Facile preparation of 3-substituted 2-quinazolinones via electrogenerated base

A new series of 3,4-disubstituted quinazolin-2-ones, with potential T-type calcium channel antagonist activity, and new 4-methylene-quinazolin-2-ones, promising catalysts as N-heterocyclic olefins, have been prepared in good yield by a simple reaction between 2-aminobenzophenone, or 2-aminoacetophenone, and cyanomethyl anion electrogenerated by acetonitrile reduction at a graphite electrode, followed by the addition of different organic isocyanates and subsequent heterocyclization.     

Flow Injection Chemiluminescence Analysis of Low Level Concentration of Hydrazine

IntroductionHydrazine is often used as high-energy propellant in space shuttle program, and it is an important precursor in polymer industry, pesticides, and pharmaceuticals1,2. However, owing to its intensive mammalian toxicity, the monitoring of hydrazine residues in environment matrices has become a priority field in industrial laboratories. Siontorou et al.3,4 and Marrazza et al.5 recently designed a kind of DNA biosensor for monitoring pollutant including hydrazine. Some electrochemical…     

Phenylboronic acid immunoaffinity reactor coupled with flow injection chemiluminescence for determination of α-fetoprotein

A reusable and sensitive immunoassay based on phenylboronic acid immunoaffinity reactor in combination with flow injection chemiluminescence (CL) for determination of glycoprotein was described. The reactor was fabricated by immobilizing 3-aminophenylboronic acid (APBA) on glass microbeads with γ-glycidoxypropyltrimethoxysilane (GPMS) as linkage. The α-fetoprotein (AFP) could be easily immobilized on the APBA coated beads through sugar-boronic interaction. After an off-line incubation, the mixture of the analyte AFP with horseradish peroxidase-labeled AFP antibody (HRP-anti-AFP) was injected into the reactor. This led the trapping of free HRP-anti-AFP by the surface coated AFP on glass beads. The trapped HRP-anti-AFP was detected by chemiluminescence due to its sensitizing effect on the reaction of luminol and hydrogen peroxide. Under optimal conditions, the chemiluminescent signal was proportional to AFP concentration in the range of 10-100 ng mL⁻¹. The whole assay process including regeneration of the reactor could be completed within 31 min. The proposed system showed acceptable detection and fabrication reproducibility, and the results obtained with the present method were in acceptable agreement with those from parallel single-analyte test of practical clinical sera. The described method enabled a low-cost, time saving and was potential to detect the serum AFP level in clinical diagnosis.     

溶胶凝胶法固定反应试剂流动注射化学发光法测定H_2O_2

采用溶胶凝胶技术对 Luminol- Co( ) - H2 O2 体系中的 Co( )和 Luminol试剂进行了固定化 ,并将其用于化学发光法测定 H2 O2 。试验结果表明 ,固定柱的洗脱液中 Co( )的浓度稳定 ,测定的线性范围为 2× 1 0 - 6～ 1× 1 0 - 4 mol·L- 1 ,相关系数大于 0 .997,检出限为 0 .6μmol·L- 1 。1 0次测定的 RSD为 1 .7% ,单次测定能在 1 min内完成。方法成功地用于雨水中 H2 O2 的测定。     

Selective determination of doxorubicin and doxorubicinol in rat plasma by HPLC with photosensitization reaction followed by chemiluminescence detection

A highly sensitive and selective high-performance liquid chromatography (HPLC) method was developed for the determination of doxorubicin (DXR) and its metabolite doxorubicinol (DXR-ol) in rat plasma. The method was based on photosensitization reaction followed by peroxyoxalate chemiluminescence detection (PO-CL). DXR and DXR-ol that were fluorescent quinones, served as a photosensitizer in the presence of a hydrogen atom donor such as ethanol under aerobic conditions to produce hydrogen peroxide. Then the generated hydrogen peroxide and DXR or DXR-ol were monitored through PO-CL reaction by mixing with aryloxalate as a single post-column reagent that enabled highly selective and sensitive determination of DXR and DXR-ol. The separation of DXR and DXR-ol by HPLC was accomplished isocratically on an ODS column within 15 min. The method involves a simple one step protein precipitation by methanol and a sample size of 50-μL was sufficient. Besides, it can detect accurately the low plasma concentrations. The detection limits (signal-to-noise ratio = 3) were 4.5 and 3.8 fmol for DXR and DXR-ol, respectively. The percentage recovery was found to be 90.7-102.4% and the inter- and intra-assay RSD values in rat plasma were 2.5-8.9%. The method has been successfully used to study pharmacokinetic profiles of DXR and DXR-ol in rats after a single-dose of DXR.     

