimized conditions, the developed method exhibited an excellent linearity (R≥0.9973) in the range of 0.01-50 µg/L, and the limits of detection (LODs) and quantification (LOQs) ranged from 0.001-0.023 and 0.003-0.078 µg/L, respectively. The recoveries of the 13 PFASs at low, medium, and high spiked levels (0.5, 10, and 100 µg/kg) were 78.1%-118%, with the intra- and inter-day precisions of 0.2%-11.1% and 0.8%-8.7%, respectively. This method was applied in analyzing real samples, and PFASs including perfluorooctanesulfonic acid, perfluorooctanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, and perfluorotridecanoic acid, were detected in all 11 samples evaluated. This method is simple, sensitive, and suitable for use in analyzing PFASs in fish samples.

[Determination of five veterinary drug residues in milk by ultra-high performance liquid chromatography-quadrupole/electrostatic field orbitrap mass spectrometry based on modified chitosan membrane purification].

Milk is an important consumer product with high nutritional value. The presence of veterinary drug residues in milk owing to the indiscriminate use of veterinary drugs may affect consumer health. In the mass spectrometric analysis of trace compounds, chromatographic co-eluting components easily interfere with the mass spectral signals obtained, affecting the accuracy of qualitative and quantitative analyses. Matrix purification is a promising method to reduce the matrix effect. Chitosan is a natural biopolymer with numerous active functional groups such as amino, acetyl, and hydroxyl groups; these groups can adsorb lipids through hydrophobic and electrostatic interactions. Chitosan also has the advantages of low production cost, stable chemical properties, and convenient modification. Novel chitosan-based materials are promising candidates for lipid purification. In this study, a chitosan membrane was modified with trimethoxyoctadecylsilane (C18-CSM). C18-CSM was prepared through one-step hydrolysis and used as a dispersive solid phase extraction (DSPE) adsorbent to purify the matrix during milk pretreatment. We combined C18-CSM with ultra-high performance liquid chromatography-quadrupole/electrostatic field orbitrap mass spectrometry (UHPLC-Q/Exactive Orbitrap MS) to develop an effective method for the extraction and determination of ofloxacin, enrofloxacin, ciprofloxacin, diazepam, and metronidazole in milk. C18-CSM was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and water contact angle testing. The results indicated that the material has a rough surface and uniformly dense cross-section. The water contact angle of C18-CSM was 104°, indicating its good hydrophobicity. The pretreatment conditions (extraction solvent, dosage of NaCl, extraction frequency, and dosage of C18-CSM) that influenced the recoveries of the five veterinary drugs were investigated in detail. The optimal conditions were established as follows: 5% formic acid in acetonitrile, 1 g NaCl, extraction 1 time, 20 mg C18-CSM. Separation was performed on a Hypersil GOLD VANQUISH column (100 mm×2.1 mm, 1.9 µm). The mobile phase consisted of 0.1% formic acid aqueous solution and 0.1% formic acid in acetonitrile, and was flowed at a rate of 0.3 mL/min. The sample injection volume was 1 µL, and the column temperature was maintained at 25 ℃. Mass spectrometric analysis was performed in positive electrospray ionization mode. To verify the necessity of the purification material, the matrix effect was investigated using the matrix-matched standard curve method. The use of C18-CSM reduced the matrix effects of the five necessity drugs from the range of -22%-8.8% to the range of -13%-3.6%, indicating that C18-CSM is a highly efficient DSPE material. Under optimal conditions, the developed method showed good linearities within the range of 0.5-100 µg/L, with correlation coefficients (r2)≥0.9970. The limits of detection(LODs) and quantification (LOQs) were 0.2 µg/L and 0.5 µg/L, respectively. To assess the accuracy and precision of the method, we prepared milk samples with three spiked levels (low, medium, and high). The recoveries of the five veterinary drugs were ranged from 79.5% to 115%, and the intra-day and inter-day relative standard deviations were 7.0%-13% (n=6) and 1.3%-11% (n=3), respectively. This study provides a simple, accurate, and reliable method for the rapid and simultaneous determination of the five veterinary drug residues in milk.

