We propose a rapid and label-free quantitative evaluation of anti-cancer drug efficacy in apoptosis using live cancer cells cultured on a sensor chip. The resultant custom-made, high-precision surface plasmon resonance (SPR) sensor monitors the inner mitochondrial membrane’s potential change (ΔΨ_m). For trans-membrane anti-cancer drugs to be effective, continuous potential changes arising from the crossing of the membrane by the drug of interest prevent ΔΨ_m monitoring. Herein, we report on a novel signaling echo method that avoids this disturbance; the cancer cells are incubated with a specific anti-cancer drug, with subsequent removal of the drug before SPR measurements. The cell reaction without any drug was monitored as the differential SPR angle rate of change for 10 min from 30 min after a sensor chip was set on a prism. The cell reaction after 60 min pre-incubation with a drug was significantly related to the conventional cell viability after 48 h (P <0.001).

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Two strategies to identify tumor cells were developed in this research via analyzing the activity of telomerase inside the cells, which is regarded as the mark enzyme of tumors. The lysate of cells was used to assay directly. In the electrochemical assay, the substrate of telomerase was incubated with the lysate, followed by PCR amplification of the elongated products. Then the oxidation peak current of guanine that existed in the hydrolyte of PCR products was used as a target to identify tumor cells. In the spectral assay, the lysate of cells was used to catalyze the elongation of the substrate of telomerase modified on the surface of gold nanoparticles. Due to the formation of G-quadruple structures after elongation and subsequent aggregation of gold nanoparticles, the changes in UV-visible spectra can also be utilized to identify tumor cells.

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A series of N-substituted pyrroles having phosphorylcholine with different methylene chain lengths between pyrrole group and phosphorylcholine group were synthesized and their electropolymerizations were performed in aqueous solution. The methylene chains were trimethylene (n = 3), pentamethylene (n = 5), nonamethylene (n = 9), and undecamethylene (n = 11), for 3-(1-pyrrolyl)propyl-2-(trimethylammonium)ethyl phosphate (5a), 5-(1-pyrrolyl)pentyl-2-(trimethylammonium)ethyl phosphate (5b), 9-(1-pyrrolyl)nonyl-2-(trimethylammonium)ethyl phosphate (5c), and 11-(1-pyrrolyl)undecyl-2-(trimethylammonium)ethyl phosphate (5d), respectively. Although electropolymerized films were produced from all pyrrole derivatives, thick and black polymer films were prepared from 5a, 5b and 5c. The pyrrole derivative with long methylene-chain 5d provided only colorless or slightly blackish thin film. Hemocompatibilities of the polymers from 5a, 5b and 5c were evaluated by platelet rich plasma (PRP) contacting studies and scanning electron microscopy (SEM) observations. The results indicated that these polymers have excellent hemocompatibility.

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A sensitive and selective spectrophotometric detection method for cysteine has been established in this paper. The assay is based on the displacement of single-stranded oligonucleotide (ssDNA) adsorbed on the surface of citrate-capped gold nanoparticles (AuNPs) by cysteine in 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid buffer solution (pH 7.2) and on the phenomenon of salt-induced AuNPs aggregation. Upon addition of cysteine, the red-to-blue color changes of the ssDNA-stabilized AuNPs associated with aggregation under high-salt conditions were easily observed with the naked eye. The absorption ratio at 520 and 600 nm was herein employed to quantify the AuNPs aggregation process. The calibration curve showed that the absorption ratio increased linearly over the concentration range of 0.1 − 1.3 μM with a limit of detection of 100 nM. Subsequently, the assay was successfully employed to determine cysteine in artificial and pharmaceutical injection samples.

