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111.
Alcohol dehydrogenase (ADH) has been immobilized on a nickel hexacyanoferrate modified microband gold electrode surface by a glutaraldehyde/bovine serum albumin (BSA) cross-linking procedure to provide a new amperometric sensor for the assay of ethanol. The resulting enzyme electrode exhibits excellent electrocatalysis for the oxidation of reduced nicotinamide-adenine dinucleotide (NADH). The amperometric determination is based on the electrochemical detection of NADH which is generated in the enzymatic reaction of ethanol with NAD(+) under catalysis of ADH. The influence of various experimental conditions was examined for the determination of the optimum analytical performance. The sensor responds rapidly to ethanol with a detection limit of (5.0 +/- 0.3) x 10(-7) mol 1(-1). The response current increases linearly with ethanol concentration up to 5 mmol 1(-1). The sensor remains relatively stable for about 1 week. 相似文献
112.
ADSORPTION OF 2,4-DICHLOROBENZOXYACETIC ACID ONTO HYPERCROSSLINKED RESIN MODIFIED BY PHENOLIC HYDROXYL GROUP (AM-1) 总被引:2,自引:0,他引:2
INTRODUCTIONAdsorption has been considered to be the best available technology for removing organics from water in the USSafe Drinking Water Act[1]. Due to many drawbacks of activated carbon[2-7], the most widely used adsorbent,hypercrosslinked polymeric adsorbents developed by Tsyurupa and Davankov[8] have been increasingly viewedas an alternative to activated carbon for selective removal of specific organic substances from contaminatedwater[9-12], and series of researches have been do… 相似文献
113.
ZhenshanPeng ChanglinYu TiejunCai QianDeng 《天然气化学杂志》2004,13(3):172-176
Mixed oxide catalyst Cs0.1Fe2Co6BiMnMo12Ox was prepared by the coprecipitation method.Selective oxidation of isobutene was carried out in a fixed-bed reactor over Cs0.1Fe2Co6BiMnMo12Ox.The results showed that the catalyst had high catalytic activity. Under the optimum reaction conditions(n(i-C4):n(O2)=1:2-1:4, space velocity=180 h^-1, T=360℃), the yields of methacrolein and methacrylic acid can reach 80% and 8%, respectively. The total yield of liquid products (methacrolein, methacrylic acid and acetic acid) can reach about 90%. 相似文献
114.
115.
Determination of Organophosphorus Pesticides in Soil by MMSPD-GC-NPD and Confirmation by GC-MS 总被引:1,自引:0,他引:1
A novel method, modified matrix solid-phase dispersion (MMSPD), has been developed for quantitative analysis of organophosphorus
pesticide residues in soil. It was based on matrix solid-phase dispersion (MSPD) and continuous liquid-solid extraction (continuous
LSE), using Florisil as sorbent and dichloromethane as the recycling solvent. Two soils with different texture and physicochemical
properties were studied to validate the method. The effect of residence time of pesticides in soil was also studied. MMSPD
was compared with MSPD and continuous LSE respectively. Determination was carried out by gas chromatography with nitrogen-phosphorus
detection (GC-NPD). The method gave recoveries ranging from 72–105% with relative standard deviations (RSDs) lower than 15%
for the pesticides studied. The limits of detection (LODs) ranged from 0.1 to 0.6 ng g−1. Two pesticide residues have been detected in real soil samples from Fujian, China, using MMSPD. The pesticides were confirmed
by gas chromatography-mass spectrometry (GC-MS) in a selected-ion monitoring (SIM) mode.
Revised: 4 and 9 April 2006 相似文献
116.
117.
The equilibrium geometries, excitation energies, force constants and vibrational frequencies for seven low-lying electronic states X 1A1, 1B1, 3B1, 1A2, 3A2, 1B2 and 3B2 of dichlorocarbene CCl2 have been calculated at the MRSDCI level with a double-zeta plus polarization basis set. Our calculated equilibrium geometry for the X 1A1 state, excitation energy for X 1A1 → 1B1 and vibrational frequencies for the X 1A1 and 1B1 states are in good agreement with experimental data. The electronic transition dipole moments, oscillator strengths for the 1B1 → X 1A1 and 1B2 → X 1A1 transitions, radiative lifetimes for the 1B1 and 1B1 states are calculated using MRSDCI wavefunctions, predicting results in reasonable agreement with experiment. 相似文献
118.
丙烯选择氧化铋钼铁复氧化物催化剂组成,结构及性能的研究 总被引:1,自引:0,他引:1
采用XRD、Raman、XPS及催化剂性能评价等手段,考察了Bi_3(FeO_4)(MoO_4)_2和Fe_2(MoO_4)_3分别存在及两者共存时对Bi-Mo复氧化物体系催化性能的影响.结果表明,这两种含Fe物种的存在都有助于改善Bi-Mo系复氧化物催化剂对丙烯选择氧化反应的催化性能.但两者在作用机理上有所不同.Fe_2(MoO_4)_3本身无催化活性,但在反应条件下可部分还原为FeMoO_4形成Fe~(3+)/Fe~(2+)氧化还原对;且其地结构上与α-Bi_2(MoO_4)_3相匹配,这些因素都有助于促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生,从而提高催化性能.Bi_3(FeO_4)(MoO_4)_2在反应条件下也可形成Fe~(3+)/Fe~(2+)氧化还原对,但由于其Fe~(3-)所处的化学环境与Fe_2(MoO_4)_3很不相同,且Fe的含量也不及Fe_2(MoO_4)_3,因此它在促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生等方面的性能较差,但它对提高催化剂表面的活性中心(Bi-Mo对)数目有贡献. 相似文献
119.
本文提出了一个灵敏的具有选择性的溶出伏安法测超痕量铜的方法。在0.01mol/LNH3·H2O-NH4Cl溶液中(pH=9.3),铜(Ⅱ)-2,2′-联吡啶(Dipy)-铬天菁S(CAS)能生成具吸附性的电活性三元络合物,在+0.1V(vs.SCE)电位下富集,阴极溶出峰电位是一0.18V,峰电流与Cu(Ⅱ)的浓度在9.0×10-9~7.0×10-7mol/L范围内成正比,检测限是3.0×10-9mol/L,这一方法已用于测定环境水中痕量铜,回收率在98.5%,102.5%之间。 相似文献
120.
Mian Chang Jiayou Yu Shaojun Wang Liping Yang Yi Yang Shihao Cai Shouheng Shi Yan Wang P. W. Zhu 《中国科学B辑(英文版)》1997,40(5):529-534
A synthetical equation is proposed to characterize the essential features of the inverse “S” type curve on the basis of summing-up
simulation approach of “S” type curve. The two physical variables in the model obtained are discussed and the detailed method
used to determine the parameters is given. The model is then presented to describe the crystallization of poly(caryleher ether
ketone) (PEEK) and thermal decomposition of poly(amide-imide) (PAI) respectively. It is found that some thermal characteristic
parameters can be well estimated from the model simu-lated in computer. 相似文献