Μm Particle Size Research Articles

Effect of Particle Size on Raman Signal Strength of Silicate Minerals

ABSTRACTUnderstanding the effects of particle size is necessary for quantifying minerals in mixtures using Raman spectroscopy. Raman signal intensity is evaluated using six common silicate minerals (two olivines, two pyroxenes, and two feldspars) at 10 particle size ranges. For olivines and feldspars, the highest peak intensities are observed in samples with 38–63 and 63–106 μm particle sizes. There is no such consistent trend for the pyroxene samples, although the overall low signal strength complicates those measurements. Raman spectra of samples with varying particle sizes appear to be influenced by two competing effects: scattering from particle boundaries and effective sampling volume.

Quality by Design Approach Driven Development and Validation of Reverse Phase‐High‐Performance Liquid Chromatography Methodology for Dual Quantification of Aspirin and Rivaroxaban

ABSTRACTClinical trials have shown that combining a modest dose of Rivaroxaban (RIV) with Aspirin (ASP) is more effective than ASP alone in reducing cardiovascular mortality, myocardial infarction, and stroke. A high‐performance liquid chromatography method developed using Quality by Design (QbD) effectively estimates ASP and RIV for routine pharmaceutical analysis. The Plackett‐Burman design assessed key factors including organic phase volume, mobile phase pH, flow rate, temperature, and injection volume using an Ishikawa fish‐bone diagram for risk assessment. These parameters were then optimized via Box‐Behnken design in 15 trials. The method meets the International Council For Harmonization standards with a mobile phase ratio of 45:55 (v/v) acetonitrile: buffer (pH 3, adjusted with orthophosphoric acid), a flow rate of 1 mL/min, a column temperature of 30°C, and an injection volume of 20 µL. A Phenomenex Luna C18 column (250 × 4.6 mm, 5 µm particle size) with detection at 251 nm ultra‐violet wavelength. The retention times of 4.54 min for ASP and 5.81 min for RIV were obtained. Validation confirmed linear ranges: 40–200 µg/mL for ASP and 2–10 µg/mL for RIV, with excellent recovery rates (ASP: 99.30%–101.9%; RIV: 98.52%–101.84%). Developed using QbD principles, the method proved specific, accurate, precise, sensitive, and robust for routine quality control of both compounds in pharmaceutical formulations.

All black: a microplastic extraction combined with colour-based analysis allows identification and characterisation of tire wear particles (TWP) in soils

While tire wear particles (TWP) have been estimated to represent more than 90% of the total microplastic (MP) emitted in European countries and may have environmental health effects, only few data about TWP concentrations and characteristics are available today. The lack of data stems from the fact that no standardized, cost efficient or accessible extraction and identification method is available yet. We present a method allowing the extraction of TWP from soil, performing analysis with a conventional optical microscope and a machine learning approach to identify TWP in soil based on their colour. The lowest size of TWP which could be measured reliably with an acceptable recovery using our experimental set-up was 35 µm. Further improvements would be possible given more advanced technical infrastructure (higher optical magnification and image quality). Our method showed a mean recovery of 85% in the 35–2000 µm particle size range and no blank contamination. We tested for possible interference from charcoal (as another black soil component with similar properties) in the soils and found a reduction of the interference from charcoal by 92% during extraction. We applied our method to a highway adjacent soil at 1 m, 2 m, 5 m, and 10 m and detected TWP in all samples with a tendency to higher concentrations at 1 m and 2 m from the road compared to 10 m from the road. The observed TWP concentrations were in the same order of magnitude as what was previously reported in literature in highway adjacent soils. These results demonstrate the potential of the method to provide quantitative data on the occurrence and characteristics of TWP in the environment. The method can be easily implemented in many labs, and help to address our knowledge gap regarding TWP concentrations in soils.

