Journal of Analytical Methods in Chemistry最新文献

Objective: Because the response of evaporating light scattering detector (ELSD) being in a nonlinear mode, there is no consensus on the method of calculating its relative correction factors (RCF), which limits the application of the quantitative analysis for multi-components by a single marker (QAMS) with LC-ELSD.

Methods: Using eight fructooligosaccharides of Morinda officinalis as a case study, the nystose (GF3) as a single standard was adopted to develop a QAMS method to simultaneously determine the other seven fructooligosaccharides with HILIC-HPLC-ELSD method. Six calculation methods of RCF were investigated to select the most reasonable method. The relative error of content between the QAMS and the external standard method (ESM) obtained from 30 batches of samples was used as an indicator to evaluate the six methods. Finally, a chemometrics analysis was performed to find the differential components among MO and its three processing products.

Results: It was first reported that only one calculation method was scientific for calculating RCF for the LC-ELSD method. The RCFs of GF3 to the other seven fructooligosaccharides (GF1-GF8) were obtained as 0.86, 0.91, 0.93, 1.05, 1.15, 1.12, and 1.18, respectively. The QAMS of eight fructooligosaccharides of Morinda officinalis was validated with good linearity (R ² > 0.9998) and accepted the accuracy of 95-105% (RSD < 1.81%) based on nystose. Finally, Morinda officinalis and its three processed products were distinguished and could be differed based on the content of the eight fructooligosaccharides.

Conclusion: The scientific calculation method of RCF would be of great significance for developing the QAMS method in Pharmacopoeia when performing the LC-ELSD method.

Hedera helix has been reported to contain a wide range of metabolites and produce many pharmacological effects. This research demonstrates the determination and evaluation of the phytochemical profiling of H. helix grown in central Vietnam. Methanolic extract of ivy had been analyzed by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). MS, and MS/MS experiments were manipulated using both negative and positive ionization modes to provide molecular mass information and production spectra for the structural elucidation of compounds. A total of 46 compounds including 24 triterpene saponins and other compounds were successfully identified of which four established saponin structures have been reported for the first time. This study has provided a base for building a quality control of the raw materials according to the profile of triterpene saponins and assessment of pharmaceutical ingredients of H. helix planted in Vietnam.

Point-of-care technology (POCT) is an important method in clinical testing in the future, which can achieve the purpose of rapid analysis. In this work, we assembled an electrochemical POC sensor for uric acid (UA) by surface modification of a screen-printed electrode. Copper nanowires were used as electrode modifiers to achieve high-performance electrochemical oxidation of UA. This electrochemical sensor can achieve linear detection of UA in the range of 10 μM to 2 mM. The detection limit of the sensor was calculated to be 2 μM. Although the detection performance of this sensor is not competitive with high-performance electrochemical sensors, it has been able to meet the needs of POC detection. At the same time, the sensor has excellent anti-interference performance. It has also been used successfully to test urine and serum samples from healthy and gout patients.

A simple, sensitive, and fluorescent immunoassay for the detection of prostate-specific antigen (PSA) based on horseradish peroxidase and silicon dioxide nanospheres as a signal amplification strategy has been described. In the design, the primary antibody (Ab₁) of PSA was first immobilized on the 96-well plates via physical adsorption between polystyrene and hydrophobic groups of the antibody molecule. The silicon dioxide nanospheres (SiO₂ NSs), with large surface area and good biocompatibility, were loaded with horseradish peroxidase (HRP) and horseradish peroxidase-labeled secondary antibodies (HRP-Ab₂) as signal amplification systems. In the presence of PSA, a sandwich-type immunocomplex composed of Ab₁-Ag-HRP-Ab₂ had been formed. Fluorescence technology was employed to obtain the response signal of the immunoassay in the L-tyrosine and H₂O₂ systems. Experiment results showed that a strong and stable fluorescent signal at 416 nm (excitation wavelength: 325 nm) was observed, and the changes in fluorescent intensity were related to the levels of PSA. Under the optimal conditions, the relative fluorescence intensity was linear with the logarithm of PSA concentration from 0.03 to 100 ng·mL^-1, with a detection limit of 0.01 ng·mL^-1 (at a signal/noise ratio of 3). In contrast to other fluorescent immunoassays, the sandwich-type immunoreaction based on the high binding ELISA plates has the advantages of being simple, stable, and easy to operate, high selectivity, small sample quantity, etc., which can be widely used in the selective detection of a variety of targets, from DNA to proteins and small molecules. Such fluorescent immunoassays should be feasible for the fields of molecular diagnosis and other life science fields in the future.