[Simultaneous determination of 21 perfluorinated and polyfluoroalkyl substances in plant oils by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry].

Edible plant oils are a key component of the daily human diet, and the quality and safety of plant oils are related to human health. Perfluorinated and polyfluoroalkyl substances (PFASs) are pollutants that can contaminate plant oil through the processing of raw materials or exposure to materials containing these substances. Thus, establishing a sensitive and accurate analytical method for the determination of PFASs is critical for ensuring the safety of plant oils. In this study, a method based on acetonitrile extraction and solid phase extraction purification combined with ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS) was developed for the simultaneous determination of 21 PFASs, including perfluorocarboxylic acids, perfluoroalkyl sulfonic acids, and fluorotelomer sulfonic acids, in edible plant oils. The chromatographic conditions and MS parameters were optimized, and the influences of the extraction solvents and purification method were systematically studied. Plant oil samples were directly extracted with acetonitrile and purified using a weak anion-exchange (WAX) column. The 21 target PFASs were separated on a reversed-phase C18 chromatographic column and detected using a triple quadrupole mass spectrometer with an electrospray ionization source. The mass spectrometer was operated in negative-ion mode. The target compounds were analyzed in multiple reaction monitoring (MRM) mode and quantified using an internal standard method. The results demonstrated that the severe interference observed during the detection of PFASs in the co-extracted substances was completely eliminated after the extraction mixture was purified using a WAX column. The 21 target PFASs showed good linearity in their corresponding ranges, with correlation coefficients greater than 0.995. The limits of detection (LODs) and limits of quantification (LOQs) of the method were in the range of 0.004-0.015 and 0.015-0.050 µg/kg, respectively. The recoveries ranged from 95.6% to 115.8%, with relative standard deviations (RSDs) in the range of 0.3%-10.9% (n=9). The established method is characterized by simple sample pretreatment, good sensitivity, high immunity to interferences, and good stability, rendering it suitable for the rapid analysis and accurate determination of typical PFASs in edible plant oils.

[Simultaneous determination of 10 quaternary ammonium salt bactericides in oral care products by high performance liquid chromatography-evaporative light-scattering detection].