Determination of Antioxidant Activity of Hibiscus Flowers by Flow Injection Analysis with Chemiluminescence Detection

This study reports a simple and rapid method for the determination of the antioxidant activity of the phenolics present in plants of the Hibiscus genus. The protocol is based on the ability of the phenolic compounds to inhibit luminol chemiluminescence through the inactivation of free radicals in a flow injection system. Using the optimized operational conditions, the antioxidant activities of several phenolics were measured. The results were explained on the basis of structure–reactivity relationships. The antioxidant activities of dried flowers of Hibiscus rosa-sinensis and Hibiscus sabdariffa were evaluated. The protocol was validated by the 2,2-diphenyl-1-picrylhydrazyl-hydrate free radical assay. The differences in the antiradical activities were explained based on the concentrations of total polyphenol and flavonoid concentrations determined by spectrophotometric methods. It was concluded that the chemiluminescence method was complementary for the evaluation of hydrophilic antioxidants in plants.     

基于Ru(bpy)2+3/AuNPs/SWCNTs/腺苷适配体电化学发光生物传感器用于腺苷的检测

利用AuNPs/Nafion复合膜技术固定Ru(bpy)2+3,采用羧基化碳纳米管固定氨基化腺苷适配体,制备腺甘电化学发光生物传感器.采用循环伏安法和电化学发光法对传感器进行表征.结果表明,此传感器具有良好的稳定性和重现性.腺苷与传感器作用后,腺苷与其适配体形成G四面体结构,Ru(bpy)2+3的电化学发光强度降低.在最佳实验条件下,电化学发光强度降低量与腺苷浓度的负对数在1.0×10-11~1.0×10-7 mol/L范围内呈良好的线性关系,线性方程为ΔIECL=-890lgC-5050,检出限(S/N=3)为5.0 × 10-12 mol/L.对1.0 × 10-10 mol/L腺苷平行测定11次,相对标准偏差为2.7%.用于尿液中腺苷的测定,加标回收率在 97.1%~110.0%之间.     

流动注射化学发光法测定头孢噻肟钠

基于在碱性介质中头孢噻肟钠对鲁米诺-K3Fe(CN)6化学发光体系的增强作用,建立了流动注射化学发光测定头孢噻肟钠的新方法.头孢噻肟钠的质量浓度与化学发光强度的变化在2.4～30 mg/L和60～300 mg/L范围内呈良好的线性关系,检出限为0.63 mg/L,对浓度为30 mg/L的头孢噻肟钠进行9次平行测定,相对标准偏差(RSD)为1.0%.该法简便、快速、可靠,将其用于头孢噻肟钠针剂的测定,结果令人满意.     

Flow injection chemiluminescence determination of the total phenolics levels in plant-derived beverages using soluble manganese(IV)

This study established a flow injection (FI) methodology for the determination of the total phenolic content in plant-derived beverages based on soluble manganese(IV) chemiluminescence (CL) detection. It was found that mixing polyphenols with acidic soluble manganese(IV) in the presence of formaldehyde evoked chemiluminescence. Based on this finding, a new FI-CL method was developed for the estimation of the total content of phenolic compounds (expressed as milligrams of gallic acid equivalent per litre of drink) in a variety of wine, tea and fruit juice samples. The proposed method is sensitive with a detection limit of 0.02 ng mL⁻¹ (gallic acid), offers a wide linear dynamic range (0.5-400 ng mL⁻¹) and high sample throughput (247 samples h⁻¹). The relative standard deviation for 15 measurements was 3.8% for 2 ng mL⁻¹ and 0.45% for 10 ng mL⁻¹ of gallic acid. Analysis of 36 different samples showed that the results obtained by the proposed FI-CL method correlate highly with those obtained by spectrophotometric methods commonly used for the evaluation of the total phenolic/antioxidant level. However, the FI-CL method was found to be far simpler, more rapid and selective, with almost no interference from non-phenolic components of the samples examined.