Journal of Analytical Methods in Chemistry最新文献

Precise and efficient identification of single-stranded nucleic acids is crucial for both pathological research and early diagnosis of diseases, such as cancers. Therefore, we have devised a novel biosensor that utilizes an elegantly designed handgrip-ring structure sensing probe to enhance the detection sensitivity and reduce background signals. The handgrip-ring structure sensing probe combines ring padlock-based target recognition and hairpin structure probe-based signal amplification. The target sequences form a binding interaction with the ring padlock in the sensing probe, leading to the elongation of the single-stranded chain with the assistance of polymerase. This elongation step results in the release of the hairpin probe, triggering a signal amplification process. This design significantly minimized the potential discrepancies that may occur during the signal amplification process, hence bestowing the approach with a low level of background signals. By utilizing this innovative design, the current biosensor demonstrates a remarkable ability to detect miRNA with a limit as low as 376 aM and single-stranded DNA sequences with a limit as low as 45.3 aM. In addition, it possesses exceptional discrimination capabilities. The efficacy of this approach in diagnosing targets was also effectively proved by the rational redesign of the ring padlock.

Inspired by the popular h-index in bibliometrics, the h-accuracy index (HAI) was suggested as a new indicator to evaluate and compare errors in analytical chemistry. The HAI simultaneously considers the "trueness" of analytical measurements and the frequency of measurements with high "trueness". The HAI was defined as if the "trueness" of at most M% of the total measurements is no less than M%, the value of HAI will be M%, where a specific definition of "trueness" was given to compute the HAI. The range of the HAI was between zero and one. The HAI was applied to two examples as a new error index: (1) to evaluate and compare the analytical results by different methods/labs and (2) to evaluate and compare the prediction performances of different multivariate calibration models. Data analysis indicated that the HAI was a reasonable, robust, easy-to-compute, and comprehensive index for evaluating and comparing errors in analytical chemistry. Moreover, the HAI could provide the information about how many measurements are good.

Yiwei decoction (YWD) is a classic prescription with the function of nourishing stomach yin. In this study, the effective components of antioxidant activity of YWD and its possible mechanism were discussed from the point of view of spectral effect relationship and network pharmacology. Firstly, the fingerprints of 10 batches of YWD were established by UPLC-PDA technique, and the 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) scavenging rate and total antioxidant capacity (T-AOC) were used as the indicators for antioxidant activity in vitro. Then, the spectral effect relationship between the fingerprint profiles and antioxidant capacity was analyzed through grey relational analysis (GRA) and orthogonal projections to latent structures (OPLS). In addition, network pharmacology was employed to predict the potential mechanisms of YWD in the treatment of antioxidant-related diseases. The spectrum-effect relationship indicated that three common peaks were likely to be the most decisive active components, identified as verbascoside, psoralen, and vitexin, respectively. Based on network pharmacology analysis, a total of 83 target genes shared by the active components and antioxidant-related diseases were collected. AKT1, HSP90AA1, SRC, CASP3, and MTOR were closely related to antioxidant therapy and considered as core therapeutic targets. The potential mechanisms of YWD were obtained through gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Finally, molecular docking simulations were conducted to evaluate the binding activities between the core therapeutic targets and corresponding compounds. The excellent core protein-compound complexes obtained by molecular docking were simulated by molecular dynamics simulation. The results showed that the active compounds had good binding ability with the selected targets. This study successfully identified the effective components of YWD and predicted the potential targets and pathways, which provided a new idea for the application of YWD in the treatment of antioxidant stress in the future. In addition, the potential active components provide valuable implications for drug screening of related diseases.

