Clenbuterol (CL), salbutamol (SAL) and ractopamine (RAC) are the three common β-adrenergic agonists, which are the main hazards in food safety and affect human health through the food chain. A convenient and efficient method is urgently required to perform on-site detection of multiple β-adrenergic agonists to avoid frequent poisoning incidents. In this paper, a 2-directional lateral flow strip technique (2-directional LFS) is developed for rapid and simultaneous detection of CL, SAL and RAC with single sampling. Compared to the conventional lateral flow strip, this 2-directional LFS technique can realize simultaneous detection of three or more target analytes without any change of intrinsic simplicity of LFS. Furthermore, this 2-directional LFS can effectively avoid the potential intrinsic cross-reactivity among the reagents to analogues. Under the optimized conditions, CL, SAL and RAC were all successfully determined with satisfactory results in both buffer and urine samples with the detection limit as low as 0.5 ng/mL. This 2-directional LFS technique can revolutionize the commercial single-analyte LFS products and can effectively widen the applications of the classic LFS in various fields.

Two novel malonyl-based chemosensors, N,N′-bis(ethyl-4′-benzoate)-1,3-propanediamide (1) and N,N′-bis(ethyl-3′-benzoate)-1,3-propanediamide (2), have been synthesized and screened towards various biologically important metal ions such as Na⁺, Mg²⁺, K⁺, Ca²⁺, Al³⁺, Cr³⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Ag⁺, Cd²⁺, Hg²⁺, Ti³⁺, and Pb²⁺. The emission spectral studies of both 1 and 2 displayed 84 – 91% turn-off emission responses selectively with Fe³⁺ ion in aqueous buffer (MeCN/H₂O, 1:4, v/v, pH = 7.4) solution. Chemosensors 1 and 2 exhibited remarkable sensing ability towards Fe³⁺ ion over other metal ions with limit of detection (LOD) of 4.28 and 4.33 μM, respectively. The binding stoichiometry of 1 and 2 with Fe³⁺ ion was studied by Benesi–Hildebrand fitting, Stern–Volmer plot and Job’s plots, revealing that both chemosensors (1 – 2) bind with Fe³⁺ metal ion in 1:1 stoichiometric ratio with the apparent association constant (K_a) 8.90 × 10³ and 11.16 × 10³ M⁻¹, respectively. Furthermore, the interactions of chemosensors (1 – 2) with metal ion were also investigated by using density functional theory (DFT) at B3LYP hybrid functional using 6-31G and LanL2DZ basis sets.

Estazolam (EST) is a common sedative-hypnotic drug with a risk of abuse. Therefore, rapid on-site detection of EST is necessary to control the abuse of EST. In this paper, a fast, simple, and sensitive method is demonstrated for the detection of EST in both water and beverages, using surface-enhanced Raman spectroscopy (SERS) techniques. Au@Ag core-shell nanoparticles (NPs) assembled on the filter paper as a SERS substrate exhibit good applicability and practicality. At the same time, density functional theory (DFT) is used to assign the vibration mode of the EST molecules, which can be used as a guide for subsequent experiments. The lowest detectable concentration of EST in aqueous solution can be as low as 5 mg/L, and signal uniformity is excellent (RSD₆₈₇ = 5.56%, RSD₁₀₀₀ = 4.35%). In addition, EST components artificially added to orange juice and pomegranate juice can be effectively detected by simple pretreatment with a minimum detection concentration as low as 10 mg/L. Therefore, this study found that the use of Au@Ag core-shell nanoparticles paper-based SERS substrate provides a quick and easy method for the detection of illegally added drugs in beverages.

An analytical methodology has been developed and validated for the purpose of identifying and quantifying four parabens (methylparaben, ethylparaben, propylparaben and n-butylparaben) in water samples. The combination of rotating disk sorptive extraction (RDSE) technology with ultra-high performance liquid chromatography (UHPLC), along with electrospray ionization source (ESI) and time of flight mass spectrometry (TOF/MS) in trap mode, allowed for eliminating derivatization processes and a reduction of the chromatographic time required, achieving a greener analytical method. In this method, detection limits and precision (%RSD) were lower than 0.018 μg L⁻¹ and lower than 9.7% for all the parabens, respectively, being better than similar works. Matrix effect and absolute recoveries were studied in tap and sewage water samples to observe suppressions of the signals for all analytes, and absolute recoveries were around 60%. This methodology was applied to the analysis of two sewage samples (punctual and composite) obtained from locations in Santiago, Chile.

