Rapid Method For Determination Research Articles

A simple, rapid, and green method for determination of three cholic acids in bio-transformed Jindanfen by HPLC-MS

AbstractA simple, rapid, and green high-performance liquid chromatography-mass spectrometry (HPLC-MS) method was developed for determination of tauroursodeoxycholic acid (TUDCA), taurocholic acid (TCA), and taurochenodeoxycholic acid (TCDCA) in bio-transformed Jindanfen (BTJDF), which is obtained from chicken bile through a bioconversion process. The sample was prepared using water. The HPLC separation was operated on a poroshell 120 EC-C18 column with a 2.0 min gradient elution procedure. Detection was performed on a single quadrupole mass spectrometer in negative mode with selected ion monitoring mode (SIM). This developed HPLC-MS method presented good linearity (r > 0.997) and sensitivity (limit of quantification, 30.0–80.0 pg) for three analytes. The relative standard deviations (RSDs) for precision, repeatability, and stability were all below 3.00%. The matrix effects and average recoveries of three analytes were 91.2–97.9% (RSDs < 1.50%) and 95.4–103% (RSDs < 3.00%), respectively. The average contents of TUDCA, TCA, and TCDCA in ten batches of samples were 33.8, 13.2, and 20.5%, respectively. Finally, the greenness of the developed method was validated by Analytical Eco-Scale and Complex-GAPI. The developed method was proved to be an eco-friendly, effective, and reliable approach for assaying the three cholic acids in BTJDF, which is help to improve the quality evaluation level of the BTJDF industry.

Cryoradiolysis of oxygenated cytochrome P450 17A1 with lyase substrates generates expected products

When subjected to γ-irradiation at cryogenic temperatures the oxygenated complexes of Cytochrome P450 CYP17A1 (CYP17A1) bound with either of the lyase substrates, 17α-Hydroxypregnenolone (17-OH PREG) or 17α-Hydroxyprogesterone (17-OH PROG) are shown to generate the corresponding lyase products, dehydroepiandrosterone (DHEA) and androstenedione (AD) respectively. The current study uses gas chromatography–mass spectrometry (GC/MS) to document the presence of the initial substrates and products in extracts of the processed samples. A rapid and efficient method for the simultaneous determination of residual substrate and products by GC/MS is described without derivatization of the products. It is also shown that no lyase products were detected for similarly treated control samples containing no nanodisc associated CYP17 enzyme, demonstrating that the product is formed during the enzymatic reaction and not by GC/MS conditions, nor the conditions produced by the cryoradiolysis process.

A novel enrichment and sensitive method for rapid determination of 4 sulfonamide antibiotics residues in fish

Sulfonamide antibiotics with superior performance are widely used in aquaculture. However, the residues of sulfonamide antibiotics in aquatic products may pose a threat to human health. In this work, a novel type of magnetic molecularly imprinted polymer (mMIP) was synthesized and coupled with ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) for the selective separation and determination of 4 sulfonamide antibiotics residues in tilapia. The structure and adsorption properties of the polymers were characterized and evaluated. The key mMIP variables were investigated to determine the optimal magnetic solid phase extraction conditions. Results showed that the mMIPs had saturated adsorption capacities of 137.4, 78.7, 65.2, and 58.4 mg/g for trimethoprim, sulfadiazine, sulfamethazine, and sulfamethoxazole, respectively. Under optimized conditions, the linear range of the method for the detection of the 4 sulfonamides was 0.1-100 ng·mL-1 (R>0.991), the detection limit was 0.015 μg·kg-1 (S/N=3), the recovery rate was 78.6-101%, and the relative standard deviation (RSD%) was 4.2-7.8%. This new rapid and ultra-sensitive pretreatment method was successfully applied to the monitoring of trace sulfonamide antibiotics residues in fish samples.

