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2004 Vol. 24, No. 07
Published: 2004-07-26
 
       光谱学与光谱分析
769 Spectroscopic Studies on Transition Metal Ions in Colored Diamonds
MENG Yu-fei1，PENG Ming-sheng1，CHEN Wen-xuan2
Transition metals like nickel, cobalt and iron have been often used as solvent catalysts in high pressure high temperature (HPHT) synthesis of diamond, and nickel and cobalt ions have been found in diamond lattice. Available studies indicated that nickel and cobalt ions could enter the lattice as interstitial or substitutional impurities and form complexes with nitrogen. Polarized microscopy, SEM-EDS, EPR, PL and FTIR have been used in this study to investigate siｘ fancy color natural and synthetic diamonds in order to determine the spectroscopic characteristics and the existing forms of transition metal ions in colored diamond lattice. Cobalt-related optical centers were first found in natural chameleon diamonds, and some new nickel and cobalt-related optical and EPR centers have also been detected in these diamond samples.
2004 Vol. 24 (07): 769-774 [Abstract] ( 1667 ) PDF (1015 KB)  ( 433 )
775 Stimulated Emission Characteristics of ZnO thin Films Deposited by Magnetron Sputtering on SiO2 Substrates
WANG Jing，ZHANG Xi-qing，TENG Xiao-ying, XIONG De-ping，LIN Peng，WANG Li，HUANG Shi-hua
ZnO thin films were deposited by magnetron sputtering on SiO2 substrates. The temperature dependence of the absorption spectra and the photoluminescence spectra was studied for ZnO thin film. The absorption of the longitudinal optical (LO) phonons and the free-excitons was observed at room temperature. The free-exciton emission was only observed in PL spectra at room temperature, the results indicate that ZnO thin films have excellent quality and low density of defects. The stimulated emission properties of ZnO thin films were investigated. When excitation intensity is above threshold, the FWHM of stimulated emission peak increases and the stimulated emission peak shows red shift with increasing excitation intensity. Our analysis shows that the optical gain is due to electron-hole plasma emission.
2004 Vol. 24 (07): 775-778 [Abstract] ( 1094 ) PDF (872 KB)  ( 447 )
779 Luminescence Properties and Up-Conversion Mechanism of Er3+-Yb3+-Tm3+Co-Doped CdF2:PbF2-Based Glass
YANG Li-wen，LIU Zheng-wei，XIAO Si-guo
Under 980 nm excitation, we obtained five intense up-conversion luminescence bands in Er3+-Yb3+-Tm3+co-doped CdF2:PbF2-based glass as follows: infrared(800 nm), red(645 nm), green (545 nm and 525 nm), blue(480 nm ) and violet(407 nm) up-conversion luminescence. With the addition of Tm3+, the intensity of 480 nm blue luminescence increased notably compared with that of co-doped Yb3+-Er3+ sample，which attributed to Tm3+ special energy level structure; logI-logP plot of the luminescence intensity versus pump power shows that 480 nm luminescence emission is a two-photon excitation process induced by the cooperative up-conversion between two Yb3+ ions and the slope of logI-logP plot decreases gradually with increasing pump power and shows a tendency to bend down. The up-conversion mechanism is analｙｚed in detail ｕnder 980 nm semicondｕctor laser eｘcitation;the dependence of 480 nm up-conversion lｕminescence intensitｙ on the pｕmp power ｕnder the steadｙ states is discｕssed bｙ ｕsinｇ rate eｑｕation and the resｕlts aｇree well with the eｘperiments.
2004 Vol. 24 (07): 779-783 [Abstract] ( 1079 ) PDF (944 KB)  ( 379 )
784 Instantaneous Emission Spectra of Epoxypropane in the Process of Deflagration to Detonation Transition
LI Ping1, 2, YUAN Chang-ying2, 4, HU Dong2, 3, LIU Jun-chao2, SUN Zhu-mei2, 3, DONG Shi2, 3, XIAO Hai-bo1
Using an intensified CCD spectroscopic detector (Princeton Instruments, ICCD PI-Max 1024 RB) which can be gated in as little as 5 ns, the synchronization of the measuring system was controlled by a digital delay generator (Stanford Research Systems, DG535), the DG535 was triggered externally by a lab-made electrical pulse generator which transformed the optical trigger signal to an electrical signal, and the light signal from the end window of an explosion shock tube was delivered by an 1 mm in diameter plastic optical fiber to the entrance slit of the spectrometer (grating of 150 g·mm-1, central wavelength of 550 nm)． The spectrum measurement of the epoxypropane in the process of deflagration to detonation transition (DDT) was then made. The instantaneous emission spectra of epoxypropane at different time of the DDT process with an exposure time of several microseconds were acquired. Results show that at the beginning of the DDT process, the emitted light was very weak and the line spectra of atoms were observed mainly; in the middle process of the DDT, the emitted light became strong and the spectra observed consisted of line spectra of atoms, band spectra of molecules plus continuous spectrum of the thermal radiation; when the detonation was formed, the emitted light got very strong, and the spectra acquired consisted of both line spectra of atoms and band spectra of molecules superimposed on the strong continuum of the thermal radiation.
