High-performance Liquid Chromatography-ultraviolet Research Articles

Improving Antioxidant Effect of Stemona tuberosa by Fermentation with Endophytic Fungus Penicillium expansum STRB13

Background: Stemona tuberosa Lour. is a plant belonging to the genus Stemona (Stemonaceae) that has been utilized in traditional Chinese medicine (TCM) for its antitussive and antiparasitic properties. Endophytic fungi have been shown to play an important role in the growth and metabolism of plants. Fermentation involving endophytic fungi tends to result in the production of new or more potent pharmacological compounds. Objective: The study aims to enhance the antioxidant activity of S. tuberosa by fermenting it with a symbiotic endophytic fungus. Methods: Seven symbiotic endophytic fungi were used to screen and ferment S. tuberosa to improve antioxidant activity estimated by 2,2’-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric ion-reducing antioxidant power (FRAP). The chemical constituent changes were characterized by ultraviolet (UV) spectrum and high-performance liquid chromatography (HPLC) analysis. Results: Penicillium expansum STRB13, an endophytic fungus associated with S. tuberosa, was screened for its ability to enhance antioxidant capacity through fermentation. The fermentation of S. tuberosa using P. expansum STRB13 significantly improved its DPPH radical scavenging activity, achieving an IC50 value of 24.2 μg/mL. Additionally, the ferric reducing antioxidant power (FRAP) of the fermented sample was fourteen times greater, measuring 388.1 ± 32.6 μmol/L compared to 27.5 ± 1.0 μmol/L in the blank sample. Differences observed between the blank and P. expansum STRB13 fermented S. tuberosa (FST) in UV spectra and HPLC analysis indicated the production of new aromatic phenolic compounds through fermentation, which contributed to the enhanced antioxidant activity. Conclusion: This is the first time reporting on the fermentation processing of S. tuberosa with symbiotic endophytic fungus. This study revealed that P. expansum STRB13 FST will be an alternative natural antioxidant. Fermentation with symbiotic endophytic fungus is a new approach to processing TCM and discovering new compounds.

Development of a simple high-performance liquid chromatography-ultraviolet detection method for selpercatinib determination in human plasma

Selpercatinib is a selective rearranged during transfection (RET) kinase inhibitor effective for the treatment of RET-positive non-small cell lung cancer, thyroid cancer, and other cancers. However, its clinical use requires careful management because of dose-dependent adverse effects and pharmacokinetic interactions. Given the multiple factors influencing selpercatinib blood levels, we hypothesized that establishing a therapeutic drug monitoring system for selpercatinib could help reduce adverse events and optimize efficacy. Therefore, we herein developed a high-performance liquid chromatography-ultraviolet (HPLC-UV) method for measuring selpercatinib blood levels to facilitate therapeutic drug monitoring in clinical practice. Proteins were precipitated with acetonitrile, and selpercatinib and the internal standard (gefitinib) were separated via HPLC-UV. The calibration curve was linear over 0.5-8.0 µg/mL with a coefficient of determination (r²) equaling 0.9996. Intra- and interday validation coefficients were both under 2.80%. The corresponding measurement precision ranged from - 1.50% to 12.60% and - 1.32% to 7.50%, respectively, with recoveries exceeding 94.43%. Thus, this study establishes a simple and sensitive method for quantifying selpercatinib in human plasma. Future studies will analyze plasma samples from patients treated with selpercatinib and utilize this method to explore the relationships among plasma concentration, efficacy, and adverse events to define the therapeutic concentration range.

Development and Validation of a Simple, Precise, and Robust Reversed-Phase High-Performance Liquid Chromatography-Ultraviolet Method for the Determination of Polyvinylpyrrolidone in Adhesives

Development and Validation of a Simple, Precise, and Robust Reversed-Phase High-Performance Liquid Chromatography-Ultraviolet Method for the Determination of Polyvinylpyrrolidone in Adhesives

Electrodeposition of Zn-Al-Layered Double Hydroxides With Interlayer Modification by Ibuprofen as Fiber Coating for Solid Phase Microextraction of Nonsteroidal Anti-Inflammatory Drugs.

