A novel emission excitation source comprising a high repetition rate diode-pumped Q-switched Nd:YAG laser and a Grimm-style glow-discharge lamp is described. Laser-ablated atoms are introduced into the He glow discharge plasma, which then give emission signals. By using phase-sensitive detection with a lock-in amplifier, the emission signal modulated by the pulsed laser can be detected selectively. It is possible to estimate only the emission intensity of sample atoms ablated by laser irradiation with little interference from the other species in the plasma.

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Complexation and conformational studies of coenzyme NAD⁺ with aluminum were conducted in acidic aqueous solutions (pH 2 - 5) by means of potentiometry as well as multinuclear (¹H,¹³C,³¹P,²⁷Al) and two-dimensional (¹H,¹H-NOESY) NMR spectroscopy. These led to the following results: (1) Al could coordinate with NAD⁺ through the following binding sites: N₇′ of adenine and pyrophosphate free oxygen (O_A¹,O_N¹,O_A²) to form various mononuclear 1:1 (AlLH₂³⁺,AlLH²⁺) and 2:1 (AlL₂^-) species, and dinuclear 2:2 (Al₂L₂²⁺) species. (2) The conformations of NAD⁺ and Al-NAD⁺ depended on the solvents and different species in the complexes. The results suggest the occurrence of an Al-linked complexation, which causes structural changes at the primary recognition sites and secondary conformational alterations for coenzymes. This finding will help us to understand role of Al in biological enzyme reaction systems.

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A micromachined flow cell (overall size; 25 × 25 × 1 mm³) was designed for the fast determination of hydrogen peroxide, based on a luminol-H₂O₂ chemiluminescence reaction catalyzed by immobilized peroxidase (POD). The flow cell consisted of a sandwich of anisotropically etched silicon and glass chips and contained a spiral channel (20 turns, 50 cm long, 150 μm wide, 20 μm depth, channel volume 1.4 μl) and two holes (1 mm diameter). POD was covalently immobilized with 3-(trimethoxysilyl)propyldietylenetriamine and glutaraldehyde on the inner surface of the channel. The chip was placed in front of a window of a photomultiplier tube and used as a flow cell in a single-line flow-injection analysis system using a luminol solution as a carrier solution. The sample volume for one measurement was 0.2 μl. The maximal sampling rate was 315 h^-1 at a carrier solution flow rate of 10 μl min^-1. A calibration graph for H₂O₂ was linear for 5 nM - 5 μM; the detection limit (signal-to-noise = 3) was 1 nM (7 fg in 0.2 μl injection). The H₂O₂ concentration in rainwater was determined using this sensor system.

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A flow injection biosensor system was proposed for the highly sensitive detection of 2,4,6-trichlorophenol (2,4,6-TCP). The system is based on the preoxidation by ceric sulfate to the corresponding benzoquinone (2,6-dichloro-1,4-benzoquinone: 2,6-DC-1,4-BQ), which was characterized using cyclic voltammetry, hydrodynamic voltammetry, and UV-vis spectrophotometry. The laccase-based biosensor used in this analytical system responded sensitively to 2,4,6-TCP after the preoxidation by ceric sulfate. The response could be based on the bioelectrocatalytic recycling of oxidation product (2,6-DC-1,4-BQ) between laccase membrane and the electrode, because the oxidation product (2,6-DC-1,4-BQ) of 2,4,6-TCP was an electrochemically reversible redox species. The signal current was linearly related to the 2,4,6-TCP concentrations in a dynamic range of 2 nM - 2 μM; the slope and the y-intercept of the straight line were 1150 nA μM^-1 and 0.88 nA, respectively. The detection limit was 1.2 nM (S/N = 3) for a 20 μl injection. Among a variety of chlorophenols and some phenolic compounds, the only interferent was 2,4-dichlorophenol.