Quaternary ammonium salt bactericides are broad-spectrum bactericides often used in oral care products because of their high antibacterial efficacy, strong penetration, and low toxicity. However, the excessive use of quaternary ammonium salt bactericides may cause contact dermatitis, scalding poisoning, and even death. Existing methods to determine quaternary ammonium salt bactericides are unable to meet current requirements owing to the lack of determination components. Therefore, establishing a simple and accurate method for the simultaneous detection of more quaternary ammonium salt bactericides is necessary. In this study, a method that couples sample pretreatment with high performance liquid chromatography-evaporative light-scattering detection (HPLC-ELSD) was developed for the simultaneous determination of quaternary ammonium salt bactericides in oral care products, including dodecyltrimethylammonium chloride, dodecyldimethylbenzylammonium chloride, benzethonium chloride, tetradecyl trimethyl ammonium chloride, tetradecyldimethylbenzylammonium chloride, N-hexadecyltrimethylammonium chloride, benzyldimethylhexadecylammonium chloride, trimethylstearylammonium chloride, stearyldimethylbenzylammonium chloride, and docosyltrimethylammonium chloride. Some of these bactericides do not absorb ultraviolet light, so a universal evaporative light-scattering detector was used owing to testing cost and stability concerns. The paste samples contained thickening agents, which are highly soluble in water but insoluble in organic solvents; these agents can seriously affect the results of sample pretreatment and damage the chromatographic column. Hence, sample dehydration was necessary. In this study, four dehydration methods were compared. Anhydrous sodium sulfate (Na2SO4) was selected, and the amount of Na2SO4 was optimized. Based on the solubility of the 10 target compounds and extraction efficiency, three extraction solvents were compared, and ethanol was selected. Ultrasonic extraction was the primary extraction process used in this study. The effects of different ultrasonication times, temperatures, and powers on the extraction recoveries were also investigated. Ultimately, the optimized conditions were as follows: extraction of the dehydrated paste and powder samples using ethanol at room temperature (25 ℃) for 20 min under 100 W ultrasound power, and dilution of the liquid sample with ethanol. After extraction, the samples were separated on an Acclaim Surfactant column (150 mm×4.6 mm, 5 µm) with 50 mmol/L ammonium acetate aqueous solution (pH=5.5) (A) and acetonitrile (B) as mobile phases. The gradient elution program were as follows: 0-5.0 min, 75%A-35%A, 5.0-15.0 min, 35%A-20%A, 15.0-20.0 min, 20%A, 20.0-21.0 min, 20%A-75%A, 21.0-25.0 min, 75%A. An external standard method was used for quantitative determination. The 10 compounds were analyzed within 25 min. Linear equations, correlation coefficients, and linear ranges were obtained by analyzing a series of mixed standard working solutions. The limits of detection (LODs, S/N=3) and quantification (LOQs, S/N=10) of the 10 components were determined. Stearyldimethylbenzylammonium chloride and docosyltrimethylammonium chloride showed good linear relationships in the range of 10-200 mg/L, while the other compounds demonstrated good linear relationships in the range of 5-100 mg/L. In all cases, correlation coefficients (R2) of no less than 0.9992 were obtained. The LODs and LOQs were in the range of 1.42-3.31 mg/L and 4.25-9.94 mg/L, respectively. Ten analytes were spiked in blank matrices, such as toothpaste (paste), mouthwash (liquid), and dentifrice powder (powder) at three levels, and the recoveries and precisions were calculated. The average recoveries were 87.9%-103.1%, and the corresponding relative standard deviations (RSDs) did not exceed 5.5% (n=6). The developed method was used to detect 109 oral care products. Benzyldimethylhexadecylammonium chloride and stearyldimethylbenzylammonium chloride revealed high detection rates. Moreover, the amount of stearyldimethylbenzylammonium chloride in one toothpaste sample exceeded regulatory requirements. Given its advantages of good precision and accuracy, the developed method is suitable for the quantitative analysis of the 10 aforementioned compounds in typical oral care products. The study findings can serve as a reference for the quality and safety monitoring of oral care products.

[Rapid determination of nine preservatives in tobacco flavor by three phase-hollow fiber-liquid phase microextraction-high performance liquid chromatography].

