1.Determination of Gasoline Properties by Fourier Transform Infr ared Spectroscopy
Huiying LIU ; Rui WEI ; Chunhua XIONG
Chinese Journal of Analytical Chemistry 2001;29(6):731-734
Combined with the partial least square regression, the oc tane number (RON), density, temperature evaporate (50%,90%), aromatics and olefi n concentration of gasoline were determined by the Fourier transform infrared spe ctroscopy at the wavenumber region of 1550~660cm-1. The experimenta l results showed that the actual values measured by the standard method were agre e with the prediction values by the proposed method.
2.Trends in Fluorescence Probe of Deoxyribonucleic Acid
Liansheng LING ; Zhike HE ; Yun ZENG
Chinese Journal of Analytical Chemistry 2001;29(6):721-724
This paper reviews the binding mode beween deoxyribonucle ic acid (DNA) and the different type of fluorescence probe. The application of t hese probes in DNA quantitation analysis and other ways is also reported. The pr ogress of DNA fluorescence probe is addressed.
3.Application of Mass Spectrometry in Structural Analysis of Saccharides
Chinese Journal of Analytical Chemistry 2001;29(6):716-720
The application of electron impact, chemical ionization , fast atom bombardment, electro-spray ionization, matrix-assisted laser desor ption ionization and tandem mass spectrometry in the structural analysis of sacc harides was reviewed, 53 papers were cited.
4.Electrochemistry and Electrocatalysis of Electropolymerized Vitamin B1 Film Electrode
Qiuxia YANG ; Yurong MA ; Wei HE ; Xuelin WANG
Chinese Journal of Analytical Chemistry 2001;29(6):713-715
A polymer film of vitamin B1 was obtained at a graphite carbon electrode by cyclic voltammetric method in phosphate buffer solution (PBS). Cyclic voltammograms of the film electrode in PBS (pH 5) exhibited one pair redox waves, Epa=350 mV,Epc=325 mV,different from monomer vitamin B1. The peak currents of poly-VB1 films was proportional to (scan rate)1/2, which showed that the charge transfer was controlled by diffusion in the polymer film. The Poly-VB1 modified electrode showed a good catalytic ability to dopamine and epinephrine. At the modified electrod, the peak potential for oxidation of dopamine occurred at 250 mV and 200 mV for epinephrine, while they were shifted towards the negative direction 100 mV and 300 mV respectively at the bare glassy carbon electrode . And their peak current had a linear relationship to the concentrations in the range of 8.0×10-7~1.0×10-4 mol/L for dopamine and 1.0×10-6~1.0×10-4 mol/L for epinephrine.
5.Transport of Glutamic Acid at Emulsion Liquid Membrane System
Changying ZOU ; Hong ZHANG ; Bianzhen XU
Chinese Journal of Analytical Chemistry 2001;29(6):682-684
The transport of glutamic acid through the surfactant liq uid membrane of trioctyl (mono) methyl ammonium chloride(Aliquat336)Span 80-toluene has been studied. The optimal experimental conditions for transport of gl utamic acid with high efficiency and high speed were obtained. The conditions we re that membrane phase was 0.020 mol/L Aliquat 336+3%(W/V)Span80+Tolu ene; Outer phase was 5×10-4 mol/L glutamic acid and Ph=9.3;Inner pha se was 0.05 mol/L HCl. The transport rate of glutamic acid reached 93% in 2 min of transport time. The phenylalanine was also transported at the optimal transpo rt conditions of glutamic acid. The transport rates of Glycine and basic amino a cids were lower. This method can be used for extraction and separation of micro amount of amino acids.
6.Preparation of Lanthanum*# Substituted PropertyHeptadecatungstodiphosphate- Polypyrrole Film Modified Electrode and Its Electr
Deliang DUAN ; Zhaizhong WANG ; Shiping ZHOU ; Gang WU
Chinese Journal of Analytical Chemistry 2001;29(6):679-681
The heptadecatungstodiphosphate substituted by L a(Ⅲ) with the formula α2-K7P2W17O61(La.OH2 ) (P2W 17La) was prepared by vacant refilling method. The anion of single substitu ted Dawson-type tungstophosphate salt was doped into the polypyrrole (PPY) film on a glassy carbon electrode (GC) by electrochemical method to prepare the chem ically modified electrode (P2W17La/PPY/GC). It maintains not only t he electrochemical activity and electrocatalytic property of P2W17L a, but also has good stability and sensitivity. In 0.50 mol/L HCl solution, th e first cathodic peak of P2W17La doping in polypyrrole film can cat alyze well the electroreduction of nitrite. The catalytic current was proporti onal to the concentration of nitrite between 6.0×10-5 and 1.0×10-2 mol/L.