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The selective enrichment behavior of a labile substance, such as hydroxides, to the surface of particular mineral particles in river water was clarified by scanning electron microscopy/energy dispersive X-ray microanalysis (SEM-EDX). Individual particles other than diatom collected on a 0.45 μm filter from the Fuji and Sagami rivers, central Japan, were analyzed by SEM-EDX and classified into seventeen groups according to the chemical composition and shape. Phosphorus, sulfur, chlorine, manganese and copper detected in each particle collected on the 0.45 μm filter could be successfully used as effective indicators of labile substance secondarily formed and adsorbed afresh in river water, because the detection frequencies of such elements are quite low, or negligible, in fresh mineral particles derived from igneous rocks. The labile substance adsorbed on mineral particles collected on the 0.45 μm filter was also evaluated by dilute-acid leaching, followed by inductively coupled plasma mass spectrometry (ICP-MS). Almost all parts of the manganese detected in individual particles were those adsorbed afresh as hydroxides together with iron and aluminum. Also, anionic elements, such as phosphorus, sulfur and chlorine, formed complexes with the hydroxides and/or were incorporated in them. Mg and/or Ca-rich aluminosilicate groups were the most effective adsorbers of such labile species. However, Si-rich and Na-, K- and Na-Ca rich aluminosilicates did not significantly adsorb the labile substance. Consequently, the remarkable selectivity was clarified in the adsorption process of labile substance to individual mineral particles in river water.

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Cluster ions and residue nanoparticles with sizes below 30 nm were generated by electrospraying (ES) and drying droplets of pure water, tap water, and aqueous solutions of salts. The mobility spectra of the cluster ions between 9.1 and 9.3 × 10^-5 m²/(V s) were measured using a differential mobility analyzer (DMA) operated at room temperature and atmospheric pressure. A modified Faraday cup and a condensation nucleus counter were used for detection. The concentrations of total residue/contaminants in the water were determined as a function of sizes of measured aerosol particles and of the initial droplets. Method detection limits were at sub-ppb level for pure water and sub-ppm level for tap water. ES/DMA is capable of simultaneously measuring the mobility distribution of cluster ions and concentration of total residue present in water samples.

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A combined apparatus of a supercritical CO₂ extractor (SFE) and a time-of-flight mass spectrometer (TOF-MS) was developed aiming at the direct analysis of extracts. A fused-silica capillary acts as both a pressure restrictor and an effluent injection nozzle into the TOF-MS. The tip of the nozzle was narrowed by melting and abrasion so that a greater pressure drop occurred at the tip. In the TOF-MS chamber, differential pumping between the main and ionization chamber kept the pressure in the ionization chamber at around 10^-3 Pa when the SFE pressure was at 9.7 to 29.4 MPa. The TOF-MS performance, a mass resolution of 263 at m/z = 146, and a sensitivity of 1.6 ng (p-dichlorobenzene) were certified by direct injection of a standard organic solution. Online detection of SFE effluent containing naphthalene, p-dichlorobenzene, phenanthrene and pyrene were successfully performed by the TOF-MS only for 48000 ionization cycles corresponding to 7.5 s.

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A high-performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of fluvoxamine and its major metabolite fluvoxamino acid in plasma. Fluvoxamine and fluvoxamino acid in plasma were extracted using a C₁₈ bonded-solid phase cartridge, followed by C₄ reversed-phase HPLC separation. Fluvoxamine, fluvoxamino acid and moperone as an internal standard were detected by ultraviolet absorbance at 254 nm. It was possible to determine both fluvoxamine and fluvoxamino acid in the concentration range of 25.0 - 200.0 ng/mL, respectively. The detection limits of both fluvoxamine and fluvoxamino acid were 10.0 ng/mL, respectively. The mean recoveries of fluvoxamine and fluvoxamino acid added to plasma were more than 94.0% and 96.5%, with a coefficient of variation of less than 7.6% and 8.2%, respectively. This method has been used for the simultaneous determination of steady-state plasma concentration (Css) of fluvoxamine and fluvoxamino acid in depressive patients treated with 200 mg of oral fluvoxamine dosed as 100 mg twice-daily. The Css values of fluvoxamine and fluvoxamino acid in twelve Japanese patients were showed individual variations, which wree in the range of 48.3 - 532.9 ng/ml and 35.6 - 307.1 ng/ml, respectively.

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A chemometric tool based on the Function of Mutual Information (FUMI) theory can provide a relative standard deviation (RSD) without repetitive measurements in high-performance liquid chromatography with electrochemical detection (HPLC-ECD). Two parameters: precision (= information content) φ and efficiency (= information content/time) θ, which were calculated from predicted RSD based on the FUMI theory, were used to optimize HPLC-ECD conditions, such as applied potential, flow rate, column length, and size of ODS porous packing. We selected catechins as analytes, and found that the most optimum applied potential and flow rate were +600 mV vs. SCE and 0.9 mL/min, respectively, because they gave the largest φ and θ values. Buffer concentration in mobile phase is less effective for giving large φ and θ values. Since the FUMI theory makes it possible to predict RSD without repetitive measurements, the present method saves considerable amounts of chemicals and experimental time, and was found to be useful for the optimization of experimental conditions for determination by HPLC-ECD.