Rapid determination of hippuric acid as an exposure biomarker of toluene using a colorimetric assay and comparison with high-performance liquid chromatography

Occupational exposure to toluene is associated with health risks that require reliable monitoring methods. Hippuric acid (HA), a urinary metabolite of toluene, serves as a valuable biomarker for such exposure. Colorimetric methods for the quantitative determination of HA have gained prominence due to their simplicity, cost-effectiveness, and suitability for field application. In the present study, a simple colorimetric technique was optimized for the determination of HA in the urine sample, and compared with a usual HPLC technique. The central composite design (CCD) was applied to examine the effective parameters on the colorimetric determination of HA. The calibration curve for HA was established within the concentration range of 6 to 100 mg L−1 with R2 = 0.97. The detection limit (LOD) and quantification limit (LOQ) were determined to be 1.8 mg L−1 and 6 mg L−1 respectively. The relative standard deviation (RSD%) was less than 5%, and the recovery% (R%) was 90.5–100.1. The overall results showed good agreement between the colorimetric and HPLC results. There was a significant relationship between the results obtained from HPLC and colorimetric methods especially for higher concentration levels of HA (≥ 500 mg/g creatinine). In conclusion, our optimized colorimetric method is a simple, cost-effective, and rapid method for determination of HA in occupational exposure, which is comparable with the HPLC technique.

Rapid and sensitive determination of trace Cd in carbonate samples using direct solid sampling electrothermal vaporization atomic absorption spectrometry

The accurate determination of cadmium (Cd) hosted and accumulated in sedimentary carbonate remains challenging due to its low concentration (ng·g−1) and complex matrix. Conventional methods, such as inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (GF-AAS), which typically rely on liquid sampling and sample digestion, are tedious, labor-intensive and time-consuming. In this study, a rapid and sensitive method for the direct determination of carbonate-hosted Cd was developed based on solid sampling electrothermal atomic absorption spectrometry (SS-ETV-AAS). This method eliminates the need of acid digestion procedure, allowing the entire analysis, including sample preparation, to be completed within 10 min. To minimize the carbonate matrix effect, ethylene diamine tetra acetic acid disodium salt (EDTA-2Na) was proposed as matrix modifier to facilitate the release of Cd, enabling fast and accurate determination of trace Cd in carbonate samples. Under optimized conditions, the Cd detection limits was found to be as low as 0.17 ng·g−1, and repeatability (relative standard deviation, RSD) was better than 8 % (n = 7). The accuracy of the proposed SS-ETV-AAS was verified by analyzing five carbonate certified reference materials (GBW07127, GBW07129, GBW07130, GBW07135 and JDo-1), two soil certified reference materials (GBW07404a, GBW07405), as well as several actual carbonate samples. All these results demonstrate that the proposed SS-ETV-AAS method provides a simple, rapid and sensitive approach for measuring trace Cd in carbonates.

Statistical optimization of two-phase hollow fiber liquid-phase microextraction for preconcentration of strychnine in the clinical and postmortem biological fluids prior to gas chromatography-mass spectroscopy detection

Strychnine is a herbal alkaloid whose role in military and doping applications as well as the nervous system stimulation and cancer therapy has been confirmed. Because of its lethal nature, even at low dosages, developing a rapid, sensitive, and accurate method for determination of this alkaloid in the clinical and postmortem samples is of great importance. In this study, a green analytical method based on the two-phase hollow fiber liquid-phase microextraction (HF-LPME) combined with gas chromatography-mass spectrometry (GC–MS) was presented for preconcentration and determination of strychnine in biological fluids. A Box-Behnken design (BBD) with three variables, including extraction time (30–90 min), solution pH (9.0–11.0), and ionic strength (1.0–3.0 mol/L) was employed to maximize the extraction efficiency of strychnine by 1-octanol. The results were satisfactorily fitted to a quadratic response surface model (R2 = 0.979, F = 34.4) which predicted the optimum conditions of operation (extraction time of 89 min, pH = 11.0, and ionic strength of 3.0 mol/L). Based on the results, the studied variables and the interaction between pH and extraction time showed highly significant effects on the process efficiency. The calibration curve was linear in the concentration range of 2.7–1000.0 µg/L (R2 = 0.9978) and the limits of detection and quantitation were found to be 0.8 and 2.7 µg/L, respectively. Moreover, the method was successfully applied to different real samples, including urine (clinical sample), bile and stomach contents, blood, and vitreous humor (postmortem samples), and relative recoveries were obtained in the range of 93.8 % to 99.8 %. The findings of this study suggest that the environmentally friendly HF-LPME method which uses a small amount of a chlorine-free solvent, is a sensitive, cost-effective, simple, and efficient preconcentration method for trace determination of strychnine in biological fluids.

