Diode Array Detection Research Articles

Cytotoxicity Screening of Sterculia striata A.St.-Hil. & Naudin (Chichá) and Arachis hypogaea L. (Peanut) and Comparative Chemical Profiles Before and After in Vitro Digestion.

This study traced the cytotoxicity, antioxidant activity, and phytochemical profile before and after in vitro digestion of nuts from Sterculia striata A. St.-Hil. & Naudin (Malvaceae) (chichá or monkey's peanut), a native plant from Brazil, in comparison with Arachis hypogaea L. (peanut). The antioxidant activity in the 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and Ferric Reducing Antioxidant Power Assay (FRAP) assays was lower in chichá when compared with peanuts, corroborating the lower concentration of polyphenols. None of the samples studied showed significant cytotoxicity in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromideDAD: diode-array detection (MTT) assays. In vitro digestion altered the phytochemical profile in both plants, increasing the concentration of rutin in fresh and roasted chichá but only in raw peanuts. In roasted peanuts, rutin was converted into quercetin. Chichá nuts have been used by the local population for centuries, and the identification of their bioactive components can be useful to promote their benefits as a functional food.

Development and validation of a HPLC method simultaneously assisted with diode array and evaporative light scattering detection for the quantification of clinical mAb infusion bags in hospital pharmacy

To secure the supply chain of the monoclonal antibody (mAb) standardized infusion bags, a reversed phase (RP) HPLC analytical method assisted with a diode array detector (DAD) and an evaporative light scattering detector (ELSD) was implemented in the pharmacy department of the university hospital center of Besançon (UHCB). For a well-defined batch, the concordance between the two detections evaluated using the Lin’s concordance correlation coefficient (CCC) (Lin’s CCC = 0.9858) and a Bland–Altman plot was excellent. The analytical quantification of the different dose-banded (DB) of the infusion bags prepared in advance were achieved using this new reversed HPLC-DAD/ELSD analytical method in less than 4 min. For a same batch of mAbs, DAD generated nearly uniform response and showed a slightly superior accuracy than did ELSD. Their agreement in terms of calculated dose is excellent. In the event of a breakdown of one of the two detectors, this allowed the mAb infusion bags to continue to be monitored and thus improved the drug supply chain safety. As well our optimized method was able to monitor degradation mAbs created by accidental stress during the time period of stockage.

The utilization of a data fusion approach to investigate fingerprint profiles of dark tea from China's different altitudes

Dark tea refers to a kind of post-fermented product, and its quality and price vary owing to the distinct altitudes at which it grows. In this study, a novel method based on high performance liquid chromatography with a diode-array detector (HPLC-DAD) and an evaporative light scattering detector (HPLC-ELSD) was proposed for the classification of dark teas from distinct altitudes in China. Through implementing a strategy fusing feature-level data to construct a combined dataset, the classification performance of dark teas from distinct altitudes in China was evaluated after preprocessing. The results suggested that, through the feature fusion strategy, the identification accuracy rate increased from <70% of a single detector to 76.923%. After the implementation of preprocessing, the identification accuracy rate was further improved. Typically, the model identification accuracy rate after short-time Fourier Transform (STFT) treatment reached 92.85%, and the AUROC value was higher than 0.84, exhibiting a favorable generalization ability. This study provides a new thinking for the identification technology of dark teas from different altitudes in China.

A magnetic imprinted polymer nano-adsorbent with embedded quantum dots and mesoporous carbon for the microextraction of triazine herbicides

A magnetic molecularly imprinted polymer (MMIP) adsorbent incorporating amino-functionalized magnetite nanoparticles, nitrogen-doped graphene quantum dots and mesoporous carbon (MIP@MPC@N-GQDs@Fe3O4NH2) was fabricated to extract triazine herbicides from fruit juice. The embedded magnetite nanoparticles simplified the isolation of the adsorbent from the sample solution. The N-GQDs and MPC enhanced adsorption by affinity binding with triazines. The MIP layer provided highly specific recognition sites for the selective adsorption of three target triazines. The extracted triazines were determined by high-performance liquid chromatography (HPLC) coupled with diode-array detection (DAD). The developed method exhibited linearity from 1.5 to 100.0 µg L−1 with a detection limit of 0.5 µg L−1. Recoveries from spiked fruit juice samples were in the range of 80.1– 108.4 %, with a relative standard deviation of less than 6.0 %. The developed MMIP adsorbent demonstrated good selectivity, high extraction efficiency, ease of fabrication and use, and good stability.

