Journal of Analytical Methods in Chemistry

Herein, a method was developed for the sensitive monitoring of carcinoembryonic antigen (CEA) by gold nanoparticles dotted prussian [email protected] core-shell nanocubes (Au NPs/[email protected]). First, a facile low-temperature method was used to prepare the uniform [email protected] core-shell nanocubes with the assistance of PVP, where PB acted as the electron transfer mediator to provide electrochemical signals, and the PANI with excellent conductivity and desirable chemical stability not only played the role of a protective layer to prevent etching of PB in basic media but also effectively improved electron transfer. Importantly, to further enhance the electrical conductivity and biocompatibility of [email protected] and to further enhance the electrochemical signal and capture a large amount of Ab₂, Au NPs were doped on the surface of [email protected] to form Au NPs/[email protected] nanocomposites. Subsequently, benefiting from the advantages of core-shell structure nanoprobes and gold-platinum bimetallic nanoflower (AuPt NF), a sandwich-type electrochemical immunosensor for CEA detection was constructed, which provided a wide linear detection range from 1.0 pg·mL⁻¹ to 100.0 ng·mL⁻¹ and a low detection limit of 0.35 pg·mL⁻¹ via DPV (at 3σ). Moreover, it displayed a satisfactory result when the core-shell structure nanoprobe-based immunosensor was applied to determine CEA in real human serum samples.

Ivermectin is a macrocyclic lactone widely used in veterinary medicine for its broad-spectrum antiparasitic properties. It has been proven to be effective and safe. The purpose of this study was to develop a high-performance liquid chromatography method with a diode array detector for ivermectin screening in feed and water for animal consumption. Furthermore, the objective was to quantify ivermectin levels that were higher than 0.5 mg/kg in solid matrixes and 0.1 mg/kg in water. Doramectin was used as process standard. Samples were extracted using solid phase extraction with silica and C-18 columns. The method involved the use of high-performance liquid chromatography (HPLC) with a diode array detector (DAD). The results were interpreted using a calibration curve built with ivermectin standards at multiple concentrations (0.5, 1, 2, 5, and 12.5 mg/kg). Statistical evaluation of data was done using ANOVA. The data analysis showed that the linear regression was highly significant (), the intercept values were not significantly different from zero, and the correlation coefficient values (>0.999) indicated excellent linearity. Further tests demonstrated that this method is also useful when studying soil matrixes. The soil was dried and analyzed in the same way as feed; the same recoveries were realized on the spiked samples. The method is easy, inexpensive, precise, and repeatable; it requires very small amounts of sample.

As one of the foods commonly eaten all over the world, eggs have attracted more and more attention for their quality and price. A method based on elemental profiles and chemometrics to discriminate between free-range and caged eggs was established. Free-range (n1 = 127) and caged (n2 = 122) eggs were collected from different producing areas in China. The content of 16 elements (Zn, Pb, Cd, Co, Ni, Fe, Mn, Cr, Mg, Cu, Se, Ca, Al, Sr, Na, and K) in the eggshell was determined using a inductively coupled plasma atomic emission spectrometer (ICP-AES). Outlier diagnosis is performed by robust Stahel–Donoho estimation (SDE) and the Kennard and Stone (K-S) algorithm for training and test set partitioning. Partial least squares discriminant analysis (PLS-DA) and least squares support vector machine (LS-SVM) were used for classification of the two types of eggs. As a result, Cd, Mn, Mg, Se, and K make an important contribution to the classification of free-range and caged eggs. By combining column-wise and row-wise rescaling of the elemental data, the sensitivity, specificity, and accuracy were 91.9%, 91.1%, and 92.7% for PLS-DA, while the results of LS-SVM were 95.3%, 95.6%, and 95.1%, respectively. The result indicates that chemometrics analysis of the elemental profiles of eggshells could provide a useful and effective method to discriminate between free-range and caged eggs.

Coal-fired power plant fly ash is a global environmental concern due to its small particle size, heavy metal content, and increased emissions. Although widely used in concrete, geopolymer, and fly ash brick production, a large amount of fly ash remains in storage sites or is used in landfills due to inadequate raw material quality, resulting in a waste of a recoverable resource. Therefore, the ongoing need is to develop new methods for recycling fly ash. The present review differentiates the physiochemical properties of fly ash from two coal combustion processes: fluidized bed combustion and pulverized coal combustion. It then discusses applications that can consume fly ash without strict chemical requirements, focusing on firing-associated methods. Finally, the challenges and opportunities of fly ash recycling are discussed.

Tetracycline is a broad-spectrum class of antibiotics. The use of excessive doses of tetracycline antibiotics can result in their residues in food, posing varying degrees of risk to human health. Therefore, the establishment of a rapid and sensitive field detection method for tetracycline residues is of great practical importance to improve the safety of food-derived animal foods. Electrochemical analysis techniques are widely used in the field of pollutant detection because of the simple detection principle, easy operation of the instrument, and low cost of analysis. In this review, we summarize the electrochemical detection of tetracycline antibiotics by bibliometrics. Unlike the previously published reviews, this article reviews and analyzes the development of this topic. The contributions of different countries and different institutions were analyzed. Keyword analysis was used to explain the development of different research directions. The results of the analysis revealed that developments and innovations in materials science can enhance the performance of electrochemical detection of tetracycline antibiotics. Among them, gold nanoparticles and carbon nanotubes are the most used nanomaterials. Aptamer sensing strategies are the most favored methodologies in electrochemical detection of tetracycline antibiotics.

Quantitative analysis of silicon tetrachloride, carbon disulfide, and dichloroethane concentrations to obtain vapor-liquid equilibrium data of the SiCl₄-CS₂ and SiCl₄-C₂H₄Cl₂ binary systems was established by Raman spectroscopy. The cheap glass sampling pipe was used as a carrier for Raman spectroscopy measurements. The Raman peak height of the internal standard was used to remove interference factors such as sampling pipe diameter, temperature, laser power, and other effects from the instrument. The peak height ratio between the Raman characteristic peak of the analyte and that of the internal standard was proportional to the analyte concentration. During the measuring process of vapor-liquid equilibrium data for the SiCl₄-C₂H₄Cl₂ binary system, the linear equation of y = 0.0068 + 0.75x with R² of 0.9939 was used for the determination of SiCl₄ concentration at the 422 cm⁻¹ band. The linear equation of y = 0.0019 + 0.2266x with R² of 0.9966 was used for the determination of C₂H₄Cl₂ concentration at the 754 cm⁻¹ band. For the SiCl₄-CS₂ binary system, the linear equation of y = 0.0494 + 4.7535x with R² of 0.9962 was used for the determination of SiCl₄ concentration at the 422 cm⁻¹ band. The linear equation of y = 0.8139 + 8.7366x with R² of 0.9973 was used for the determination of CS₂ concentration at the 654 cm⁻¹ band. The concentration of standard samples calculated by these standard curves was compared with the actual value to verify the accuracy of this method. The reproducibility is good when determining silicon tetrachloride and dichloroethane concentrations for the SiCl₄-C₂H₄Cl₂ binary system, with RSEP values of 2.81% and 2.17%, respectively. Meanwhile, the RSEP values are 3.55% and 4.16%, respectively, when determining silicon tetrachloride and carbon disulfide concentrations for the SiCl₄-CS₂ binary system.