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Potassium-decyl-18-crown-6 was used as a highly selective and efficient carrier for uphill transport of silver as AgBr_2^- complex ion through a chloroform bulk liquid membrane. When thiosulfate anion was used as a metal ion acceptor in the receiving phase the amounts of silver transported across the liquid membrane after 120 and 180 min were 87.0 ± 1.8% and 96.0 ± 1.9%, respectively. The selectivity and efficiency of silver transport from aqueous solution containing Cu²⁺, Zn²⁺, Ni²⁺, Cd²⁺, Pb²⁺ and Fe³⁺ ions were investigated. In the presence of EDTA at pH = 4 as suitable masking agent in the source phase, the interfering effects of Pb²⁺ and Fe³⁺ ions were diminished drastically.

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A new wire-coated silver ion-selective electrode with a wider concentration range (10^-7 M - 10^-1 M) was developed using 2-mercaptobenzothiazole (MBT) as a neutral ionophore. An optimum mixture of PVC, ionophore, dioctylphtalate (DOP) as a plasticizer and sodium tetraphenylborate (NaTPB) as an ion-pairing agent was used in preparing the coatings. The effect of various parameters, such as the electrode bed nature, coating composition and solution pH, on the efficiency of the electrode is described. It has been shown that platinum acts as a more suitable bed for electrode preparation, and exhibits a slope of 59.5 ± 1 mV over the whole range of studied concentrations. The selectivity coefficient of the electrode towards various interfering cations as well as its reproducibility, response time and lifetime of the electrode were estimated. The developed electrode was successfully used for the determination of trace amounts of silver in human hair and photographic waste as real samples and in the potentiometric titration of halides as an indicator electrode.

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An on-line Ag/Al galvanic cell was studied and employed to generate electrochemiluminescence (ECL) of calcein blue. The potential of the galvanic cell could be adjusted by varying the components of flow reagent or by using different metals to substitute for Ag or Al. The reported cell exhibited perfect capability of supplying a stable potential for ECL generation. Because the weak ECL of calcein blue could be greatly sensitized in the presence of calcium in alkaline solution, calcium contents in milk and vegetable samples were assayed; the results were validated with ICP-AES method. The method gave linear results in 1.0 × 10^-4 mol L^-1 to 8.0 × 10^-6 mol L^-1 calcium concentration range and the 3σ limit of detection was to be 2.0 × 10^-6 mol L^-1. Experiment results imply that this model of ECL detection could be applied for instrument miniaturization with easy fabrication.

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Sum frequency vibrational spectra for hexadecanethiol (HDT) adsorbed on thin gold film deposited on the surface of a CaF₂ prism have been measured using total-internal reflection broad-bandwidth sum frequency generation (TIR-BBSFG) spectroscopy. The bands attributed to the CH₃ symmetric and asymmetric stretching vibrational modes were observed in the sum frequency vibrational spectra. The orientation of the methyl groups was analyzed using the ratio of the intensities of the two modes. The methyl groups of HDT on the thin gold film were much more randomly orientated than those on Au(111).

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The details of a method used to determine the As(III)/As(V) ratio in soil by arsenic K-edge XANES spectroscopy are described. The spectra of mixtures of NaAs(III)O₂ and NaH₂As(V)O₄, conducted for an As(III)/As(V) calibration, were well-fitted by combining normalized spectra of NaAsO₂ and Na₂HAsO₄, where the coefficients multiplied by the normalized spectra were identical to the molar ratio of As(III) and As(V) in the mixtures. XANES spectra of arsenic in soil samples could also be fitted by a linear combination of the spectra of NaAsO₂ and Na₂HAsO₄, which enabled us to estimate the As(III)/As(V) in a soil containing 10.2 mg/kg arsenic. The As(III)/As(V) ratio in the soil was compared with that of a soil solution contacted with the soil determined by HPLC-ICP-MS, showing that As(III) is distributed to water more readily than As(V). The application of the XANES method is important for a better understanding of the behavior of As(III) and As(V) independently in a natural aquifer.