Tobacco flavors are extensively utilized in traditional tobacco products, electronic nicotine, heated tobacco products, and snuff. To inhibit fungal growth arising from high moisture content, preservatives such as benzoic acid (BA), sorbic acid (SA), and parabens are often incorporated into tobacco flavors. Nonetheless, consuming preservatives beyond safety thresholds may pose health risks. Therefore, analytical determination of these preservatives is crucial for both quality assurance and consumer protection. For example, BA and SA can induce adverse reactions in susceptible individuals, including asthma, urticaria, metabolic acidosis, and convulsions. Parabens, because of their endocrine activity, are classified as endocrine-disrupting chemicals. Despite extensive research, the concurrent quantification of trace-level hydrophilic (BA and SA) and hydrophobic (methylparaben, ethylparaben, isopropylparaben, propylparaben, butylparaben, isobutylparaben, and benzylparaben) preservatives in tobacco flavors remains challenging. Traditional liquid phase extraction coupled with high performance liquid chromatography (HPLC) often results in high false positive rates and inadequate sensitivity. In contrast, tandem mass spectrometry offers high sensitivity and specificity; however, its widespread application is limited by laborious sample preparation and significant operational costs. Therefore, it is crucial to establish a fast and sensitive sample pretreatment and analysis method for the nine preservatives in tobacco flavors. In this study, a method for the simultaneous determination of the nine preservatives (SA, BA and seven parabens) in tobacco flavor was established based on three phase-hollow fiber-liquid phase microextraction (3P-HF-LPME) technology combined with HPLC. To obtain the optimal pretreatment conditions, extraction solvent type, sample phase pH, acceptor phase pH, sample phase volume, extraction time, and mass fraction of sodium chloride, were examined. Additionally, the HPLC parameters, including UV detection wavelength and mobile phase composition, were refined. The optimal extraction conditions were as follows: dihexyl ether was used as extraction solvent, 15 mL sample solution (pH 4) was used as sample phase, sodium hydroxide aqueous solution (pH 12) was used as acceptor phase, and the extraction was carried out at 800 r/min for 30 min. Chromatographic separation was accomplished using an Agilent Poroshell 120 EC-C18 column (100 mm×3 mm, 2.7 µm) and a mobile phase comprising methanol, 0.02 mol/L ammonium acetate aqueous solution (containing 0.5% acetic acid), and acetonitrile for gradient elution. Under the optimized conditions, the nine target analytes showed good linear relationships in their respective linear ranges, the correlation coefficients (r) were ≥0.9967, limits of detection (LODs) and quantification (LOQs) were 0.02-0.07 mg/kg and 0.08-0.24 mg/kg, respectively. Under two spiked levels, the enrichment factors (EFs) and extraction recoveries (ERs) of the nine target analytes were 30.6-91.1 and 6.1%-18.2%, respectively. The recoveries of the nine target analytes ranged from 82.2% to 115.7% and the relative standard deviations (RSDs) (n=5) were less than 14.5% at low, medium and high levels. The developed method is straightforward, precise, sensitive, and well-suited for the rapid screening of preservatives in tobacco flavor samples.

[Determination of electrosynthesized urea products by igh performance liquid chromatography based n porous graphitic carbon column].

Urea is a simple organic compound that is widely used in both the industry and daily life. Compared with conventional methods, the preparation of urea by electrochemical synthesis is more environmentally friendly and sustainable. However, after the reaction, low amounts of urea and high concentrations of inorganic ions, including [Formula: see text] concentration was achieved without interference. Thus, the developed method can be applied for the detection of trace urea and other related ions in urea-containing electrolyte products.

[Determination of sodium cyclamate in Baijiu by pre-column derivatization-high performance liquid chromatography with fluorometric detection].

Sodium cyclamate in Baijiu is a key item in the China National Food Safety Supervision and Inspection Plan. A simple, economical, sensitive, and reliable method is urgently needed for routine analysis and internal quality control. A method based on high performance liquid chromatography with fluorescence detection (HPLC-FLD) was developed for the determination of sodium cyclamate in Baijiu by o-phthalaldehyde derivatization. First, the sodium cyclamate in the sample solution was converted into amino compounds using the desulfurization reaction under acidic conditions. Next, 400 g/L sodium hydroxide solution was added to the sample solution for neutralization. The amino compounds in the sample solution were then derivatized with o-phthalaldehyde to produce indole-substituted derivatives that are capable of producing fluorescence signals. Separation was carried out on a C18 column (250 mm×4.6 mm, 5 µm) in isocratic elution mode using a mobile phase consisting of acetonitrile and phosphate buffer. Finally, the eluate was monitored using a fluorescence detector, and an external standard method was used for quantification. A good linear relationship was obtained in the range of 0.1-2.0 mg/L, with correlation coefficients greater than 0.999. The average recoveries of sodium cyclamate spiked at levels of 0.1-1.0 mg/kg in Baijiu samples ranged from 90.7% to 100.9%, with relative standard deviations (RSDs) of 3.5%-5.6% (n=6). The limits of detection and quantification were 0.03 and 0.10 mg/kg, respectively. Nine Baijiu samples collected from the market were tested, and the results demonstrated that the contents of sodium cyclamate detected by the developed method were consistent with those obtained using the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method described in GB 5009.97-2016 (the third method). The proposed method is economical, sensitive, specific, and accurate; thus, it provides a basic approach for the determination of sodium cyclamate in Baijiu samples and has great potential for routine analysis in foodstuffs.