2004 Vol. 24 (07): 784-786 [Abstract] ( 1784 ) PDF (859 KB)  ( 492 )
787 The Characteristic of Photoelectron Decay Spectra in Silver Halide Microcrystals
LI Xiao-wei, HAN Li, GENG Ai-cong, YANG Shao-peng, FU Guang-sheng
Photoelectrons plays an important role in the latent image formation process of silver halide materials, and the decay characteristic of photoelectrons are dependent on the structure of silver halide microcrystals to a great eｘtent. In this paper, the decay spectra of free photoelectrons and shallow-trapped electrons were obtained bｙ optics and microwave doｕble resonance technoloｇｙ． The depth and density of electron traps in silver halide microcrystals were discussed. Moreover，ｕsinｇ the lifetime of free photoelectrons, the optimal doping amount of shallow electron trap dopants was found bｙ analｙｚinｇ the distribｕtion condition of electron traps in silver halide.
2004 Vol. 24 (07): 787-789 [Abstract] ( 1364 ) PDF (847 KB)  ( 389 )
790 The Influence of Thickness of SiO2 on the Electron Acceleration in Cathodluminescence-Like Emission
LIU Shan-shan, TENG Feng, XU Zheng, LIU Ming, SUN Shi-ju, XU Xu-rong
The authors investigated the property of cathodluminescence-like(CL-like) emission in the device of MEH-PPV sandwiched between two SiO2 layers. The authors observed in addition to the inherent electroluminescence of MEH-PPV, a shorter emission peak which is considered to be corresponding to HOMO-LUMO transition. From the relative change of these two peaks with the variation of the thickness of SiO2, The authors studied the electron acceleration ability of SiO2.
2004 Vol. 24 (07): 790-794 [Abstract] ( 1024 ) PDF (936 KB)  ( 413 )
795 Study of Rare Earth Bifunctional Chelate BCPDA-Eu3+ Labeling Protein
PAN Li-hua1, AN Jin-long1, XIE Wen-bing1, GUAN Ming2
The authors labeled bovine serum albumin (BSA) with a new europium chelator 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA) which was synthesized by solid phase time-resolved fluorescence immunoassay (TRFIA) technology. The process of BCPDA-labeling-BSA reaction was studied. Using Coomassie brilliant blue method, concentrations of BSA and BCPDA were determined in BCPDA-BSA labeled sample. The labeling reaction condition was studied. Labeling ratio and protein labeling recovery were calculated. BCPDA-BSA-Eu3+ complex has a very large Stokes shift (270 nm) and can emit very strong fluorescence band at 611.2 nm which is very narrow (10 nm). BCPDA-BSA-Eu3+ complex exhibits very long fluorescence lifetimes by the experiment demonstration. Also, BCPDA and protein-BCPDA-Eu3+ complex is relatively stable.
2004 Vol. 24 (07): 795-798 [Abstract] ( 1592 ) PDF (860 KB)  ( 396 )
799 Synthesis and Luminescence Properties of Europium(Ⅲ) Complexes with Camphoric Acid and 1,10-Phenanthroline
WANG Xi-gui1，WU Hong-ying1，WENG Shi-fu2，WU Jin-guang2
The complexes of europium(Ⅲ) with camphoric acid and 1,10-phenanthroline have been synthesized and characterized by elemental analysis, 1H NMR, IR and FT-Raman. The compositions of the complexes have been confirmed to be Eu2(CA)3·2H2O and Eu2(CA)3(phen)2 (CA: camphoric acid, phen: 1,10-phenanthroline). In addition, the camphoric acid and 1,10-phenanthroline-mixed coordination compounds of Eu3+-La3+ have been synthesized. Three-dimensional fluorescence spectra showed that the optimum excitation wavelength was 310 nm, and the strongest emission wavelength was 612 nm. When 310 nm light was used as an excitation wavelength, the seven bands due to 5D0-7F0(579 nm), 5D0-7F1(594 nm), 5D0-7F2(612 and 620 nm), 5D0-7F3(650 nm) and 5D0-7F4(689 and 697 nm) were observed between 550-700 nm, in which 5D0-7F2 transitions contain two lines(612 and 620 nm), and 5D0-7F4 transitions also contain two lines(689 and 697 nm). The excitation spectra showed that excitation band was from 240 to 340 nm, and the maximum was at about 310 nm. The fluorescence studies on all of samples showed that the fluorescence intensities of europium ions were sensitized by lanthanum ions, but the peak position of their emission band did not shift obviously.
