Analytical Letters

Avan, Asiye Aslıhan; Filik, Hayati

doi: 10.1080/00032719.2024.2307457pmid: N/A

Abstract This work evaluates the electrochemical performance of copper and nitrogen codoped Ti3C2T x MXene (or Cu@N − Ti3C2T x ) for purine sensing. Aniline/cupric ion solid complex was synthesized by reaction of aniline with CuCl2 (Cu(aniline)2Cl2). Subsequently, the obtained CuCl2-aniline coordination complex was mixed with Ti3C2T x MXene and carbonized in an autoclave. Subsequently, a new electrochemical sensor was designed based on a hybrid of Cu/N-codoped Ti3C2T x MXene on a glassy carbon electrode modified to be a Cu@N − Ti3C2T x electrode. The nanomaterials were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy techniques. The analytes were determined using differential pulse voltammetry. The detection limits were 0.01 for adenine and 0.02 μM for guanine, while the linear response ranges of both analytes were from 0.1 to 10 μM. This sensing device has been further employed in the individual and simultaneous detection of adenine and guanine in artificial sweat with 98–102% recoveries.

Subak, Hasret

doi: 10.1080/00032719.2024.2308051pmid: N/A

Abstract Two sequences of DNA (single-strand DNA (ssDNA) and double-strand DNA (dsDNA)) modified disposable electrodes were designed to investigate the effect of antitumor agent drug idarubicine (IDA) on the DNA chain structure. The effect of IDA on DNA structure was analyzed by square wave voltammetry (SWV) depending on not only the guanine signal but also IDA oxidation response. The present study included the electrochemical investigation of IDA and the investigation of the biomolecular interaction between IDA and DNA. IDA was detected in buffer and urine using disposable pencil graphite electrodes (PGE) with SWV and cyclic voltammetry (CV)). The detection limit (LOD) of IDA in urine samples was 0.089 µg mL−1 with SWV under optimum conditions. For the biomolecular interaction of IDA and DNA, all electrochemical conditions, such as the concentration of DNA, concentration of IDA, interaction phase (at electrode surface/in solution phase), the interaction pH, and the interaction time were optimized. IDA interacted biomolecularly with DNA at the electrode surface and in solution phase using two methods. There is no previous electrochemical study performed on the interaction of IDA with ssDNA. Hence, the effect of IDA on both ssDNA and dsDNA was presented for the first time.

Lou, Xuerui; Li, Minglei; Guo, Weiwei; Fu, Yingjie; Xi, Hui; Li, Peng; Zhao, Wuduo; Sun, Shihao

doi: 10.1080/00032719.2024.2308054pmid: N/A

Abstract Electronic cigarettes (E-cigarettes) have become popular around the world. An important reason is the variety of available flavors. However, many countries have imposed restrictions on flavor substances in E-cigarettes due to their potential health risks. Therefore, it is necessary to develop an effective way to identify flavorings in E-cigarette liquids. In this work, direct analysis in real time-mass spectrometry (DART-MS) in the quick strip (QS) mode was developed and applied to determine flavorings in the E-cigarettes. Vanillin, ethyl vanillin, maltol, and ethyl maltol were quantified. Meanwhile, the ionization efficiency of flavorings in the different solvents was compared in the QS mode, which revealed that the solvent boiling point was related to the analyte ionization efficiency. The effect of endogenous matrix (propylene glycol and glycerol) on flavoring ionization was also investigated. Calibration curves with satisfactory linearity (R 2 > 0.99) were established from 1 to 1000 μg L−1. Good sensitivity (limits of detection [LODs] < 0.3 μg L−1), recoveries (92.6% to 104.7%), and acceptable repeatability (relative standard deviations < 14.6%, n = 5) were obtained. The limits of quantification (LOQs; 10–50 μg g−1) for the E-cigarette liquid sample were much lower than the regulatory limits. The developed method provided a simple way for rapidly determining flavorings in E-cigarettes.

