依文思蓝-溴酸钾催化体系测定亚硝酸根

本文研究了亚硝酸根的一个新指示反应。在稀磷酸溶液中,依文思蓝-溴酸钾的氧化还原反应受亚硝酸盐催化使依文思蓝褪色。测定灵敏度为7.8×10-11g/mL亚硝酸态氮[当lg（Ao/A）=0.001 b=l cm)。测定范围0—3.5μg NO2/25mL,相对标准偏差1.64%。已用于测定自来水和唾液中的NO2-。     

A Fluorescence Quenching Method for the Determination of Nitrite with Indole

A new fluorescence quenching method has been developed to determine nitrite in water and food samples. The method is based on the reaction between nitrite and the fluorescent indole to form a compound which has no fluorescence in acidic medium. The fluorescence intensity was measured in 1 cm quartz cell with excitation and emission wavelengths of 285 and 350 nm, respectively. The relationship was obtained between the fluorescence intensity and nitrite concentration in the range 0.01–0.6 μg ml⁻¹. The detection limit was 2.5 ng ml⁻¹. The proposed method was applied to determine nitrite in water and food samples. The mechanism involved in the reaction was studied.     

亚硝酸根在磷钼镍杂多酸-聚吡咯膜修饰电极上的伏安行为及其含量测定

研究了亚硝酸根(NO     

Modifying the Steric Properties in the Second Coordination Sphere of Designed Peptides Leads to Enhancement of Nitrite Reductase Activity

Protein design is a useful strategy to interrogate the protein structure‐function relationship. We demonstrate using a highly modular 3‐stranded coiled coil (TRI‐peptide system) that a functional type 2 copper center exhibiting copper nitrite reductase (NiR) activity exhibits the highest homogeneous catalytic efficiency under aqueous conditions for the reduction of nitrite to NO and H₂O. Modification of the amino acids in the second coordination sphere of the copper center increases the nitrite reductase activity up to 75‐fold compared to previously reported systems. We find also that steric bulk can be used to enforce a three‐coordinate Cu^I in a site, which tends toward two‐coordination with decreased steric bulk. This study demonstrates the importance of the second coordination sphere environment both for controlling metal‐center ligation and enhancing the catalytic efficiency of metalloenzymes and their analogues.     

Au/Fe3O4/壳聚糖纳米复合物NO2-传感电极

以壳聚糖为保护膜、玻碳为基底,用纳米Au和Fe₃O₄磁性纳米粒子构建了新型亚硝酸盐（NO₂^-）传感电极. 实验表明,该传感电极对NO₂^-有良好的电催化氧化活性,NO₂^-浓度(5.0×10^-6 ~ 2.0×10^-3 mol·L^-1)与氧化峰电流之间呈良好的线性关系（R = 0.9996）,检出限7.1×10^-7 mol·L^-1, 其灵敏度高、选择性好、重现性好.     

流动注射化学发光法测定水样中的痕量亚硝酸根

亚硝酸根对鲁米诺溴酸钾体系的化学发光具有显著增强作用。据此,结合流动注射技术,建立了一种简单、快速测定NO-2的新方法。方法的线性范围为4.0×10-12～4.0×10-9g/L;检出限为2.0×10-12g/L(3σ);分别对1.0×10-11g/L和4.0×10-10g/L的NO-2进行了平行测定(n=11),其相对标准偏差分别为1.3%与1.5%。用于实验室自来水、饮用纯净水以及雨水中的NO-2的测定,回收率为94%～105%,取得了满意的结果。     

气相法CO与亚硝酸甲酯偶联合成草酸二甲酯用Pd/α-Al2O3催化剂的研究

 一氧化碳与亚硝酸甲酯(CH3ONO)在负载型Pd/α-Al2O3催化剂上合成草酸二甲酯(DMO)的反应,其催化剂活性与载体的性质及所添加的助剂密切相关. 载体的双峰孔分布是影响催化剂活性的关键因素; 在双峰孔的基础上,载体的比表面积、孔径及孔体积的增大使催化剂活性升高; 助剂的添加可有效地提高Pd的分散度,减小Pd的粒径,从而使CH3ONO转化率从57.1%升高到84.7%,DMO时空收率可达到898 g/(L·h). 助剂添加后,活性组分Pd的含量可以从1%降至0.3%,而DMO时空收率仍可达到745 g/(L·h).     

时间分辨傅立叶变换红外发射光谱技术研究叔丁基亚硝酸酯的光解动力学

利用时间分辨傅立叶变换红外(TR-FTIR)发射光谱技术对叔丁基亚硝酸酯355 nm激光光解动力学进行研究. 通过对实验观测到的光解产物NO的时间分辨红外发射谱进行分析, 获得了NO的转动温度和相对振动布居, 并发现了振动布居的反转现象. 结合前人的工作, 我们确认了光解产物NO的最大振动布居量子数υ与光解光激发的母体分子N=O伸缩振动的泛频跃迁所涉及的振动量子数υ*之间的关系为υ=υ*-1.     

A Novel Catalytic Method for the Oxidation of Sulfides to Sulfoxides with Silica Sulfuric Acid and Sodium Nitrite in the Presence of KBr and/or NaBr as Catalyst

Highly efficient selective oxidation of sulfides to sulfoxides by NaNO₂ and silica sulfuric acid catalyzed with KBr or NaBr has been reported. This oxidation was carried out in the presence of wet SiO₂ (50% w/w) in acetonitrile at room temperature with good to excellent yields.     

浊点萃取光度法测定水样中亚硝酸根

A new method for the determination of trace nitrite by spectrophotometric after cloud point extraction was proposed.The effects of experimental conditions such as acidity,concentration of chromogenic reagent and surfactant,equilibration temperature and time on cloud point extraction were discussed.Under the optimum conditions,a good linear relationship was obtained in the range of 4.0～200 μg/L of the nitrite(r=0.9998),the detection limits of 0.43 μg/L.The recoveries fell in the range from 97.7% to 102.4% an...