2004 Vol. 24 (07): 799-802 [Abstract] ( 1548 ) PDF (946 KB)  ( 504 )
803 Investigation of PP／PE Blend with FTIR Mapping
ZHENG Ai-guo1, ZHAO Ying1, XU Yi-zhuang2*, WANG Du-jin1, ZHANG Xiu-qin1, ZHOU Yong1, WENG Shi-fu2, WU Jin-guang2，XU Duan-fu1
The polｙpropｙlene／polｙethｙlene(PP／PE) blends with different weiｇht ratio were studied bｙ FTIＲ spectroscopｙ． The characteristic absorption bands of PP and PE in different blends were compared． It was foｕnd that the ratio of the characteristic absorption peaｋ areas of PP to those of PE is correlated with the weight ratio of PP to PE in the blends. Based on the above resｕlts，FTIＲ mappinｇ techniｑｕe was applied to characteriｚe the samples prepared bｙ embeddinｇ PP fiber into molten PE film，and the distribｕtion of PP and PE in the blends can be obtained from the ratio of the characteristic peaｋ areas of PP to PE． Good aｇreements have been observed between the IＲ mappinｇ imaｇe and the imaｇe obtained ｕsinｇ polariｚed optical microscope． These resｕlts indicated that FTIＲ mappinｇ techniｑｕe is an effective tool to investiｇate the phase separation behavior of polｙmer blends based on the ratio of the characteristic peaｋ areas of different polｙmers．
2004 Vol. 24 (07): 803-805 [Abstract] ( 1940 ) PDF (1060 KB)  ( 571 )
806 In-Situ Study on the Crystallization of PCL Films Using FTIR
KONG Xiang-ming，HE Shu-gang，WANG Kun-hua，XIE Xu-ming
The crystalline behaviors of PCL(poly(ε-caprolactone))thin film on Si and KBr substrates have been studied in-situ using FTIR with a heat stage． In the crystalline process，due to the decrease in free volume and the increase in interaction among different molecules，the peak of CO shifted to lower wave number and the crystalline peak of C—O—C and C—H appeared． The degree of crystallinity has been calculated through the comparison between the peaks of crystal and amorphous parts． FTIR study on the films cast from solution with different concentrations showed that the thicker the film is，the higher crystallinity it has． This may be due to the substrate effect or geometric confinement． It was also shown that under the same preparation condition，the film on KBr wafer had higher degree of crystallinity than that of film on Si wafer．
2004 Vol. 24 (07): 806-809 [Abstract] ( 1568 ) PDF (1701 KB)  ( 361 )
810 In-Situ IR Study of Adsorption and Decomposition of Methanol on γ-Al2O3，CeO2 and Their Supported Pd Catalysts
YANG Cheng, DONG Qing-nian, REN Jie, SUN Yu-han*
The adsorption and decomposition of methanol on γ-Al2O3 and CeO2 supports，and Pd／Al2O3 and Pd/CeO2 catalysts were studied by in-situ FTIR technique. The possible pathway of methanol decomposition on Pd／Al2O3 and Pd/CeO2 catalysts was analyzed according to the interaction of Pd and the supports. Methanol was dehydrogenated into DME or decomposed towards CO and H2 over different active phase on Pd／Al2O3 catalyst. A synergistic effect between Pd and CeO2 on the activity of Pd／CeO2 catalyst for methanol decomposition was proved.
2004 Vol. 24 (07): 810-812 [Abstract] ( 1588 ) PDF (879 KB)  ( 383 )
813 Study on the Gas-Phase Reaction of α-Pinene with Ozone by LP-FTIR
LIU Zhao-rong，HU Di
The gas-phase reaction of α-pinene with ozone was tailed by LP-FTIR under 1.0×105 Pa and (296±3)K. The spectra were analyzed and a preliminary predication of the possible products was made. Then the mechanism of this reaction was extrapolated according to the IR data.
2004 Vol. 24 (07): 813-816 [Abstract] ( 1044 ) PDF (940 KB)  ( 368 )
817 Self-Assembly and Characterization of Pt Nanoparticles by Electrochemistry and In-Situ FTIR Reflection Spectroscopy
CHEN Wei，SUN Shi-gang*
Pt nanoparticles (Ptn) were prepared by chemical reduction method. The average dimension of Ptn is about 2.5 nm in diameter determined from TEM studies. The Pt nanoparticles were then self-assembled on massive Au substrate. The process of self-assembly was investigated with Fe(CN)4-／3-6 for redox probe reaction. The result showed that the dithiol assembled on Au surface is inactive for electron transfer. However after assembly of Pt nanoparticles on the dithiol, the Au/SS-Ptn electrode becomes conductive again for electron transfer. The adsorption of CO on the Pt nanoparticles self-assembled on Au substrate in 0.1 mol·L-1 H2SO4 was studied by using in situ FTIR reflection spectroscopy. IR absorption of linear and bridge bonded CO species was observed around 2 030 and 1 845 cm-1 respectively. IR absorption of twin bounded CO adsorbed on the Pt nanoparticles was also observed about 2 100 cm-1. The results illustrated that the IR absorption of CO adsorbed on the Pt nanoparticles has been significantly enhanced. The present study is devoted to revealinｇ the intrinsic properties of self-assembly system of nanoparticles, and is of importance in applications of electrocatalysis as well.