Simultaneous qualitative and quantitative analysis for evaluating constituents of Atractylodis macrocephalae rhizome by UPLC-QTOF-MS

AbstractAtractylodis macrocephalae rhizome (AMR) belongs to medicine food homology. Its' clinical application of invigorating the spleen-stomach of AMR was applied to various diseases. In this research, a UPLC-QTOF-MS method was developed for qualitative and quantitative analysis of AMR, simultaneously. A Waters Acquity BEH C18 column (2.1 mm × 100 mm, 1.7 μm particle size) was used for separation of AMR multi-components. The column was eluted with a mobile phase of 0.1% formic acid-water and 0.1% formic acid-acetonitrile. Electron spray ionization with positive-ion mode and external standard method was utilized for quantifying the nine analytes in AMR. Constituents of AMR were scanned by UPLC-QTOF-MS and then identified by mass fragments and chromatographic information compared with the published literature and reference standards. Under positive mode, a total of 61 chemical compositions including 16 terpenoids, 8 polyacetylenes, 6 aromatics, 5 flavonoids, 5 coumarins, 5 organic acids, 4 amino acids, 3 fatty acids, 3 aliphatics, 2 steroids, and 2 alkenes, a nucleoside and an aldehyde were identified. Simultaneously, the contents of three amino acids (L-tyrosine, L-phenylalanine, and L-tryptophan), three sesquiterpenoids (atractylenolide Ⅲ, atractylenolide Ⅱ, and atractylenolide Ⅰ), a flavonoid (rutin), an organic acid (ferulic acid), and a pentacyclic triterpenoid (oleanolic acid) were determined in seventeen AMR batches. Amino acids and triterpenoid were quantified for the first time in AMR. The UPLC-QTOF-MS method developed in this article was reliable, practical, and useful for qualitative and quantitative evaluation of AMR multi-components.

Standardized Ileal Digestibility of Amino Acids in Hybrid Rye Ground to Two Particle Sizes and Fed With or Without Multienzyme Supplement to Young Growing Pigs.

A newly developed hybrid rye with enhanced ergot resistance has potential as an alternative energy source for pigs. An experiment was conducted to evaluate the effects of particle size (PS) and multienzyme supplement (MES) on the apparent total tract digestibility (ATTD) of energy and nutrients and the standardized ileal digestibility (SID) of amino acids (AA) in hybrid rye fed to growing pigs. Bono and Gatano, two hybrid rye varieties, were ground to either a coarse (1111 and 1210 μm) or a fine (594 and 717 μm) PS using a hammer mill. Eighteen ileal-cannulated barrows (initial BW = 18.2 ± 1.0 kg) were randomly assigned to 1 of 9 dietary treatments in a replicated 9 × 3 incomplete Latin square design to give six observations per treatment. Among the nine experimental diets, eight featured two hybrid rye varieties (Bono or Gatano), either coarsely or finely ground, as the only source of AA with or without MES, while an N-free diet was used to estimate the endogenous losses of AA at the distal ileum. All diets contained titanium dioxide as an indigestible marker. Each period lasted 9 days, with the first 5 days being for adaptation followed by 2 days each for faecal and ileal digesta collection. Data were analysed using the MIXED procedure of SAS, with the final model having variety, PS, MES, their two-way interactions, and a three-way interaction. No interactions were noted except that the apparent ileal digestibility and SID of crude protein (CP) and most AA in Gatano had greater effects of MES than Bono (Variety × MES; p < 0.05). The ATTD of dry matter (DM), gross energy (GE) and CP were greater (p < 0.05) in Bono diets than in Gatano diets. Finely ground hybrid rye diets had higher (p < 0.05) ATTD of neutral detergent fibre assayed with a heat stable amylase and expressed inclusive of residual ash (NDF) and ether extract compared to coarsely ground hybrid rye diets. Dietary MES supplementation increased (p < 0.05) the ATTD of DM, GE, CP, NDF, acid detergent fibre expressed inclusive of residual ash, and ash in hybrid rye diets. In conclusion, the nutrients digestibility of hybrid rye can be affected by its variety. PS reduction improved the nutrient digestibility in hybrid rye, and MES supplementation improved the energy and AA digestibility in hybrid rye fed to growing pigs.