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Implantable fine needle-type glucose sensors with an outer diameter of less that 0.2 mm were fabricated using a low-cost and non-animal origin polyamide, γ-polyglutamic acid (PGA) as a glucose oxidase (GOx) immobilizing material. Two types of PGA, γ-polyglutamic acid (PGAH) and γ-polyglutamic acid sodium salt (PGANa), were employed to prepare GOx immobilized film by the covalent attachment of GOx using water-soluble carbodiimide (EDC). Nafion/cellulose acetate composite film and polyurethane/polydimethylsiloxane composite film were employed as a permselective inner film and a biocompatible outer film, respectively. The procedure of enzyme-immobilized film fabrication affected the stability of the sensor; that is, GOx immobilized film prepared by pouring a mixture solution of GOx and EDC on a PGA precoated surface showed higher sensor stability than that prepared by pouring a mixture solution of GOx, PGA and EDC. Although, obvious differences in the sensor properties were not observed between the use of PGANa and PGAH, the electrode prepared with PGAH had a lower swelling degree. The glucose sensors prepared with both PGANa and PGAH were practically not affected by the existence of electroactive compounds, such as uric acid, and provided long-term stability for approximately 5 weeks. These sensors also showed good performance in horse serum.

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A capillary electrophoresis with electrochemical detection was developed for the simultaneous determination of three flavonoids (naringenin, rutin, quercetin) and ascorbic acid. It was found that naringenin, rutin, quercetin and ascorbic acid were well separated within 5 min in borate buffer solution (pH 8.6, 24 mM). The detection limit was 1.0 μM for naringenin, 8.0 μM for rutin, 2.0 μM for ascorbic acid and 0.5 μM for quercetin. The protocol was successfully applied for the determination of the analytes in rat serum and excrement. Recovery results ranged from 90.9 to 108.6%.

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Humic substances (HS) from well waters, fertilizers, and synthetic phenolic polymers were characterized by elemental and UV-VIS spectroscopic analyses. Capillary zone electrophoresis (CZE) with UV absorption detection was used to analyze the lignin-derived phenolic distribution in the degradation residues after alkaline CuO oxidation of HS samples. Eleven phenols with p-acetyl, vanillyl and syringyl substituents were selected to optimize the CZE parameters. For well waters and fertilizers, the content of phenolic fragments was in agreement with the findings of the elemental and spectroscopic measurements. Additionally, parameters derived from the vanillic acid/vanilline, syringyl acid/syringaldehyde, p-hydroxyl/vanillyl and syringyl/vanillyl ratios matched analogous studies on dissolved organic matter from natural waters and on humic acids from terrestrial substances. The amount of phenolic monomer bonded within two synthetic HS polymers was found to be 25.9% protocatechuic acid and 71.3% gallic acid.

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Third-hand smoking was quantitatively evaluated with a polymer-packed sample preparation needle and subsequent gas chromatography–mass spectroscopy analysis. The extraction needle was prepared with polymeric particles as the extraction medium, and successful extraction of typical gaseous volatile organic compounds (VOCs) was accomplished with the extraction needle. For an evaluation of this new cigarette hazard, several types of clothing fabrics were exposed to sidestream smoke, and the smoking-related VOCs evaporated from the fabrics to the environmental air were preconcentrated with the extraction needle. Smoking-related VOCs in smokers’ breath were also measured using the extraction needle, and the effect of the breath VOCs on third-hand smoking pollution was evaluated. The results demonstrated that a trace amount of smoking-related VOCs was successfully determined by the proposed method. The adsorption and desorption behaviors of smoking-related VOCs were clearly different for each fabric material, and the time variations of these VOCs concentrations were quantitatively evaluated. The VOCs in the smokers’ breath were clearly higher than that of nonsmokers’; however, the results suggested that no significant effect of the smokers’ breath on the potential pollution occurred in the typical life space. The method was further applied to the determination of the actual third-hand smoking pollution in an automobile, and a future possibility of the proposed method to the analysis of trace amounts of VOCs in environmental air samples was suggested.

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The combination of vapor-phase generation (VPG) and Fourier-transform infrared (FTIR) spectrometry was performed as an alternative analytical technique for the determination of water-soluble penicillin G (PENG). Samples were transferred into a heated reactor, and a potassium iodate solution was injected into the reactor. Carbon monoxide (CO) generated under these conditions was carried via a N₂ gas carrier stream inside the IR gas cell, and the corresponding FTIR spectra were continuously recorded as a function of time. Analytical measurements were made using the maximum absorbance of the CO band at 2170 ± 4 cm⁻¹. Various factors influencing the analytical signals were evaluated and selected. The figures of merit of the proposed method involve a linear calibration curve over the range of 3 to 320 mg L⁻¹, a limit of detection of 0.5 mg L⁻¹ and a precision of 2.6%. The method was successfully applied to PENG determination in pharmaceutical preparations.