Exploring advanced strategies in SPME-HPLC-DAD: Enhancing analytical precision and diverse applications in modern era

In analytical chemistry, the synergy between innovative sample preparation techniques and advanced chromatographic methods has paved the way for unprecedented advancements in the analysis of complex samples. Solid Phase Microextraction (SPME) stands out as a powerful tool for extraction, and preconcentration. When coupled with High-Performance Liquid Chromatography (HPLC) equipped with a Diode Array Detector (DAD), the integrated SPME-HPLC-DAD system emerges as a sophisticated analytical platform, offering enhanced sensitivity, selectivity, and versatility for various applications. Desorption is accomplished by either depositing organic solvent in the desorption chamber or else by flowing the mobile phase through the desorption chamber specificity. An ordinary description, along with a visual illustration, has been thoroughly provided for concepts of developed well-known enhanced thin film SPME cartridges (Figure 2). The tabular representation is also available with proper description like technique name, targeted analyte, column used, mobile phase used, %RSD, extraction recovery, LOD, and data acquired R2 also considered Based on the information available in the present study. Discussed SPME with HPLC-DAD brings a great turning point by successfully utilization in biomedical sciences, environmental monitors, food safety, and clinical analysis This cost-effective, readily available technique is both environmentally friendly and stable, allowing for rapid, reliable, and accurate measurements across a wide range of analyte concentrations, thanks to the utilization of hyphenated techniques. The different strategies of SPME with HPLC -DAD and possible future apllications have been incorporated in the review. The understanding of these techniques is still limited and challenging.

Exploring antioxidant and α-glucosidase inhibition in Eugenia L. extracts: a comprehensive phytochemical study

This study analysed extracts obtained from the leaves of Eugenia uniflora, E. involucrata, and E. myrcianthes to determine their chemical composition, antioxidative properties, and α-glucosidase inhibitory capacity. By using liquid chromatography with a diode array detector, we identified chlorogenic acids, flavonoids, tannins, proanthocyanidins, saponins, and triterpenes in the extracts. The antioxidant activities of the extracts were found to be directly related to their total phenolic, flavonoid content and enzyme inhibition. The E. uniflora aqueous extract showed significant inhibition of α-glucosidase (IC50 0.98 µg mL−1), indicating its potential as a non-competitive inhibitor for managing Diabetes Mellitus. This study contributes to the existing knowledge on the chemical and biological aspects of Eugenia genus.

Phenolic compound profiling and antioxidant potential of different types of Schisandra henryi in vitro cultures.

Schisandra henryi is an endemic species of medicinal potential known from traditional Chinese medicine. As part of this study, a complex biotechnological and phytochemical assessment was conducted on S. henryi with a focus on phenolic compounds and antioxidant profiling. The following in vitro cultures were tested: microshoot agar and callus, microshoot agitated, and suspension, along with the microshoot culture in PlantForm bioreactors. Qualitative profiling was performed by ultra-high-performance liquid chromatography with a photodiode array detector coupled with ion-trap mass spectrophotometry with electrospray ionization and then quantitative analysis by high-performance liquid chromatography with a diode array detector using standards. In the extracts, mainly the compounds from procyanidins were identified as well as phenolic acids (neochlorogenic acid, caffeic acid, protocatechuic acid) and catechin. The highest content of phenolic compounds was found for in vitro agar microshoot culture (max. total content 229.87mg/100g DW) and agitated culture (max. total content 22.82mg/100g DW). The max. TPC measured using the Folin-Ciocalteu assay was equal to 1240.51mg GAE/100g DW (agar microshoot culture). The extracts were evaluated for their antioxidant potential by the DPPH, FRAP, and chelate iron ion assays. The highest potential was indicated for agar microshoot culture (90% of inhibition and 59.31nM/L TEAC, respectively). The research conducted on the polyphenol profiling and antioxidant potential of S. henryi in vitro culture extracts indicates the high therapeutic potential of this species. KEY POINTS: • Different types of S. henryi in vitro cultures were compared for the first time. • The S. henryi in vitro culture strong antioxidant potential was determined for the first time. • The polyphenol profiling of different types of S. henryi in vitro cultures was shown.