Development and Validation of a Capillary Zone Electrophoresis-Tandem Mass Spectrometry Method for Simultaneous Quantification of Eight β-Lactam Antibiotics and Two β-Lactamase Inhibitors in Plasma Samples.

Monitoring plasma concentrations of β-lactam antibiotics is crucial, particularly in critically ill patients, where variations in concentrations can lead to treatment failure or adverse events. Standardized antimicrobial regimens may not be effective for all patients, especially in special groups with altered physiological parameters. Pharmacokinetic/pharmacodynamic (PK/PD) studies highlight the time-dependent antibacterial activity of these antibiotics, emphasizing the need for personalized dosing. Therapeutic drug monitoring (TDM) is essential, requiring rapid and accurate analytical methods for precise determination of drugs in biological material (typically plasma or serum). This study presents a novel capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) method designed for the simultaneous quantification of five penicillin antibiotics, two cephalosporins, one carbapenem, and two β-lactamase inhibitors in a single run. The method involves a simple sample pretreatment-precipitation with organic solvent-and has a run time of 20 min. Optimization of CZE separation conditions revealed that 20 mM ammonium hydrogen carbonate (NH4HCO3) serves as the optimal background electrolyte (BGE). Positive electrospray ionization (ESI) mode, with isopropyl alcohol (IP)/10 mM ammonium formate water solution (50/50, v/v) as the sheath liquid, was identified as the optimal condition for MS detection. Method validation according to the Food and Drug Administration (FDA) guideline for development of bioanalytical methods demonstrated satisfactory selectivity, linearity, recovery, robustness, and stability. The method's practicality was evaluated using the Blue Applicability Grade Index (BAGI), yielding a score of 77.5. Moreover, the greenness of the proposed method was evaluated by two commonly used metric tools-Analytical GREEnness (AGREE) and Green Analytical Procedure Index (GAPI). The developed CZE-MS/MS method offers a practical and reliable approach for quantifying a broad spectrum of β-lactam antibiotics in plasma. Its ability to simultaneously quantify multiple analytes in a single run, coupled with a straightforward sample pretreatment, positions it as a valuable and prospective tool for TDM in critically ill patients.

Application of a Green Deep Eutectic Solvent for Preconcentration and Determination of Copper and Cadmium in Food, Cosmetic, and Water Samples

Background:: Determination of environmental pollutants is important due to their harmful effects on the health of living organisms. However, direct measurement of many of these pollutants is not possible due to their low concentrations, which necessitates the need for sample preparation methods. One of the rapid and simple sample preparation methods is the Air-Agitated Liquid-Liquid Microextraction (AALLME) method, which requires toxic organic solvents that can lead to environmental pollution. Therefore, finding green solvents like Deep Eutectic Solvents (DESs) to replace them can be investigated. Methods:: A novel Deep Eutectic Solvent (DES) was synthesized from a combination of choline chloride and 2-phenylethanol with a molar ratio of 1:4, and it was examined using FT-IR analysis. This solvent was used in an AALLME method for measuring copper and cadmium heavy metal ions in complex real samples with Flame Atomic Absorption Spectroscopy (FAAS). Results:: The influential parameters of this method, such as solution pH (5.4), extraction cycles (12), and extraction solvent volume (440 μL), were optimized utilizing central composite design (CCD). Underneath the optimized circumstances, the detection limits for Cu2+ and Cd2+ were 0.14 and 0.09 ng mL-1, and the linear dynamic range was 0.47-50.0 and 0.32-22.5 ng mL-1, respectively. The preconcentration factors for these cations were 139.7 and 133.4, respectively. Conclusion:: Combining this novel green solvent and rapid sample preparation method for the preconcentration and determination of the studied heavy metal ions has shown promising results in terms of enrichment factors and detection limit values.

Accurate Detection of G-Series Agent Simulants by Pseudo-Multiple Reaction Monitoring on Miniature LIT-MS.