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A simple discrete flow system for the photometric determination of iron using a glass syringe as a mixer of a solution and as a sample cell has been developed. The system was assembled from a coupler combining a light source (a light-emitting diode, LED), a glass syringe, a photodiode detector (PD) and two plastic core fiber optics. The reagent and sample solutions were sucked into a syringe, and were then mixed by a reciprocating motion of a plunger, or simply turning the syringe upside down several times, manually. After mixing, the absorbance of the solution was measured in situ. The analytical figures of this system and the mixing method were tested with a methyl orange solution and evaluated through iron(III) determination by a 1,10-phenanthroline method. The proposed system was applied to the determination of iron(III) using 1,10-phenanthroline and thiocyanate as chelating reagents and an off-line concentration method using an activated-carbon column. By this simple system, iron(III) in a river-water certified reference material (CRM), JSAC 0302-3, and river-water samples were successfully determined with a detection limit (3σ) of 20 μg L⁻¹.

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In this paper, we describe the fabrication and analytical characteristics of fluorescence-based copper ion-sensing glass slides. To construct the sensor, a naphthalimide derivative N-allyl-4-(bis(pyridin-2-ylmethyl)amino)ethylamino-1,8-naphthalimide (1) with a terminal double bond was synthesized and photo-copolymerized with 2-hydroxyethyl methacrylate (HEMA) on a glass surface treated with a silanizing agent. In the presence of Cu²⁺ at pH 7.24, the resulting optical sensor undergoes fluorescence quenching. Thus, the proposed sensor with visible excitation can behave as a fluorescent sensor for the selective detection of Cu²⁺. In addition, the sensor exhibits satisfactory selectivity, reproducibility and response time. The sensing membrane possesses a relatively long lifetime of at least 2 months. The linear response range covers a concentration range of Cu²⁺ from 4.0 × 10⁻⁷ to 6.0 × 10⁻⁴ mol/L and the detection limit is 2.0 × 10⁻⁷ mol/L. The determination of Cu²⁺ in river water samples shows satisfactory results.

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A disposable molecular valve, consisting of a membrane coated with alginate gel, which is partially cross-linked with Ca²⁺, was developed based on a volume change and/or dissolution of the gel in response to the cation concentration. The valve automatically opened upon an increase in the concentration of cations such as H⁺, Na⁺, Ca²⁺, Mg²⁺, Cu²⁺, or Al³⁺. The concentration where the valve opens was 1 × 10⁻⁴ to 2 × 10⁻⁴ M for Ca²⁺, Cu²⁺, and Al³⁺, but the solution volume passed vs. concentration increased in the order of Ca²⁺, Cu²⁺, and Al³⁺. For Na⁺ and Mg²⁺ the valve opening concentration was ca. 1 × 10⁻² and 1 × 10⁻³ M, respectively. Two mechanisms were proposed to account for the opening of the valve. One is due to a shrinking of the gel caused by cations; the other is due to dissolution of the gel. The former corresponds for the cases of Ca²⁺, Cu²⁺, and Al³⁺, and the latter does for Na⁺ and Mg²⁺. The valve closed over the pH range from 3 to 12, whereas it opened below and above this range. The effects of anions and pressure were also studied.

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A fully automated pretreatment system based on sequential injection solid-phase extraction (SPE) coupled to a graphite furnace atomic absorption spectrometer (Auto-Pret-GFAAS system) was developed to determine trace amounts of cadmium and lead. A handmade minicolumn packed with a chelating resin was used for the preconcentration of both metals. All protocol for the on-line SPE method was controlled by home-made software. A trigger switch that was placed next to the graphite furnace was used to synchronize the home-made software with built-in software in the GFAAS. One milliliter of sample solution was flowed through into the minicolumn, the analytes were collected and concentrated on the solid phase, and the analytes were eluted with nitric acid (3 M), and detected by GFAAS. The limits of detection (3σ) for cadmium and lead were 0.20 and 2.6 ng L⁻¹, respectively. The sample throughput was 47 h⁻¹ for 1 mL sample loading. The proposed sensitive method with the original Auto-Pret-GFAAS system was applied to the determination of cadmium and lead in tap water and in leached solutions from ceramic ware using 4% acetic acid.