Assessment of induced allelopathy in crop-weed co-culture with rye-pigweed model

This study evaluates induced allelopathy in a rye-pigweed model driven by rye’s (Secale cereale L.) allelopathic potential as a cover crop and pigweed’s (Amaranthus retroflexus L.) notoriety as a weed. The response of rye towards pigweed’s presence in terms of benzoxazinoids (BXs) provides valuable insight into induced allelopathy for crop improvement. In the 2 week plant stage, pigweed experiences a significant reduction in growth in rye’s presence, implying allelopathic effects. Rye exhibits increased seedling length and BXs upsurge in response to pigweed presence. These trends persist in the 4 week plant stage, emphasizing robust allelopathic effects and the importance of different co-culture arrangements. Germination experiments show rye’s ability to germinate in the presence of pigweed, while pigweed exhibits reduced germination with rye. High-performance liquid chromatography with diode-array detection (HPLC-DAD) analysis identifies allelopathic compounds (BXs), 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) in rye. Rye significantly increases BX production in response to pigweed, age-dependently. Furthermore, pigweed plants are screened for possible BX uptake from the rhizosphere. Results suggest that allelopathy in rye-pigweed co-cultures is influenced by seed timing, and age-dependent dynamics of plants’ allelopathic compounds, providing a foundation for further investigations into chemical and ecological processes in crop-weed interactions.

Development of bioactive films loaded with extract and polysaccharide of Pinus brutia bark.

Society's interest in natural and clean products in many areas, such as food and cosmetics, has increased considerably. It has led to the development of new techniques in the packaging of products so that the wastes from the preferred products can be recycled. In this context, Pinus brutia bark was preferred within the scope of the study to transform natural wastes into functional components and use them as packaging material. P. brutia bark (PBB) samples were collected from Bursa, Turkey. PBB samples were ultrasonically extracted using various solvents (acetone, butanol, ethanol, ethyl acetate, hexane, methanol, petroleum ether, and water) and a solvent-acidic hydrolysis system. The phenolic content profile of PBB samples was determined using high-performance liquid chromatography with diode-array detection, and total flavonoid content, antioxidant capacity, and total phenolic content were determined. Chitosan-polyvinyl alcohol (CS-PVA) films loaded with polysaccharides and containing methanolic extract were developed. The physical, chemical, and mechanical properties of the films were characterized. It is known that the thickness of the films determines the mechanical properties required to maintain the integrity of the packaging during storage and transport. From the results of the study, it was concluded that the elongation at break value was higher in CS-PVA-PBB-M films (111.08%±10.46%), Young's modulus (31.74±21.37N/mm2), and tensile strength (3.01±0.50N/mm2) values were higher in CS-PVA films. In this case, it was concluded that adding proanthocyanidin to edible films gives flexibility to the films.

Comparative study of sample preparation procedures to determine the main compounds in ayahuasca beverages by QuEChERS and high-performance liquid chromatography analysis.

