Analytical Methods最新文献

Rapid and sensitive detection of citrus huanglongbing (HLB) is critical for the control of this devastating disease. In this study, we have evaluated using a piezoelectric finger (PEF) with a 0.4 mm probe to measure the elastic modulus of a leaf to detect HLB in four different species of citrus including grapefruit (GFT), pumelo (PUM), lemon (LEM), and Valencia orange (VAL). Diseased citrus leaves were harvested from trees testing positive for the presence of Candidatus Liberibacter asiaticus (Las), the causal agent of HLB, and included both symptomatic leaves, which were blotchy mottle or yellowing and asymptomatic leaves, which did not display outward symptoms. Healthy leaves were harvested from trees testing negative for Las. The results indicated that the PEF elastic modulus test exhibited an overall 94% sensitivity and 90% specificity against the Las status of the trees for all four citrus types combined. Comparative quantitative real-time polymerase chain reaction (qPCR) tests on the same leaves showed an overall 89% sensitivity and 100% specificity against the Las status of the trees. While a Cohen–Kappa coefficient of 0.81 was obtained between the PEF and qPCR predictions, suggesting a “strong” agreement between the PEF and qPCR tests, a more detailed examination indicated that PEF was more sensitive overall in detecting the Las positive trees than qPCR, particularly from asymptomatic leaves for which PEF was 96% sensitive versus 78% sensitive by qPCR, indicating the potential of using PEF for early detection of HLB.

Environmental monitoring faces increasing demands for rapid, sensitive, and cost-effective analytical methods to detect various pollutants. Three-dimensional (3D) printing technology has emerged as a transformative approach for fabricating electrochemical sensors, offering unprecedented flexibility in electrode design and potential for customization. This comprehensive review examines recent advances in 3D-printed electrochemical sensors for environmental analysis, focusing on manufacturing technologies, materials development, and surface modification strategies. We analyze various printing approaches, including fused deposition modeling, stereolithography, and selective laser melting, discussing their relative advantages and limitations for electrode fabrication. The review explores conductive materials development, from carbon-based composites to novel metal-containing filaments, and examines crucial surface modification techniques that enhance sensor performance. Key applications in environmental monitoring are evaluated, including the detection of heavy metals, pathogens, antibiotics, and organophosphates, with particular attention to analytical performance metrics and real-world applicability. Technical challenges are critically assessed, including limitations in printing resolution, material conductivity, and long-term stability. The review concludes by identifying promising research directions, such as the integration of advanced materials and the development of automated manufacturing processes, highlighting opportunities for improving sensor performance and commercial viability in environmental monitoring applications.

Correction for ‘Development of a novel UHPLC-UV combined with UHPLC-QTOF/MS fingerprint method for the comprehensive evaluation of Nao-Luo-Xin-Tong: multi-wavelength setting based on traditional Chinese medicinal prescription composition’ by Lina Wang et al., Anal. Methods, 2019, 11, 6092–6102, https://doi.org/10.1039/C9AY01975H.

Objective: To establish a rapid, convenient and accurate visual detection protocol for human adenovirus serotype 3 in children's respiratory infections based on LAMP–NALF. Methods: Adenovirus serotypes prevalent in the region (Changzhou City, Jiangsu Province, China) were analyzed by assessing the results of tNGS analysis of respiratory pathogens in children. On this basis, multiple sets of LAMP primers were designed for the adenovirus hexon gene as the detection target. Optimal primer combinations were further screened, and the composition of the reagent system and amplification procedures were improved to achieve efficient amplification. To realize an instrument-independent, fast-testing strategy, by combining NALF, which is based on the principle of lateral chromatography, small molecule antigens were modified for primers. Moreover, amplification products were bound to the corresponding antibodies on nucleic acid chromatography test strips for visualization. Finally, a series of tests were performed to validate the sensitivity, specificity, and methodological consistency of the LAMP–NALF assay. Results: Adenovirus infections in children in this region during this period were mainly caused by serotype 3. The optimal amplification temperature for optimal primers of LAMP was 65 °C. The combination of LAMP and NALF could detect femtogram-grade positive plasmid of the hexon gene; besides, there was no cross-reactivity with five other types of common respiratory pathogens in children. The agreement between the LAMP–NALF assay and tNGS/qPCR for detecting the adenovirus in 100 respiratory clinical specimens was 98%. Conclusion: The combination of LAMP and NALF can achieve rapid, convenient and accurate detection of human adenovirus type 3, which can provide a powerful support for the pathogenic diagnosis of adenoviral infections in children, thus contributing to the promotion of the development of point-of-care testing for pathogens.