Rapid and accurate on-site detection of chemical warfare agents (CWAs) could defend military and civilian populations against current and emerging chemical weapons. With the development of ambient ionization and linear ion trap technology, the rapid and accurate quantitative determination method of CWAs based on direct ionization and multistage mass spectrometry has attracted widespread attention. In this study, a microliter electrospray ionization-miniature linear ion trap mass spectrometry (LIT-MS) instrument was designed and constructed, and the effects of quadrupole enhanced dipole resonance excitation on the resolution and sensitivity were investigated; consequently, the parameters of CWAs detection were optimized. Based on the broad time-frequency ion excitation technology, accurate multiple reaction monitoring (MRM) quantitative analysis of DMMP (G-series agent simulants, m/z 125 → m/z 93) was obtained. The linear correlation coefficient in the concentration range of 1 to 20 μg/mL could reach 99.02%, and the relative standard deviations (RSD) of continuous repeatability, interday repeatability, and intraday repeatability were all less than 10%. The results showed that the accurate pseudo-MRM detection method based on miniature linear ion trap mass spectrometry for CWAs detection was feasible.

Optimization and Applications of Instrumental and Preconcentration Neutron Activation Analysis Methods for Rapid Determination of Selected REE by Utilizing their Short‐Lived Activation Products**

AbstractDetermination of Rare Earth Elements (REEs) using spectroscopic methods is challenging. Conventional Instrumental Neutron Activation Analysis (INAA) method utilizing Pneumatic Carrier Facility (PCF) of Dhruva research reactor has been optimized with the short‐lived isotopes such as 161Gd, 165mDy and 153/155Sm for quantification of Gd, Dy and Sm respectively. Such isotopes are difficult to observe by conventional INAA with longer cooling periods owing to their very short half‐lives (1–3 mins). In this work, such isotopes are not only observed but also utilized as activation product for rapid determination of these REEs. The standardized method has been utilized for the first time in liquid samples involving nuclear fuel like U3O8 wherein TBP/n‐dodecane has been applied for chemical separation of Uranium prior to analysis. The INAA method has also been applied for validating the stoichiometry of Gd in Gd3+ co‐doped Zn2P2O7:Tb3+ green emitting solid‐state phosphors, which plays a very pivotal role in sensitizing the terbium ion in its performance for solid state lighting. We believe with huge current demand of REEs in research, science and technology; INAA can be a game changer wherever needed for quantification with high precision and accuracy and can also be extended to other REEs of interest.

A high-throughput method for the determination of 14 UV-filters in human plasma by LC-MS/MS: Minimize interferences from proteins and phospholipids in the matrix

Accurate monitoring of UV-filters exposure levels in human plasma is a challenge because of the significant differences in the physicochemical properties of UV-filters, as well as the matrix effect caused by abundant proteins and phospholipids in plasma. Therefore, an effective and rapid method for simultaneous determination of 14 UV-filters in human plasma using protein precipitation-solid phase extraction (SPE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Acetonitrile with 0.1 % formic acid and 10 % isopropanol (v/v) were used as mobile phases. A gradient elution on an ACQUITY UPLC BEH-C18 column at 30 °C and 0.3 mL/min flow rate was applied for separation. The electrospray ionization positive or negative modes were selected to determine the corresponding analyte to increase selectivity and sensitivity. Results showed that acetonitrile-tetrahydrofuran (v/v, 8:2) as the extraction solvent can effectively precipitate protein in plasma and improve the solubility of UV-filters. The HybridSPE cartridge improved the removal efficiency of phospholipids, while 1 mL of methanol elution increased the extraction recoveries of targets. Fourteen UV-filters achieved good linearities, low detection limits (0.050 to 0.10 μg/L) and quantification limits (0.10 to 1.0 μg/L). Method accuracy and precision, extraction recoveries, and storage stabilities of all analytes met the criterion of 80–120 %. Moreover, this method was successfully applied for the determination of UV-filters in plasma randomly collected from adults. Nine of 14 UV-filters were determined and their concentrations were distributed widely, suggesting a big variation of individual UV-filters exposure.