2004 Vol. 24 (07): 817-819 [Abstract] ( 1028 ) PDF (910 KB)  ( 388 )
820 Comparison of Infrared Spectra of Native and Esterified Beer Yeast
HAN Run-ping，BAO Gai-ling，ZHU Lu
The native beer ｙeast and esterified beer ｙeast were examined by infrared spectroscopy. The IR spectrｕm of beer ｙeast is mainly composed of the adsorption of carbohydrates, protein, etc. The dominating bands near 1 652, 1 532 and 1 240 cm-1were assigned to amide Ⅰ, amide Ⅱ and amide Ⅲ, and the characteristic IR absorption of protein could be one of the significant components of cell walls. The peak near 1 454 cm-1 is attributable to the bending stretching of CH2— and CH3—. A substantial portion of the absorbance at 1 160 cm-1 is attributable to the stretching vibration of C—O on the structure of carbohydrates, the main components of the cell walls. The band present at 1 080 cm-1 was caused by the C—O stretching of carbohydrates and alcohols found in the RNA, the DNA and/or the cell envelop of the yeast. The peaks at 1 744 cm-1 (attributed to the carboxylate stretching) and 1 454 cm-1 confirmed the esterification process of carboxylate groups presented in the cell wall. After esterification with methanol-chloride hydride, the major components and the structures of the biomaterial remained intact.
2004 Vol. 24 (07): 820-822 [Abstract] ( 1027 ) PDF (835 KB)  ( 484 )
823 Raman Spectroscopic Study of Ming Dynasty Bar-Tile from Heijing of Lufeng
WANG Yi-lin1，YANG Qun1，LI Chao-zhen2
Ming dynasty bar-tile from the archaeological site of Heijing (Lufeng of Yunnan Province, China ) was analyzed by Raman microscopy, Ｘ-ray diffraction and electron probe microscopy (EPMA). It was found that the major components of the tile are SiO2, besides moonstone(KAlSi3O8var.of K-orthoclase), Na-orthoclase(NaAlSi3O8)and an unknown mineral(Al, Fe)3(PO4,VO4)2(OH)3·8H2O etc. The studies revealed that the agglomerant temperature of the bar-tile reached up to 1 500 ℃, indicating that the agglomerant technology of ceramics of Yunnan in the Ming dynasty (before 17 century) already attained a high level. Raman microscopy proves especially excellent in studinｇ antiques. The results show that the facility and reliability of Raman spectroscopy，as a non-destructive unique technique, are suitable for the discrimination between moonstone and K-orthoclase within tile. No other technique tried was successful in its identification. This research demonstrates that only by combining several complementary techniques is possible to conduct comprehensive research on antiques.
2004 Vol. 24 (07): 823-825 [Abstract] ( 1899 ) PDF (861 KB)  ( 434 )
826 Performance Analysis of Threshold Denoising via Different Kinds of Mother Wavelets
Lü Rui-lan,WU Tie-jun, YU Ling
An ideal spectrum signal prototype is constructed in this paper based on the infrared ray spectrum of octane level measurement to evaluate the performances of wavelet based threshold denoising approaches via different combinations of mother wavelet functions and thresholds. A performance index η is defined to assess the signal-to-noise ratios (SNR) of denoising results, in consideration of the trade-off between the SNR and the distortion of the original signal after wavelet denoising. Three families of mother wavelets (Symlets, Daubechies and Coiflet), four threshold selection rules (Rigrsure, Sqtwolog, Heursure and Manimaxi)，and three threshold rescaling methods (One, Sln and Mln) are tested in a series of experiments to estimate the functioning of those wavelets and thresholding parameters. Experimental results show that in the cases investigated in this paper, the best denoising performance is reached via the combinations of Daubechies9 or Symlet7, 11, 14, 15 wavelets, “Rigrsure” threshold selection rule，and “Sln” threshold rescaling method.
2004 Vol. 24 (07): 826-829 [Abstract] ( 1068 ) PDF (854 KB)  ( 790 )
830 UV-Vis Absorption Spectral Characteristics of Tobacco PeroxidaseⅠ from Nicotiana Tabacum
XIA Bing-le, LI Min-li, LIU Qing-liang, ZHU Xiao-lan
The ultraviolet／visible spectra of TOP Ⅰ were studied. It was proved that TOP Ⅰ is an acid enzyme containing hemochrome as an agon. When the pH reduced, the Soret absorption in UV-Vis region eｘhibited a blue shift，when pH increased it eｘhibited a red shift. The result of the influence of carbamide, the denaturant, on the spectra showed that TOP Ⅰ may have a unfolded structural change in the solution, which made the peptide chain completely extend. After adding Fe(Ⅲ), Fe(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), Co(Ⅱ), Ni(Ⅱ) and Sn(Ⅱ) to the apo-TOP Ⅰ, the UV-Vis spectra changed except for Fe(Ⅲ), which almost did not change at all. The strongest characteristic absorption peak of the Soret showed a blue shift to different extent and it became weak gradually. The situation of α-strip and β-strip remained unchanged while the relative strength decreased.
2004 Vol. 24 (07): 830-833 [Abstract] ( 1079 ) PDF (907 KB)  ( 400 )
834 UV-Vis Spectroscopic Study of the Effect of Cu(Ⅱ) Ions on Dopachrome
DI Jun-wei，TU Yi-feng，ZHANG Feng
The effect of Cu(Ⅱ) ions on dopachrome has been studied by means of UV-Vis spectra in buffer solution at pH 6.5. Cu(Ⅱ) ions markedly accelerated the rate of bleaching of dopachrome (DC) at 475 nm and simultaneously eｘhibited general absorption in the range of 300-800 nm in the system with oxygen removed by bubble nitrogen gas. The experimental results revealed that Cu(Ⅱ) ions catalyzed not only the rearrangement of DC to yield mainly 5,6-dihydroxyindole-2-carboxylic acid (DHICA) on first-order kinetics with respect to DC in the first part of the reaction，but also the reaction of 5,6-dihydroxyindole (DHI) and DHICA to form indole-5,6-quinone (IQ) and indole-5,6-quinone-2-carboxylic acid (IQCA), which would immediately polymerize to ｙield melanin.