Ayahuasca is a psychoactive drink originally consumed by indigenous people of the Amazon. The lack of regulation of this drink leads to uncontrolled consumption, and it is often consumed in religious contexts. The aim of this work is to compare three miniaturised extraction techniques for extracting the main ayahuasca compounds from beverages. Three sample pretreatment techniques were evaluated (dispersive liquid-liquid microextraction [DLLME], microextraction by packed sorbent [MEPS] and QuEChERS [Quick, Easy, Cheap, Effective, Rugged and Safe]) for the simultaneous extraction of N,N-dimethyltryptamine (DMT), tetrahydroharmine (THH), harmine, harmaline, harmol and harmalol from ayahuasca beverage samples. Then, the most promising technique (QuEChERS) was chosen to pre-concentrate the analytes, subsequently detected by high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD). The procedure was optimised, with the final conditions being 500 μL of extractor solvent, 85 mg of primary secondary amine (PSA) and 4s of vortexing. The analytical method was validated, showing to be linear between 0.16 and 10μg/mL for β-carbolines and between 0.016 and 1μg/mL for DMT, with coefficients of determination (R2) between 0.9968 and 0.9993. The limit of detection (LOD) and lower limit of quantification (LLOQ) were 0.16 μg/mL for all compounds, except for DMT (0.016 μg/mL) and extraction efficiencies varied between 60.2% and 88.0%. The analytical methodology proved to be accurate and precise, with good linearity, LODs and LLOQs. This method has been fully validated and successfully applied to ayahuasca beverage samples.

Leaves of Allium cepa and Xylopia aethiopica fruits as potent sources of natural antioxidant for stabilization of viscera FISH oil during accelerated storage

The present study investigated the antioxidant activities of methanolic extracts of two local plants and their capacities to preserve the quality of viscera fish oil during storage. The total phenolic, total flavonoids and tannins contents were analyzed by colorimetry, the preliminary antioxidant tests done and identification of phenolic compounds by HPLC-DAD (Diode Array Detector) and ESI-MS. After these evaluation, the plant extracts were added in viscera fish oil at concentration 200–1000 ppm. The oxidative stability of these fish oil samples was evaluated by measuring their qualities indices during 16 days at 70 °C. Here, oils were collected at the day 0, 4, 8, 12 and 16. The total phenolic, flavonoids and tannins contents in Xylopia aethiopica fruits were 15.62 g Eq acid galic/100g of dry extract, 10.85 mg Eq quercetin/100g of dry extract and 0.79 mg Eq cathechin/100 mg of dry extract. Those of Allium cepa leaves were 6.85 g Eq acid galic/100g of dry extract, 1.50 mg Eq quercetin/100g of dry extract and 0.11 mg Eq cathechin/100 mg of dry extract. All the methanolic extracts exhibited antioxidant activity. The results recorded after FRAP assay revealed the low IC50 (12.87 mg/mL) in Allium cepa extract compared to that of Xylopia aethiopica extract (44.90 mg/mL). These local plants contain many classes of phenolic compounds and they can be used in oil and fat industries as alternative of synthetic antioxidants.

Targeted analysis for the detection of phenolics and authentication of Albanian wines using LC-DAD/ESI–MS/MS combined with chemometric tools

In recent years, Albania has seen a significant increase in wine production, which can be attributed to the growing interest in the diversity of native grape varieties. Among the most popular grape varieties are Kallmet, Shesh i zi (ShiZ), Shesh i bardhë (ShiB), and Cerruje, which are known for their distinctive wines as well as the planted area. A study was conducted to investigate the influence of the territory and vintage on phenolic compounds of single-variety wines from these grape varieties. Liquid chromatography identified and quantified thirty-one phenolic compounds, sub-grouped into flavonoids and non-flavonoids, with diode-array detection coupled to electrospray ionization tandem mass spectrometry (LC–DAD–ESI/MSn). Within the red wines group, the ShiZ variety wine presented the highest phenolic content (1037 mg/L), followed by Kallmet cv. (539 mg/L); conversely, in the white wine group, the ShiB wines (699 mg/L) were distinguished from the Cerruje variety. Gallic acid was the main phenolic compound, followed by procyanidin B3. ShiB and ShiZ had the highest levels, at 215 and 136 mg/L, respectively. Among flavanols, (+)-catechin was found in the highest levels, with the maximum in Kallmet cv. red wine (58.9 mg/L), followed by (-)-epicatechin (29.1 mg/L). The ShiB wine had the highest content of flavonols, with quercetin-3-O-glucuronide and quercetin-3-O-glucoside as the main contributors. The highest quantity of stilbenoids belonged to Kallmet red wine (1.59 mg/L). Applying Principal Component Analysis (PCA) in red and white wine groups made a good separation possible according to variety and region. However, a separation according to vintage year was not successful.

