Method For Determination Of Content Research Articles

Antioxidant characterization of fruits of the Family Cactaceae: Hylocereus undatus, Selenicereus megalanthus, and Hylocereus polyrhizus

In this study, the antioxidant capacity of the peel and pulp of three Pitaya species was investigated: Hylocereus undatus, Selenicereus megalanthus, and Hylocereus polyrhizus. The methods used include the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, the thiobarbituric acid reactivity assay (TBARS) for inhibition of lipid peroxidation, and the Folin-Ciocalteau method for determination of total phenolic content. Regarding the TBARS results, the peel sample of 20% H. polyrhizus showed the highest antioxidant capacity in both solvents (water and alcohol) analyzed. Regarding the pulp, the H. undatus sample in the aqueous extract was the sample with the highest antioxidant potential (12.5%). In the ethanolic extract, the sample of H. polyrhizus pulp (25%) showed the highest antioxidant potential, as did the peel at a concentration of 20%. Using the DPPH method, the peel sample of the 5% aqueous extract of H. undatus can be highlighted with a greater antioxidant capacity. Regarding the pulp, the sample with the highest potential was the 20% H. undatus in the aqueous extract. In the ethanolic extract, the H. undatus samples from the peel and pulp showed the highest antioxidant potential with 25 and 50%, respectively. In terms of phenolic content, no significant difference was found between the peel samples, but among the pulp samples, H. undatus had the lowest concentration. It can be concluded that the different pitaya species exhibited significant antioxidant capacity, suggesting that pitaya consumption could potentially provide benefits to human health due to its bioactive compounds.

RESEARCH & DEVELOPMENT OF P2O5 DETERMINATION METHOD IN PHOSPHATE FERTILIZERS AND ITS VALIDATION

The validation of chemical measurement for Phosphorus determination in fertilizers followed a chain of experimental procedures to ascertain the performance characteristic (PC), connecting Precision, accuracy, reproducibility, recovery, linearity, limit of detection and of quantification. Performance characteristics are accomplished to ensure that analytical method fits the purpose of particular testing. This method was conducted in three stages those were preparation, testing and data processing. The standard test method for determination of P2O5 content in fertilizers used for regulatory purpose is somewhat lengthy and time taking. A modification was done to the standard method to create a more efficient approach that meets validation criteria and is suitable for analyzing advisory fertilizer samples. During the year 2023-24, comprehensive research and development activity were carried out at Soil and Water Testing Laboratory (SWTL) for Research, Faisalabad and analytical data was generated. The obtained results were processed statistically and compared with the acceptance requirements. The coefficient of determination (R2), precision and accuracy/recovery percentage respectively were 0.9996, 0.3-1.10% and 98.01-102.34%, while LOD and LOQ were 0.84 and 2.25%. Based on the results the study concluded that the modified test method applied to determine P2O5was appropriate for its intended use based on the acceptance criteria of performance characteristics set forth in the validation protocol and can be applied as routine method at laboratory.

MoistNet: Machine vision-based deep learning models for wood chip moisture content measurement

Quick and reliable measurement of wood chip moisture content is an everlasting problem for numerous forest-reliant industries such as biofuel, pulp and paper, and bio-refineries. Moisture content is a critical attribute of wood chips due to its direct relationship with the final product quality. Conventional techniques for determining moisture content, such as oven-drying, possess some drawbacks in terms of their time-consuming nature, potential sample damage, and lack of real-time feasibility. Furthermore, alternative techniques, including NIR spectroscopy, electrical capacitance, X-rays, and microwaves, have demonstrated potential; nevertheless, they are still constrained by issues related to portability, precision, and the expense of the required equipment. Hence, there is a need for a moisture content determination method that is instant, portable, non-destructive, inexpensive, and precise. This study explores the use of deep learning and machine vision to predict moisture content classes from RGB images of wood chips. A large-scale image dataset comprising 1,600 RGB images of wood chips has been collected and annotated with ground truth labels, utilizing the results of the oven-drying technique. Two high-performing neural networks, MoistNetLite and MoistNetMax, have been developed leveraging Neural Architecture Search (NAS) and hyperparameter optimization. The developed models are evaluated and compared with state-of-the-art deep learning models. Results demonstrate that MoistNetLite achieves 87% accuracy with minimal computational overhead, while MoistNetMax exhibits exceptional precision with a 91% accuracy in wood chip moisture content class prediction. With improved accuracy (9.6% improvement in accuracy by MoistNetMax compared to the best baseline model ResNet152V2) and faster prediction speed (MoistNetLite being twice as fast as MobileNet), our proposed MoistNet models hold great promise for the wood chip processing industry to be efficiently deployed on portable devices, such as smartphones.