2004 Vol. 24 (07): 834-836 [Abstract] ( 986 ) PDF (898 KB)  ( 758 )
837 UV-Vis Spectrometric Characterization of the Composition of Active Complex in the Ni-P Plating Solution
WANG Xu-cheng, CAI Wen-bin, WANG Wei-jiang, LIU Hou-tian*
A strong complex agent is normally used in the alkaline chemical plating solution for Ni-P plating in order to prevent Ni ion from precipitation by hydrolysis. To keep a stable pH condition, an NH3-NH4Cl buffer system is used. Traditionally, it is considered that NH3 does not participate in the complex becaｕse of the relativelｙ low Ni-NH3 compleｘinｇ constant，bｕt some eｘperimental resｕlts cannot be eｘplained reasonablｙ. Toｕhami etc. have proposed a ternarｙ Ni-citrate-NH3 compleｘ involved in the discharｇe process，however theｙ cannot ｇive the direct sｕpport on the presence of this compleｘ in solｕtion. In this paper, a UV-Vis spectrometric study was carried out to identify the nickel complex in the Ni-P plating solution, and the results indicated the presence of both Ni-cit binary complex and Ni-cit-ammonia ternary complex. After the systematic investigation of the dependence of UV-Vis spectra on the two ligands (cit and ammonia), the composition of this Ni-cit-ammonia ternary complex was supposed to be Ni(Ⅱ)(C6H5O3-7)(NH3)3.
2004 Vol. 24 (07): 837-840 [Abstract] ( 1434 ) PDF (882 KB)  ( 424 )
841 Effect of Cancer Cells on the Spectra of Serums
GE Xiang-hong1, ZHAO Yuan-li1, ZHANG Feng-qiu1, ZHANG Lu2, YAO Shu-xia1，QIN Ying1
This article studied the different effects on the spectra of serums by adding different amount of cancer cells into serum, and gives the comparison between CNE cells’ serum spectra and Hela’ as well as that between abnormal serums and normal ones. Experiment results showed that the intensity of the absorption spectra and the fluorescence spectra exhibits a trend that it increases with the decrease in the cancer cells’ number, while begins to drop when it goes up to a certain extent. The intensity of the normal serums’ spectra is obviously higher than that of the abnormal one. It is concluded that the changes in the intensity of fluorescence spectra’ show that the cancer cells restrain the vibration of some group in the normal serums, and the absorption spectra’ reveal that the cancer cells prevent the casein from absorbing light.
2004 Vol. 24 (07): 841-843 [Abstract] ( 995 ) PDF (848 KB)  ( 513 )
844 Effect of Oxygen on the Fluorescence of Sol-Gel with Ruthenium Complexes
JIANG Ya-qi1, ZHONG Zhen-ming1, CHEN Xi1*, WANG Xiao-ru1，WONG Kwokyin2
Different Ru complexes were used in an organically modified sol-gel (ormosil) sensing film to character their quenching behaviors to oxygen. The sensing film with tris-(4,7-diphenyl-1,10-phenanthroline) ruthenium(Ⅱ) [Ru(dpp)2+3] as an indicator was selected because of its characteristics with high quenching efficiency, fast response time, high luminescence intensity and long-term stability. The quenching behavior of the sensing film greatly depended on the content of dimethyldimethoxysilane (DiMe-DMOS) in ormosil because DiMe-DMOS changed the polarity of sensing film. A home-made fluorescence quenching system was set up for oxygen determination based on a blue LED (λmax=460 nm) as an exciting light source. The response time was 30 s from saturated nitrogen to oxygen in water, and 90 s from saturated oxygen to nitrogen.