This study reports the construction of a novel SPME fiber based on chitosan and glutaraldehyde as coating material composites combined with high-performance liquid chromatography with an ultraviolet detector (HPLC-UV) for extraction and detection of phenobarbital. In this technique, the chitosan biopolymer, as a new coating of SPME fiber, was produced on the stainless-steel wire, using glutaraldehyde and phenobarbital as cross-linker and template, respectively. For comparison, a nonimprinted polymer was created using the same procedure to evaluate fiber selectivity (but without the addition of phenobarbital). The SPME-MIP fiber coating was characterized by field emission scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermal gravimetric analysis. The efficiency of fiber was then improved by adjusting the impact of numerous factors such as pH, extraction time, desorption time, desorption solvent, and stirring rate. The results showed that the proposed fiber has a linear range of 0.01-4 μg·mL^-1, and detection limit of 7.5 ng·mL^-1. The average recoveries in the four concentration levels for the spiked river and well water samples were 95.7 and 95.3%, with relative standard deviations of 3.8 and 5.9% for single fiber and between fibers, respectively.

In this study, a temperature programmed oxidation-infrared (TPO-IR) technique was improved and applied in the analysis of sulfur occurrence and genesis in phosphate rock. Phosphate rocks from three regions (KYP, ZJP, and WAP) were selected for the detection of sulfur species by TPO-IR combined with XRD, SEM, EDS, and XPS characterization. TPO-IR results show that the total sulfur contents of the three phosphate rocks were 2.14% for KYP, 1.18% for ZJP, and 1.06% for WAP. In the low-temperature area (<1000°C), TPO-IR detected that both KYP and WAP contain FeS with a characteristic temperature of about 513°C and their contents were 9.22‰ and 0.64‰, respectively. In high-temperature areas (>1000°C), the TPO-IR curves suggest that sulfate is the main sulfur species in the three phosphate rocks. Typically, the characteristic temperature near 1070^oC belongs to MgSO₄, and the characteristic temperature near 1290°C belongs to CaSO₄. Due to the incomplete TPO-IR database of sulfur reference materials at present, it is not possible to assign all sulfur species in high-temperature areas. However, in a sense, this research provides theoretical basis and experimental support for the application of the TPO-IR technique for the detection of sulfur species in other solid minerals.

According to the sixth edition of China's "New Coronavirus Diagnosis and Treatment Plan (NCDTP)," ReDuNing injection (RDN) was firstly introduced to treat severe and critical COVID-19, whereas its combination with broad-spectrum antibiotics was suggested to take with extreme caution and full reasons. Therefore, we aim to describe the pharmacokinetics of seven active phytochemicals and semiquantification of nine relevant metabolites in ReDuNing injection (RDN) after combining with cefuroxime sodium (CNa) for injection in rat plasma. Male Sprague-Dawley rats were randomly assigned to six groups, and they were intravenously administered, respectively, with different prescriptions of RDN (2 mL/kg) and CNa (225 mg/kg). At different time points (0.03, 0.08, 0.17, 0.24, 0.33, 0.50, 0.67, 1, and 6 h) after administration, the drug concentrations of iridoids glycosides, organic acids, and metabolites in rat plasma were determined using ultrahigh-pressure liquid chromatography coupled with linear ion rap-orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap-MS), and main pharmacokinetic parameters were estimated by noncompartment model. The results showed that there were differences in pharmacokinetic parameters, AUC_(0-t), T_1/2, C _max, CL of iridoids glycosides, and organic acids, after the intravenous administration of the different combinations of RDN and CNa. Moreover, different combinations of the injections also resulted in different curves of relative changes of each metabolite. The obtained results suggested that RDN and CNa existed pharmacokinetic drug-herb interactions in rats. The findings not only lay the foundation for evaluating the safety of RDN injection combined with CNa but also make contributions to clinically applying RDN injection combined with CNa, which works potentially against severe forms of COVID-19.