17O NMR spectroscopy protocol for the determination of water content in liquids produced by pyrolysis and hydrothermal liquefaction

BackgroundThere is an urgent need to replace fossil-based fuels and chemicals with bio-based, renewable alternatives. Water content is a critical parameter in these liquid products since water affects their quality and properties. However, currently existing methods for bio-oil water content determination have limitations and thus, there is a need to find methods that are versatile, work for a wide water content and sample consistency range repeatably and reliably and are safe for the user and the environment. ResultsIn this research, a17O NMR spectroscopy protocol for water content determination of pyrolysis and hydrothermal liquefaction (HTL) liquids was developed and compared with the standard method Karl Fischer (KF) titration. The approach showed linearity over a wide concentration range, and the changes to the measurement parameters caused only minor effects to the results (≤0.8 percentage points) indicating robustness. The method is also accurate since the absolute differences between experimental and theoretical water contents varied from 0.08 % to 2.09 %. Additionally, the precision of the method, based on the relative standard deviations (RSD) of the three replicate measurements of pyrolysis and HTL samples, was good (RSD <1.82 %). The method was applied to samples containing 1–98 wt% water. Overall, the 17O NMR spectroscopy and KF titration results were well aligned with each other suggesting that the 17O NMR spectroscopy is a potential alternative for the conventional KF titration. SignificanceThis is the first study on the use of 17O NMR spectroscopy protocol for water content quantification. The results indicate that the protocol is an accurate, linear, and precise technique for water content determination of a wide range of samples. Furthermore, the method does not require hazardous chemicals or calibration standards, and the sample preparation is straightforward. The non-destructiveness of the method also enables further studies on the sample, e.g. by 1H NMR spectroscopy.

Validation of the spectrophotometric method for the quantitative determination of nimesulide in solid dispersions systems obtained by centrifugal fiber formation

In order to increase the water solubility of the non-steroidal anti-inflammatory active pharmaceutical ingredient, nimesulide, solid dispersed systems were developed using the innovative technology of centrifugal fiber formation. Accordingly, in order to obtain correct results regarding the degree of increase in the solubility of nimesulide in solid dispersed systems, it is necessary to select a method for determining the quantitative content of the active pharmaceutical ingredient in the developed polymer composites. The aim of the study was to develop and validate a spectrophotometric method for the quantitative determination of nimesulide in solid dispersed systems obtained by centrifugal fiber formation. A small commercially available cotton candy machine «Cotton candy maker» (China) was used to produce solid dispersed systems of nimesulide by the method of centrifugal fiber formation. Spectrophotometric studies were performed using an OPTIZEN POP UV spectrophotometer (Meсasys, South Korea) in quartz glass cuvettes with an optical layer thickness of 1 cm (Agilent, USA). The developed spectrophotometric method for the quantitative determination of nimesulide content in centrifugally formed polymeric solid dispersed systems is based on the qualitative reaction of nimesulide with a 0.1 M sodium hydroxide solution, resulting in the formation of a yellow compound with a maximum optical absorption at 400 nm. The validation characteristics of the proposed method, in particular, specificity, linearity, precision, and robustness, were investigated. It was confirmed that the wavelength of 400 nm is specific for the analysis. It was proved that the method is linear (R2 = 0.999) in the range of nimesulide concentrations 80–120%. The accuracy of the method was confirmed at the level of convergence and reproducibility. When changing the wavelength by ± 2 nm, the standard deviation is 0.12%, which indicates the robustness of the developed method. Thus, it is proved that all the selected validation characteristics of the developed spectrophotometric method for determining the quantitative content of nimesulide in centrifugally formed polymeric solid dispersed systems meet the acceptance criteria, which confirms the validity of the method.