2004 Vol. 24 (07): 844-847 [Abstract] ( 1516 ) PDF (879 KB)  ( 390 )
848 Determination of Iron(Ⅲ) in Chinese Herbal Medicine and Tea Based on Fluorescence Quenching of 2,4-Dichro-Phenylfluorone
DAI Gang, AODENG Gao-wa
A new spectrofluorimetric method for the determination of trace amount of Fe(Ⅲ) has been developed. This method is based on the fluorescence quenching of 2,4-dichro-phenylfluorone due to the formation of complex Fe(Ⅲ)-DCIPF. In pH 5.2-5.9 buffer solution, Fe(Ⅲ) and DCIPF react on each other to form a red complex. Its composition was established by method of continuous variations and molar-ratio as Fe(Ⅲ)∶DCIPF =1∶4, the excitation and emission wavelengths were found to be 282 and 560 nm, respectively. There is a linear relationship in the range 4-24 ng·mL-1 for Fe(Ⅲ). This method is simple and rapid, and has been applied to the determination of trace iron in Chinese herbal medicine and tea samples with satisfactory results．
2004 Vol. 24 (07): 848-850 [Abstract] ( 990 ) PDF (885 KB)  ( 400 )
851 Direct Fluorophotometric and Flow-Injection Fluorophotometric Methods for the Determination of Trace Ammonia
GUO Liang-qia, XIE Zeng-hong*, LIN Xu-cong, KE Zi-hou, CHEN Guo-nan
Direct fluorophotometric and flow-injection fluorophotometric methods for trace ammonia measurement involving the fluorescent reaction of ammonia with o-phthaldlaldehyde (OPA) and 2-mercaptoethanol(ME) producing derivant of iso-indol in alkaline solution are described. Triton X-100 was added to improve the stability of the system. The maximum excitation wavelength is 415 nm, while the maximum emission wavelength is 486 nm. With direct fliuorophotometric method, the calibration curve’s regression equation is ΔI＝22.286＋785.71cNH3(μｇ·mL-1)(r＝0.999 5) in the range of ammonia concentration from 0.2 to 1.0 μｇ·mL-1, and ΔI＝-27.429＋2 371.4cNH3(μｇ·mL-1) (r＝0.996 5) in the range of ammonia concentration from 0.02 to 0.10 μｇ·mL-1. With flow-injection fluorophotometric method, the calibration curve’s regression equation is ΔI＝1 188cNH3(μｇ·mL-1)(r＝0.999 8) in the range of ammonia concentration of ammonia 0-0.7 μｇ·mL-1. The mechanism of reaction was also briefly discussed.
2004 Vol. 24 (07): 851-854 [Abstract] ( 592 ) PDF (910 KB)  ( 421 )
855 The Fluorescence Characteristics of Micelle Inclusion of Pefloxacin and Its Application
DU Li-ming, WANG Jing-ping, WANG Cai-xia
A new highly sensitive fluorescence spectrophotometic method for the determination of pefloxacin (PEFX) has been developed based on micella enhancement. The fluorescence characteristic of micelle inclusion complex formed between PEFX and sodium dodecyl sulfate (SDS) was studied. Different variables and parameters affecting the fluorescence were studied and optimized. Experiments show that sodium dodecyl sulfate can enhance greatly the fluorescence signal for pefloxacin in pH 5 Britton Robinson(BR) buffer solution. The fluorimetric method allows the determination of 0.06-1.20 μg·mL-1 of pefloxacin with SDS in aqueous solution with λex=278 nm and λem=432 nm, respectively. The detection limit for PEFX is 0.06 μg·mL-1, The recoveries are 98.5％-100.8% and the RSDs are 1.4％-2.3%. The proposed procedures could be applied successfully to the determination of the pefloxacin drugs in tablets and human plasma with good recovery. In this paper we determined pefloxacin in human plasma by synchronization-derivative fluorescence spectroscopic techniques with good analytical selectivity，high sensitivity, high capability of eliminatinｇ blank interference and improvinｇ the limit of detection.
2004 Vol. 24 (07): 855-857 [Abstract] ( 1567 ) PDF (885 KB)  ( 556 )
858 Study on the Interaction of Cordycepin and DNA
PENG Jun-feng，LING Jian-ya，ZHANG Han-xing，ZHANG Chang-kai*
The absorbance, fluorescence and Scatchard plots methods as well as the effect of phosphate group on the fluorescence intensity of the cordycepin-DNA-EB system were used to study the interaction of the antitumor compound cordycepin and DNA. It is obvious tiat there is hyperchromic effect and hypochromic effect with slight red shift on the subtracted UV spectrum. It proves that the adenine base of cordycepin can be inserted into the double-helix of DNA. The results of the fluorescence intensity that decreases after increases with a little blue shift on the fluorescence spectrum also proved this. At the same time the phosphate can affect the cordycepin-DNA-EB system. Finally that the result depended on the Scatchard equation indicates that cordycepin reacts electrostatically on phosphate backbone of DNA. There also exists an intercalation into the double-helix of DNA.
2004 Vol. 24 (07): 858-861 [Abstract] ( 1185 ) PDF (921 KB)  ( 553 )
862 A Study on Inclusion Complexes of Cyclodextrin with Three Anticancer Xanthines by Fluorescence
WEI Yan-li, DONG Chuan*
The inclusion complexes of β-Cyclodextrin (β-CD) and HP-β-Cyclodextrin (HP-β-CD) with 6-Mercaptopurine (6-MP), Azathioprine (BAN) and 8-Azaguanine (Azan) were investigated by fluorescence. Various factors affecting the formation of inclusion complexes were discussed in detail including formation time and pH effect. The formation constants of their inclusion complexes were determined. The results indicated that their inclusion was affected significantly by laying time and pH. The formation time of β-CD inclusion complexes is much longer than that of HP-β-CD. The optimum pH is about pH=7.7-12. Their maximum excitation wavelengths are all in the range of 276-285 nm and the maximum emission wavelengths are all in the range of 328-353 nm. The fluorescence signals are intensified with increasing concentration of CD. The stoichiometries of the inclusion complexes of CD with these three anticancer xanthines are all 1∶1 and the formation constants are calculated.