A fast, simple and efficient surface floating organic droplet–based air–assisted liquid–liquid microextraction for simultaneous extraction of multiclass pesticides from environmental water, mineral water and soft drink samples by HPLC–DAD

A fast, simple, efficient and selective surface floating organic droplet–based air–assisted liquid–liquid microextraction method coupled with high performance liquid chromatograph–diode array detector was developed for simultaneous extraction of six multiclass pesticides. The developed method was validated for the extraction, enrichment and quantitative determination of trace level multiclass pesticides from environmental water, mineral water and soft drink samples. The effect of experimental parameters such as type and volume of extraction solvent, addition of salt, solution pH and extraction number were successfully optimized. Under the optimum conditions, the method showed good linearity for all the six multiclass pesticide residues with coefficient of determination within the range of 0.9979–0.9994. The limit of detection and quantification were in the range 0.01 to 0.07 µg L−1 and 0.03 to 0.25 µg L−1, respectively. The reproducibility and repeatability study in terms of %RSD were in the range of 0.88–5.28 and 1.35–6.08, respectively, indicating good precision of the method. The method exhibited acceptable mean relative recovery (%RR) in the range of 71.82 to 110.16 % with %RSDs (n = 3) less than 8 % for all the samples. Thus, the developed method could be utilized as selective extraction and preconcentration of multiclass pesticides from environmental water samples, mineral water and soft drink samples, as well as samples with similar matrices.

Development of a Simultaneous Normal-Phase HPLC Analysis of Lignans, Tocopherols, Phytosterols, and Squalene in Sesame Oil Samples.

The objective of this study was to develop a simultaneous analytical method for the determination of lignans, tocols, phytosterols, and squalene using high-performance liquid chromatography coupled with a diode array and fluorescence detector (HPLC-DAD-FLD). The method employed a VertisepTM UPS silica HPLC column (4.6 × 250 mm, 5 µm) with a mobile phase mixture of n-hexane/tetrahydrofuran/2-propanol. This approach enabled the simultaneous analysis of ten compounds within 22 min. The linear correlation (R2) exceeded 0.9901. The limit of detection (LOD) and limit of quantitation (LOQ) were up to 0.43 µg mL-1 for lignans and tocopherols and up to 326.23 µg mL-1 for phytosterol and squalene. The precision and accuracy of the intra-day and inter-day variation were less than 1.09 and 3.32% relative standard deviations (RSDs). Furthermore, the developed method was applied for the analysis of targeted compounds in twenty-eight sesame oil samples (1775-8965 µg g-1 total lignans, 29.7-687.9 µg g-1 total tocopherols, 2640-9500 µg g-1 phytosterol, and 245-4030 µg g-1 squalene). The HPLC method that has been developed was proven to be a reliable and effective tool for the determination of those functional compounds among sesame oil samples.

Implications of the Propagation Method for the Phytochemistry of Nepeta cataria L. throughout a Growing Season.