Study on Fingerprint and Multiple Indicators for Quantitative Detection Method Development in Powdered Milk Thistle Extract

Introduction: Silymarins are the main active ingredient in milk thistle extract, reflecting the quality of extract products. The detection methods for silymarins in different pharmacopoeia standards may vary, which may lead to inconsistent detection results. Method: Due to the lack of research on related fingerprint spectra, its qualitative work is hard to carry out. Hence, based on existing standard methods, an HPLC method was established by optimizing the gradient program of the mobile phase. Results: The effectiveness of this method and the fingerprint was also studied. The similarity of 31 batches of samples ranged from 0.791 to 1.000, indicating the characteristic spectrum formed can be well used for qualitative analysis. Conclusion: Under optimal analytical conditions, the six silymarin compounds in the samples can achieve good baseline separation from the matrix with good resolution. At the same time, the LOD was 25 mg/kg, and the recovery rates at three levels ranged from 92% to 108%, with RSDs less than 4%. The fingerprint spectrum and content determination method established in this study had good repeatability and high accuracy, which can provide a new method for quality control of milk thistle extract.

Determination of Taurine in Infant Formula and Adult/Pediatric Nutritionals by Ultra High-Performance Liquid Chromatography with Multiple Reaction Monitoring-Mass Spectrometry: Single-Laboratory Validation, First Action 2022.08.

Taurine (2-aminoethanesulfonic acid) is an essential β-amino acid, which is one of the most abundant intracellular amino acid component in humans. The level of free taurine in human milk is higher than in bovine milk. Since taurine is considered important for the development of a newborn, fortification of infant nutrition with taurine is common. This publication describes a rapid method for the determination of taurine in infant formula and adult/pediatric nutritionals. This publication demonstrates the suitability and applicability of the method to determine taurine content in infant formula and adult/pediatric nutritionals. Test portions are deproteinized by acid in an aqueous environment prior to analysis. The level of taurine is analyzed by hydrophilic interaction chromatography (HILIC) coupled with multiple reaction monitoring MS (MRM-MS). Quantitation is accomplished using a stable isotope-labeled internal standard (SILS) for taurine. The accuracy of the method was validated using standard reference materials and spike recovery studies. The average recoveries ranged between 92% and 105%. The relative standard deviation repeatability (RSDr) and relative standard deviation intermediate precision (RSDiR) were in the range of 0.7-4.6% (RSDr) and 1.3-6.7% (RSDiR). The limit of quantitation (LOQ) was below the requirement of 0.5 mg/100 g. The single-laboratory validation (SLV) of the method for determination of taurine content in infant formula and adult/pediatric nutritionals demonstrates that it meets the requirements per AOAC INTERNATIONAL Standard Method Performance Requirements (SMPR) 2014.013. A fast method to selectively determine the content of taurine in infant formula and adult/pediatric nutritionals was evaluated and found to be fit for purpose for routine product compliance testing. Based on the results of this SLV, the method was approved by the AOAC Stakeholder Program on Infant Formula and Adult Nutritionals (SPIFAN) Expert Review Panel for SPIFAN Nutrient Methods for First Action Official MethodsSM status.

Gold nanoparticle-enhanced D-shaped optical fiber sensor for mercury ion detection.

