Diode Array Research Articles

Greener method proposal for the determination of phenolic compounds and coumarins in aged sugarcane spirits using green bio-based solvents in HPLC-DAD-FLD system

High Performance Liquid Chromatography (HPLC) has been the most used analytical technique for analyzing phenolic compounds and coumarins in aged sugarcane spirit samples. It requires a significant amount of organic solvents, often toxic, as the mobile phase. The use of green bio-based solvents is a good alternative in the implementing more eco-friendly methods. Therefore, this work aims to propose a greener chromatographic method for the determination of phenolic compounds and coumarins in sugarcane spirit samples aged in different woods, using bio-based organic solvents (ethanol and acetic acid) in HPLC system with diode array and fluorescence detectors. Different metric tools (AGREE, ComplexMoGAPI, BAGI and Analytical Eco-scale) were used to evaluate the greenness of the analytical method. The proposed method was rigorously validated: linearity (R2 ≥ 0.9901); LOD (0.05 to 0.55 mg l-1); LOQ (0.25 to 5.00 mg l-1); precision (0.13 % ≤ RSD ≤ 18.6 %). The concentrations of total phenolic compounds and coumarins were up to 7.22 mg l-1. The sugarcane spirit aged in umburana presented the highest concentration of total phenolic compounds and coumarins with emphasis on trans-cinnamic acid (4.74 ± 0.01 mg l-1) and catechin (1.22 ± 0.02 mg l-1). All samples presented coumarin concentrations (<5.00 mg l-1) within the limit acceptable by legislation (10 mg l-1). The AGREE score (0.72) showed that the proposed method was greener and sustainable compared to other methods. The application of new mobile phase using green bio-based solvents proved to be advantageous from a Green Analytical Chemistry point of view.

Feasibility of a Novel Lighting System to Reduce Nighttime Falls in Assisted Living Residents With Dementia

ObjectivesTo determine the feasibility of conducting a trial of a novel nighttime lighting system designed to support postural stability in assisted living (AL) residents, and to estimate intervention effectiveness by comparing the incidence of nighttime falls during the novel lighting condition to that in a control condition featuring a standard nightlight. DesignRandomized crossover trial. The intervention consisted of 3 custom-designed linear arrays of amber light-emitting diodes (LEDs) arranged in strips: 1 strip aligned horizontally across the top of the bathroom/entry doorframe containing 68 LEDs and 2 strips of 140 LEDs each aligned vertically down the sides of the doorframe. The control condition was 1 standard nightlight in the bedroom and 1 in the bathroom. Residents were randomized to treatment sequences, receiving each condition for 1-2 quarters. Setting and ParticipantsFive AL communities serving exclusively residents with dementia or having separate units for residents with dementia, with at least 30 beds and at least 5 residents in private rooms. Residents were eligible if they had dementia, were ambulatory, did not share a bedroom, were not on hospice or expected to die within the year, and were not expected to transfer to another setting within the year. MethodsOutcomes included recruitment, retention, incident falls, and satisfaction. ResultsThirty-eight residents of the 5 communities participated (56% recruitment rate), and 24 family members completed surveys about their satisfaction with the lighting system. Cameras captured falls data for 92% of 8591 resident nights. The incidence density for falls was 34% lower in the intervention condition than the control condition (incidence density ratio 0.66, 95% CI 0.35, 1.22), which did not reach statistical significance (P = .18). Conclusions and ImplicationsThis low-cost intervention was feasible with high satisfaction. Building on these results, the intervention is being evaluated in a larger clinical trial. A novel lighting system to reduce falls could ultimately benefit millions of older adults across all settings.