Optimization of the Homogenization Process of Ginseng Superfine Powder to Improve Its Powder Characteristics and Bioavailability.

As consumer demands evolve for health supplements, traditional ginseng products are facing challenges in enhancing their powder characteristics and bioavailability. The objective of this study was to prepare a novel ginseng superfine powder using a high-pressure homogenization (HPH) process. Response surface methodology was employed to determine the effects of HPH parameters (pressure, number of passes, and concentration) on particle size and the dissolution of the saponin components of the superfine powders. The Box-Behnken design of experiments was applied to ascertain the optimal HPH parameters for the smallest particle size and the highest dissolution of the saponin components. For the powders obtained at different parameters, the characterization of tap density, bulk density, flowability, water-holding capacity, appearance, and taste were observed. The optimized experimental conditions for the HPH process were as follows: 15,000 psi (pressure), 3 (number of passes), and 1 kg/L (concentration). The optimized values were 55 μm (particle size) and 83 mg/g (dissolution of the saponin components), respectively. The method offered technical support for the application of the HPH process in the preparation of ginseng powders. The objects of this research could be broadened to include a diverse array of botanical materials, addressing contemporary demands for cost-effectiveness and sustainability within the industry.

Insecticidal efficacy of local diatomaceous earth compositions with different particle sizes against stored grain pests

In this study, the efficacy of a mixture of local diatomaceous earth (DE) with different diatomite compositions and particle sizes against stored-grain pests, Sitophilus oryzae L., 1763 (Coleoptera: Curculionidae), Tribolium confusum du Val, 1863 (Coleoptera: Tenebrionidae), and Rhyzopertha dominica (F., 1792) (Coleoptera: Bostrichidae) adults was investigated in 2023 in the Entomology Laboratory of the Department of Plant Protection, Faculty of Agriculture, KSU. In biological tests, 500 and 1000 ppm concentrations (mg DE/kg wheat) of different particle sizes (≤ 20, 20-75, 75-150, and ≥ 150 µm) of DE mixture and original DE (≤ 250 µm) were applied to wheat. The highest mortality rate for all insect species tested at 500 ppm was obtained from DE treatments of ≤20 µm. At 1000 ppm, 100% mortality was observed for T. confusum and S. oryzae in almost all particle size DE-treatments, whereas no local DE treatments resulted in 100% mortality for R. dominica adults. Moreover, the greatest reduction in the number of F1 generation adults for S. oryzae and R. dominica was obtained in the DE treatment of ≤20 µm at 500 and 1000 ppm. In conclusion, local DE mixture treatments with ≤ 20 µm particle size were found to be highly effective in the control of stored-grain pests.

Development and Validation of a New Eco-Friendly HPLC-PDA Bioanalytical Method for Studying Pharmacokinetics of Seliciclib

Background and Objectives: Seliciclib (SEL) is the first selective, orally bioavailable potential drug containing cyclin-dependent kinase inhibitors. Preclinical studies showed antitumor activity in a broad range of human tumor xenografts, neurodegenerative diseases, renal dysfunctions, viral infections, and chronic inflammatory disorders. To support the pharmacokinetics and aid in therapeutic monitoring of SEL following its administration for therapy, an efficient analytical tool capable of quantifying the concentrations of SEL in blood plasma is needed. In the literature, there is no existing method for quantifying SEL in plasma samples. This study introduces the first HPLC method with a photodiode array (PDA) detector for the quantitation of SEL in plasma. Materials and Methods: The chromatographic resolution of SEL and linifanib as an internal standard (IS) was achieved on Zorbax Eclipse Plus C18 HPLC column (150 mm length × 4.6 mm internal diameter, 5 µm particle size), with a mobile phase composed of acetonitrile–ammonium acetate, pH 5 (50:50, v/v) at a flow rate of 1.0 mL min−1. Both SEL and IS were detected by PDA at 230 nm. The method was validated according to the ICH guidelines for bioanalytical method validation. Results: The method exhibited linearity in concentrations ranging from 50 to 1000 ng mL−1, with a limit of quantitation of 66.1 ng mL−1. All remaining validation parameters satisfied the ICH validation criteria. The environmental sustainability of the method was verified using three extensive tools. The proposed HPLC-PDA method was effectively utilized to study the pharmacokinetics of SEL in rats after a single oral administration of 25 mg/kg. Conclusions: The proposed method stands as a valuable tool for studying SELs for pharmacokinetics in humans. It aids in achieving the targeted therapeutic advantages and safety of treatment with SEL by optimizing the SEL dosage and dosing schedule.