To characterize volatile organic compounds (VOCs) and aromatic sensory properties in Yun cigar, 27 samples from four origins were analyzed using SPME-HS-GC/MS and sensory analysis. The investigation results were analyzed using principal component analysis (PCA), Fisher linear discriminant analysis (LDA), and Pearson correlation analysis. In Yunnan cigars, the content of nicotine and neophytadiene accounted for over 90% of the total VOC content. Nicotine was significantly positively correlated with neophytadiene and phytol. The cigars from four origins were clearly classified by the PCA of VOCs. Four region discrimination functions were established through the LDA of 14 compounds, and the validation accuracy was 100%. The sensory descriptors with the highest geometric mean were woody, roasted, fresh-sweet, bean, and scorched. Acetophenone, megastigmatrienone A, and thunbergene were positively correlated with multiple aroma descriptors, while nicotine was negatively correlated with multiple aroma descriptors.

This work introduces a Nafion-coated copper(I) oxide nanoparticle electrode (Nafion/Cu₂O/GC) designed for the electrochemical detection of methanol (CH₃OH). The responses of the composite material toward CH₃OH were enhanced by the selective permeation of CH₃OH through the hydrophilic channels of the Nafion membrane in combination with the electroactivity of Cu₂O nanoparticles. The sensor displayed a linear detection range of 0.33-100 mM CH₃OH with a sensitivity of 0.17 μA·mM^-1 and a detection limit (3 s/m) of 0.10 mM. It exhibited excellent reproducibility with a relative standard deviation of <5%. The sensor's practical applicability was demonstrated through recovery studies on hand sanitizer samples, achieving ca. 100% recovery. The sensor was further used to elucidate CH₃OH adsorption on activated carbon, revealing that the process conforms to the Langmuir isotherm model.

The study assessed the concentration of natural radionuclides in soil samples from the Bambasi district in Ethiopia's Benishangul Gumuz region using a gamma-ray spectrometer equipped with a high-purity germanium (HPGe) detector. The measured activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K in soil samples varied from 46.2 ± 2.25 to 88.49 ± 5.73 Bq/kg, 73.4 ± 4.12 to 119.65 ± 8.45 Bq/kg, and 176.78 ± 8.63 to 396.71 ± 25.39 Bq/kg, respectively. The average concentration of ²³⁸U and ²³²Th exceeded the recommended worldwide population weighted average values of 32.0 and 45.0 Bq/kg, respectively, while the average concentration of ⁴⁰K was below the recommended value of 420.0 Bq/kg. The mean absorbed dose rate was calculated to be 91.6 ± 5.1 nGy/h, which is above the recommended safe value of 59 nGy/h. The average annual effective dose equivalents for indoor and outdoor exposure were determined to be 2.65 ± 0.14 mSv/y and 0.66 ± 0.1 mSv/y, respectively. The calculated mean values of the internal hazard index, external hazard index, and gamma index across all soil samples were 0.72 ± 0.05, 0.55 ± 0.02, and 0.72 ± 0.02, respectively, all below the recommended safe threshold of one. These findings suggest that the activity concentrations observed in the soil samples exceed safe levels, indicating the necessity for further investigation into radioactivity levels and epidemiological studies regarding potential hazards from high background radiation.

Aim: To establish the HPLC fingerprints for Feiqizhong tablets and to simultaneously determine fourteen contents in Feiqizhong tablets.

Methods: The analysis of the methanol extract of this drug was performed on a 30°C thermostatic Shimadzu Shim-pack GIST-C18 column (250 mm × 4.6 mm, 5 um), with the mobile phase comprising acetonitrile (A) -0.1% phosphoric acid (B) flowing at 1.0 mL/min in a gradient elution manner (0-10 min, 88% A; 10-30 min, 88%-50% A; 30-60 min, 50%-30% A; 60-65 min, 30% A; 65-70 min, 30%-88% A; 70-75 min, 88% A), and the detection wavelength was fixed at 246 nm.