Correction for ‘Strategies for the detection of site-specific DNA methylation and its application, opportunities and challenges in the field of electrochemical biosensors’ by Chenliu Ye et al., Anal. Methods, 2024, 16, 5496–5508, https://doi.org/10.1039/D4AY00779D.

Oxalyl chloride is widely used in industry. Due to its high toxicity, it can pose a serious threat to human health and the environment. Therefore, it is necessary to develop a convenient and reliable detection method. Herein, we report a novel ratiometric fluorescent probe for detecting oxalyl chloride. The fluorescence of the probe solution changes from red to yellow after O-formylation of the probe with oxalyl chloride, and the probe has a low detection limit, good selectivity, and short response time. Finally, a portable test strip based on the probe was prepared and successfully combined with a smartphone to detect oxalyl chloride in air.

Diamide insecticides are being widely registered worldwide, yet most of them lack established maximum residue limits (MRLs) in agricultural products. In this study, we combined a QuEChERS (quick, easy, cheap, efficient, rugged, and safe) extraction method with high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) analysis to simultaneously identify and quantify ten diamide insecticides in seven matrices for the first time. The method was validated in accordance with SANTE/11312/2021 guidelines, including sensitivity, linearity, trueness, and precision. Excellent linearity (R² > 0.99) was obtained for all diamide insecticides within the concentration range of 5–1000 µg kg⁻¹. The limit of detection (LOD) and limit of quantification (LOQ) were 0.01–1 µg kg⁻¹ and 5 µg kg⁻¹, respectively. The recoveries of the ten diamide insecticides at three levels (5, 100, and 1000 µg kg⁻¹) ranged from 76.6% to 108.2% with good intra-day relative standard deviation (RSD_r) (1.0–13.4%) and inter-day relative standard deviation (RSD_R) (2.3–15.7%). The proposed method was applied to analyze 70 real agricultural product samples, and only six samples contained diamide insecticides. The results demonstrated that the method was both convenient and reliable for detecting diamide insecticides in agricultural products. The method was then applied to analyze agricultural product samples collected in a field trial to estimate the MRLs for the next step.

Retraction of ‘Application of new N- and S-doped amorphous carbon in D-μSPE and its combination with deep eutectic solvent-based DLLME for the extraction of some mycotoxins from soymilk’ by Anahid Rezaeefar et al., Anal. Methods, 2021, 13, 4604–4613, https://doi.org/10.1039/D1AY01057C.

This study introduces an in situ sorbent formation dispersive solid-phase extraction method for the simultaneous extraction of seven metal ions (V, Cr, Ni, Cu, Zn, Cd, and Pb) in petroleum samples. For this purpose, a home-made extraction device was used to perform the method on a relatively high volume of sample solution. The method employed cyclen as both a sorbent and a chelator. Also, a magnetic ionic liquid was used as the collection/dissolution solvent. Rigorous optimization yielded a wide linear range, low detection limits, good precision (relative standard deviations ≤8.5%), and high extraction recoveries (56–72%). The method's performance was validated in real petroleum samples from Iraq and Iran, demonstrating its applicability, accuracy, and robustness against matrix effects. The method was successfully utilized for the determination of target metal ions in real samples.

In general, insects are considered pests in agricultural areas, and their control is essential for high productivity of the cultivated areas. Control of these insects can be achieved by the inhibition of enzymes present in the insect's body. The enzyme acetylcholinesterase (AChE) is present in the neuromuscular junctions of vertebrates and invertebrates, and it is an important target for pest control. Herein, we present the development of a disposable electrochemical biosensor based on AChE (Bio-AChE) to rapidly evaluate the presence of new potential inhibitors in crude extracts of plants. Bio-AChE was constructed by modifying the disposable screen-printed carbon electrode (SPCE) with glutathione-decorated gold nanoparticles on which AChE was covalently immobilized. Electrochemical studies confirm the effective immobilization of the enzyme, and the Bio-AChE was applied to assess the inhibitory activity of azadirachtin, obtained from Azadirachta indica, which is a well-known AChE inhibitor. The proposed biosensor showed excellent results, demonstrating the inhibition activity of azadirachtin against AChE. The crude extracts of Picramnia riedelli, P. ciliata, and Toona ciliata were evaluated with the Bio-AChE, and all showed inhibition percentage values of around 50%. The extracts were evaluated by ¹H NMR spectra, which identified classes of natural compounds that could be responsible for the inhibition activity. The proposed disposable Bio-AChE was shown to be a reliable method for simple and rapid screening of new inhibitors in plant extracts, opening an avenue for the screening of new natural products with potential for pest control.