Overcoming the Strong Sample Solvent Effect for Sustainability Measurement Challenges in Liquid Chromatography. Example for Bisphenol-A.

This paper describes an approach to achieve low parts per billion (ppb) concentration level detection using a reversed-phase ultrahigh-performance liquid chromatographic ultraviolet absorbance detection method with large-volume feed injection (FI) for analytes in dichloromethane (DCM). FI is a novel technology that allows sample injection at a defined speed into the LC mobile phase. We demonstrate this approach for a mixture of bisphenol A and its diglycidyl ether derivatives in DCM. DCM is a very strong injection solvent at reversed-phase LC conditions and is typically immiscible with a starting reversed-phase gradient mobile phase containing a high percentage of water. As a result, reduced separation performance and even peak splitting are seen with classic flow-through injection. The method setup comprised an octyl-bonded core-shell stationary phase (150 × 4.6 mm i.d., 2.7 μm particle size) with a water/acetonitrile mobile phase gradient and an exceptionally high injection volume of 45 μL of DCM solution using FI. Optimization of feed speed (1%) and isocratic hold duration (4 min) was crucial for final separation conditions. FI delivered more than a 20-fold improvement in the limit of detection (LOD) compared to standard flow-through injection while maintaining peak resolution. The LOD of the final method ranged between 1 and 10 ppb in the polymer resin. This methodology has high potential for trace analysis in a large variety of applications that suffer from the "strong solvent effect".

Microplastics release from infant feeding bottles and milk storage bags

The health impairment of microplastics (MPs) in infants has received considerable attention, with oral ingestion being an important exposure route. However, research remains limited on MPs released in feeding bottles (FBs) and breastmilk storage bottles (BSBs) during daily use. To address this gap, our study investigated the MPs released from polyphenylene sulfone resins (PPSU)-FBs, silicone-FBs, polyethylene (PE)-BSBs, and low-density polyethylene (LDPE)-BSBs under typical usage conditions. Our findings revealed that the four materials of FBs and BSBs can release 1465–5893 particles/L MPs (median concentration). The predominant MPs released from all FBs and PE-BSBs were identified as PE, while LDPE-BSBs predominantly released polyethylene terephthalate (PET) and acrylates (ACR). Approximately 70% of MPs were found within the 20–50 μm particle size range. Higher temperatures led to a two-fold increase in the total MPs. Notably, infants would additionally intake 2080–5910 MPs per day through FBs and BSBs. Months with higher nutritional requirements, and when using silicone FBs and LDPE BSBs, increased the ingestion of MPs in infants. In conclusion, our study highlighted that those FBs and BSBs can precipitate varying numbers, types, and particle sizes of MPs. To protect infants from MPs ingestion, it is recommended to choose non-plastic FBs and non-plastic breastmilk storage containers.

Global patterns of lake microplastic pollution: Insights from regional human development levels