Yang, Chengbo; Cai, Zhilong; Li, Qingzhi; Tang, Feng; Wu, Jingjun; Yang, Jia; Zhang, Yurong; Li, Bo; Yang, Ping; Ye, Xin; Yang, Liming

doi: 10.1080/00032719.2024.2308071pmid: N/A

Abstract Spectroscopy has become prominent in medical surveillance due to its low cost, speed, and nondestructive testing. However, the issue of class unbalance in medical data causes existing algorithms to favor the majority classes, leading to their malfunction. This study attempts to propose a parallel type method based on two modified feature selection methods to achieve visible spectral discrimination of unbalanced urine specific gravity (USG) data. Firstly, the root mean square error (RMSE) of successive projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS) were modified by increasing weight coefficients. Then, SPA, CARS, modified SPA (mSPA), modified CARS (mCARS), tandem connection of SPA and CARS (CARS-SPA), tandem connection of mSPA and CARS (mCARS mSPA), parallel connection of SPA and CARS (CARS + SPA), and parallel connection of mSPA and CARS (mCARS + mSPA) were used to select characteristic wavelengths from the full spectrq. Finally, based on the variable subsets extracted by each method, the random forest (RF) models were established to verify the performance of the parallel strategy and modification method. The results showed that the RF model of mCARS + mSPA achieved effective discrimination of USG with high accuracy (92.81%), high sensitivity (0.9270), and high resolution (0.9280). It means that a parallel hybrid based on two modified feature selection methods can effectively select feature wavelengths beneficial for minority class recognition, achieving the mining of spectral features of unbalanced data. At the same time, this study also provides a novel example of the strategy of parallel feature selection methods.

Tang, Xiangkai; Li, Huaiping; Ye, Shanrong; Tian, Wei; Sun, Yujie; Chen, Lu; Zhou, Lili

doi: 10.1080/00032719.2024.2308078pmid: N/A

Abstract Juvenile hormone III (JH III) maintains larval characteristics in insects and promotes ovary development in adults. Hydroprene, kinoprene, and methoprene are synthesized analogs based on natural JH III. A novel and precise method was established to mitigate the matrix effects and concurrently determine these juvenile hormone analogs in tea employing gas chromatography-tandem mass spectrometry (GC-MS/MS). Water addition as a sample extraction approach was utilized and contrasted with protocols excluding water. Concurrently, the sought compounds underwent extraction with 1% (v/v) acetic acid-acetonitrile, followed by purification utilizing 0.1 g graphitized carbon black (GCB), 0.4 g primary secondary amine (PSA), and 0.4 g C18. Following separation via a DB-17MS column, detection of the analytes was conducted through GC-MS/MS in dynamic multiple reaction monitoring (DMRM) mode with quantification by a matrix-matching standard curve. Satisfactory linear relationships were established for the trio of juvenile hormone analogs within a 0.01–0.32 mg/L range, exhibiting correlation coefficients (R2) exceeding 0.999 and quantitation limits (LOQs) approximately spanning 0.005–0.01 mg/kg. Mean recoveries, spanning three concentrations (0.02, 0.1, 0.2 mg/kg), varied between 77.6% and 115.9%. The relative standard deviations (RSDs, n = 6) were from 0.5% to 5.8%. Detection of the juvenile hormone analogs was accomplished in tea samples. In summary, this investigation demonstrated a proficient approach in addressing complications by diminishing the matrix effects in a complex sample.

Vijayan, Anupama; Prakash, John

doi: 10.1080/00032719.2024.2308785pmid: N/A

Abstract The global practice of blending bioethanol with petroleum fuels serves the dual purpose of reducing fuel costs and mitigating vehicular emissions. However, variations from the stipulated amount of bioethanol in petroleum fuels can be detrimental to engine longevity and performance. Notably, portable analytical devices capable of swiftly and accurately assessing fuel samples without necessitating prior pretreatment have been developed by researchers. This review aims to elucidate the advances and prevailing trends in analytical tools such as electrochemical, spectroscopic, electrical, optical fiber-based, and physical parameter-based techniques for the determination of blended fuel composition.

Qin, Haixiao; Dong, Yang; Cui, Houxin; Deng, Jiachun; Ma, Junjie

doi: 10.1080/00032719.2024.2309330pmid: N/A

Abstract Oil spills cause serious harm to aquatic ecosystems, so rapid and accurate monitoring is needed to take timely action. Traditional methods usually use satellite remote sensing, buoy sensors, or unmanned aerial vehicles (UAVs). Satellite remote sensing is affected by resolution, transit time, and weather conditions, so it is impossible to monitor oil spills in small-scale and inclement weather conditions continuously and accurately. Buoy monitoring is a point-based measurement, unable to obtain the oil spill distribution, UAVs are limited by endurance time, and cannot conduct long-term monitoring. Here shore-based hyperspectral scanning image technology is proposed, which combines hyperspectral image and remote sensing technology with high resolution and spectral extraction capabilities. This method provides long-term, high-frequency, and real-time monitoring, forecasting, and early warning. A shore-based hyperspectral imaging device was developed to complete the actual field data acquisition and model verification in Three Gorges of China. The results show the precision of oil spill recognition is 84%, and the oil spill recall rate is 89% using the developed weighted CatBoost oil spill classification. The water recognition is close to 100%. The recall rate is also near 100%. The average relative error of oil spill thickness based on the multi-scale continuous wavelet transform model is 23.1%, which shows that the method is effective and can be extended in the oil-spill monitoring for ports, factories, and pipelines.