In this study, in situ electrodeposition of Zn─Al-layered double hydroxides (Zn─Al-LDHs) on the surface of pencil graphite substrate were practiced with interlayer modification by ibuprofen. The prepared composite increases the efficiency of the proposed method by increasing the level of interaction between the sorbent and the selected analytes including acetylsalicylic acid and naproxen (NAP) in real sample. Eventually, the extracted target analytes were injected into high-performance liquid chromatography ultraviolet (HPLC-UV) for their measurement. The experimental design including PBD and BBD was implemented to obtain the maximize efficiency and optimal condition for extraction of the target analytes. Therefore, in optimal conditions, limits of detection of 0.33-0.64µgL-1, linear dynamic range (LDR) of 1-100µgL-1 (with r2>0.9934), and limits of quantification (LOQs) of 1.1-2.1µgL-1 were obtained for target analytes by SPME-HPLC-UV. The intra-day relative standard deviation (RSD%) were found to range in 3.90%-5.30% (4.90%-6.80%) at concentration of 5-50µgL-1 (2-10µgL-1). According to obtained result, the relative recovery was calculated between 90% and 109%. Therefore, the obtained results showed that the selected method has a suitable performance for the preconcentration and extraction of acetylsalicylic acid and NAP in biological samples.

Synthesis of Functionalized Pyridine Modified Magnetic Nanoparticles for Utilization in Magnetic Solid-Phase Extraction of Tebuconazole and Propiconazole Followed by Quantification via High-Performance Liquid Chromatography-Ultraviolet Detection.

In the current study, a new magnetic sorbent (Fe3O4@2,6-diamino-4-(3,4-dihydroxyphenyl) pyridine-3,5-dicarbonitrile) was prepared as a new and efficient sorbent to be used in the magnetic solid-phase extraction method to extract tebuconazole and propiconazole as model compounds. In this regard, effective parameters such as pH of the sample solution, desorption volume, ionic strength, extraction time, desorption time, and amount of the magnetic sorbent were optimized using experimental design. In the optimal condition, the linear dynamic ranges for tebuconazole and propiconazole were between 0.5 and 200.0µg/L. Also, the limits of detection, limits of quantification, and relative standard deviations were 0.21-0.14µg/L, 0.49-0.45µg/L, and 1.3%-4.6%, respectively. The estimated enrichment factors for tebuconazole and propiconazole were 22 and 28, respectively. The absolute recovery (AR%) values for tebuconazole and propiconazole were also 67% and 84%, respectively. Finally, the proposed method was used for determination of tebuconazole and propiconazole in cucumber, tomato, orange, and lemon fruits. The obtained result confirmed that the presented method is capable for the analysis of the selected analytes in complicated matrices. In addition, the ARs% were in the range of 67%-84%. The result proved that the presented method can be an alternative to the extraction process of various pesticides.

Rapid and efficient high-performance liquid chromatography-ultraviolet determination of total amino acids in protein isolates by ultrasound-assisted acid hydrolysis

This study presents the optimization and validation of an ultrasound-assisted acid method for the HPLC-UV determination of amino acids in plant-based proteins. The research focuses on enhancing hydrolysis efficiency and reducing environmental impact. Ultrasound treatment significantly accelerated hydrolysis by creating cavitation, which increases local pressure and temperature, leading to faster reaction rates. The optimal condition was a 30-minute treatment at 90 °C with 6 M hydrochloric acid. The 9-fluorenylmethyloxycarbonyl chloride derivatization was best performed at pH 9.0 using borate buffer, ethanol as the organic solvent, and a 5-minute derivatization time with a 5 mM concentration. The method’s analytical performance, validated according to FDA guidelines, showed excellent selectivity, specificity, linearity (r2 > 0.999), accuracy (recovery between 80–118 %), and precision (RSD<10.9). The analysis of 15 plant-based proteins revealed distinct amino acid profiles. Compared to traditional acid hydrolysis methods, the ultrasound-assisted approach demonstrated no significant difference in results (p-value > 0.05), confirming its reliability. The optimized ultrasound-assisted method is a reliable and efficient alternative for amino acid analysis, offering significant cost and time savings while maintaining high analytical performance. These findings are crucial for nutritional planning and developing functional foods to improve health outcomes.