Microplastics have emerged as a pervasive pollutant across various environmental media. Nevertheless, our understanding of their occurrence, sources, and drivers in global lakes still needs to be completed due to limited data. This study compiled data from 117 studies (2016–May 2024) on microplastic contamination in lake surface water and sediment, encompassing surface water samples in 351 lakes and lake sediment samples in 200 lakes across 43 countries. Using meta-analysis and statistical methods, the study reveals significant regional variability in microplastic pollution, with concentrations ranging from 0.09 to 130,000 items/m3 in surface water and from 5.41 to 18,100 items/kg in sediment. Most microplastics were under 1 mm in particle size, accounting for approximately 79 % of lake surface water and 76 % of sediment. Transparent and blue microplastics were the most common, constituting 34 % and 21 % of lake surface water and 28 % and 18 % of sediment, respectively. Fibers were the dominant shape, representing 47 % of lake surface water and 48 % of sediment. The primary identified polymer types were polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Countries like India, Pakistan, and China had higher contamination levels. Positive correlations were found between microplastic abundance in surface water and factors like human footprint index (r = 0.29, p < 0.01), precipitation (r = 0.21, p < 0.05), and net surface solar radiation (r = 0.43, p < 0.001). In contrast, negative correlations were observed with the human development index (r = −0.61, p < 0.01) and wind speed (r = −0.42, p < 0.001). In sediment, microplastics abundance correlated positively with the human footprint index (r = 0.45, p < 0.001). This study underscores the variability in microplastic pollution in global lakes and the role of human activities and environmental factors, offering a valuable reference for future research.

Simultaneous Estimation of Atazanavir &amp; Ritonavir in API &amp; Marketed Formulations by Using RP-HPLC

Development and validation of RP-HPLC method for simultaneous estimation of Atazanavir and Ritonavir in their combined tablet dosage form. Atazanavir and Ritonavir are antiviral agents used in treatment of HIV. A simple, precise, rapid, accurate and cost-effective high- performance liquid chromatography (HPLC) method was successfully developed and validated for simultaneous estimation of Atazanavir and Ritonavir in their combined tablet dosage form. The selected mobile phase was Methanol: Phosphate Buffer in proportion 65:35 v/v respectively. The optimized columns used are C18 column, Symmetry and Zodiac column. X bridge C18 (4.6×150 mm, 5 µm) particle size was found to be ideal as it gave good peak shape and resolution at 1ml/min flow for Atazanavir and Ritonavir. In this study, the validation of Atazanavir and Ritonavir in API and marketed formulations were performed keeping in accordance with the parameters like system suitability, specificity, linearity, accuracy, precision (reproducibility &amp; repeatability), robustness. The developed stability indicating method is capable for determination of impurities of Atazanavir and Ritonavir in combined tablet dosage form as well as individual dosage forms also. The method has been successfully validated according to ICH guidelines and the results obtained by using RP – HPLC are rapid, accurate and precise. The proposed methods were successfully applied for the analysis of synthetic mixtures and pharmaceutical formulations of Atazanavir and Ritonavir.

Particle Shape-Based Evaluation of the Leaching of Sphalerite Ore in Dilute Acid Solutions

In this study, the effects of changes in particle shapes on dissolution efficiencies in zinc (Zn) recovery from a lead-zinc (Pb-Zn) ore by acid leaching method were investigated. In the experiments with nitric acid (HNO3), sulfuric acid (H2SO4), and hydrochloric acid (HCl), particle size (75-106-150 µm), solids ratio (5-10-15-20-25%), leaching time (30-60-120-180-240 min), acid dosage (0.25-0.5-1-2-5 M) and pulp temperature (30-40-50-60-70 oC) parameters were analyzed. Optimum results were obtained under the conditions of 75 µm particle size, 15% solids ratio, 120 min leaching time, 0.5 M acid dosage, and 50°C pulp temperature for H2SO4; 106 µm particle size, 25% solids ratio, 60 min leaching time, 0.5 M acid dosage, and 70°C pulp temperature for HCl; 75 µm particle size, 20% solids ratio, 60 min leaching time, 1 M acid dosage, and 50°C pulp temperature for HNO3. As a consequence of the tests performed under these optimized conditions, 97.32%, 96.38% and 96.06% Zn dissolution efficiencies were obtained. Within the context of particle shape factor research, microscope images of the leaching residues were obtained from the experiments in which the pulp temperature, acid dosage, and leaching time parameters were examined. The samples obtained from the experiments with all three acids were compared with the ore samples, and the impacts of changes in circularity, roundness, and solidity values on dissolution efficiencies were interpreted.