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A method has been described for the determination of arsenic species (arsenite and arsenate) by hydride generation-atomic fluorescence spectrometry (HG-AFS). The experimental conditions that influence the fluorescence intensity and the reduction of arsenic were investigated and optimized, and the influences from foreign ions and their elimination were studied. The detection limit was found to be 79.7 ng L^-1. The proposed method was applied to the determination of arsenic species in water leachate of traditional Chinese medicines with a recovery range of 91.1 - 109.5%.

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A new chemiluminescence method for the determination of carbamazepine (CBZ) has been developed. The method is based on the chemiluminescence produced in the reaction of tris(2,2′-bipyridine)ruthenium(III) and CBZ in an acidic medium. The chemiluminescence intensity was enhanced by organic solvents in the reaction system. Under the optimum experimental conditions, the calibration curve was linear over the range 4.0 × 10 ^{- 3} - 8.6 × 10^-7 mol/L for CBZ. The detection limit (S/N = 3) was 2.5 × 10^-7 mol/L and the relative standard deviation of six replicate measurements was 2.6% for 4.0 × 10^-4 mol/L of CBZ. The possible reaction mechanism were also discussed. The chemiluminescence method was successfully applied to assay the CBZ contents in pharmaceutical tablets.

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A simple kinetic spectrophotometric method is described for the determination of famotidine. The method is based on the oxidation of the drug with alkaline potassium permanganate. The reaction is followed spectrometrically by measuring the rate of change of the absorbance at 610 nm. The initial-rate and fixed-time (at 12 min) methods are adopted for determining the drug concentration. The calibration graphs are linear in the ranges of 2 - 10 μg mL^-1 and 1 - 8 μg mL^-1 using the initial-rate and fixed-time methods, respectively. The method has been applied to the determination of famotidine in tablet formulations. The obtained results are compared statistically with those given by a reference spectrophotometric method.

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The kinetic method is based on a catalytic effect on the oxidation of sodium pyrogallol-5-sulfonate by hydrogen peroxide. The reaction is followed spectrophotometrically at 436.8 nm. The kinetic parameters of the reaction are reported and a rate equation is suggested. The calibration graph is linear in the range 10 - 200 ng cm^-3. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. This method has high sensitivity and good selectivity when anions are concerned as well. That is why it can be successfully applied to determination of iodide in real samples (mineral water and soil) directly after the elimination of cations, which interfere. The method was applied to determine iodide in natural waters and soil.

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The H-point standard addition method (HPSAM) was applied to the simultaneous determination of Bi(III) and Sb(III). This method is based on the difference in the absorbance of complexes of Bi(III) and Sb(III) with iodide in acidic media in different wavelength pairs. The results showed that Bi(III) and Sb(III) can be determined simultaneously with concentration ratios of 15:1 to 1:20. First-derivative spectrophotometry was also used for the simultaneous determination of Bi(III) and Sb(III) based on their complexes with iodide. The proposed methods were successfully applied to the simultaneous determination of Bi(III) and Sb(III) in synthetic samples.

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The quadruple complex formed by terbium with 4-chlorosalicylic acid (CSA), EDTA and cetyltrimethylammonium bromide (CTMAB) has been used for the sensitive spectrofluorometric determination of terbium in mixed rare earths. The effect of the experimental conditions on the fluorescence intensity was defined. Under the optimum conditions selected, the fluorescence intensity was linear with the terbium concentration in the range of 3.0 × 10^-8 − 1.0 × 10^-5 mol/L with a detection limit of 8.0 × 10^-9 mol/L (S/N = 3). It has been satisfactory for the determination of terbium in mixed rare earths with good recovery.