Development and Validation of a High-Performance Liquid Chromatography-Ultraviolet Spectrometry Method for Ampicillin and its Application in Routine Therapeutic Drug Monitoring of Intensive Care Patients.

Ampicillin/sulbactam, a combination of a β-lactam and β-lactamase inhibitor, is widely used in clinical settings. However, therapeutic drug monitoring (TDM) of ampicillin is not commonly performed, particularly in intensive care units (ICUs). The purpose of this study was to develop and validate a rapid and cost-effective high-performance liquid chromatography (HPLC)-ultraviolet spectrometry method to quantify ampicillin in human serum and evaluate its clinical application in ICU patients. Sample cleanup included a protein precipitation protocol, followed by chromatographic separation on a C18 reverse-phase HPLC column within 12.5 minutes using gradient elution of the mobile phase. The assay was validated according to the German Society of Toxicology and Forensic Chemistry criteria. Clinical applications involved the retrospective analysis of TDM data from ICU patients receiving continuous infusion of ampicillin/sulbactam, including the attainment of target ranges and individual predicted and observed pharmacokinetics. The method was robust, with linear relations between the peak area responses and drug concentrations in the range of 2-128 mg/L. The coefficient of variation for precision and the bias for accuracy (both interday and intraday) were less than 10%. Clinical application revealed variable pharmacokinetics of ampicillin in ICU patients (clearance of 0.5-31.2 L/h). TDM-guided dose adjustments achieved good therapeutic drug exposure, with 92.9% of the samples being within the optimal (16-32 mg/L) or quasioptimal (8-48 mg/L) range. This method provides a practical solution for the routine TDM of ampicillin, facilitating individualized dosing strategies to ensure adequate therapeutic drug exposure. Given its simplicity, cost-effectiveness, and clinical relevance, HPLC-ultraviolet spectrometry holds promise for broad implementation in hospital pharmacies and clinical laboratories.

Preparation and evaluation of Fe3O4@C@NiCo-LDH@CDs composites for magnetic solid-phase extraction of trace endocrine disruptors.

The widespread use of endocrine disruptors (EDPs) has certain potential hazards to organisms and environments, and it is particularly important to develop effective pretreatment methods before detection of EDPs in complex samples. In this work, a novel magnetic nanocomposite decorated with layered double hydroxides (LDHs) and carbon dots (CDs) was designed and prepared for magnetic solid-phase extraction (MSPE) of EDPs (bisphenol S, bisphenol F, bisphenol A, bisphenol AF, diethylstilbestrol and 4-cumylphenol) combined with high-performance liquid chromatography-ultraviolet (HPLC-UV) detection. The prepared composites were characterized by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), and the adsorption mechanism towards these EDPs might be mainly based on hydrogen bonds and π-π conjugation. Under the optimized conditions, the proposed method showed limits of detection within 0.05-0.50 μg L-1 and limits of quantitation within 0.2-2.0 μg L-1, and good linearity (R2 ≥ 0.9975) was presented in the range of 0.2-200 μg L-1. Finally, the Fe3O4@C@NiCo-LDH@CDs composite-based MSPE-HPLC-UV method was applied for enrichment and determination of EDPs in water, milk, and tea beverage samples with recoveries in the range of 81.2-119.8% and relative standard deviations below 9.7%.