Development of a technique for determining the viability of dormant organisms in powdered substances

The purposes of pharmaceutical biotechnology and quality control of probiotics containing lyophilized bacterial preparations, as well as the purpose of ensuring biological safety, require methods for rapid determination of the viability of dormant forms. This paper describes an approach to determining the viability of dry powdered substances. Lyophilized powder of Kalanchoe daigermontiana, dry dormant eggs of Artemia salina, and dry powder of Lycopodium sp. spores were proposed as model objects. Suspensions of virus-like particles (VLPs) to SARS-CoV-2 were proposed as a cell-free reference material. The following methods of elemental analysis were used in the study: X-ray fluorescence spectroscopy (XRF) on an energy-dispersive device, atomic absorption spectroscopy with electrothermal atomization, and Zeeman background correction (GZ-AAS). The free water content was determined by NMR spin echo. A new method was also used for recording the kinetics of changes in broadband radio emission in the centimeter and millimeter wavelength ranges, with a measurement duration of up to 20 minutes. Live and inactivated powdered preparations of K. daigermontiana and A. salina were prepared and characterized by elemental composition, water content, and spin-spin relaxation time (T2). For these live and inactivated preparations, it was determined that the flux density of intrinsic thermal radio emission decreases by an order of magnitude with the loss of viability. In the future, the results obtained will allow for a rapid test of the viability of lyophilized therapeutics (from medicinal plants to bacterial mixtures that stabilize the intestinal microflora).
 Keywords: millimeter emission, X-ray fluorescence analysis, NMR spin echo, nanoparticles, powdered substances, medicinal plant raw materials

Probing the Alcoholysis Degree of Polyvinyl Alcohol by Synergistic Coordination-Regulated Fluorescence.

Polyvinyl alcohol (PVA) with abundant hydroxyl groups (-OH) has been widely used for membranes, hydrogels, and films, and its function is largely affected by the alcoholysis degree. Therefore, the development of rapid and accurate methods for alcoholysis degree determination in PVAs is important. In this contribution, we have proposed a novel fluorescence-based platform for probing the alcoholysis degree of PVA by using the (E)-N-(4-methoxyphenyl)-1-(quinolin-2-yl)methanimine (QPM)-Zn2+ complex as the reporter. The mechanism study disclosed that the strong coordination between -OH and Zn2+ induced the capture of the QPM-Zn2+ complex and promoted its subsequent immobilization into the noncrystalline area. The immobilization of the QPM-Zn2+ complex restricted its molecular rotation and reduced the nonirradiative transition, thus yielding bright emissions. In addition, the practical applications of this proposed method were further validated by the accurate alcoholysis degree determination of blind PVA samples with the confirmation of the National Standard protocol. It is expected that the developed fluorescence approach in this work might become an admissive strategy for screening the alcoholysis degree of PVA.

Selective adsorption and identification of penicillin G sodium in milk by molecularly imprinted polymer doped carbon dot.

A carbon dot (CD) was prepared by o-phenylenediamine and water, which showed bright yellow fluorescence under ultraviolet light irradiation (λ = 580nm), and verified good fluorescence quenching effect on penicillin G sodium (Png-Na). Using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, and Png-Na as a template, a kind of composite microsphere combining CD and molecularly imprinted polymer (MIP) was synthesized by surface-initiated atomic transfer radical polymerization (SI-ATRP). For reasons ofcomparison, we also prepared MIP without CD and non-imprinted polymers (NIPs). Through static and dynamic adsorption experiments, the maximum adsorption capacity was 47.05mgg-1 and the equilibrium time was 30min. High-performance liquid chromatography (HPLC) was utilized to determine the content of Png-Na in the spiked milk samples. A sensitive, rapid, and simple method for determination of Png-Na in food samples was developed. The utilized approach enabled the quantification of Png-Na within theconcentration range 20-1000μg L-1 (with a limit of detection of 5μg L-1). The recoveries achieved were in the range 93.3-98.2%, with a relative standard deviation of 1.2-4.2%. The results demonstrated that CD@MIP possessed the capability of specific adsorption and fluorescence detection of Png-Na, enabling simultaneous detection and enrichment of Png-Na in real samples.

Pharmacokinetic study of multicomponent in Hong-Hua-Xiao-Yao tablet.