We propose a novel, ultrasensitive and low-cost sensor using reversible addition-fragmentation chain transfer (RAFT) polymerization as a signal amplification strategy for the detection of CYFRA 21-1 DNA fragment, a tumor marker of non-small cell lung carcinoma. The peptide nucleic acid (PNA) probes were firstly immobilized on magnetic beads (MBs) to capture the CYFRA 21-1 DNA specifically. After hybridization, CPAD was tethered to the hetero duplexes through carboxylate-Zr⁴⁺-phosphate chemistry. Subsequently, a number of fluorescent tags were introduced to the heteroduplexes through RAFT polymerization, leading to an amplification of the fluorescence signal. The sensor demonstrates a low limit of detection (LOD) of 0.02 fM. It has great selectivity with respect to base mismatch DNA, and high anti-interference ability in normal human serum. Overall findings of the study suggest that proposed sensor holds enormous potential to be used as a tool for the early-stage diagnosis of lung cancers.

A cholesterol mono-derivatized β-cyclodextrin was synthesized and bonded onto silica gel (SBA-15) to obtain a cholesterol mono-derivatized β-cyclodextrin-bonded stationary phase (CHCDP). The chemical structures of mono-derivatized β-cyclodextrin and CHCDP were characterized by infrared spectroscopy, mass spectrometry, elemental analysis and thermogravimetric analysis, correspondingly. Furthermore, the separation ability of CHCDP in terms of achiral compounds was systematically evaluated by separating benzene homologs, polycyclic aromatic hydrocarbons (PAHs) and some positional isomers. As a result, CHCDP completely separated five benzene homologs and nine PAHs within 30 min under the reversed-phase. In addition, the chiral chromatographic property of CHCDP was also evaluated by separating some racemic compounds including flavanones, triazoles, β-blockers, etc. The results showed that the CHCDP exhibited high enantioselectivities towards most of selected analytes. The enantioresolutions were in the range from 1.43 to 2.51 on CHCDP. Especially the resolutions of 2′-hydroxyflavanone, hexaconazole, Dns-serine and atenolol were as high as 1.94, 1.91, 2.15 and 1.57, respectively. Obviously, the CHCDP was a versatile stationary phase with chiral and achiral separation capabilities in multi-mode chromatography, which was related to the introduction of cholesterol to the port of cyclodextrin, enhancing the hydrophobic interaction of cyclodextrin with achiral compounds, while maintaining the inclusion complexation of it with chiral compounds as well.

Based on our previous work, we have constructed a new electrochemical biosensor to detect epidermal growth factor receptor (EGFR) gene mutation, which was a significant therapeutic effect predictor of target drugs for non-small cell lung cancer. In order to lower the detection limit to detect the small amount of EGFR gene status, we have employed lambda exonuclease (λ-Exo) to form a hybridization–digestion cycle. The reaction stages are depicted as follows: the target DNA hybridized with auxiliary DNA which had been modified with the λ-Exo recognition site; then, the double strands were cleaved by λ-Exo. The target DNA was released completely, and continued to hybridize with remaining auxiliary DNA, which formed a recycle for target reutilization. Finally, we detected the remaining auxiliary DNA to evaluate the amount or status of the EGFR gene. The reutilization of target DNA will help to achieve an enlarged signal with a small amount of target DNA, and the detection limit of the biosensor decreased down to 10 pM. Meanwhile, our assay can differentiate wild genes from the mutational gene of EGFR with excellent specificity. Our signal amplification method provides a research foundation for the detection system of the electrochemical biosensor by employing exonuclease, and impels the biosensor to be developed as a suitable method for EGFR detection in clinical applications.

An air-segmentation approach has been introduced to a feedback-based and subsequent fixed triangular wave-controlled flow ratiometry to suppress axial dispersion in flow titration. The flow rate of a base solution containing an indicator is linearly varied with a control signal, V_c, supplied by a computer. The solution is merged with an acid solution under a constant total flow rate. Air is introduced to the merged solution in order to segment the solution with air bubbles. Both phases are led to a UV/Vis detector without phase separation. Air signals are removed by signal processing. The effect of the lag time between the merging of solutions upstream and the sensing of the corresponding signal downstream is offset by feedback-based upward and downward V_c scans, and thus the V_c that gives the equivalence composition is determined. Subsequently, fixed triangular wave control is applied to a narrower V_c range with a higher scan rate to enhance the throughput rate (maximally 11.8 titrations/min). Air-segmentation has been found to be effective to reduce axial dispersion and to preserve the titrand/titrant composition upon their just being merged. Consequently, the applicable range is extended especially to lower titrand concentration. The proposed method has been successfully applied to various acid-base titrations, including the nonaqueous titration of the Japanese Pharmacopoeia drug.

