急性酒精中毒的鼠脑内乙醛及其单胺神经递质缩合物的测定

应用高效液相色谱法测定了急性酒精中毒后新生鼠脑中乙醛的含量,以及乙醛分别与多巴胺、5-羟色胺的缩合产物1-甲基-6,7-二羟基-1,2,3,4-四氢异喹啉(Salsolinol,Sal)和6-羟基-1-甲基-1,2,3,4-四氢-β-咔啉(6-OH-MTHβC)的含量。采用2,4-二硝基苯肼(DNPH)的乙腈溶液在60℃水浴中衍生15min提取脑匀浆中的乙醛,离心后进行色谱分离,检测波长为360nm,本方法简单准确,灵敏度高。应用本方法测定鼠脑组织中的乙醛含量时发现,急性酒精中毒后新生鼠脑内乙醛的含量在24h内显著高于盐水对照组(P<0.05)。同时,采用HSF5柱分离和库仑阵列电化学检测的方法对Sal和6-OH-MTHβC进行分析表明,乙醛浓度升高后,急性酒精中毒鼠脑内Sal和6-OH-MTHβC的含量显著升高(P<0.05)。乙醛的非正常代谢及内源性神经毒素的生成可能在酒精的神经毒性机理中发挥了重要作用。     

Determination of acetaldehyde in saliva by gas-diffusion flow injection analysis

The consumption of ethanol is known to increase the likelihood of oral cancer. In addition, there has been a growing concern about possible association between long term use of ethanol-containing mouthwashes and oral cancer. Acetaldehyde, known to be a carcinogen, is the first metabolite of ethanol and it can be produced in the oral cavity after consumption or exposure to ethanol. This paper reports on the development of a gas-diffusion flow injection method for the online determination of salivary acetaldehyde by its colour reaction with 3-methyl-2-benzothiazolinone hydrazone (MBTH) and ferric chloride. Acetaldehyde samples and standards (80 μL) were injected into the donor stream containing NaCl from which acetaldehyde diffused through the hydrophobic Teflon membrane of the gas-diffusion cell into the acceptor stream containing the two reagents mentioned above. The resultant intense green coloured dye was monitored spectrophotometrically at 600 nm. Under the optimum working conditions the method is characterized by a sampling rate of 9 h⁻¹, a linear calibration range of 0.5–15 mg L⁻¹ (absorbance = 5.40 × 10⁻² [acetaldehyde, mg L⁻¹], R² = 0.998), a relative standard deviation (RSD) of 1.90% (n = 10, acetaldehyde concentration of 2.5 mg L⁻¹), and a limit of detection (LOD) of 12.3 μg L⁻¹. The LOD and sampling rate of the proposed method are superior to those of the conventional gas chromatographic (GC) method (LOD = 93.0 μg L⁻¹ and sampling rate = 4 h⁻¹). The reliability of the proposed method was illustrated by the fact that spiked with acetaldehyde saliva samples yielded excellent recoveries (96.6–101.9%), comparable to those obtained by GC (96.4–102.3%) and there was no statistically significant difference at the 95% confidence level between the two methods when non-spiked saliva samples were analysed.     

Application of wet effluent diffusion denuder for measurement of uptake coefficient of gaseous pollutants

The comparison of theoretical approaches describing the collection of analyte in the cylindrical wet effluent diffusion denuder (CWEDD) with experimental data is presented. Various absorption liquids were tested for the collection of formaldehyde (distilled-deionized water, H₂SO₄ solution), acetaldehyde (distilled-deionized water) and nitrous acid (distilled-deionized water, sodium carbonate and sodium bicarbonate solutions of various concentrations and sodium phosphate pH 6-8) in CWEDD. pH of absorption liquids significantly influences the collection of formaldehyde as well as nitrous acid. The collection efficiency of formaldehyde for 0.05 M H₂SO₄ as absorption liquid was generally higher than for distilled-deionized water. Absorption liquid pH markedly affected the collection efficiency of HONO too (with increasing pH the collection efficiency increase). Data derived by Gormley-Kennedy equation for all investigated compounds were overestimated especially for higher flow rates of air, data calculated with respect to Henry constant are not in good agreement with experimental data and are considerably depended on a determination of the Henry constant value. The CWEDD can be alternative tool for the determination of uptake coefficient. Obtained uptake coefficients were in good agreement with data found in other literature.     

Ion-Velocity Map Imaging Study of Photodissociation Dynamics of Acetaldehyde

The photodissociation dynamics of acetaldehyde in the radical channel CH3＋HCO has been reinvestigated using time-sliced velocity map imaging technique in the photolysis wavelength range of 275-321 nm. The CH3 fragments have been probed via （2＋1） resonance-enhanced multiphoton ionization. Images are measured for CH3 formed in the ground and excited states （v2=0 and 1） of the umbrella vibrational mode. For acetaldehyde dissociation on T1 state after intersystem crossing from S1 state, the products are formed with high translational energy release and low internal excitation. The rotational and vibrational energy of both fragments increases with increasing photodissociation energy. The triplet barrier height is estimated at 3.8814-0.006 eV above the ground state of acetaldehyde.     