Method Development and Validation for the Simultaneous Estimation of Lobeglitazone Sulphate and Glimepiride by HPLC Method.

A simple, precise, and accurate reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed for the simultaneous estimation of lobeglitazone sulfate and glimepiride in bulk and tablet dosage forms. The method involved selecting various chromatographic parameters. Specifically, a new method was developed using a 250 mm × 4.6 mm (HSS) reverse-phase C18 column with 5 µm particle size (Shim-pack C18, 250 × 4.6 mm; 5 µm). The mobile phase consisted of 40 volumes of phosphate buffer (pH 3) and 60 volumes of acetonitrile, with methanol as the diluent, running as an isocratic elution. The flow rate was set at 1.0 mL/min, and UV detection was performed at 254 nm. The injection volume was 2 µL, and the total runtime was 10 minutes. The recoveries for lobeglitazone sulfate were found to be in the range of 101% to 100.6%, while those for glimepiride were in the range of 101.5% to 100%. The method’s accuracy is evident from these results. The inter-day and intra-day precision of the new method were both below the maximum allowable limit (RSD% ≤ 2.0), as per International Council on Harmonisation (Q2 R1) guidelines. The method exhibited a linear response, with correlation coefficient (r2) values of 0.9972% for pioglitazone and 0.998 for glimepiride. The validation parameters, such as accuracy, precision, linearity, specificity, stability in the analytical solution and robustness, met the acceptance criteria. Hence, this method can be effectively used for the simultaneous estimation of lobeglitazone sulfate and glimepiride in both bulk and pharmaceutical dosage forms.

A green and sensitive electromembrane extraction (EME) method for the determination of dialkylphosphates in maternal urine and amniotic fluid

Organophosphates compounds are extensively used pesticides, whose metabolites, dialkyl phosphates, are considered as bioindicators of human exposure. Recently, research has indicated that they can affect thyroid endocrine function. Pregnant women are a particularly vulnerable cohort to these effects due to concerns about prenatal exposure to environmental pollutants. For the first time an electromembrane microextraction method is proposed for the simultaneous determination of seven dialkylphosphate metabolites in maternal urine and amniotic fluid, which is compatible with mass spectrometry detection and achieves highly sensitive levels of quantitation. Dialkylphosphates were extracted from a 10 mL donor solution at pH 7 into a 50 µL acceptor solution at pH 12 using 1-octanol as the supported liquid membrane and applying 60 V for 10 min at 600 rpm. The obtained extracts were analysed by ion pair liquid chromatography coupled to a triple quadrupole mass spectrometer, using an Acquity UPLC® BEH C18 column (100 mm × 2.1 mm i.d., 1.7 µm particle size) at 30 °C. Under optimal extraction conditions, the preconcentration factors were achieved were up to 178-fold, allowing for high sensitivity levels, in the order of ng mL−1. The limits of quantitation were within 0.075 ng mL−1 (diethyl thiophosphate) and 1.67 ng mL−1 (dimethyl phosphate) in maternal urine samples and within 0.015 ng mL−1 (diethyl thiophosphate) and 0.5 ng mL−1 (dimethyl dithiophosphate) in amniotic fluid samples. The comparative study revealed a significant improvement in terms of analysis time, sensitivity, greenness, and practicality. Finally, the applicability of the method for the determination of selected dialkylphosphates was demonstrated in paired maternal urine and amniotic fluid samples. These results suggest potential placental transfer to the offspring.