Determination of calcium β‑hydroxy-β-methylbutyrate content in special medical formula food and sports nutrition food by solid-phase extraction and high performance liquid chromatography

Calcium β‑hydroxy-β-methylbutyrate (CaHMB) can promote muscle growth, prevent muscle atrophy, and enhance immunity, therefore, it is widely used as a nutritional supplement in special medical formula food and sports nutrition food. Many methods for the detection of CaHMB have been reported, but the pretreatment method for these reported literatures directly involves extraction using hydrochloric acid solution, without any purification steps. A method for accurately determining CaHMB in special medical formula food and sports nutrition food was established for the first time using solid-phase extraction (SPE) purification and high-performance liquid chromatography method (HPLC). The samples were extracted and precipitated protein using methanol-water solution, purified using SPE method and analyzed by HPLC on diode array detector (DAD) mode under external standard method. The method obtained excellent calibration linearity (r2>0.9993) and a satisfactory analysis of the targeted compound, which were evaluated with calibration standards over the range of 0.020–2.00 mg/mL. The limit of quantifications (LOQs), which defined as the lowest spiking level, were set at 0.4 g/100 g (special medical formula food) and 1.0 g/100 g (sports nutrition food). The average recoveries were within 92.9–104% for the analytes, and the relative standard deviations (RSDs) were below 3.93%, measured at low, medium, and high concentrations. Moreover, the positive sample analysis results indicated that CaHMB was detected on 10 real special medical formula food and sports nutrition food products, the contents of which were generally consistent with their labeled values, with measured values ranging from 97.1 % to 119 % of the labeled values. These results suggested that the developed highly sensitive and specific method is highly feasible for monitoring of the target analyte in special medical formula food and sports nutrition food.

Association of macular pigment optical density with plasma macular carotenoids levels and serum lipids in South Indian healthy volunteers and patients with early age-related macular degeneration.

Purpose: The objective of the present study was to investigate the relationship between macular pigment optical density (MPOD) and plasma carotenoids [(L) and (Z)] and serum lipids in South Indian young healthy volunteers and patients with early age-related macular degeneration (AMD). Methods: Two hundred and fourteen (N = 214) study participants (Healthy control group (N) = 178; Early AMD group (N) = 36) were enrolled after getting their written informed consent. The MPOD of the study participants was assessed using MPS II (Electron Technology, UK) after completing their routine ocular examination. Serum lipids were measured by the standard technique. Plasma levels of L, Z, lycopene and beta-carotene were estimated by high performance liquid chromatography with photo diode array detector. Statistical analysis used: Correlations among variables in serum, plasma and the MPOD were established using Spearman's rho correlation coefficient. Results: The overall mean MPOD in healthy control group and early AMD group were found to be 0.47 ± 0.16 (N = 178; 317 eyes) and 0.35 ± 0.22 (N = 36; 38 eyes) at 1° eccentricity respectively and were found to be statistically significant (p < 0.001). A strong positive association was found between plasma L, Z and L + Z and MPOD. Serum HDL showed a strong negative association with MPOD and other lipids showed a very weak association. MPOD was unaffected by body mass index. Conclusions: MPOD is positively associated with plasma L,Z and L + Z, adding further evidence that additional intake of L/Z may be beneficial in delaying the risk of AMD in our population.

“Welcome to the jungle”: TLC-SERS to wade through real complex mixtures of synthetic dyes

The finding of numerous synthetic strategies between the 19th and 20th century fostered the production of an extensive spectrum of organic dyes for artistic and industrial applications. Shortly after, challenges emerged related to the rapid deterioration of these products. Nowadays, the characterization of coloured pieces of art produced in the first half of the XXth century is further complicated by the absence of reference materials with an unambiguous composition, which are frequently a mixture between the starting dyes and their degradations products. Here we demonstrate as Surface Enhanced Raman Spectroscopy coupled with the simplest separation technique, i.e. Thin Layer Chromatography, is able beyond to recognize several synthetic dyes also to identify their isomers and degradation products. The occasion was the study of a catalogue of dyed textile swatches, produced in 1951 by the well-known Italian industry ACNA (Azienda Coloranti Nazionali e Affini). An apparently easy task turned out to be, indeed, not at all obvious as we found out that the actual composition of the reference samples seldomly corresponded to the declared one. TLC-SERS investigation of historical textile swatches was complemented by the integration of liquid chromatography coupled with a diode array detector and high-resolution mass spectrometry (HPLC-DAD-HRMS). This approach allowed us to validate the findings of TLC-SERS and to distinctively characterise synthetic by-products and degradation markers resulting from the deterioration of the dyes.