高效液相色谱法测定卷烟粘合剂中甲醛、乙醛的含量

提出了预衍生化高效液相色谱法测定卷烟粘合剂中甲醛、乙醛含量的方法。卷烟粘合剂中醛经纯净水提取,离心机离心后分取部分上层清液,与2,4-二硝基苯肼衍生反应,生成的甲醛和乙醛的2,4-二硝基苯腙,用C18柱进行分离,用乙腈与水的混合物作流动相。在358nm紫外波长下检测,用醛衍生物配制标准定量。甲醛和乙醛在0.10～10.0mg·mL-1范围内呈线性。甲醛加标回收率在98.3%～118.9%之间,乙醛加标回收率在79.2%～89.2%之间,相对标准偏差(n=5)均小于5%。     

Assignment, fit, and theoretical discussion of the ν10 band of acetaldehyde near 509 cm

The lowest small-amplitude vibration in acetaldehyde (CH₃CHO) is the in-plane aldehyde scissors mode ν₁₀ at 509 cm⁻¹. This mode lies about 175 cm⁻¹ above the top of the barrier to internal rotation of the methyl group and is relatively well separated from other small-amplitude vibrational states (the next fundamental occurring more than 250 cm⁻¹ higher). It thus provides an excellent example of an isolated small-amplitude fundamental (bright state) embedded in a bath of dark states. Since the bath states at these energies are not too dense, and since they arise purely from states of the large-amplitude torsional vibration of the methyl rotor, a detailed spectroscopic analysis of interactions between the bright state and the bath states should be possible. This paper represents the first step toward that goal. We have assigned several thousand transitions in the ν₁₀ band (J ? 28, K ? 12), and have carried out a simultaneous fit of 2400 of these transitions (J ? 15, K ? 9) with over 8100 transitions to the torsional bath state levels. Three vibration-torsion interactions, which give rise to rather global level shifts of the order of 1 cm⁻¹ in the ν₁₀ levels, have been identified and quantitatively fit. A number of vibration-torsion-rotation interactions, which give rise to localized (avoided-crossing) shifts in ν₁₀ have also been determined. The present analysis indicates the need for reliable spectroscopic information on more of the torsional bath states in the immediate vicinity of the ν₁₀ levels. Possible ways of obtaining such information in future studies are considered.     

Structures and thermodynamic stabilities of the C2H4O isomers: Acetaldehyde,vinyl alcohol and ethylene oxide

Ab initio molecular orbital theory with a sequence of basis sets ranging from minimal to triple zeta plus polarization and with electron correlation incorporated using Möller-Plesset perturbation theory terminated at third order (MP3) is used to examine the structures and relative energies of the C₂H₄O isomers, acetaldehyde, vinyl alcohol and ethylene oxide. Acetaldehyde is indicated to be the most stable isomer with vinyl alcohol lying 45 kJ mol^–1 and ethylene oxide 114 kJ mol^–1 higher in energy. The theoretical structures and energies are in reasonable agreement with the best available experimental data.     

Effect of TMB/P123 ratios on physicochemical properties of mesocellular foam carbon (MCF-C) as catalyst for ethanol dehydrogenation

The preparation of mesocellular foam carbon catalysts with different ratios of 1,3,5-trimethyl benzene (TMB)/P123 is represented for investigation in catalytic activity via ethanol dehydrogenation to acetaldehyde. The TMB was used as a swelling agent and P123 acted as template-structuring. The physicochemical properties of synthesized catalysts were determined using Brunauer-Emmett-Teller (BET) surface area analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM)–energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), ammonia temperature-programmed desorption (NH₃-TPD), and carbon dioxide temperature-programmed desorption (CO₂-TPD). The evidence suggested that various ratios of TMB/P123 can differently control the mesostructure including the pore size, specific surface area, and pore volume. Particularly, MCF-C 3.5 catalyst (TMB/P123 of 3.5) enhanced the catalytic via ethanol dehydrogenation. Interestingly, effectively controllable pore structure of catalysts is beneficial for the desorption of selective product such as acetaldehyde leading to remarkably increased yield of acetaldehyde. Furthermore, the MCF-C 3.5 evidently exhibited outstanding stability at temperature of 400 °C for 12 h. Thus, it can be reasonably selected the ratio of TMB/P123 as 3.5, which is dominantly facilitated either high diffusion of reactant or high stability without losing of the traditional structure compared with other ratios of TMB/P123.     

Photocatalytic Degradation of Acetaldehyde on Mesoporous TiO2: E?ects of Surface Area and Crystallinity on the Photocatalytic Activity

"Mesoporous TiO2 powder and films with worm-like channels were synthesized by an evaporation-induced self-assembly approach. The as-prepared samples were calcined at different temperature to investigate the effect of calcined temperature on the mesostructure and the photocatalytic activity. Acetaldehyde photodegradation in gas phase was employed to evaluate the photocatalytic activity of mesoporous TiO2. Results showed that all the calcined powder samples exhibited higher photocatalytic activities than that of Degussa P25. The sample calcined at 400 oC, which showed higher activity than other samples, possessed a homogeneous pore diameter of about 6.0 nm and an 11.0 nm crystalline anatase pore wall, as well as large surface area of 117 m2/g. It was speculated that two factors of surface area and crystallinity affected the photocatalytic activity of mesoporous TiO2 photocatalyst. The mesoporous TiO2 films fabricated by spin-coating also had high photocatalytic activities."     

流动注射化学发光测定乙醛的研究

本文研究了应用Ｇａ（没食子酸）－Ｈ２Ｏ２－ＯＨ＾－化学发光体系，流动注射技术测定乙醛的条件，如反应介质及其ｐＨ值，Ｇａ及Ｈ２Ｏ２溶液的浓度，温度，试液混合次序与化学发光强度的关系等，选择了流动注射系统的若干参数，所拟定的方法测定乙醛的浓度范围为每ｍＬ１．７×１０＾－３～４．４×１０＾－７ｇ，相对标准偏差为１．８％（２×１０＾－５ｇ／ｍＬ，乙醛溶液进行１１次平行测定）检出限为每ｍＬ３．１×１０＾－８