Simultaneous Estimation of Pregabalin and Duloxetine Used to Treat Nerve Pain by Stability Indicating RP-HPLC Method Using the QBD Approach

Objective: A novel stability indicating RP-HPLC method was developed and validated for the simultaneous estimation of Pregabalin and Duloxetine by using the QBD approach. Method: To determine the optimal parameters for the duloxetine and pregabalin study, we used Design Expert version 13.0 in this work. The mobile phase consisted of 0.8 ml/min of methanol: water (80:20, v/v) with o-phosphoric acid-adjusted pH 3.A 250 mm × 4.6 mm ID, 5 μm particle size Cosmosil C18 column was used. The UV-3000-M detector was used to detect at 218 nm. Results: Duloxetine's retention time was 7.153 ±0.1 min, whereas Pregabalin's was 4.481±0.1 min. The ICH parameters like linearity, accuracy, robustness, ruggedness, LOD and LOQ, and system suitability were determined. Likewise, the tailing factors were found to be 1.27 and 1.26, while the theoretical plates of duloxetine and pregabalin were found to be 8313 and 8549, respectively. The recovery study shows the results (99.37–99.84% for pregabalin and 99.03–99.74% for duloxetine), and the precision was obtained with a %RSD of less than 2%. The result of the assay was 99.92 % for pregabalin and 99.39% for duloxetine. The developed method was used for the forced degradation study. The Box-Behnken design experiment using Design Expert 13.0 was adopted for the QBD approach. Conclusion: All the values obtained for different parameters were within the acceptable range of ICH. The developed method can be routinely used for the simultaneous estimation of Pregabalin and Duloxetine by using the QBD approach.

Simultaneous determination of 13 biogenic amines and their metabolites in liquid fermented food by HPLC-QTRAP-MS without derivatization

Biogenic amines and their metabolites (BAs) are among the most frequently detected compounds in liquid fermented foods, raising significant concerns about the potential risks they pose. To rapidly and selectively determine BAs, this study proposed and validated a method for the simultaneous determination of 13 BAs in liquid fermented foods using high performance liquid chromatography-triple quadrupole/linear ion trap mass spectrometry (HPLC-QTRAP-MS) without derivatization. The simultaneous separation and determination of histamine (HIS), tyramine (TYR), putrescine (PUT), octopamine (OCT), 2-phenylethylamine (2-PHE), dopamine (DOP), spermidine (SPD), epinephrine (EPI), agmatine (AGM), 5-hydroxytryptamine (5-HYD), tryptamine (TRY), L-noradrenaline (L-NOR), cadaverine (CAD) were achieved using a Waters Atlantis Premier BEH Z-HILIC (1.7 μm particle size, 100 mm × 2.1 mm id) column with a mobile phase consisting of water (containing 0.025 % formic acid) and acetonitrile (containing 0.1 % formic acid). The analysis of target compounds was performed with electrospray ionization (ESI) in positive ion mode, multiple reaction monitoring (MRM), information dependent acquisition (IDA), enhanced product ion (EPI), and multi-step mode analysis combined with EPI library searching. To enhance the extraction efficiency of BAs, factors such as extraction solvent, filter membranes, extraction methods, pH, oscillation speed, time and temperature were systematically investigated. The results demonstrated that the method exhibited low limits of detection (LOD) and quantification (LOQ), ranging from 0.05 to 2.00 µg/L and 0.16 to 6.60 µg/L, respectively. The method also showed satisfactory reproducibility, with intra-day and inter-day relative standard deviations ranging from 0.90 % to 3.80 % and 2.65 % to 8.27 %, respectively. Additionally, it had a broad linear range from 0.05 to 200.00 µg/L with excellent linearity (R>0.99) and an average recovery rate between 65.68 % and 115.14 %. Overall, the results demonstrated that the established method was convenient to operate, offered a short analysis time, and achieved high accuracy and sensitivity. It met the qualitative and quantitative requirements for detecting 13 BAs in liquid fermented food, thus providing strong technical support for BAs detection.