Investigating the quality of extraction and quantification of bioactive compounds in berries through liquid chromatography and multivariate curve resolution

Berries are a rich source of natural antioxidant compounds, which are essential to profile, as they add to their nutritional value. However, the complexity of the matrix and the structural diversity of these compounds pose challenges in extraction and chromatographic separation. By relying on multivariate curve resolution alternating least squares (MCR-ALS) ability to extract components from complex spectral mixtures, our study evaluates the contributions of various extraction techniques to interference, extractability, and quantifying different groups of overlapping compounds using liquid chromatography diode array detection (LC-DAD) data. Additionally, the combination of these methods extends its applicability to evaluate polyphenol degradation in stored berry smoothies, where evolving factor analysis (EFA) is also used to elucidate degradation products. Results indicate that among the extraction techniques, ultrasonication-assisted extraction employing 1% formic acid in methanol demonstrated superior extractability and selectivity for the different phenolic compound groups, compared with both pressurized liquid extraction and centrifugation of the fresh berry smoothie. Employing MCR-ALS on the LC-DAD data enabled reliable estimation of total amounts of compound classes with high spectral overlaps. Degradation studies revealed significant temperature-dependent effects on anthocyanins, with at least 50% degradation after 7 months of storage at room temperature, while refrigeration and freezing maintained fair stability for at least 12 months. The EFA model estimated phenolic derivatives as the main possible degradation products. These findings enhance the reliability of quantifying polyphenolic compounds and understanding their stability during the storage of berry products.Graphical abstract

Automated multicolumn screening workflow in ultra-high pressure hydrophilic interaction chromatography for streamlined method development of polar analytes

The pharmaceutical industry is rapidly advancing toward new drug modalities, necessitating the development of advanced analytical strategies for effective, meaningful, and reliable assays. Hydrophilic Interaction Chromatography (HILIC) is a powerful technique for the analysis of polar analytes. Despite being a well-established technique, HILIC method development can be laborious owing to the multiple factors that affect the separation mechanism, such as the selection of stationary phase chemistry, mobile phase eluents, and optimization of column equilibration time. Herein, we introduce a new automated multicolumn and multi-eluent screening workflow that streamlines the development of new HILIC assays, circumventing the existing tedious ‘hit-or-miss’ approach. A total of 12 complementary columns packed with sub-2 µm fully porous and 2.7 µm superficially porous particles operated on readily available ultra-high pressure liquid chromatography (UHPLC) instrumentation across a diverse set of commercially available polar stationary phases were investigated. Different mobile phases with pH ranging from pH 3 to 9 were evaluated using different organic modifiers. The gradient and column re-equilibration were judiciously set to ensure a reliable assay screening framework that indicates promising conditions for subsequent method optimization to achieve resolution of challenging mixtures. This UHPLC screening system is coupled with a diode array and charged aerosol detectors (DAD, CAD and mass spectrometry) to ensure versatile detection for a variety of compounds. This fast-screening platform lays the foundation for a convenient generic workflow, accelerating the pace of HILIC method development and transfer across both academic and industrial sectors.

Electrospray ionisation suppression in aquatic dissolved organic matter studies – Investigation via liquid chromatography–mass spectrometry