7.Determination of Depolymerization Products in Supercritic al Methanolysis of Poly(ethylene terephthalate)polyester by Reversed Phase High Performance Liquid Chromatography
Yong YANG ; Changming ZHANG ; Yuanyuan XU ; Yongwang LI ; Hongwei XIANG
Chinese Journal of Analytical Chemistry 2001;29(6):676-678
qualitative and quantitative analysis of solid depolymerization products for supercritical methanolysis of ploy(ethylene terephthalate) polyester (PET) were studied by means of reversedphase high performance liquid chromatogr aphy on ZorbaxC8(4.6mm×250mm) with 70%(V/V) methanol as mobile phase. The results showed that the solid depolymerization products were mainly composed of dimethyl terephthalate (DMT), methyl(2hydroxyethyl)terephthalate (MHET), bis(hydroxyethyl)tere phthalate (BHET), dimers and oligomers, which could be separated effectively under the above chromatographic conditions. The calibration curves of DMT and BHET were linear in the range of 1.0~45 mg/L (n=8),r=0.9998~1.0000 and RSD<2.8%. The determination limits of DMT and BHET were 4.0×10-4μg and 6.0×10-4μg respectively.
8.Adsorptive Voltammetric Behavior of Riboflavine Tetrabut yrate and Its Measurement of Rate Constant at the Mercury Electrode
Hongyan GAO ; Yinglin ZHOU ; Yonghuai ZENG
Chinese Journal of Analytical Chemistry 2001;29(6):667-670
Cyclic voltammetry shows that, in a supporting ele ctrolyte of NaOH,riboflavine tetrabutyrate(RT)has a pair of cathodic and anodi c peaks at Hg electrode. The peak potentials Epc=Epa=-0.64 V(vs.Ag/Agcl). The adsorptive characteristics of RT are explored in detai ls with various methods. The adsorbed species is most probably neutral molecule of RT.The saturated adsorption amount of RT at Hg electrode is 5.42×10-11 mol/cm2 and every RT molecule occupied 3.06 nm2. On the surface of HMDE ,the adsorption of RT obeys Frumkin dasorption isotherm. The adsorptive coeffic ient β,the attractive factor γ are 4.60×105,1.10 and the adsorption free energy ΔG, is -32.30 kJ/mol, respectively. The electrode proc ess kinetic behavior has also been studied by using cyclic voltammetry. Under th e experimental conditions the rate constants for electron transfer are determine d. The values of ks are in good agreement with literature′s results.
9.Extraction of Active Compound in Curcuma Phaeocaulis Valeton by Supercritical Fluid Extraction and Trapping with Silica Gel Column
Shulian CHEN ; Jing YOU ; Guojun WANG
Chinese Journal of Analytical Chemistry 2001;29(6):664-666
The essential oil of curcuma phaeocaulis valeto n can be extracted by supercritical fluid CO2 modified with ethanol. The recov ery of active compound, curdione, could be improved when supercritical fluid ext raction with trapping by silica gel column was used and then eluted the analytes with hexane, ether and ethanol. The relative recovery of curdione increased fro m 10.7% to 34.7%.
10.Capillary Electrophoresis of Neurotransmitters Under the Control of Radial Electric Field
Chinese Journal of Analytical Chemistry 2001;29(6):661-663
Separations of neurotransmitters such as dopamine (DA), ser otonin (5-HA), norepinephrine (NE) and epinephrine (E) were performed successf ully using a homemade electric field modulated capillary electrophoretic system, which could offer both radial and axial electric fields with only one high volt age power supply. DA and 5-HT were eluted simulaneously and could not be resolv ed in 0.01 mol/L phosphate buffer at pH 2.5. Alcohol additives, such as methanol , ethanol or 1-propanol were added to the buffer to change the solvation shell of the solutes, which changed their effective sizes and electrophoretic mobiliti es of the solutes accordingly. The optimum composition was a buffer of 20% (V /V) 1-propanol, with resulted resolutions 0.74 (DA/5-HT), 0.56(5-HT/NE) and 0.77 (NE/E). If a positive radial voltage of 6.6 kV was applied, the resolut ions were improved to 1.48, 0.71 and 1.32, respectively.