A high-throughput screening method for the complexation between metal ions and drugs was established by combining solid-phase extraction (SPE) using a nitrilotriacetic acid (NTA) modified silica spin cartridge with subsequent HPLC analysis. First, a test metal ion solution was passed through the NTA cartridge, then a test drug solution diluted in phosphate buffered saline (pH 7.4) was passed through the metal-chelated NTA cartridge. The complexation behavior between the metal and the drug on the NTA cartridge was evaluated by HPLC quantification of the drug in the SPE eluate. Comprehensive analysis of the complexation behavior between 11 different metal ions and 55 drugs showed that Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Cr³⁺ and Fe³⁺ formed complexes with 12, 5, 4, 2, 1 and 1 kinds of drugs, respectively. Bromazepam selectively formed complexes with Cu²⁺, Ni²⁺ and Co²⁺.

A multiple channel-type concentric grid nebulizer (m-CGrid) was developed for realizing efficient online standard addition in inductively coupled plasma optical emission spectrometry (ICP-OES) without premixing of liquids before nebulization. The m-CGrid can nebulize two independent liquids without premixing due to a unique structure, having two independent liquid-flow capillaries inside a single nozzle and a grid screen (over 350 mesh per inch) placed on the hole of the nozzle. The grid acts as both a flow damper and sieve; two liquids are well-mixed with a gas flow in a small space just before the grid screen, and the mixture breaks up into small droplets by passing through the grid. The m-CGrid nebulizer provides almost the same or better spray performance compared with a conventional nebulizer, such as Meinhard nebulizer; the primary aerosols were much finer (D₅₀: 2.9 and 3.1 μm for two channels) than those generated with Meinhard nebulizer type C (D₅₀: 19.5 μm). The signal intensities in ICP-OES obtained with two liquid channels were almost the same and were 2- to 3-fold higher than that obtained with the Meinhard nebulizer for 23 elements. The performance of m-CGrid in an online standard addition was demonstrated in the analysis of NIST SRM1577b bovine liver and NIES No. 3 Chrorella. The analytical results were in good agreement with their certified values.

This present research applied the ATR-FTIR technique and principle component analysis (PCA) to investigate molecular surface changes in pre-carbonized solid biomass, called Kindai Bio-coke (BIC) and Japanese cedar. The product is utilized as an alternative to coal coke in the cupola furnace in the steel industry in order to reduce CO₂ emissions. The aim is to explore key elements for improving the BIC product applications from the fundamental molecular scale by using PCA to distinguish between changes during the BIC transformation and the differences in BIC samples. Results revealed that transformation occurred at the surface of Japanese cedar raw materials and Japanese cedar BIC. Major changes were observed in the O–H, C–H and C–O stretching regions. The intensity of the IR bands attributed to aliphatic methyl (CH₃) and methylene (CH₂) stretching modes increased, while a weak O–H stretching intensity associated with BIC hydrophobic characteristic decreased.

An intensive analysis of far-infrared (far-IR), low-frequency Raman, and wide angle X-ray diffraction (WAXD) data has been performed by two-dimensional correlation spectroscopy (2D-COS) as a function of the blend ratio of poly(3-hydroxybutyrate)/poly(4-vinylphenol) (PHB/PVPh). Homospectral 2D-COS revealed that a weak band at 128 cm⁻¹ in the far-IR spectra appeared more clearly in the 2D correlation spectra. Heterospectral 2D-COS (far-IR/low-frequency Raman and far-IR/WAXD) provided very important results that were hardly detected in the conventional 2D-COS. A far-IR peak at 130 cm⁻¹ in the heterospectral 2D-COS had negative correlations with the peaks in the low-frequency Raman spectra at 81, 100, and 110 cm⁻¹ and WAXD profile 8.78 and 11.01°. These results indicated that those peaks have different origins; the 130 cm⁻¹ peak comes from the intermolecular C=O···H–O hydrogen bond between PHB and PVPh, while those for low-frequency Raman and WAXD peaks are the features of PHB crystalline structure.