Mercury ions (Hg2+) are highly toxic heavy metal ions that pose serious health risks to humans when present at concentrations above the safety threshold. Therefore, the development of a rapid and effective Hg2+ detection method is of significant importance. In this study, based on surface plasmon resonance (SPR) technology integrated with COMSOL simulation analysis, a highly sensitive and selective Hg2+ sensing system is constructed. Initially, gold nanoparticles and the surface of a fiber-optic gold film are modified by sodium sulfide (Na2S). In the presence of Hg2+, the sulfur ions on the modified gold film and gold nanoparticles specifically bind to Hg2+, forming the composite structure Au/S-Hg2+-S/AuNPS. Due to the strong electromagnetic coupling between the gold nanoparticles and the gold film, a significant SPR wavelength shift occurs. These results show that the Hg2+ sensor has high sensitivity and enhanced selectivity. The detection limit for mercury ions was 8.15 nM, and the recovery rate in real environmental samples was up to 90.1-97.3%. This sensing system provides an alternative method for rapid and accurate determination of mercury content.

Recent progress in lanthanide-based fluorescent nanomaterials for tetracycline detection and removal.

Tetracycline (TC) has been widely used in clinical medicine and animal growth promotion due to its broad-spectrum antibacterial properties and affordable prices. Unfortunately, the high toxicity and difficult degradation rate of TC molecules make them easy to accumulate in the environment, which breaks the ecological balance and seriously threatens human health. Rapid and accurate detection of TC residue levels is important for ensuring water quality and food safety. Recently, fluorescence detection technology of TC residues has developed rapidly. Lanthanide nanomaterials, based on the high luminescence properties of lanthanide ions and the high matching with TC energy levels, are favored in the real-time trace detection of TC due to their advantages of high sensitivity, rapidity, and high selectivity. Therefore, they are considered potential substitutes for traditional detection methods. This review summarizes the synthesis strategy, TC response mechanism, removal mechanism, and applications in intelligent sensing. Finally, the development of lanthanide nanomaterials for TC fluorescence detection and removal is reasonably summarized and prospected. This review provides a reference for the establishment of a method for the accurate determination of TC content in complex food matrices.

Biochemical composition and volatile profile analysis of three varieties of Coffea arabica and their correlation with the microclimate of Mount Tangkuban Perahu, West Java, Indonesia

Abstract. Firnabillah RA, Mustari E, Marwani E. 2024. Biochemical composition and volatile profile analysis of three varieties of Coffea arabica and their correlation with the microclimate of Mount Tangkuban Perahu, West Java, Indonesia. Biodiversitas 25: 3264-3276. The quality of coffee is determined by various biochemical compounds, including chlorogenic acid, caffeine, trigonelline, sucrose, and oil, as well as the volatile metabolite profile in coffee beans. Genetic factors and environmental conditions at the coffee cultivation site influence the composition of these compounds. This study aimed to analyze the biochemical composition and volatile profile of various coffee samples, including Ateng, Tim-Tim, and Sigarar Utang, and investigate their correlation with microclimate factors. Different analytical methods were used to examine the green beans, including High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) for caffeine, chlorogenic acids, sucrose, and trigonelline, Soxhlet methods for oil content determination, and Gas Chromatography-Mass Spectrometry (GC-MS) for volatile compound analysis. The results showed distinct biochemical components and metabolite profiles among the three arabica coffee varieties. The Ateng variety had the highest concentrations of chlorogenic acid, while the Tim-Tim variety had the lowest content of these compounds. Trigonelline and caffeine content was similar across all varieties. Sucrose content was highest in the Sigarar Utang variety, while oil content was higher in the Ateng and Tim-Tim varieties compared to Sigarar Utang. Principal Component Analysis (PCA) showed significant metabolite variation among the three varieties, with PC1 and PC2 accounting for 69.2% of the variance. Furthermore, Partial Least Squares-Discriminant Analysis (PLS-DA) successfully distinguished the three varieties and identified potential biomarker compounds for classification. Additionally, the study discovered that the environmental factor, specifically light intensity affected the sucrose and oil compounds in arabica green beans coffee. The study concluded that the three varieties' biochemical composition and volatile metabolites differed. Certain compounds were found to correlate with measured microclimatic factor.