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In a weak acid medium, some aminoglycoside antibiotics, such as kanamycin (KANA), gentamicin (GEN), tobramycin (TOB) and neomycin (NEO), or acid bisazo dye Evans Blue (EB) can only produce very weak resonance Rayleigh scattering (RRS) signals. However, when two agents react with each other to form ion-association complexes, the RRS intensity can be greatly enhanced and a new RRS spectrum with a significant enhancement of the RRS intensity in the wavelength range from 350 nm to 600 nm can be observed. The maximum scattering peak is at 570 nm. There is linear relationship between the RRS intensity and the antibiotic concentration in the range of 0.01 - 6.0 μg mL^-1 at 570 nm. This RRS method for the determination of aminoglycoside antibiotics at trace-amount levels has been developed. The detection limits (3σ) of the four antibiotics, whose order of sensitivity from high to low ranks as KANA > NEO > TOB > GEN, are 5.2 - 6.9 ng mL^-1. This method has good selectivity and has been successfully applied to the quick determination of antibiotics not only for injections and ear drops, but for clinic serum samples as well. In addition, the reaction mechanism by using a quantum chemistry method and the influencing factors of the RRS spectra and the enhancement reasons of RRS have been discussed.

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The ¹H-magnetic resonance imaging technique was applied for monitoring the extent of the heat coagulation in the shell egg. It is demonstrated that spin-spin relaxation time (T₂) is an effective marker to observe the extent of coagulation in egg white and yolk and that the T₂ value image is quite useful to recognize non-destructively the extent and status of coagulation of the heated eggs. This technique can also be applied to the material science as well as food science for observation of the inner status of the objects.

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The electrochemical oxidation of iodide ion in the presence of 4-hydroxycoumarin (1) was studied using cyclic voltammetry and controlled-potential coulometry. The result indicates that the resulting iodine takes part in a halogenation reaction and reacts with 4-hydroxycoumarin (1). According to the obtained results, a new and simple coulometric titration method with potentiometric end-point detection for the determination of 4-hydroxycoumarin (1) is presented. In the presented method, 2 - 200 μmol of 4-hydroxycoumarin (1) was successfully determined.

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The utility of 4-(4-nitrophenyl)-1,2,4-triazoline-3,5-dione (NPTAD) as a derivatization reagent in the analysis of 25-hydroxyvitamin D₃ [25(OH)D₃] using liquid chromatography/electron capture atmospheric pressure chemical ionization-mass spectrometry (LC/ECAPCI-MS) was examined. The derivatives of 25(OH)D₃ with NPTAD underwent electron capture in the APCI source in the negative-ion mode and provided 30-fold higher sensitivity compared to an intact compound. This derivatization-LC/ECAPCI-MS method was applied to a plasma 25-hydroxyvitamin D₃ assay, and gave satisfactory results in sensitivity, specificity, measurable range and throughput of the analysis.

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This paper describes the application of a combined orthogonal array design and overlapping resolution mapping to the optimization of miceller electrokinetic chromatography for the separation of 10 substituted benzenes. The most important factors were first determined according to an OA₁₆(2¹⁵) through 16 pre-designed experiments; a second set of experiments was carried out according to a triangle overlapping resolution mapping scheme, in which 7 pre-planed experiments were executed and global optimum conditions for the separation were obtained.

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Uptake of alkane (C₅ - C₉) and alcohol (C₄ - C₇) solutes by both strong acid cation exchange resins and strong base anion exchange resins in aqueous medium has been studied. The amount of solute taken up by resins is directly proportional to the solute concentration equilibrium with resins. Hydrophobic interaction between the solute and the resin matrix appears to play an important role in the uptake phenomenon.

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An on-line system for enrichment and determination of lead(II) is presented. It is based on the adsorption of lead(II) ions on a minicolumn packed with active carbon loaded with Pyrogallol Red. After preconcentration step, the metal ions are eluted automatically by 5.0 ml of 0.50 M nitric acid solution and the lead ion contents were determined by atomic absorption spectrometry. The influence of chemicals, pH and flow variables were studied as well as effect of potential interfering ions. Under the optimum conditions, the lead ions in aqueous samples were concentrated about 100 fold by the column. The detection limit was 0.001 μg ml^-1. The recovery percent of spliced lead(II) was in the range of 98% - 103%.

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A simple and sensitive spectrophotometric method for the determination of a thiobarbituric acid-reactive substance (TBARS) in human hair has been developed. The proposed method is based on the formation of a red-colored product by the reaction of products of lipid peroxidation with thiobarbituric acid in an acidic medium. The absorbance of the resulting red product was measured at 534 nm. The linear dynamic range was between 1.0 and 20 μmol/L. The recoveries were 98.3 - 105.0%, and the relative standard deviations (RSD) were 0.32 - 1.24, respectively. TBARS in digested hair sample was stable for 3 days at room temperature. It was found that, using this method, the hair TBARS concentration in smokers (0.116 ± 0.030 μmol/g, n = 30) was significantly higher than that in non-smokers (0.096 ± 0.015 μmol/g, n = 30) (p < 0.05).