Ionisation suppression is a persistent issue in electrospray ionisation mass spectrometry, which decreases the signal of co-eluting analytes. In non-targeted analysis, where analyte and organic matrix identity is unknown, this poses a very challenging analytical problem when it comes to quantitatively assessing differences between samples, including in a compositional sense. In this study, I demonstrate the problems that arise due to ionisation suppression using a very simple sample mixing scheme between a fresh, metabolite rich sample (a leaf leachate) and a forest pond water. Samples were analysed after solid phase extraction on Agilent PPL and using high performance liquid chromatography coupled to electrospray ionisation – Orbitrap mass spectrometry, charged aerosol detector and diode array detector, the latter two allowing quantification of eluting material. I found that more than half of the well-resolved analytes expected to be present (at equal concentration) were completely lost from detection after mixing with pond water DOM. The average recovery of analytical signal (i.e., the signal weighted average), was about 50%, and was highly variable between analytes. Ionisation suppression also affected the signal obtained from the geochemical background DOM, and material recovery decreased slightly when mixing samples and extracting at a higher volume on PPL. Overall, the results showed that ionisation suppression is an extremely important problem for comparison of biogeochemical samples, even when only considering presence and absence of detected features. A multi detector approach and liquid chromatographic separation adds great value in comparison to use of only high resolution mass spectrometry (in direct infusion mode).

Comparation of chicoric acid and rosmarinic acid in fresh and dry herbs of sweet and purple basil (Ocimum basilicum L.) populations

Ocimum basilicum is used either as a fresh or dry herb. Most used species are characterized by sweet and purple leaves and are typically used for culinary purposes and in traditional medicine. Therefore, it is important to analyse the content of functional compounds, rosmarinic acid and chicoric acid, in dry and fresh form of the plant. It was determined that rosmarinic acid and chicoric acid content of dry and fresh form of sweet, purple, and purple flower colored of the plant by high pressure liquid chromatography equipped diode array detector (HPLC-DAD). According to obtained results, it was observed that the distribution of rosmarinic acid in fresh samples varied between 128.38 and 4072.20 mg kg-1 DW, and in dry samples between 1792.20 and 8149.45 mg kg-1 DW. It is clearly observed that rosmarinic acid content in dry samples higher than fresh samples. The concentration of chicoric acid in fresh samples varied between 51.53 and 2278.40 mg kg-1 DW and it varied in dry samples between 38.55 and 555.85 mg kg-1 DW. Chicoric acid levels in dry samples were observed to be lower than fresh samples. These changes were found statistically significant (p

Porphyrin Production by Corynebacterium diphtheriae Strains from Clinical Isolates.

Porphyrins are intermediate metabolites involved in the biosynthesis of vital molecules, including heme, cobalamin, and chlorophyll. Bacterial porphyrins are known to be proinflammatory and are associated with biofilm formation. This study investigated porphyrin production by strains of Corynebacterium diphtheriae using emission spectroscopy, high-performance liquid chromatography with fluorescence detection, diode array detector, and mass spectrometry. Emission spectroscopy revealed characteristic porphyrin emission spectra in all strains, with coproporphyrin III predominating. Qualitative analysis by different chromatographic methods identified coproporphyrin III, uroporphyrin I, and protoporphyrin IX in all strains. Quantitative analysis revealed strain-dependent coproporphyrin III production. Further studies are required to investigate the relationship between porphyrin production and the virulence potential of Corynebacterium diphtheriae.

Dissipation behaviour and dietary risk evaluation of pesticides on cucumber.

Cucumber (Cucumis sativus L.) is the world's most widely consumed salad vegetable, and it is frequently treated with pesticides to prevent pest and disease outbreaks. Pesticide residues in food commodities impede trade and pose a major health risk. Prior to residue estimation, the QuEChERS approach was validated utilising criteria such as limit of detection, limit of quantitation, linearity, accuracy, and precision. The residues of carbendazim, cypermethrin, ethion, profenofos, quinalphos, and triazophos were examined using a Gas Chromatograph equipped with an Electron Capture Detector or a Flame Photometric Detector and a high-performance liquid chromatography coupled to a photo diode array. The initial deposits of carbendazim, cypermethrin, ethion, profenofos, quinalphos, and triazophos at the prescribed dose were 1.235, 0.407, 0.817, 0.960, 0.628, and 0.985mg/kg, respectively, with a pre-harvest interval of 5.58-11.30days. According to the consumer risk evaluation data, the Hazard Quotient is less than one, and the Theoretical Maximum Dietary Intake is less than the Maximum Permissible Intake and Maximum Residue Limit, both of which are considered safe for human consumption at the authorised dose.