Quality evaluation of WuweiZhenju tablets based on HPLC fingerprint, content determination and chemical pattern recognition analysis

AbstractObjectiveTo establish a method for the high-performance liquid chromatography (HPLC) fingerprint and content determination of Wuwei Zhenju Tablets, and combine with chemical pattern recognition analysis to provide basis for its quality evalution.MethodsBased on HPLC, taking the chromatographic peak of puerarin as the reference peak, the fingerprints of 10 batches of Wuwei Zhenju Tablets were established and the similarity evaluation was carried out to determine the common peaks. SPSS 26.0 and SIMCA 14.1 software were used to evaluate the overall quality of Zhenju Tablets by cluster analysis and principal component analysis. The contents of chlorogenic acid, puerarin, daidzin, isochlorogenic acid B, isochlorogenic acid A and aurantio-obtusin in the samples were determined by the same method.ResultsTwenty-six common peaks were identified in the fingerprints of 10 batches of Wuwei Zhenju Tablets, and the similarity evaluation was greater than 0.985. Ten chromatographic peaks were identified as neochlorogenic acid, chlorogenic acid, caffeic acid, puerarin, daidzin, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C, aurantio-obtusin and betaine. Combined with cluster analysis and principal component analysis, 10 batches of samples can be clustered into two categories, which can distinguish different Zhenju tablets. The model established in pattern recognition research can accurately identify Wuwei Zhenju tablets, and the prediction results are ideal. The six index components had a good linear relationship in their respective concentration ranges. The contents of chlorogenic acid, puerarin, daidzin, isochlorogenic acid B, isochlorogenic acid A and aurantio-obtusin in 10 batches of Wuwei Zhenju Tablets were 2.902–5.819, 3.693–49.680, 1.449–10.654, 2.768–7.724, 2.941–6.343 and 0.071–0.089 mg g−1, respectively.ConclusionThe HPLC fingerprint and multi-component content determination method of Wuwei Zhenju Tablets were established for the first time. The method is simple, efficient and accurate, and can effectively provide experimental basis for the quality control and evaluation of the preparation.

Comprehensive Study of Total Nitrogen Content and Microfluidic Profiles in Additive-Enriched Plant-Based Drinks.

The growing consumption of plant-based milk substitutes raises important questions about their composition. The various additives used by manufacturers, including those employed as flavor enhancers, protein additives, and stabilizers, may contain both protein and non-protein nitrogen components. In our study, we examined not only popular milk alternatives but also other milk substitutes made from specific plants. We present a reproducible and rapid method for the simultaneous qualitative and quantitative determination of the total nitrogen content in milk alternatives, focusing on applicability. Using the microchip gel electrophoretic method, we determined that the total nitrogen content differed from the protein content indicated on the packaging. Our results, along with statistical evaluations, supported the hypothesis that different brands of products, derived from the same plant source, resulted in different microfluidic profiles, likely due to the presence of additives. As expected, the microfluidic profiles of additive-free products differed from those of fortified products made from the same plant-based milk replacer. Total nitrogen content provides crucial information for individuals with kidney disease, as is essential to reduce the burden on the kidneys to slow deterioration, alleviate symptoms and avoid complications.

Chemical composition combined with network pharmacology and quality markers analysis for the quality evaluation of Qing-fei-da-yuan granules.