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A modified and highly sensitive spectrophotometric method for the determination of nitrate in trace quantities in environmental samples is described. The method is based on the reaction of nitrate ion with brucine and 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) in sulfuric acid medium to yield a violet-colored product which is stable for over two days. The optimum photometric range for the determination of nitrate is 0.04 - 0.16 μg cm^-3 and the Sandell’s sensitivity being 0.000279 μg cm^-2. The proposed method is applied to various water samples and the results indicate that the reaction is highly sensitive than the original brucine method.

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C₁₄H₁₀O₂Se₂ is monoclinic, P2₁/c. The unit-cell dimensions at 293 K are a = 12.795(2), b = 12.126(2), c = 9.0179(13)Å, β = 107.074(6)°, V = 1337.5(3)ų, and Z = 4. The R value is 0.048 for 2319 observed reflections. The dihedral angle between the plane C4-C7(O2)-Se1 and C9-C8(O1)-Se2 is 85.6(2)°, keeping the Se atom unshared electron pairs in a more stable configuration with the rest of the molecule. The packing in the crystal is entirely due to van der Waals forces.

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The crystal structure of the title compound, [Ni(C₈H₂₀N₄)(C₁₂H₈N₂)](ClO₄)₂, has been determined by X-ray diffraction. The Ni(II) ion is six coordinated with four nitrogen atoms of the tetradentate macrocyclic ligand and two nitrogen atoms of the bidentate ligand in a distorted octahedron geometry. The folded tetradentate macrocyclic ligand adopts a configuration having four five-membered chelate rings in distorted eclipsed conformations. The four hydrogen atoms of the amine groups of the macrocyclic ligand are on the same side towards the bidentate ligand.

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3,3-Dichloro-N-p-methoxyphenyl-4-(2-phenylstryl)-2-azetidinone (C₂₂H₁₅Cl₂NO₂) was studied by X-Ray analysis, which indicated a monoclinic space group, P2₁/c, with a = 9.619(5), b = 13.879(4), c = 14.161(5)Å, β = 100.16(3)°, V = 1860.8(13)ų, Z = 4, D_c = 1.414 g cm^-3, μ(Mo K_α) = 0.366 mm^-1 and F₀₀₀ = 816. The structure was solved by direct methods and refined to R = 0.041 for 4026 reflections [I > 2σ(I). The β-lactam ring (2-azetidinone) has antimicrobial affects. The substituents of the methoxyphenyl and phenyl substituents do not change the activity property of the beta-lactam ring, and the activity properties depend on the planarity of the β-lactam ring.

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The title compound, C₂₆H₂₀N₆BrRu(BF₄), crystallizes in the centrosymmetric space group P2₁/n and consists of discrete complex units. The Ru(II) ion is octahedrally coordinated to one 2,2′:6′,2″-terpyridine (tpy), one 2-(phenylazo)pyridine (azpy) and a Br atom in trans-axial position at a distance of 2.547(5)Å. The shorter Ru-N (azo) distance (1.960(3)Å) than the Ru-N(py) distance (2.061(3)Å) signifies a strong π-backbonding, which leads to a longer, N=N (azo) bond (1.304(4)Å).

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The structure of the Diels-Alder cycloadduct formed from 2-(1,2,3-1H-benzotriazol-1-yl)-2-(p-tolyl)-2H-isoindole and dimethyl acetylenedicarboxylate was proved as 11-aza-1-(1,2,3-1H-benzotriazol-1-yl)-11-(4-methylphenyl)-tricyclo-[5.2.1.0^2,7]undeca-2,4,6,9-tetraene-9,10-dioic acid dimethyl ester. The benzotriazole moiety was located as its 1-yl form, analogous to previous reports. The benzotriazole and the benzene (of tricyclo framework) planes were twisted with an angle of 115.83°. Intramolecular close contacts between benzotriazole and ester are characteristic [N(3)…C(26), 2.754(3)Å; N(3)…H(22), 3.26(4)Å]. The shortest contact of N(3)…H(22) accounting for the rotation of the methyl group is estimated to be 3.10 Å, which might be reasonable as C-H…N-type hydrogen bonding.

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