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We describe a pretreatment method before determining the total fluoride in solutions containing tetrafluoroborate ion (BF₄⁻) with ion-selective electrodes (ISEs). BF₄⁻ was quantitatively converted to free fluoride by reacting with aluminum ions. The total fluoride concentration was then determined by ISE analysis without preliminary steam distillation using a tartrate- and tris(hydroxymethyl)methylamine (TRIS)-based total ionic strength adjustment buffer (TISAB). We investigated the effects of various factors on the decomposition of BF₄⁻ with aluminum ions, including the concentration of aluminum, pH, reaction temperature, and reaction time. The quantitative decomposition of BF₄⁻ was complete after 2 h at 50°C or 1 h at 70°C.

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The synergistic effect of 18-crown-6 derivatives, such as 18-crown-6 (18C6), cis-dicyclohexano-18-crown-6 (DC18C6) and dibenzo-18-crown-6 (DB18C6), on the extraction of trivalent lanthanoids (Ln³⁺) into an ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, with 2-thenoyltrifluoroacetone (Htta) was investigated. The extractability of lighter Ln³⁺ was enhanced by adding 18C6 or DC18C6, whereas no enhancement of the extractability was observed by adding DB18C6. Moreover, the synergistic effect by the crown ether (CE) was increased along with the decrease in the atomic number of Ln. In the synergistic extraction system, Ln³⁺ was extracted as cationic ternary complexes Ln(tta)₂(CE)⁺ and Ln(tta)(CE)²⁺, and it was suggested that the formation of the Ln(tta)(CE)²⁺ complex as an extracted species results in the large synergistic effect. This synergistic effect originated in a size-fitting effect of CE on complexation to Ln³⁺.

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A novel vector calibration method, hyperplane intercept, is proposed for grey analytical systems to resolve the concentrations of the chemical components from the multi-component data gained from attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. This method is capable of quantifying a particular component known to be present in the mixture without having to know the identity of the rest of the components. Through the target factor analysis (TFA), a section of the IR spectrum of the interested component is chosen to calculate the concentration by the proposed hyperplane intercept method. Results calculated from on-line ATR-FTIR spectroscopy data of cyclohexanone ammoximation process are used to illustrate the simplicity and efficiency of this proposed method.

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A green chemistry system that utilizes natural extract as an alternative reagent for determination of metal ions has been investigated. The extract of green tea, a common beverage, is used for quantification of iron. The green tea extract was prepared in acetate buffer pH 4.8 and could be used without further purification with a simple flow injection (FI) system. The intensity of iron-green tea extract complexes was monitored using a green LED photometer. The use of natural reagent combined with the simple FI-LED photometer set up offers an alternative low cost and rapid system for the determination of metal ions. Detection limit of 0.05 ppm of Fe(III) ion and sampling rate of 180 injections h⁻¹ were achieved. Application of this system to the analysis of iron in pharmaceutical samples was demonstrated, and the results agreed well with those from the AOAC method.

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The binding equilibrium of N-alkylpyridinium ions to nonionic surfactant micelles was investigated through the changes in the electrophoretic mobility of the alkylpyridinium ions in capillary zone electrophoresis. The binding constants thus determined increased with increasing molecular volume of the alkylpyridinium ions. However, the binding constants are small compared with the ones for the anionic alkylbenzenesulfonate and polynitrophenolate ions at the same molecular volume.

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This work proposes a flow system suitable for the rapid screening of formaldehyde contaminated in food. The system is based on the concept of a flow analyzer with a Hantzsch reaction. An operating procedure was developed for multiple tasking and high sample throughput. This resulted in a significant sample throughput of 51 samples h⁻¹. Under the optimized conditions, linear calibration from 10 to 100 μM was obtained. The system gave a limit of detection and a limit of quantitation of 0.06 and 0.10 mg kg⁻¹, respectively. The system was successfully applied to re-hydrated dry squids, vegetables and mushrooms.

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