Qing-fei-da-yuan granules (QFDYGs) had been proved to be an effective TCM prescription for treating coronavirus disease 2019 (COVID-19), which are composed of a variety of TCMs, and characterized by multiple components, multiple targets and overall regulation. It is meaningful to further study the chemical composition and pharmacology of QFDYGs for quality evaluation. However, due to the complexity of the components of QFDYGs, there are no reliable and simple analytical methods for current quality evaluation. In this work, antipyretic activity assessment of QFDYGs in the LPS-induced New Zealand rabbit model was carried out to verify the efficacy firstly. It was proved that QFDYGs can be used to relieve fever to help preventing or controlling the prevalence of influenza and pneumonia. Subsequently, UHPLC-ESI-QTOF-MS/MS combined with network pharmacology, quality markers and fingerprint analysis were used to establish the quality control condition. The chemical compositions were analyzed by UHPLC-ESI-QTOF-MS/MS, and 79 of them were identified, such as arecoline, mangiferin, paeoniflorin, etc. Then, the network pharmacology strategy based on 45 candidate components (CCs) in conjunction with influenza and pneumonia diseases was employed to screen the potential active ingredients. According to the drug-CCs-genes-diseases (D-CCs-G-D) networks, baicalein, honokiol, baicalin, paeoniflorin, saikosaponin A, glycyrrhizic acid and hesperidin were selected as quality markers. And a method for content determination of the 7 quality markers was established by optimizing extraction methods, chromatographic conditions and methodological verification. Finally, the quality of 15 batches of QFDYGs was evaluated by using the 7 quality markers combined with fingerprints and principal component analysis (PCA). The analyzed results showed that baicalin, paeoniflorin, glycyrrhizic acid and hesperidin were the high content and stable quality markers. QFDYGs were characterized by overall consistency and individual ingredient differences among the 15 batches. Our quality evaluation study will provide reference for the further development and research of QFDYGs.

Study on UPLC–MS/MS Method for Four Compositions of Cangzhu

Background The legal quality control of Cangzhu is used the single component as an evaluation indicator, which would not be enough to reflect the authenticity of quality. It is necessary to select several typical chemical components as the basis for quality control of medicinal materials and decoction pieces to reflect the content of effective ingredients. Purpose Based on UPLC-MS/MS, the study aimed to build the content determination method of atractyloidin, atractylidin A, atractylenolide I, and atractylenolide III in Cangzhu from different sources. Materials and Methods Agilent SB-C18 (2.1 × 100 µm, 1.8 µm) was used to be the stationary phase. The mobile phase system was formed by water-formic acid (1000:1) and acetonitrile-formic acid (1000:1) in gradient elution. The column temperature set at 40℃, and the flow rate was 0.3 mL min–1. Results The contents of atractyloidin, atractylidin A, atractylenolide I, and atractylenolide III had good linearity in a certain range (r2 ≥ 0. 9990). The RSD of the precision, stability and repetitive test results were less than 3.00%. In addition, the content of the four components were some different among different patches of Cangzhu. Conclusion The method was simple, rapid and highly sensitive, which was suitable for the determination of atractyloidin, atractylidin A, atractylenolide I, and atractylenolide III in Cangzhu.

Quality evaluation and grading standard discussion on Cinnamomi Ramulus

This study explored the relationship between the appearance traits and internal components of Cinnamomi Ramulus pieces, so as to provide a reference for the quality evaluation and the formulation of grade standards. This study determined the appearance traits and index component contents of 41 batches of Cinnamomi Ramulus pieces in the core producing areas of Guangxi and Guangdongand established the HPLC characteristic map method. The weight of the pieces, the narrowest diameter, and the widest diameter of the tr ansverse section were used as the indices of appearance traits. The content of index components(cinnamic acid and cinnamalde hyde)was determined by the established content determination method. The chromatographic characteristics were determinedon a Waters XBridge C_(18)(4. 6 mm×250 mm, 5 μm) column with a mobile phase consisting of 0. 1% phosphoric acidacetonitrile and gradient elution at the flow rate of 1 mL ·min~(-1). The column temperature was 30 ℃, and the detection wavelength was 254 nm. Cluster analysis, principal component analysis, and other stoichiometric methods were used to analyze the correlation between theap pearance traits and the index/characteristic components of Cinnamomi Ramulus pieces and compare the qu ality differences of the piecesfrom different batches and plac es. The results showed that the larger weight, the narrowest diameter, andthe widest diameter of the tra nsverse section indicated lowercontent of main indexes/characteristic components, and there was a synergistic decreasing trend amongd ifferent components. The overall quality of Cinnamomi Ramulus pieces in Guangdong Province and Guangxi Province was similar, but there were still differences between different origins and different batches of the same origin. It is scientific and feasible to evaluatethe quality of Cinnamomi Ramulus pieces and establish grading standards based on the appearance traits and index/character istic components. The research provides a more scientific and comprehensive basis for the quality control evaluation and standardformulation of Cinnamomi Ramulus.