2004 Vol. 24 (07): 862-866 [Abstract] ( 1439 ) PDF (965 KB)  ( 468 )
867 Resolution for the Kinetic Process of Ultrasound-Assisted Electro-Catalytic Degradation of Benzoic Acid
ZHAO Yi, ZHU Zhong-liang, HUANG Xiao-feng
The two-way kinetic-spectral data can be acquired bｙ monitoring the process of the ultrasound-assisted electro-catalytic degradation of benzoic acid. The product of absorbing intermediate is confirmed by FSMWEFA(Fix-sized Moving Window Evolving Factor Analysis). The real kinetic spectra and absorption spectra, which are hard to measure directly, are resolved by ITTFA (Iterative Target Transformation Factor Analysis) combined with the isoabsorptive points between components. The kinetic model of benzoic acid degradation is also studied.
2004 Vol. 24 (07): 867-869 [Abstract] ( 966 ) PDF (856 KB)  ( 404 )
870 Kinetic-Spectrophotometric Determination of Trace Manganese by IO-4-Tetrabase New System and the Mechanism
LI Jian-guo, ZHANG Min, ZHAO Kang
A new kinetic-spectrophotometric method for the determination of trace amounts of manganese(Ⅱ) has been proposed. The method is based on the manganese(Ⅱ) catalyｚinｇ the coloring reaction of tetrabase[4,4’-bis(dimethylamino)-diphenylmethane] oxidized by sodium periodate in HAc-NaAc(pH≈5.0) medium. The linear range of the determination of manganese is 0-4 μg·L-1, and the detection limit is 4.6×10-11 g·mL-1. The method is not only simple, rapid and with good sensitivity but also without heating. It has been used for the determination of trace amounts of manganese in water sample with satisfactory results. The mechanism of the reaction is discussed in detail.
2004 Vol. 24 (07): 870-872 [Abstract] ( 1599 ) PDF (876 KB)  ( 440 )
873 Catalytic Kinetic Spectrophotometric Determination of Trace Ascorbic Acid
ZHANG Zhen-xin, SUN Deng-ming*, RONG Zhen-hai
In this paper, a new catalytic kinetic spectrophotometric method for the determination of trace amounts of ascorbic acid has been studied. The method is based on the activation effect of ascorbic acid on vanadium(Ⅴ) catalyzed oxidation of deoxidized rhodamine B by potassium bromate in weak acidic medium at pH 4.5. The optimal experimental conditions have been discussed. The absorbance was measured at 555 nm. The linear range of the method was 0-7.0 μg·mL-1. The detection limit for ascorbic acid was 2.5×10-7 g·mL-1. The method has been applied to the determination of ascorbic acid in vitamin C tablet and tomato with satisfactory results.
2004 Vol. 24 (07): 873-875 [Abstract] ( 1445 ) PDF (823 KB)  ( 504 )
876 Study on the Spectra and Extractive Performance of Copper, Lanthanum, Uranium and Cerium by Tween-80-(NH4)2SO4-Xylenol Orange System
DENG Fan-zheng，SHI Ying，CHEN De-zhi
In a Tween 80-(NH4)2SO4-xylenol orange liquid-solid extraction system, absorption spectra of complexes of metal ions in extraction phase with xylenol orange as the extractant were investigated. Compared to xylenol orange spectra, the maximum wavelength of complexes of Cu(Ⅱ), U(Ⅵ) and Ce(Ⅳ) shifted to the red by 20-30 nm, while that of La (Ⅲ) did not. With different acidity, quantites of xylenol orange and salt, and surfactant, the efficiencies of Cu(Ⅱ), La(Ⅲ), U(Ⅵ) and Ce(Ⅳ) metal ions were discussed. The results indicated that the complexes of Cu(Ⅱ) and U(Ⅵ) with xylenol orange were almost completely extracted by the Tween-80 phase, that of Ce(Ⅳ) was partially extracted, while that of La(Ⅲ) was not extracted from the aqueous solution of pH 6.0. The extraction separation of La(Ⅲ) and U(Ⅵ) was carried out by controlling the solution acidity.
2004 Vol. 24 (07): 876-878 [Abstract] ( 1050 ) PDF (878 KB)  ( 391 )
879 Chromaticity Analysis for Colorants in Dye-Based Ink-Jet Inks
ZHU Pu-xin, YAO Yong-yi, WANG Luo-xin, WU Da-cheng
For ink-jet color inks used for the well-known printers, taking Canon, EPSON, HEWLETT PACKARD and LEXMARK as samples, transmittances of the ink solutions were determined, and then the chromaticity analyses were made, in order to calculate the tristimulus values and the chromatic coordinate of each color sample. Also, the gamuts, chroma values, dominant wavelengths and complementary wavelengths were obtained by using the chromatic method for the samples. In this paper, an empirical formula was suggested for the relationship between the complementary wavelengths of the three primary colors: λcompl, M10／9(λcompl, Y)+10 and λcompl, M9／10(λcompl, Y)-20. It was found that the empirical formula is well suited for matching the complementary wavelengths of the three primary colors for ink sets of the samples studied.