Extraction and detection of sulfonamide antibiotics in milk using magnetic solid-phase adsorbent based on molecular mechanics and DFT calculations

Based on the foundation of calculations in molecular mechanics and density functional theory (DFT) for in-depth mechanistic studies, this paper proposes the sample multi-residue analysis method of five common sulfonamide antibiotics (SAs) in milk. Fe3O4 nanoparticles modified magnetic graphene oxide nanoribbons (Mag-GONRs) with superior dispersibility and dispersion stability, were developed and firstly utilized to rapidly extract residual SAs from milk. Therefore, various SAs in complex samples could be simultaneously determined solely by high performance liquid chromatography-ultraviolet detector (HPLC-UV) without the need for complicated pretreatment processes. In order to obtain satisfactory extraction efficiency, indispensable investigation and optimization were conducted on some parameters influencing the extraction efficiency. And the extracted SAs were determined by. Good linearity for all analytes was achieved with appropriate correlation coefficients (R2 higher than 0.9978). The limits of detection ranged from 0.060 to 0.075 ng·mL−1. Recoveries of the sulfonamides in spiked milk samples were between 79.6 % and 114.6 %, with relative standard deviations within 12 %. Interestingly, with the assistant of computational chemistry, the efficient extraction of Mag-GONRs onto SAs has been validated at the molecular and quantum levels, further elucidating the adsorption mechanism based on non-covalent interactions. In the context of theoretical research and experimental results mutually supporting each other, a practical detection method with actual application value has been proposed in monitoring the residual sulfonamides in milk by the common devices.

In-tube solid-phase microextraction of polycyclic aromatic hydrocarbons from refinery water samples using UiO-66/polyacrylonitrile electrospun nanofibers followed by high-performance liquid chromatography-ultraviolet detection.

A simple and quick fiber-in-tube solid-phase microextraction (FIT-SPME) was introduced for the extraction and determination of nine polycyclic aromatic hydrocarbons followed by a high-performance liquid chromatography-ultraviolet detector in refinery water samples. For this purpose, a water-resistant metal-organic framework with a high surface area called UiO-66 has been applied in the form of an electrospun coating on stainless steel wires. After that, all the fibers were packed in the lumen of a stainless-steel tube to make the extraction phase. Both one variable at a time and experimental design methods have been used to optimize effective parameters on FIT-SPME. Under optimum conditions, the method demonstrated good linearity between 0.5 and 1000.0µg/L with a coefficient of determination greater than 0.9906. Furthermore, the limits of detection values ranged from 0.2 to 1.5µg/L. The intra-day and inter-day relative standard deviations were<8.4% and<9.7%, respectively. Lastly, the proposed method was applied to extract and determine analytes in four refinery water samples as well as surface water containing high total dissolved solids, and well waters where satisfactory results have been obtained.

Determination of anamorelin concentration in human plasma using a simple high-performance liquid chromatography-ultraviolet detection method

Anamorelin, a non-peptide ghrelin analog and growth hormone secretagogue, is a novel oral drug used to treat cancer cachexia. Patients with cancer cachexia frequently use several drugs and anamorelin is a substrate of cytochrome P450 (CYP) 3A4; therefore, drug-drug interactions with CYP3A4 inhibitors and inducers pose a clinical problem. In this study, we aimed to determine the concentration of anamorelin in human plasma using a simple high-performance liquid chromatography-ultraviolet (HPLC-UV)-based method. The analysis involved extracting a 200-μL plasma sample and protein precipitation using solid-phase extraction. Anamorelin was isocratically separated using a mobile phase consisting of 0.5% potassium dihydrogen phosphate (pH 4.5) and acetonitrile (61:39, v/v) on a Capcell Pack C18 MG II column (250 mm × 4.6 mm) at a flow rate of 1.0 mL/min and monitored at a detection wavelength of 220 nm. The calibration curve was linear within a plasma concentration range of 12.5-1,500 ng/mL, with a coefficient of determination of 0.9999. The intra- and inter-day coefficients of variation were 0.37-6.71% and 2.05-4.77%, respectively. The accuracy of the assay and recovery were 85.25-112.94% and > 86.58%, respectively. This proposed HPLC-UV method is simple and can be applied in clinical settings.