Research Progress on Active Ingredients and Product Development of Lycium ruthenicum Murray.

Lycium ruthenicum Murray possesses significant applications in both food and medicine, including antioxidative, anti-tumor, anti-fatigue, anti-inflammatory, and various other effects. Consequently, there has been a surge in research endeavors dedicated to exploring its potential benefits, necessitating the organization and synthesis of these findings. This article systematically reviews the extraction and content determination methods of active substances such as polysaccharides, anthocyanins, flavonoids, and polyphenols in LRM in the past five years, as well as some active ingredient composition determination methods, biological activities, and product development. This review is divided into three main parts: extraction and determination methods, their bioactivity, and product development. Building upon prior research, we also delve into the economic and medicinal value of Lycium ruthenicum Murray, thereby contributing significantly to its further exploration and development. It is anticipated that this comprehensive review will serve as a valuable resource for advancing research on Lycium ruthenicum Murray.

Prediction of cyanidin 3-rutinoside content in Michelia crassipes based on near-infrared spectroscopic techniques.

Currently the determination of cyanidin 3-rutinoside content in plant petals usually requires chemical assays or high performance liquid chromatography (HPLC), which are time-consuming and laborious. In this study, we aimed to develop a low-cost, high-throughput method to predict cyanidin 3-rutinoside content, and developed a cyanidin 3-rutinoside prediction model using near-infrared (NIR) spectroscopy combined with partial least squares regression (PLSR). We collected spectral data from Michelia crassipes (Magnoliaceae) tepals and used five different preprocessing methods and four variable selection algorithms to calibrate the PLSR model to determine the best prediction model. The results showed that (1) the PLSR model built by combining the blockScale (BS) preprocessing method and the Significance multivariate correlation (sMC) algorithm performed the best; (2) The model has a reliable prediction ability, with a coefficient of determination (R2) of 0.72, a root mean square error (RMSE) of 1.04%, and a residual prediction deviation (RPD) of 2.06. The model can be effectively used to predict the cyanidin 3-rutinoside content of the perianth slices of M. crassipes, providing an efficient method for the rapid determination of cyanidin 3-rutinoside content.

Analysis of chemical compositions in different parts of Isodon japonicus using UPLC-Q-TOF-MS technique combined with chemometrics

In order to analyze the similarities and differences of chemical compositions between the roots and stems and leaves of Isodon japonicus(IJ), this study utilized UPLC-Q-TOF-MS technology to systematically characterize its chemical compositions, analyzed and identified the structure of its main compounds, and established a method for simultaneous determination of its content by refe-rence substance. A total of 34 major compounds in IJ, including 14 reference compounds, were identified or predicted online. Moreover, an UPLC-UV content determination method was developed for 11 compounds [danshensu, caffeic acid, vicenin-2,(1S,2S)-globoidnan B, rutin,(+)-rabdosiin,(-)-rabdosiin,(1S,2S)-rabdosiin, shimobashiric acid C, rosmarinic acid, and pedalitin]. The method exhibited excellent separation, stability, and repeatability, with a wide linear range(0.10-520.00 μg·mL~(-1)) and high linearity(R~2&gt;0.999). The average recovery rates ranged from 94.72% to 104.2%. The principal component analysis(PCA) demonstrated a clear difference between the roots and stems and leaves of IJ, indicating good separation by cluster. Furthermore, the orthogonal partial least squares discriminant analysis(OPLS-DA) model was employed, and six main differentially identified compounds were identified: rosmarinic acid, shimobashiric acid C, epinodosin, pedalitin, rutin, and(1S,2S)-rabdosiin. In summary, this study established a strategy and method for distinguishing different parts of IJ, providing a valuable tool for quality control of IJ and a basis for the ratio-nal utilization and sustainable development of IJ.