[Metabolite identification and metabolic pathway analysis of Platycodonis Radix extracts from Tongcheng city in rats].

In this study, we delved into the prototypical components and metabolites of Platycodonis Radix extracts(PRE) from Tongcheng city in plasma, urine and feces of rats, and revealed its metabolic pathways and metabolic rules in vivo. The prototypical components and metabolites of PRE in rats were characterized and identified by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) and mass defect filter(MDF). The biological samples were analyzed by ACQUITY UPLC BEH C_(18)(2.1 mm×100 mm, 1.7 µm), with 0.1% formic acid water(A)-0.1% formic acid acetonitrile(B) as mobile phase, and the biological samples were analyzed in negative ion mode by electrospray ionization mass spectrometry(ESI-MS). Twelve prototypical saponins and twenty-seven metabolites were detected in plasma, urine and feces of rats treated with PRE by oral administration. Eleven prototypical components and nine metabolites were detected in plasma, eleven prototypical components and eight metabo-lites were detected in urine, and ten prototypical components and twenty metabolites were detected in feces. Further studies showed that the metabolic pathways of PRE in rats mainly include oxidation, reduction, acetylation, stepwise hydrolytic deglycosylation, glucuronidation and so on. This study provides a scientific basis for clarifying the pharmacological basis and mechanism of PRE from Tongcheng city.

A nitrogen-specific detector for high performance liquid chromatography.

We describe a nitrogen-specific detector (NSD) for aqueous mobile phase-based high performance liquid chromatography (HPLC). It is based by means of total hydrophilic organic nitrogen detection. Separated analytes are photooxidized online and converted to nitrate, followed by an ultravilet absorbance detector. It features response dependant on the product of nitrogen number in the molecule and its molar concentration, no matter what is ultravilet-absorbing or not. The HPLC equipped with NSD can quantify nitrogen-containing analytes via a sole standard of potassium nitrate for calibration. This results in identical calibration curve for all nitrogen-containing analytes, obviating individual calibration. The limit of detection of NSD is 4.3 µM N/L, and its linear range is up to 4 mM N/L.

An Analysis of Capsaicin, Dihydrocapsaicin, Vitamin C and Flavones in Different Tissues during the Development of Ornamental Pepper.

As a fruit and vegetable crop, the ornamental pepper is not just highly ornamental but also rich in nutritional value. The quality of ornamental pepper fruits is given in their contents of capsaicin, vitamin C (VC), flavonoids and total phenols. The study concentrated on the accumulation of capsaicin and dihydrocapsaicin in different tissues of 18 peppers during fruit growth and development. The results showed that the pericarp and placenta contained significantly higher levels of capsaicin than dihydrocapsaicin. Additionally, the placenta contained significantly higher levels of both capsaicin and dihydrocapsaicin compared to the pericarp. The content of capsaicin was in the range of 0-6.7915 mg·g-1, the range of dihydrocapsaicin content was 0-5.329 mg·g-1. Interestingly, we found that the pericarp is rich in VC (5.4506 mg·g-1) and the placenta is high in flavonoids (4.8203 mg·g-1) and total phenols (119.63 mg·g-1). The capsaicin is the most important component using the correlation analysis and principal component analysis. The qPCR results substantiated that the expression of genes in the placenta was significantly higher than that in the pericarp and that the expression of genes in green ripening stage was higher than that in red ripening stage. This study could be utilized to select the best ripening stages and tissues to harvest peppers according to the use of the pepper and to the needs of producers. It not only provides a reference for quality improvement and processing for consumers and market but also provides a theoretical basis for high-quality pepper breeding.