Deciphering the anti-diabetic potential of Dipsacus asperoides root: Identification of active compounds and quality assessment

The plant Dipsacus asperoides C. Y. Cheng et T. M. A., has been traditionally utilized as a medicinal plant in China due to its roots known as “Dipsaci Radix”. It is suggested that Dipsaci Radix exhibits antihyperglycemic, hypolipidemic, and antioxidant properties, along with down-regulating effects on advanced glycation end-products (AGEs) formation. However, there are currently no reliable reports on the effective components derived from Dipsaci Radix for anti-diabetes. In this study, the methanol extract and its corresponding ethyl acetate (EA) fraction of Dipsaci Radix were investigated as potential natural sources of antidiabetic agents and antioxidants by in vivo methods. The existence of phenolic components in extract and fraction enhances their antioxidant and antidiabetic properties. This is evidenced by the fact that all isolated phenolic compounds exhibited such properties, with half of them (Compound 2, 4, 5, 8, 10) displaying multidirectional inhibitory effects. Quality evaluation of these active components using high performance liquid chromatography-ultraviolet (HPLC-UV) technology combined with grey relational analysis provides further information regarding the spectrum-effect relationship between active components and their activities. Among them, the presence of the active ingredient “5-O-caffeoylquinic acid” significantly contributes to the antidiabetic and antioxidant properties of Dipsaci Radix. This holds promising applications in traditional health products and cosmeceuticals.

A method validation of determination of melamine in marketed infant formula and milk powder of Iran

Melamine is a recognized food contaminant that can arise incidentally or intentionally in specific categories of food. This study aimed to validate the melamine detection and quantification in infant formula and milk powders and also analyzed 40 samples consist of infant formula and milk powders from commercially available food products, from different geographic regions of Iran. The approximate content of melamine in samples was measured by High-performance liquid chromatography-ultra violet (HPLC–UV) system. A calibration curve (R2 = 0.9925) was established for detection of melamine in the range of 0.1–1.2 μg mL−1. Limit of quantification and limit of detection were 1 μg mL−1 and 3 μg mL−1, respectively. The presence of melamine in infant formula and milk powdered was investigated and it was observed that the amount of melamine in samples of infant formulas and milk powders was 0.001–0.095 mg kg−1 and 0.001–0.004 mg kg−1, respectively. These values were found to be within the prescribed limits by the European Union and Codex Alimentarius Commission legislation. It is important to note that the consumption of these dairy products, which contain low content of melamine, does not pose any significant threat to consumer health. Furthermore, the results of the risk assessment confirmed this issue.

Green determination of glucocorticoids in water environment based on novel polydopamine coated iron tetroxide via magnetic dispersive solid phase microextraction

As the potential risks on human and aquatic animal exposed to the glucocorticoids in environment, it is essential to detect anti-epidemic pharmaceutical in real water samples. In this work, a core-shell shape, magnetic suspension particle sorbents of Fe3O4@oleic acid@polydopamine (Fe3O4@OA@PDA) were synthesized for magnetic dispersive solid phase microextraction (MDSPME), which possessed considerable dispersibility in water samples and extracted three glucocorticoids through hydrogen bonding with high detection sensitivity. The adsorption process of MDSPME was investigated by thermodynamic and kinetic theory, which demonstrated that the kinetic processes of adsorption were in accordance with the quasi second order kinetic model, and the adsorption isotherm was in accordance with the Freundich model. Combined with high performance liquid chromatography-Ultraviolet spectrophotometer detector, the proposed method had a linear range of 5–200 μg/L with an ultra-low detection limit down to 0.5–1.1 μg/L. The Green Analytical Greenness Metric (AGREE) software was employed to evaluate the greenness of the analytical method. This work presented an effective strategy for creating ultrasensitive and cost-effective probe for detection in anti-epidemic drugs.