A study on the simultaneous determination of nitrogen content and 15N isotope abundance in plants using peak height intensities at m/z 28 and 29

A method for simultaneous determination of nitrogen content and 15N isotope abundance in plants was established by Elemental analysis-gas isotope ratio mass spectrometry. Taking poplar leaves and l-glutamic acid as standards, nitrogen content was determined using the standard curve established by weighted least squares regression between the mass of nitrogen element and the total peak height intensity at m/z 28 and 29. Then the 15N isotope abundance was calculated with the peak height intensity at m/z 28 and 29. Through the comparison of several sets of experiments, the impact of mass discrimination effect, tin capsule consumables, isotope memory effect, and the quality of nitrogen on the results were assessed. The results showed that with a weight of 1/x2, the standard curve has a coefficient of determination (R2) of 0.9996. Compared to the traditional Kjeldahl method, the measured nitrogen content deviated less than 0.2 %, and the standard deviation (SD) was less than 0.2 %. Compared to the sodium hypobromite method, the 15N isotopic abundances differed less than 0.2 atom%15N, and the SD was less than 0.2 atom% 15N. The established method offers the advantages of being fast, simple, accurate, and high throughput, providing a novel approach for the simultaneous determination of nitrogen content and 15N isotope abundance in plant samples.

Transdermal diffusion research on functional substances of Jingu Zhitong Gel

This study systematically explored the transdermal diffusion law of functional substances of Jingu Zhitong Gel(JGZTG). The transdermal diffusion research methods of JGZTG were investigated by single factor trial with the automated transdermal(dry-heat) sampling system. High performance liquid chromatography(HPLC) content determination method was established to determine the contents of ferulic acid, senkyunolide I, cinnamic acid, hydroxy-ε-xanthoxylin, hydroxy-α-xanthoxylin, and hydroxy-β-xanthoxylin in the transdermal diffusion solution of JGZTG. The transdermal diffusion law of the components within 16 h was investigated. The results showed that the optimal transdermal diffusion method of JGZTG was as follows: Rat skin was used as the transdermal barrier; normal saline was used as the receiving medium; the dosage of JGZTG was 0.3 g, and the receiving solution was extracted by ethyl acetate. The results of transdermal diffusion showed that the release of ferulic acid, cinnamic acid, and senkyunolide I increased significantly at 0-8 h and slowed down at 8-16 h. The drug release was a synergic process of diffusion and dissolution, in which ferulic acid and cinnamic acid followed Higuchi and Ritger-Peppas equations, and liguolactone I followed Higuchi equation. The transdermal diffusion curves of hydroxy-ε-zanthoxylin, hydroxy-α-zanthoxylin, and hydroxy-β-zanthoxylin showed continuous release within 16 h, and the drug release was skeleton dissolution. The diffusion law followed zero-order equation, first-order equation, and Ritger-Peppas equation. In clonclusion, it is a controlled release of ferulic acid, ligustrone I, cinnamic acid, hydroxy-ε-pyrroxylin, hydroxy-α-pyrroxylin, and hydroxy-β-pyrroxylin in JGZTG, which can maintain stable blood drug concentration with 16 h, and the cumulative transmittance of each component with 12 h can reach 80% of cumulative transmittance with 24 h, which is in line with the clinical drug use law of bis in die.