Dose rate correction for the novel 2D diode array MapCHECK 3.

To investigate the dose rate dependence of MapCHECK3 and its influence on measurement accuracy, as well as the effect of dose rate correction. The average and instantaneous dose rate dependence of MapCHECK2 and MapCHECK3 were studied. The accuracy of measurements was investigated where the dose rate differed significantly between dose calibration of the MapCHECK and the measurement. Measurements investigated include: the central axis dose for different fields at different depths, off-axis doses outside the field, and off-axis doses along the wedge direction. Measurements using an ion chamber were taken as the reference. Exponential functions were fit to account for average and instantaneous dose rate dependence for MapCHECK3 and used for dose rate correction. The effect of the dose rate correction was studied by comparing the differences between the measurements for MapCHECK (with and without the correction) and the reference. The maximum dose rate dependence of MapCHECK3 is greater than 2.5%. If the dose calibration factor derived from a 10 × 10 cm2 open field at 10cm depth was used for measurements, the average differences in central diode dose were 0.8%±1.0% and 1.0%±0.8% for the studied field sizes and measurement depths, respectively. The introduction of wedge would not only induce -1.8%±1.3% difference in central diode dose, but also overestimate the effective wedge angle. After the instantaneous dose rate correction, above differences can be changed to 1.9%±8.1%, 0.2%±0.1%, and 0.0%±0.9%. The pass rate can be improved from 98.4% to 98.8%, 98.3%-100.0%, and 96.3%-100.0%, respectively. Compared with MapCHECK2 (SunPoint1 diodes), the more pronounced dose rate dependence of MapCHECK3 (SunPoint2 diodes) should be carefully considered. To ensure highly accurate measurement, it is suggested to perform the dose calibration at the same condition where measurement will be performed. Otherwise, the dose rate correction should be applied.

Phenolic Compounds Synthesized by Trichoderma longibrachiatum Native to Semi-Arid Areas Show Antifungal Activity against Phytopathogenic Fungi of Horticultural Interest

Fungal diseases are a major threat to the horticultural industry and cause substantial postharvest losses. While secondary metabolites from Trichoderma sp. have been explored for their antifungal properties, limited information exists on the phenolic compounds produced by less studied species like Trichoderma longibrachiatum. In this study, phenolic compounds were extracted from a liquid culture of T. longibrachiatum using various solvents and methods (conventional and ultrasonic-assisted). Phenolic compounds were quantified by spectrophotometry and identified by high-performance liquid chromatography with diode array detection (HPLC-DAD). The antifungal activity against Alternaria alternata and Fusarium oxysporum was determined by mycelial growth inhibition assays, maximum growth rate (µmax) by the Gompertz equation, and spore germination tests. Although no significant differences (p ≥ 0.05) were found between the extraction methods, the type of solvent significantly influenced the phenolic content (p ≤ 0.05). Extraction with 70% ethanol showed the highest content of phenolic compounds and flavonoids. More than eight phenolic compounds were detected. Further, this is the first report of the phenolics ferulic, chlorogenic and p-coumaric acids identification in T. longibrachiatum, along with flavonoids such as epicatechin and quercetin, among others. The 70% ethanolic extracts notably inhibited the mycelial growth of A. alternata and F. oxysporum, reducing their maximum growth rate by 1.5 and 1.4 mm/h, respectively. Furthermore, p-coumaric and ferulic acids significantly inhibited spore germination of both pathogens, with a minimum inhibitory concentration (MIC) of 1.5 mg/mL and a minimum fungicidal concentration (MFC) of 2 mg/mL. These findings demonstrate the potential of T. longibrachiatum and its phenolic compounds as viable alternatives for biological control in horticulture and postharvest disease management.