Aflatoxins, fumonisins, citrinin, and zearalenone contents and health risk estimates in bee products in Turkey

Food contamination is an important global food safety issue. This study aimed to detect aflatoxins (AFB1, AFB2, AFG1, AFG2), fumonisins (FB1, FB2), citrinin (CIT), and zearalenone (ZEA) in four bee product groups (honey, royal jelly, bee pollen, propolis) in Turkey. Additionally, exposure and risk assessments were made for mycotoxins detected in these products. Mycotoxin analyzes in bee products were carried out by high-performance liquid chromatography-ultraviolet (HPLC-UV) and liquid chromatography-tandem mass spectrometry (LC/MS-MS) methods. The most frequently detected mycotoxins in all bee products were ZEA (37.5%) and AFB2 (36.6%). The analysis showed that the average concentrations of FB2 (2.091 μg/kg), AFB1 (0.595 μg/kg), and ZEA (0.009 μg/kg) in all bee products were above the detection limit levels, while the levels of AFB2, AFG1, AFG2, FB1, and CIT were below the limit of detection. When comparing bee products, it was found that honey samples were more exposed to AFB2 and FB1, bee pollen to FB1, propolis to AFB2, and royal jelly to ZEA contamination. AFG1 and CIT were not detected in propolis and bee pollen, respectively. All mycotoxins analyzed in the study pose no health risks when bee products are consumed daily.

Determination of the Chemical Content of Shilajit in Terms of Ten Different Polyphenolic Compounds by UAE Method and HPLC Analysis

Shilajit (Mumio) is a complex of natural bioactive compounds that has historically been used as a therapeutic cream for many skin diseases and is suitable in traditional medicine for diseases such as diabetes, Alzheimer's and cancer. In this study, to determine the polyphenolic content of Shilajit, extracts obtained at 45 degrees were analyzed by High Performance Liquid Chromatography-Ultraviolet (HPLC-UV) for the quantitative analysis of ten different polyphenolic compounds. As a result of the experimental study, 28.99±1.23 µg/g routine, 25.47±1.67 µg/g ferulic acid, 41.49±0.41 µg/g resveratrol and 532.19±8.21 µg/g taxifolin was obtained. This study's results will significantly contribute to sectors such as the extraction of bioactive substances, scaling studies, and their use as food supplements and pharmaceutical applications.

Alien species water hyacinth realizes waste into treasure: The preparation of biomass sorbent to determine benzoylurea insecticides in tea products.

A fast and effective analytical method with biomass solid-phase microextraction sorbent combined with a high-performance liquid chromatography-ultraviolet detector was proposed for the determination of benzoylurea (BU) insecticides in tea products. The novel sorbent was prepared by activating and then carbonizing water hyacinth with a fast growth rate and low application value as raw material and showed a high specific surface area and multiple interactions with analytes, such as electrostatic action, hydrogen bonding, and π-π conjugation. After optimizing the three most important extraction parameters (pH [X1], sample loading rate [X2], and solution volume [X3]) by Box-Behnken design, the as-established analytical method showed good extraction performance: excellent recovery (80.13%-106.66%) and wide linear range (1-400µg/L) with a determination coefficient of 0.9992-0.9999, a low limit of detection of 0.02-0.1µg/L and the satisfactory practical application results in tea products. All these indicate that the water hyacinth-derived material has the potential as a solid-phase extraction sorbent for the detection and removal of BU insecticides from tea products, and at the same time, it can also achieve the effect of rational use of biological resources, maintaining ecological balance, turning waste into treasure, and achieving industrial production.

Simultaneous determination of six catechins and caffeine in tea and wine using salting-out assisted liquid-liquid extraction and high-performance liquid chromatography with ultraviolet detection.

Catechins, renowned for their antioxidant properties and health benefits, are commonly present in beverages, particularly tea and wine. An efficient and cost-effective salting-out assisted liquid-liquid extraction (SALLE) method has been developed and validated for the simultaneous determination of six catechins and caffeine in tea and wine samples using high-performance liquid chromatography-ultraviolet (HPLC-UV). This method demonstrates outstanding performance: linearity (1-120µg/mL, r2>0.999), accuracy (96.5%-103.4% recovery), and precision (≤14.7% relative standard deviation), meeting validation requirements set by the US Food and Drug Administration. The reduced sample size (0.1g) minimizes matrix interferences and costs without compromising sensitivity. All analytes were detected in Camellia sinensis teas, with green tea displaying the highest total catechin content (47.5-100.1mg/mL), followed by white and black teas. Analysis of wine samples reveals the presence of catechin in all red and white wines, and epigallocatechin gallate in all red wine samples, highlighting the impact of winemaking processes on catechin content. The SALLE-HPLC-UV approach represents a green alternative by eliminating organic waste, surpassing conventional dilution methods in specificity and sensitivity for catechin determination. AGREEprep assessment emphasizes the strengths of the SALLE procedure, including material reusability, throughput efficiency, minimal sample requirements, low energy consumption, and the absence of organic waste generation.