Catnip (Nepeta cataria L.) plants produce a wide array of specialized metabolites with multiple applications for human health. The productivity of such metabolites, including nepetalactones, and natural insect repellents is influenced by the conditions under which the plants are cultivated. In this study, we assessed how field-grown catnip plants, transplanted after being propagated via either single-node stem cuttings or seeds, varied regarding their phytochemical composition throughout a growing season in two distinct environmental conditions (Pittstown and Upper Deerfield) in the state of New Jersey, United States. Iridoid terpenes were quantified in plant tissues via ultra-high-performance liquid chromatography with triple quadrupole mass spectrometry (UHPLC-QqQ-MS), and phenolic compounds (phenolic acids and flavonoids) were analyzed via UHPLC with diode-array detection (UHPLC-DAD). The highest contents of total nepetalactones in Pittstown were found at 6 weeks after transplanting (WAT) for both seedlings and cuttings (1305.4 and 1223.3 mg/100 g, respectively), while in Upper Deerfield, the highest contents for both propagules were at 11 WAT (1247.7 and 997.1 mg/100 g, respectively) for seed-propagated and stem cuttings). The highest concentration of nepetalactones was associated with floral-bud to partial-flowering stages. Because plants in Pittstown accumulated considerably more biomass than plants grown in Upper Deerfield, the difference in nepetalactone production per plant was striking, with peak productivity reaching only 598.9 mg per plant in Upper Deerfield and 1833.1 mg per plant in Pittstown. Phenolic acids accumulated in higher contents towards the end of the season in both locations, after a period of low precipitation, and flavone glycosides had similar accumulation patterns to nepetalactones. In both locations, rooted stem cuttings reached their maximum nepetalactone productivity, on average, four weeks later than seed-propagated plants, suggesting that seedlings have, overall, better agronomic performance.

Color-tunable, multifunctional photochromic composites for wearable UV monitoring and biomechanical energy harvesting

Organic-inorganic hybrid photochromic materials have been considered one of the most promising photochromic candidates for light detection and information anti-counterfeiting. However, challenges still exist, such as single-color variation, long decoloration time, and lack of in-depth understanding of the photochromic mechanism. Here, a three-component photochromic composite system was designed, composed of two polymer matrices (electron donors) and phosphotungstic acid. By adjusting the ratio of one electron donor, the composite can initiate color change from transparent to deep blue, near-colorless, light mauve, mauve, and grey mauve, respectively, upon UV light irradiation, which has never been reported. These composites also feature flexibility, mechanical robustness, high transparency, faster photochromic reversibility, as well as dispensing printing. Importantly, the underlying multi-color photochromic mechanism is elucidated by leveraging the theoretical simulation and characterization techniques. A UV detection bracelet for real-time UV monitoring and a proton conductor for a wearable biomechanical energy harvester were fabricated using the photochromic composites, indicating application potentials for smart wearable electronics. This work introduces a new type of organic-inorganic photochromic composite and explores the photochromic mechanism, which may guide the design of new photochromic systems for future wearable technologies.

Metal-Organic Framework (MOF-199) Coated by Molecularly Imprinted Poly MMA-EGDMA for Solid Phase Extraction of Carbofuran from Fruit Samples

A selective adsorbent was synthesized based on the coating of a molecularly imprinted poly (methyl methacrylate-ethylene glycol dimethacrylate) (poly (MMA-EGDMA)) on the surface of metal-organic frameworks (MOFs) to obtain MMA-EGDMA@MOF-199 and used for the separation and preconcentration of carbofuran. Subsequently, carbofuran was determined by high-performance liquid chromatography with a diode array detector (HPLC-DAD). X-ray diffraction, field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis were used to characterize the synthesized adsorbent. Both pH and extraction time were optimized as crucial extraction parameters. The adsorption capacity of the adsorbent was 20 mg g−1. The selectivity of the synthesized adsorbent for similar compounds was also investigated. Under the optimal conditions, the calibration curve was linear from 1.0 to 400 μg L−1. A high extraction efficiency (94%) was obtained for carbofuran with a limit of detection (LOD) of 0.4 µg L−1. The adsorbent was successfully applied to the SPE of carbofuran from fruit samples after its extraction, followed by high-performance liquid chromatography analysis.