240 Feed preference of weanling pigs fed diets containing extruded corn ground to different particle sizes

Abstract The objective was to test the null hypothesis that there were no effects of reducing particle size of extruded corn on feed preference by weanling pigs. Three corn-based diets containing extruded corn ground to 700, 500, or 300 μm were prepared. An 8-d feed preference test was conducted with all possible combinations of the three diets. Each pair of diets constituted a treatment group (i.e., 700 vs. 500 μm; 700 vs. 300 μm; 500 vs. 300 μm). A total of 48 growing pigs [initial body weight (BW) = 12.1 ± 1.34 kg] were allotted to the three preference test combinations using a randomized complete block design with initial BW group as the blocking factor, resulting in eight replicate pens per treatment group. Two pigs were housed in each pen. Pigs had ad libitum access to feed and water. For each preference test, each pen contained two feeders with two of the three diets. Feeder positions within each pen were switched daily to minimize positional preference. Feed allotments and feed disappearances were recorded daily. Feed preference (%) was calculated by dividing the amount of feed disappeared for each diet by the total amount of two diets consumed by pigs. Three statistical models for each preference test included particle size of corn as fixed effect and block as random effect. Results indicated that pigs had greater (P &amp;lt; 0.05) daily feed disappearance and preference for corn with 700 µm on d 1, 4, 5, 7, and 8 when pigs had a choice between 700 µm vs. 500 µm (Table 1). For the other two preference tests, which were 700 µm vs. 300 µm and 500 µm vs. 300 µm, pigs had a greater (P &amp;lt; 0.05) preference for the larger particle size corn (700 and 500 µm, respectively) for d 3 to 8. In conclusion, it was demonstrated that pigs have a preference for larger particle sizes of extruded corn when given the choice. This may be a result of better texture of feed, a satisfying chewing experience, and the perception of greater bulkiness provided by greater particle sizes. However, further research with longer-term feeding trials is needed because pigs may have already adapted to consuming diets with 700 µm particle size prior to the experiment, which is similar to commercial diets.

Study of the impurity dissolution kinetics, rheological characterization, and hydrodynamic aspects during the bioleaching of iron ore pulp in a bioreactor

AbstractThis research aims to study the rheological behavior and impurities dissolution kinetics in a bioleaching process of two particle sizes and three different pulp densities, which are analyzed and compared. It was found that the small particle size with 40% (w/w) pulp density provides the maximum dissolution of impurities in the shortest bioleaching time (in 2 days). Furthermore, through a CFD simulation in a system with 40% (w/w) pulp density and 44 μm particle size, a stirring speed of 700 rpm provides the best mixing conditions in the bioreactor, enabling good distribution of recirculation zones and adequate streamline patterns with a viscosity map that minimizes regions of high and low viscosity. Graphical abstract

The use of an RP-HPLC-UV method for the analysis of oxcarbazepine in the presence of its preservatives; stability studies and application to human plasma samples

AbstractA simple, sensitive, selective, accurate and precise method was developed and fully validated for determination of oxcarbazepine (OXC) in presence of their preservatives and determination of oxcarbazepine (OXC) in human plasma. A reversed phase liquid chromatography (RP-HPLC) with UV detection techniques were applied for separation and quantification of studied drug OXC. Successful separation of the drug from methyl paraben (M.P.), propyl paraben (P.P.) and potassium sorbate (P.ST.) was achieved on a Kromasil C18 column (5 μm particle size, pore size 300 Å, l × I.D. 250 × 4.6 mm). The mobile phase that contain aqueous 0.05M potassium dihydrogen phosphate buffer (pH 7): acetonitrile, (50: 50, %v/v). The method was linear over concentration ranges 5.0–50 μg mL−1 for OXC. Bioanalytical validation of the developed method was carried out according to US-FDA guidelines and revealed a good linear relations over a range of (5.0–50), (0.5–10), (0.05–0.15), and (1.0–10) μg mL−1 for OXC, M.P, P.P, and P.ST, respectively, with a correlation coefficient (R2) of more than 0.999. Limit of detection (LOD) were 1.15, 0.03, 0.01 and 0.04 μg mL−1 for OXC, M.P, P.P, and P.ST, respectively, Intra and inter-day precisions, calculated as percentage relative standard deviation (% RSD), were lower than 2.0%. The developed method can be applied for routine drug analysis, therapeutic drug monitoring and bioequivalence studies through the analysis of plasma samples taken from blood bank.