Qufeng Zhitong capsule (QZC) is a well-known Chinese patent medicine that has been widely applied for the clinical treatment of rheumatoid arthritis and other inflammatory diseases. To date, its material basis is still unclear, which has greatly limited its clinical application. In this study, by taking advantage of ultra-high-performance liquid chromatography tandem Q-Exactive Orbitrap high-resolution mass spectrometry, 16 chemical components such as gallic acid, protocatechuic acid, and neochlorogenic acid in QZC were characterized and unambiguously identified based on comparison with the corresponding reference standards. In addition, the correlation between the focused components and their corresponding raw herbs from QZC prescription was investigated. For the first time, the relationship between the components mentioned above and their anti-inflammatory activity was explored via network pharmacology analysis, and a visualized network of "medicinal materials-QZC-compounds-targets-pathways" was established. Based on the brief prediction results of network pharmacological analysis, ultra-performance liquid chromatography coupled with photodiode array detector method was validated in terms of linearity, limit of detection, limit of quantification, precision, repeatability, stability, and recovery test and was successfully employed to determine 16 compounds in 28 batches of QZCs, which confirmed the feasibility and reliability of the established method for the quantitative analysis of 16 compounds in QZC. Considering the content and bioactivity of the tested components, four compounds were recommended as candidate indicators for quality evaluation ultimately. The potential value of this study could not only support a quality evaluation of QZC but also provide a theoretical basis for further in-depth research of QZC in clinical research.

Nucleotide sugars, the activated forms of monosaccharides, are important intermediates of carbohydrate metabolism in all organisms. Here, we describe a method for the detection and quantification of UDP-glucose and UDP-galactose in maize in order to compare their metabolism in both wild-type and mutated plants. Triple quadrupole operating in a multiple reaction monitoring mode was used to quantify nucleotide sugars. The limits of detection for UDP-glucose and UDP-galactose were 0.50 and 0.70 ng·mL^-1, respectively. The recoveries of the method ranged from 98.3% to 103.6% with the relative standard deviations less than 6.3%. To prove the applicability of this method, we analyzed several sets of maize extracts obtained from different cultivars grown under standardized greenhouse conditions. All the results demonstrated the suitability of the developed method to quantify UDP-glucose and UDP-galactose in maize extracts.

To analyze pesticide residues, GC coupled with quadrupole-Orbitrap MS (GC-Orbitrap-MS) has become a powerful tool because of its unique characteristics of accurate mass full-spectrum acquisition, high resolution, fast acquisition rates, and overcoming matrix interference. This paper presents an efficiency evaluation of GC-Orbitrap-MS for identification and quantitation in the 352 pesticide residues analysis of chrysanthemum flowers in full-scan mode. A streamlined pretreatment approach using one-step extraction and dilution was used, which provided high-throughput processing and excellent recovery. The samples were extracted using acetonitrile. The extracted solution was purified by a Sin-QuEChERS Nano column to suppress the matrix in chrysanthemum flowers and determined by GC-Orbitrap-MS. The calibration curves for the 352 pesticides obtained by GC-Orbitrap-MS were linear in the range of 0.5-200 μg·kg^-1, with the correlation coefficients higher than 0.99. The limits of detection (LODs) and the limits of quantification (LOQs) for the 352 pesticide residues were 0.3-3.0 μg·kg^-1 and 1.0-10.0 μg·kg^-1, respectively. The average recoveries in chrysanthemum flower at three levels were 95.2%, 88.6%, and 95.7%, respectively, with relative standard deviations (RSDs) of 7.1%, 7.5%, and 7.2%, respectively. Lastly, the validated method and retrospective analysis was applied to a total of 200 chrysanthemum flower samples bought in local pharmacies. The proposed method can simultaneously detect multipesticide residues with a good performance in qualitative and quantitative detection.