Toward a new classification Method: Fractal dimension applied to chromatographic wine data

A study of Argentine wines was carried out by direct injection of the samples without previous treatment in a high-performance liquid chromatography system coupled to a diode array detector (HPLC-DAD). The collected data, corresponding to six different varietals (Bonarda, Cabernet Sauvignon, Malbec, Merlot, Syrah, and Tempranillo), were processed with a new chemometric approach: determining the fractal dimension of principal components or fractal dimension analysis (FDA). A comparative study of the efficiency of the new proposed model to discriminate wine samples according to botanical origin was made with methods based on a linear multivariate resolution curve-alternating least squares model (MCR-ALS) previously reported. The results show that the fractal dimension analysis of the data improves the discrimination between all the varietals studied, allowing better discrimination in relation to other reported methodologies. Finally, a comparative analysis of the method’s sustainability was carried out using the Analytical Eco-Scale indicator. This analysis demonstrated that the method based on fractal analysis is a simple procedure that meets most of the Green Analytical Chemistry requirements.

Sperm quality analyzer: A portable LED array microscope with dark-field imaging.

Sperm quality analysis plays an important role in diagnosing infertility, which is widely implemented by computer-assisted sperm analysis (CASA) of sperm-swimming imaging from commercial phase-contrast microscopy. A well-equipped microscope comes with a high cost, increasing the burden of assessment, and it also occupies a large volume. For point-of-care testing (POCT) of sperm quality, these factors are confronted with the challenges of low-cost and portable instruments. In this study, an encoded light-emitting diode (LED) array illumination is employed to achieve a portable microscope with multicontrast imaging for sperm quality analysis. This microscopy has dimensions of 16.5 × 14.0 × 25.0 cm, and its dark-field (DF) imaging provides high-contrast sperm image data which is suitable for CASA. According to DF imaging, we developed a software of LabCASA, which can used to assess the motility characteristics of sperm. Compared with TrackMate, the difference in motility parameters from our software was less than 10% in the coefficient of variation (CV). The sperm motility parameters vary with the chamber temperature, which further confirms the reliability of our system with DF imaging. The DF imaging provides strong robustness for tracking sperm's motion under different microscopes. For assessment of the motility parameters, our system can work at a lower cost with a plastic structure. This system with DF imaging is suitable for portable POCT of sperm quality analysis, which is highly cost-effective in resource-constrained circumstances.

Exploring the Potential of Anthocyanin-Based Edible Coatings in Confectionery-Temperature Stability, pH, and Biocapacity.

This study aims to develop purple-coloured polymeric coatings using natural anthocyanin and desoxyanthocianidins (3-DXA) colourants for application to chocolate almonds. The objective is to achieve a stable and uniform colour formulation throughout processing and storage, enhancing the appearance and durability of the almonds to appeal to health-conscious consumers and align with market demands. Plant materials like sweet potato pulp, sweet potato peel, radish peel, black carrot, and sorghum were employed to obtain the desired purple hue. Anthocyanidins and 3-DXA were extracted from the matrices using solvent extraction and ultrasound-assisted methods at different pH values. High-performance liquid chromatography with diode array detection (HPLC-DAD) and high-resolution tandem mass spectrometry (HRMS/MS) were used to identify the compounds in the extracts. The highest antioxidant capacities, as measured by the DPPH• and FRAP methods, were observed in purple sweet potato and dye factory extracts, respectively; meanwhile, sorghum extract inhibited both α-amylase and α-glucosidase, indicating its potential for managing postprandial hyperglycemia and type 2 diabetes. The degradation kinetics of coloured coatings in sugar syrup formulations with anthocyanins and 3-DXA revealed that locust bean gum offered the best colour stabilization for plant extracts, with sorghum extracts showing the highest and black carrot extracts the lowest colour variation when coated with Arabic gum. Sweet potato pulp extracts exhibited less colour variation in sugar pastes, both with and without blue spirulina dye, compared to factory dye, highlighting their potential as a more stable and suitable alternative for colouring purple almonds, particularly over a five-month storage period. This study supports sustainable practices in the confectionery industry while aligning with consumer preferences for healthier and environmentally friendly products.