Hong-Hua-Xiao-Yao tablet (HHXYT) is attracting attention increasingly because of its use in treatment of mammary gland hyperplasia (MGH) and menopausal syndrome. However, its pharmacokinetics remains unclear. This study developed a sensitive and rapid method for simultaneous determination of 10 compounds of HHXYT in rat plasma by liquid chromatography-tandem mass spectrometry and to compare the pharmacokinetics of these compounds in MGH rats and sham operated rats. The linearity, accuracy, precision, stability and matrix effect were within acceptable ranges. This established method was successfully applied to a pharmacokinetics study of 10 compounds in sham operated and MGH rats. According to the results, the bioavailability of glycyrrhetinic acid was highest in MGH rats and sham operated rats. The mean residence times of glycyrrhetinic acid and glycyrrhetinic acid 3-O-glucuronide were higher than those of the other compounds while the mean residence time and half-life of liquiritin, isoliquiritin and paeoniflorin were lower. Some pharmacokinetic parameters of ormononetin, liquiritigenin, isoliquiritigenin, liquiritin, isoliquiritin, paeoniflorin, protocatechuic acid and senkyunolide I were significantly different between MGH rats and sham operated rats. This study elucidated the dynamic changes of multiple components in rats after oral administration of HHXYT systematically and comprehensively, which provided guidance for clinical application.

Accurate determination of sorghum origin based on hyperspectral imaging technology and machine learning

AbstractSorghum is an important crop, and the quality of sorghum of the same variety from different geographic origins varies greatly. This study focuses on HongYingZi sorghum from five distinct origins, employing a combination of hyperspectral imaging (HSI) technology and machine learning algorithms to investigate methods for classifying sorghum origin. Multiplicative scatter correction and the Savizkg‐Golay algorithms were used to preprocess HSI data, and the characteristic wavelengths were screened by the successive projections algorithm (SPA). Based on AdaBoost, ExtraTreesClassifier, Gradient Boosting, Decision Tree, and Random Forest algorithms, classification models based hyperspectral data were established respectively, and validation experiments were conducted. The results show that for the full‐band spectra, the ExtraTreesClassifier algorithm has the highest accuracy; the average accuracy on the training set and test set were 0.9925 and 0.9854, respectively. The classification results were visualized and analyzed using Python. The results highlight the effectiveness of HSI combined with machine learning algorithms in achieving nondestructive detection of sorghum origin within the same variety. This study provides a precise method for rapid and nondestructive determination of sorghum origin.

A greener, rapid and accurate microwave-assisted hydrogen peroxide digestion method for ICP-OES determination of heavy metals in pet food samples

Microwave-assisted hydrogen peroxide digestion (MW-AHPD) method for determination of Cd, As, Pb, Sn, and Cr in South African pet food samples by inductively coupled plasma-optical emission spectroscopic (ICP-OES) is reported. Multivariate tools and wheat flour certified reference material (FAP80467) assessed limiting factors and reproducibility of the methods respectively. The resulted optimum conditions were: 200 °C, 40 mins, 0.5 g, and 5 mol/L for temperature, time, sample mass and H2O2 concentration, respectively. The method demonstrated excellent accuracy (96–98%), reproducibility (≤ 2.1%) and high detection limits (0.0675–0.3765 µg/g). Then, real pet food samples made from maize, rice, vegetables, fish, and wheat were digested and concentration levels of Cd, Pb, As, Cr and Sn ranged between 11.2 and 22.6, 6.4–11.9, 3.44–13.4, 0.44–2.98 and 0.18–0.98 µg/g, respectively. The three metal ions were above the minimum tolerable limits (Cd: 10 µg/g, Pb:10 µg/g, As: 12.5 µg/g) for some of the fish and wheat based pet food according to the South African regulatory standard. Furthermore, using the AGREEPrep metric tool the method was assessed and had a score of 0.76, confirming its greenness. These findings present MW-AHPD method as an alternative for determination of heavy metals in pet food by ICP-OES.