Study on determination methods and analysis of micronutrients in take-away meals

To comprehensively analyze the trace nutrient contents in take-away meals, the simultaneous detection method of common vitamins in take-away meals were explored based on the samples&apos; matrix, and the content of trace nutrients in take-away meals was analyzed combined with inductively coupled plasma-mass spectrometry(ICP-MS) detection of common elements. Fifty-seven take-away meals were collected randomly and analyzed. Vitamins were determined by high performance liquid chromatography-ultraviolet detector tandem fluorescence detector after pretreatment of samples including enzymatic digestion, hydrolysis and extraction. The separation was performed on a C_(18) column(250 mm×4.6 mm, 5 μm) with ion-pair acid reagents as the mobile phase for water-soluble vitamins and methanol for fat-soluble vitamins. Vitamin B_1, vitamin B_2, nicotinic acid, nicotinamide and vitamin A were detected by ultraviolet detector(UVD), while vitamin B_6 and E by fluorescence detector(FLD). Elemental analysis of calcium, magnesium, sodium, potassium, zinc, selenium and copper in the take-away meals was carried out according to GB 5009.268-2016 by ICP-MS to comprehensively evaluate the contents of micronutrients. Through optimization of chromatography and sample pretreatment conditions, the sensitivity of the established detection method can meet the needs of micronutrient evaluation with the detection limits and quantification limits of vitamins in the range of 0.002-0.098 mg/100 g and 0.007-0.327 mg/100 g, respectively. Good precision was obtained(&lt;10%). The spiked recovery rates were 80.5%-103.8%(n=6). The result showed that the contents of micronutrients in take-away meals were generally low. The detection rates of vitamins ranged from 21.1% to 98.2%. The proposed method is simple and sensitive, and the contents of vitamins and elements determined were low in the collected take-away meals.

Dispersive liquid–liquid microextraction based on deep eutectic solvent followed by high-performance liquid chromatography-ultraviolet for imidacloprid, hexythiazox, and fenpyroximate determination: Experimental design approach

Dispersive liquid–liquid microextraction (DLLME) of three insecticides, including imidacloprid (I), hexythiazox (H), and fenpyroximate (F), was performed as an efficient method for separation and preconcentration using a deep eutectic choline chloride-acetic acid solvent (DES) followed by determination by high-performance liquid chromatography-ultraviolet (HPLC-UV). The experimental design approach (central composite design) was used to optimize the effective parameters. According to the results, the addition of salt had no significant effect on extraction among the four parameters studied, including pH, DES volume (dispersive solvent), salt concentration, and chloroform volume. The optimized conditions in the DES-DLLME-HPLC-UV method were pH = 6.00, 100 µL DES, and 138 µL chloroform. Under optimized conditions, a wide linear range of 1.00 × 10−3-20.00 µg mL−1 was obtained for three insecticides. The enhancement factors were 11.22, 58.04, and 39.65 and the limit of detection of 3.00 × 10−4, 2.00 × 10−4, and 2.00 × 10−4 µg mL−1, and the limit of quantification of 9.00 × 10−4, 8.00 × 10−4, and 6.00 × 10−4 µg mL−1 were also determined for imidacloprid, hexythiazox, and fenpyroximate, respectively. The presence of other components including benomyl, dimethoate, mancozeb, captan, thiodicarb, carbendazim, and oxyfluorfen, showed no significant interference effect on the determination of three insecticides up to 50-fold. The method is eco-friendly benign, sensitive, precise, and straightforward as shown by the results.