Results: There were one hundred and five common peaks in the HPLC fingerprints of twenty batches of samples with similarities of more than 0.953. Among them, fourteen major active components with a high response value in the chromatogram were selected for quantification, including eupalinolide B, tanshinone IIA, chlorogenic acid, psoralenoside, isopsoralenoside, icariin, amygdalin, caffeic acid, calycosin-7-O-β-D-glucoside, salvianolic acid B, quercetin, psoralen, isopsoralen, and bakuchiol. Fourteen constituents showed good linear relationships within their own ranges (r ≥ 0.9985), whose average recoveries were 90.71-106.14% with RSD values of 0.23-1.22%.

Conclusion: A rapid and effective method for the separation and detection of components in Feiqizhong tablets is established, which can provide a basis for quality control and quantitative detection.

The analysis of toxic and essential elements in human matrices is used in clinical diagnostics and for biomonitoring of different populations to study related health outcomes. This work aimed to develop fast and reliable methods for the analysis of a broad range of elements in liquid human matrices, such as whole blood, serum, and urine, with a similar setup for the three matrices and different analysis needs. An easy and fast-forward dilute-and-shoot method for 33 elements (i.e., Ag, Al, As, B, Ba, Be, Bi, Cd, Ce, Co, Cr, Cu, Hg, I, Li, Mn, Mo, Ni, Pb, Pd, Pt, Sb, Se, Sn, Sr, Te, Th, Tl, U, V, W, Zn, and Zr) was developed. 200 µL of either sample material was diluted with an alkaline reagent to a volume of 4 mL in total. Sample dilution and preparation of matrix-matched calibration standards were performed in 48-well plates by an automated liquid handler. Diluted samples were analyzed by inductively coupled plasma mass spectrometry on a Perkin Elmer NexIon 300D ICP-MS instrument equipped with an ESI-FAST SC2DX autosampler in kinetic energy discrimination mode with helium as cell gas at either 4.8 mL or 5.7 mL and 1600 W RF generator power. The method validation results showed good accuracy for fresh human samples from an external quality assessment scheme with measured concentrations within the assigned concentration ranges. Good precision and reproducibility for most elements were demonstrated with variation coefficients below or far below 8% and 15% for whole blood, 8% and 10% for serum, and 10% and 10% for urine, respectively. The developed reagent and instrumental setup were applicable to all three matrices. This minimizes the risk of human errors when switching between analyses of the different sample matrices and allows a rapid and easy analysis of whole blood, serum, and urine within one day if needed. The method demonstrated robustness over time, withstanding minor changes in the preparation of working solutions and samples, instrumental analysis, and setup. Analysis of human real samples showed the method's applicability for 33 toxic and essential elements in whole blood, serum, and urine and at concentrations relevant to clinical diagnostics as well as biomonitoring.

A rapid and simple inductively coupled plasma atomic emission spectrometry (ICP OES) method was developed and validated for the determination of macroelements including calcium (Ca), phosphorus (P), potassium (K), sodium (Na), and magnesium (Mg) in Australian retail pasteurised milk. The milk samples were digested using the mixture of 70% HNO₃ and 30% H₂O₂ (2 : 1, v/v) in an open-tube digester block at 120°C for 4 h. The validated ICP OES method showed good linearity for all elements (R ² > 0.9993). The method limits of quantification (LOQ) for Ca, P, K, Na, and Mg were 19.85, 8.97, 100.8, 41.92, and 11.56 µg·g^-1, respectively. Recoveries were in the range of 91.54-116.0%. Repeatability and interday reproducibility expressed as the relative standard deviation (% RSD) was below 5.0%. The contents of macroelements in 6 retail pasteurised milk samples were between 1099.32 and 1348.65 µg·g^-1 (Ca), 914.01 and 1091.21 µg·g^-1 (P), 1362.76 and 1549.74 µg·g^-1 (K), 288.89 and 323.22 µg·g^-1 (Na), and 97.62 and 110.57 µg·g^-1 (Mg). Principal component analysis (PCA) revealed that retail pasteurised milk samples were distinctly separated into four groups on the first two principal components (PCs). The difference in the macroelement content between milk brands might be affected by milk regions.