Chemical fingerprinting and multicomponent quantitative analysis for quality control of Cinnamomum tamala collected from Western Himalaya by HPLC-DAD

Cinnamomum tamala, commonly known as “Indian bay leaf” or “Tejpat”, is an economically important plant widely used in medicine, food and cosmetic industries. Growing demand for its leaf and bark in the herbal trade and non-availability of quality materials lead to large-scale species admixture and adulteration in the global market. The present study aims at developing a validated HPLC-DAD (High-performance liquid chromatography coupled with diode array detection) method and multiple markers-based chemical fingerprints for quality evaluation of C. tamala leaf extracts. Five bioactive compounds, viz., coumarin, cinnamyl alcohol, cinnamic acid, cinnamaldehyde and cinnamyl acetate, were identified and quantified in 28 samples collected from the western Himalayan region of India. The chromatographic separation was achieved on Shimadzu Shimpak C18 column (dimension 250 × 4.6 mm, pore size 5 μm) with a gradient elution of mobile phase using acetonitrile and 0.1 percent phosphate buffer and the chromatograms were obtained at a wavelength of 265 nm. The method validation was done by analyzing the linearity, LOD, LOQ, precision, stability, repeatability and recovery rates of standard compounds for quantitative analysis. The values of coefficient of correlation (R2) were found to be close to 1 for linearity and similarity analysis; and standard deviation was less than 3 percent in case of precision, stability, repeatability and recovery rates. The content of target compounds such as coumarin, cinnamyl alcohol, cinnamic acid, cinnamaldehyde and cinnamyl acetate varied in the range of 0–1.09, 0–0.05, 0.07–0.51, 0.39–1.27 and 0–0.27 percent, respectively. In the chemical fingerprint of C. tamala leaves, a total of 13 peaks were assigned as common peaks. The results of the study indicated that the HPLC method now developed combining chemical fingerprint with quantification of analytes could serve as a useful tool for quality evaluation of herbal raw materials of C. tamala and a valuable reference for further study.

Design and fabrication of a molecularly imprinted electrochemical sensor with high sensitivity for zearalenone assessment in maize

A highly sensitive and selective molecularly imprinted polymer-based electrochemical sensor was developed for rapid detection of zearalenone (ZEA) in maize samples. The sensor exhibited a wide linear dynamic range from 1 × 10−4 to 1 × 102 ng/mL with an impressive limit of detection of 3.4 × 10−5 ng/mL. It demonstrated excellent selectivity towards ZEA over structurally similar mycotoxins and provided accurate quantification in spiked maize extracts with recoveries ranging from 92 % to 108 % and relative standard deviations under 10 %. Comparative analysis with a conventional HPLC-fluorescence detection method revealed strong correlation (R2 = 0.982) between the two datasets. The proposed imprinted electrochemical sensing platform offers distinct advantages of simplicity, portability, cost-effectiveness, and high analytical performance, making it a promising tool for rapid on-site screening of ZEA contamination in food commodities.

Determination of sulfonamide antibiotics by magnetic porous carbon solid-phase extraction coupled with capillary electrophoresis

Sulfonamide antibiotics (SAs) have been widely used as antibacterial drugs for the prevention and treatment of livestock and poultry diseases, but they seriously threaten human health because they can accumulate in humans. Therefore, it is highly important to develop methods for monitoring sulfonamide residues in aquaculture and food. In this research, based on the generation of porous carbon (PC) by the pyrolysis of sodium citrate, magnetic porous carbon (PC@Fe3O4) was synthesized by a solvothermal method and used as an adsorbent for the magnetic solid-phase extraction of SAs. The effects of the proportion of PC in PC@Fe3O4, adsorbent dosage, adsorption time, eluent type, extraction pH, salt concentration and eluent dosage on the extraction efficiency were systematically studied. The adsorption performance and behavior of PC@Fe3O4 on SAs were evaluated using adsorption kinetics and adsorption isotherms, and the adsorption mechanism was preliminarily discussed. Under optimal conditions, combined with capillary electrophoresis diode array detection, a sensitive detection method for SAs was developed. The proposed method can be used for the determination of six SAs in fishpond water and milk samples, with a linear range of 0.5–200 ng mL−1, detection limits of 0.24–0.34 ng mL−1, and spiked recoveries of 85.9–109.0 %.