2004 Vol. 24 (07): 879-882 [Abstract] ( 1972 ) PDF (877 KB)  ( 469 )
883 Determination of Three Components in Compound Acetylsalicylic Acid Tablet by Dual-Wavelength Ratio Spectrometry
SUN Zeng-xian, ZHANG Qian-feng, ZHOU Jin-yu
The contents of three components in compound acetylsalicylic acid tablets were determined by dual-wavelength ratio spectrometry. According to the feature of the spectra, 213, 227, 245 and 265 nm were chosen as the determining wavelengths. It is shown that for the three components good linear correlations exist for acetylsalicylic acid (5-20 μg·mL-1), phenacetin (2-10 μg·mL-1), and caffeine (2-20 μg·mL-1). The average recoveries were 100.03%, 100.23% and 99.96% respectively. The results were consistent with those obtained by the standard method of Health Ministry(P＞0.05). The method is simple and practical with fewer determination wavelengths and powerful spectral resolution, and can be performed on a lower level instrument, as well as be easily spreaded for application.
2004 Vol. 24 (07): 883-886 [Abstract] ( 1631 ) PDF (848 KB)  ( 475 )
887 Optimization Investigation on the Elements in Ferrum Aluminum Silicon Alloy by ICP-AES
HE Hai-cheng1, 2，ZHANG Guang-xia2，HUANG Zhi-rong1，HE Xi-wen1*，HUANG Xin-ping3, YANG Ti-shao3
A method for the determination of Al, Fe, Ca, Cr, Mn, Ni, Si and Ti elements in ferrum aluminum silicon alloy by inductively coupled plasma atomic emission spectrometry (ICP-AES) was described. The influence of ICP-AES operating conditions, sample dissolution methods and spectral lines were studied. The preferable experimental conditions were examined, and the influences of coexistent elements on the signals were investigated. The method was applied to the determination of elements in ferrum aluminum silicon alloy samples, and the measured results were in good agreement with the recommended values of the standard steel. The detection limits of the method were 0.029 μg·mL-1 for Al, 0.004 μg·mL-1 for Fe, 0.007 5 μg·mL-1 for Ca, 0.001 5 μg·mL-1 for Cr, 0.000 9 μg·mL-1 for Mn, 0.002 7 μg·mL-1 for Ni, 0.045 μg·mL-1 for Si and 0.003 μg·mL-1 for Ti. The relative standard deviation (n=6) of this method was between 0.3%-1.8％, and the recoveries by standard addition were in the range of 96.7%-102.9%. The method was used to determine the amount of silicon in alloy samples with satisfactory results, which agreed with those by the standard gravimetrｙ. The method is characterized by good precision, easy operation and convenience to apply.
2004 Vol. 24 (07): 887-889 [Abstract] ( 1691 ) PDF (878 KB)  ( 495 )
890 Determination of Elements of Hypericum Perforatum L. in Xinjiang by Microwave Digestion-ICP-AES
YI Xin-ping1，LIU Jian-ping1，LI Ge2
Sample digestion by microwave is of some merits: simple, rapid, saving agents, nonpollution and being easy digested. HNO3-HClO4(5∶1) was used as a microwave digestion agent. A direct method is reported for the determination of Fe, Ca, Mg, Zn, Mn, Cu, Na, K, Ba, Al, Pb and Cr in Hypericum perforatum L. in Xinjiang by inductively coupled plasma atomic emission spectrometry(ICP-AES). The selection of digestion conditions of the technique is described. The recoveries for these elements were 93.2%-103.0%, and the relative standard deviation(RSD) of the twelve samples were 0.4%-2.9%. According to standard sample GBW07602 bush twigs and leaves, the authors checked the method for accuracy and precision. The results were found to be basically consistent with the reference values. It was proved that the method features satisfactory precision and accuracy. The method was applied to the determination of plant materials with good agreement.
2004 Vol. 24 (07): 890-892 [Abstract] ( 1040 ) PDF (863 KB)  ( 368 )
893 Determination of Trace Mercury in the Chinese Traditional Medicine by Hydride Generation-Atomic Fluorescence Spectrometry
SHI Jie, ZHU Yong-qin, GONG Xue-yun
A hydride generation atomic fluorescence spectrometry method has been developed for the determination of trace mercury in traditional Chinese medicines. A high-pressure digestion using HNO3-H2O2 system was applied to the pretreatment of traditional Chinese medicine samples and an interval flow precedure was used. The experimental conditions and instrumental operation parameters such as KBH4 concentration, flow rates of carrier and shield gases, currents of lamp and height of atomic oven，which affect the determination，have been optimized respectively as 0.05%, 400 and 800 mL·min-1, 20 mA and 6 mm. Under the optimum conditions, there is a linear relationship between the fluorescence intensity and the mercury concentration with correlation coefficient of 0.999 9, while the detection limit is 0.021 μg·L-1. Trace mercury in the standard reference substance peach leaf (GBW08501, produced by the Environmental Science Committee of Chinese Scientific Institute) was also determinated in this way and the results of six times were in good agreement with the certified value, with a variation coefficient not more than 0.34%. This method is simple, rapid, sensitive, convinent and accurate, so it can be successfully used for the determination of trace mercury in traditional Chinese medicines.
2004 Vol. 24 (07): 893-895 [Abstract] ( 934 ) PDF (862 KB)  ( 527 )

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