A clear and positive correlation between the CO₂ concentration and the blood-sugar level has been observed via a non-invasive and time-dependent monitoring of CO₂ concentration from human breath, which is carried out by using a home-made gas chromatography (GC)/milli-whistle compact analyzer. The time-dependent sampling of the CO₂ concentration correlated between 5.0 to 5.6% (1% = 10⁴ ppm) in accordance with blood-sugar level variations of 80 to 110 mg/dL. The analytical method results in a rapid, continuous and non-invasive determination of blood-sugar level via measurement of the CO₂ concentration exhaled from the lungs.

We describe here a magnetic molecular imprinted polymeric ionic liquid (MMIPIL) film by using a functionalized ionic liquid (3-vinyl-4-amino-5-imidazole carboxamide chloride, IL) and Fe₃O₄@Polyrutin–COOH as a functional monomer and supporting materials. The change in the direction of the charge density in the structure of MMIPIL polymer resulted in a red shift of about 100 nm for the characteristic group of –C=O. Polyrutin containing an electron-rich benzene ring and multiple hydroxyl groups not only prevented the aggregation of Fe₃O₄, but also benefitted to immobilize template molecules. More symmetric amino groups in the template molecules generated more hydrogen bonds and other synergistic effects between MEL and the functional monomers, which resulted in a highly-matched and highly stable MMIPIL sensor. The proposed magnetic sensor lowered the matching potential, and enhanced the signal for the detection of melamine (MEL) in milk powder. Under the optimum conditions, the MEL template molecule showed a significant linear relationship between 5.0 × 10⁻³ and 0.8 μg/L with a detection limit (S/N = 3) of 1.5 × 10⁻³ μg/L. The MMIPIL sensor showed wonderful selectivity and exhibited facile, fast and efficient results in the monitoring MEL with recoveries of between 96.5 and 108.3%.

Concentrated protein-like fluorophores of dissolved organic matter (DOM) in Lake Biwa were analyzed using sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis (2-DE). As a result, it was found that the protein-like fluorophores in Lake Biwa are likely to be dissolved proteins released from phytoplankton. SDS-PAGE analysis revealed that protein-like fluorophores from Lake Biwa usually consist of proteins with molecular weights of 33 – 35, 42 – 45, 56 – 59 and 62 – 66 kDa. The molecular weights (MWs) and isoelectric points (pIs) of dissolved proteins in Lake Biwa were firstly clarified using 2-DE. The 2-DE patterns of proteins in Lake Biwa were compared with those for algal DOM released from four kinds of lake phytoplankton, Microcystis aeruginosa, Staurastrum dorsidentiferum, Cryptomonas ovata, and Fragilaria capucina. Some of the protein spots in 2-DE of Lake Biwa were similar to those of algal DOM released during cultivation. The relations between monthly changes in the electrophoretic gel images of lake water samples and those in the community structure of phytoplankton in Lake Biwa were observed. These results suggest that some of the dissolved proteins in Lake Biwa are likely derived from phytoplankton.

This paper presents a study of the size distributions of colloidal nanoparticles using an online dynamic light scattering (DLS) unit with a uni-tau multi-bit correlator (UMC) combined with a centrifugal field-flow fractionation (CF3) separator. Conventionally, the FFF-UV-MALS system utilizing field-flow fractionation (FFF) combined with a UV detector and multi-angle light scattering instrument (MALS) could be used to obtain the particle size distribution of colloidal nanoparticles. Lately, DLS as a technique to measure the size distributions of colloid materials has become prevalent. However, the DLS instrument will practically measure only the large particles in a multi-modal particle mixture. Therefore, the CF3-DLS w/UMC system that was developed consisted of a CF3 unit connected to an online DLS instrument with UMC. The system could measure the volume- or number-based size distribution with highly quantitative and accurate histograms for multi-modal samples. The size distributions were validated with size distributions obtained by images of an atomic force microscope (AFM). Two types of colloidal silica nanoparticles with different distribution widths were used in this study.

Xylitol separation from a polyol mixture of the byproducts from bioethanol production processes was performed by liquid chromatography using short columns packed with lanthanide ion-loaded ion-exchange resins. Xylitol was successfully separated with sufficiently high resolution using adsorbents with medium rare-earth metal ions, such as Nd³⁺ and Sm³⁺. The adsorbents’ specific nature is explained by the so-called “gadolinium break,” which is known as a discontinuous behavior of thermodynamic parameters in complexation of the lanthanide series. From the observed behavior, the optimum lanthanide ions could be chosen to prepare appropriate adsorbents for ligand-exchange chromatography of given polyol mixtures.