Rapid determination of impurities in carbon dioxide for food by gas chromatography

This article describes the experimental principle and method of rapid determination of carbon monoxide, methane, propane, total hydrocarbon, methanol, ethylene oxide, acetaldehyde, vinyl chloride, benzene, and other common impurities in carbon dioxide by gas chromatograph. By using food additive carbon dioxide as a sample, the rapid analysis conditions, such as chromatographic column, valve switching time, and column box temperature control, were optimized. The retention time of impurity components in food additive carbon dioxide was determined using the external standard method. The relative standard uncertainty of CH4, C3H8, CO, CH3OH, CH2CH2O, CH3CHO, CH2CHCl, and C6H6 analysis is within 3% by using the established analytical method proposed in this article, which is equivalent to the national standard GB 1886.228-2016. The linear correlation coefficient r is greater than 0.9995, and the linear error is not greater than 2.0, indicating excellent linearity. In the meantime, in the case of 6 consecutive sample injections, the detection time is shortened by nearly three times. The experimental results show that the analytical method established in this article is suitable for the rapid determination of impurities in carbon dioxide for food, which can improve the accuracy of experimental results and work efficiency.

Developing a rapid analytical method for simultaneous determination of apigenin and gallic acid: validation and application in a nanoliposomal formulation

Objective Apigenin and gallic acid are natural compounds that are useful as antioxidant, anti-inflammatory and anticancer agents, especially when used together in combination. Therefore, the development and validation of a simultaneous method of analysis for both compounds in pure form and when encapsulated in an advanced delivery system such as liposomes would be useful. Methods Analysis was performed using C18 column under isocratic conditions. The mobile phase was acetonitrile: water containing 0.2% orthophosphoric acid at a ratio of 67:33, flow rate 1 ml/min, and detection wavelength 334 nm for apigenin and 271 nm for gallic acid. Results The assay method was linear at the concentration range (5–600 µg/mL) with R2 of 1 for both drugs. The method was also shown to be precise and robust with RSD less than 2% with LOD (0.12, 0.1 µg/mL) and LOQ (4.14, 3.58 µg/mL) for apigenin and gallic acid respectively. The method was also applicable for the determination of the entrapment efficiency of both drugs when co-loaded in a nanoliposomal formulation. Conclusion The described HPLC method was shown to be suitable, sensitive, and reproducible for the simultaneous identification and quantification of apigenin and gallic acid. The analytical results were accurate and precise, with good recovery, low limit of detection, and the chromatographic assay was accomplished in less than 3 min, suggesting the suitability of the method for routine analysis of both drugs in pharmaceutical formulations.

Stable and reproducible MIP-ECL sensors for ultra-sensitive and accurate quantitative detection of Estrone.

Estrone (E1), as an endogenous estrogen, has a variety of physiological functions in human body and is of great significance to human health. On the other hand, it is a widely distributed and highly disturbing environmental endocrine disruptor in water. Therefore, there is an urgent need to develop a sensitive, rapid, and inexpensive method for the on-site determination of E1, which is not only for clinical diagnosis and treatment, but also for the investigation and monitoring of endogenous estrogen pollution in environmental water. In this study, Ru(bpy)3 2+/MWCNTs/Nafion/gold electrodes were prepared by surface electrostatic adsorption and ion exchange. A molecularly imprinted membrane (MIP) with the capability to recognize E1 molecules was prepared by sol-gel method, and the electrodes were modified with MIP to form an electrochemical luminescence sensor (MIP-ECL). This method simultaneously possesses ECL's advantage of high sensitivity and MIP's advantage of high selectivity. Moreover, the addition of carboxylated multi-walled carbon nanotubes (MWCNT-COOH) improved the functionalization of the gold electrode surface and increased the binding sites of MIP. Meanwhile, the good conductivity of MWCNTs promoted electron transfer and further improved the sensitivity of the sensor. The sensor showed a wide linear interval in which the E1 concentrations can range from 0.1μg/L to 200μg/L, along with a high linear correlation coefficient (R 2 = 0.999). The linear regression equation of the sensor was Y = 243.64x-79.989, and the detection limit (LOD) was 0.0047μg/L. To validate our sensor, actual samples were also measured by the reference method (LC-MS/MS), and it was found that the relative deviation of quantitative results of the two different methods was less than 4.1%. This indicates that the quantitative results obtained by this sensor are accurate and can be used for rapid in situ determination of E1 in clinical samples and environmental water.