Lei, Kang; Wang, Ke

doi: 10.1080/00032719.2024.2310624pmid: N/A

Abstract In sports, noninvasive analysis and monitoring of the human health condition are important to ensure the well-being of the sportsperson and prevent injuries. Multiple biomarker-related substances in body fluids can serve as physiological information and health or health status indicators to detect possible dangers to the athlete. As the glucose content in perspiration may vary with gender and the parts of the body, it is important to develop a highly sensitive and selective glucose detection method. Here, CdTe quantum dots (QDs) are wrapped with a zeolitic imidazolate framework (ZIF-8) to create a fluorescence sensor platform (QD@ZIF-8), which is successfully employed for the determination of glucose levels in human perspiration. The synthesis of QD@ZIF-8 is quickly and easily achieved at room temperature through a one-step process. The resulting platform exhibits strong fluorescence, emitting at a wavelength of 587 nm when excited at 360 nm. The application of ZIF-8 as a transition layer to envelope the CdTe QDs effectively provide chemical and thermal stability, excellent dispersibility, and size selectivity. The sensor is utilized to measure perspiration glucose levels in a diverse group of male and female subjects, revealing significant differences in perspiration glucose concentrations.

Valdez, Carlos A.; Hok, Saphon; Cho, David S.; Vu, Alexander K.

doi: 10.1080/00032719.2024.2310630pmid: N/A

Abstract In the field of chemical warfare agents (CWAs), ethanolamines are important building blocks for the preparation of nerve agents belonging to the V-series such as VX and VR as well as the nitrogen-based mustards. In this work, the determination of three members in this class of Schedule 2B reportable chemicals, namely N,N-dimethylethanolamine (DMEA), N,N-diethylethanolamine (DEEA), and N,N-diisopropylethanolamine (DIEA) by electron ionization gas chromatography-mass spectrometry (EI-GC-MS) is presented. The three dialkylethanolamines were spiked in a high organic content soil matrix featured during the 45th Organization for the Prohibition of Chemical Weapons (OPCW) proficiency test (PT) at two separate concentrations each (1 and 10 µg/g separately), simulating values often encountered during these tests. The N,N-dialkylethanolamines were O-alkylated using benzyl bromide and sodium carbonate at 55 °C and were detected as their benzylated versions by electron ionization GC-MS. The benzylation of each dialkylethanolamine yielded derivatives with higher molecular weight and therefore different GC-MS profiles such as longer retention times and sharper peak chromatography relative to their unmodified counterparts. These characteristics enable the analytical chemist to detect and confirm these important CWA-related chemicals specifically in instances where they are present in low concentrations (i.e. <10 µg/g) among more abundant interferences.

Wang, Rong; Lin, Tingting; Nie, Qiyang; Qin, Caihong; Luo, Yougang; Wang, Ruijuan; Wang, Shulong; Jing, Yiqi

doi: 10.1080/00032719.2024.2310640pmid: N/A

Abstract Hexa-peri-hexabenzocoronene (HBC) modified glassy carbon electrodes (HBC/GCEs) was fabricated by an electrochemical synthesis, solving the difficulty of the preparation of HBC films because of its poor solubility. HBC/GCE was used as a sensing electrode for the voltammetric investigation of imidacloprid (IDP). The presence of HBC increased the conductivity of GCE, and showed good electrocatalytic activity toward the reaction of IDP. Therefore, the HBC enhanced the electrochemical signal of IDP, which increased the sensitivity of the sensor. The best performance was obtained by optimizing the electrochemical synthesis time, pH and enrichment time. The linear response range and the limit of detection were 5 to 750 μmol·L−1 and 1.5 μmol·L−1, respectively. Moreover, the proposed sensor also exhibited good repeatability, selectivity and stability, and promising applications for real sample.