Stability indicating RP-HPLC method development and validation for the determination of pyrimethamine in an oral paediatric suspension

The aim of this study is to validate a high-performance liquid chromatography (HPLC) – UV assay method for a stability assay of an oral suspension of PYR developed for newborns. Analyses were performed by HPLC with a Kinetex Coreshell C18 column, thermostated at 40°C, coupled to a diode array (λ=230 nm, 280 nm, scan from 190 to 400 nm) with an acetonitrile/methanol/KH2PO4 buffer gradient (pH 3, 10 mM). A forced degradation study was performed to validate the stability-indicating character. PYR was subjected to acidic (pH 2) and basic (pH 12) hydrolysis stress, thermal hydrolysis stress at native pH (60°C and 4°C), H2O2 oxidation stress (3 % and 15 %) and photolysis stress (UV and natural light) at day 0, 3 and 16. Linearity, specificity, precision, and accuracy of this assay method have been tested. Forced degradation tests demonstrated the stability indicator character of the method and showed that PYR was very sensitive to oxidation, sensitive to light (UV) and insensitive to hydrolysis (thermal and pH). The method of quantification was linear, specific, precise, and accurate according to ICH recommendations. A stability study on the formulation under development will be carried out with this HPLC – UV method.

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 0.01mg/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.

HPLC-DAD method for simultaneous determination of gallic acid, catechins, and methylxanthines and its application in quantitative analysis and origin identification of green tea

The high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD) was optimized for the simultaneous determination of 11 compounds, belonging to polyphenols (gallic acid and seven catechins) and methylxanthines (caffeine, theobromine, and theophylline). The results obtained for all the validation parameters of the HPLC-DAD method showed that the method is sensitive enough for routine analysis with basic chromatographic equipment, thus it has a significant potential to be highly applicable in common laboratory practice. The method was used in the analysis of 60 green tea infusions originating from four tea-producing countries. The dataset contributes to enhancing current data on green tea. The analysis of green tea extracts revealed significant differences depending on the origin of the samples. Linear Discriminant Analysis (LDA) was applied to test the accuracy of identification of the origin of the tea samples, based on the chemical composition of tea with a focus on polyphenolic compounds and methylxanthines analysed in this study. Based on cross-validation results, the model showed 93.75 % accuracy in the classification of green tea originating from Japan, China (Mainland), China (Taiwan) and South Korea.

Implementation of an impurity diagnostic suite on the Pegasus-III experiment.

A suite of diagnostics used to assess impurity content and dynamics has been updated, upgraded, and installed on the Pegasus-III Experiment. Typical plasma parameters during local helicity injection start-up are τshot ∼ 10 ms, ne ∼ 1 × 1019 m-3, and Te ∼ 50eV. The deployed diagnostics are compatible with this modest temperature and density regime and provide species identification, source localization, and estimation of radiation losses. Impurity species are determined by recording time-evolving, single line-of-sight spectra at 1.25 kfps using a SPRED (Survey, Poor Resolution, Extended Domain) vacuum ultraviolet spectrometer. SPRED is equipped with 450 g/mm grating, giving a spectral resolution of 0.33nm and a spectral range from ∼10 to 110nm, useful to identify light impurity species in this temperature and density range. An absolutely calibrated spectrometer that collects light from the plasma at Rtan = 15.9cm and Δt ≥ 2ms is used as a visible survey spectrometer and for continuum measurements. The radiated power from the plasma is estimated with a photodiode-based diagnostic. Two 16-channel absolute extreme ultraviolet diode arrays are placed behind pinhole apertures, resulting in 32 lines of sight at Z = 0, with a spatial resolution of 2-3cm and a time response of 60kHz. A photometrically calibrated collinear Dα/near infrared filtered photodiode-based system measures the Dα emission and around 1040nm. All these instruments have been designed to suppress electromagnetic interference from megawatt-class switching power supplies.