ANALYST, MAY 1993, VOL. 118 61N Conference Report Huayi International Symposium on Analytical Chemistry: October 20-24, 1992, Wuhan, People‘s Republic of China The Huayi International Symposium on Analytical Chemistry brought together over 200 participants from different countries. Most of the delegates were Chinese-speaking (‘huayi’) analytical chemists so the official languages for the symposium were Chinese and English. The programme was extensive and included 10 Plenary Lectures, a number of invited lectures and oral presentations that covered various aspects, fundamental as well as applied, of analytical chemistry. After a ‘welcome’ by the organizer, Yun’e Zeng (Wuhan University, Wuhan, P.R. China) and the opening by Hong Gao (Nanjing University, Nanjing, P.R. China), the Plenary Lecture by K.L. Cheng (University of Missouri, Kansas City, MO, USA) discussed some common and significant miscon- ceptions in analytical chemistry present in the literature and textbooks. One example of these misconceptions is the mis-use of the Nernstian equation in non-faradaic poten- tiometry. According to Cheng, this is the second Nernstian hiatus in electroanalytical chemistry after the first as pointed out by John Bockris (Modern Electrochemistry, Plenum Press, New York, 1977, vol. 1, p. 17). Cheng pointed out that the important role of OH- in the development of a potential by a glass electrode was ignored, and talking about the measure- ment of hydrogen ion concentration in a solution of, say, 18 moll-’ KOH was a nonsense, as 1 1 of such a solution did not contain a single hydrogen ion! Chromatography Chromatography was the main topic in the section on separation science.Peichang Lu (Dalian Institute of Chemical Physics, Academia Sinica, Dalian, P.R. China) gave an upbeat presentation of the state-of-the-art of expert systems in chromatography. He reviewed the systematic research work of his group in the field of high-performance liquid chromato- graphy (HPLC) expert systems. The recommendation of column systems, intelligent optimization of the chromato- graphic process and qualitative identification of unknown samples were important parts of the designed expert system. Jieke Cheng (Wuhan University), the General Secretary of this symposium, reviewed the recent works of his group in the field of HPLC of metal complexes, the synthesis of tetra- phenylporphyrin derivatives with fluorine, chlorine or bro- mine substituents and their retention characteristics.A micro-volume detector for HPLC and high-performance capillary electrophoresis (HPCE) was presented by Yanzhuo Deng (Wuhan University). The He-Ne laser beam focused by a lens passes through the sample cell and produces an interference pattern. The change of light intensity in the interference ring centre, which is proportional to the change of refractive index, is monitored using a photodetector. The laser interferometric detection was also used by Deng for capillary zone electrophoresis (CZE). Yung-Lin Chen (J & W Scien- tific, Folsom, CA, USA) discussed tailor made stationary phases and other recent works in the field of HPLC.The synthesis of nitrogen-containing crown ether bounded station- ary phase, BCN18-C6, for HPLC via a solid-phase reaction pathway was reported by Shilu Da (Wuhan University). Caiying Wu (Wuhan University) studied the selectivity of a crown ether polysiloxane stationary phase. Jianxiong Feng (Jiangxi Academy of Agricultural Science, Nanchang, P.R. China) used HPLC to study the correlation between the content of free monosaccharides and disaccharides in stalks, roots of tomato varieties and their antiviral ability. The protein folding on the hydrophobic surface of stationary phases for high-performance hydrophobic interaction chro- matography (HPHIC) was studied by Xindu Geng (Northwest University, Xi’an, P.R. China). Boli Zuo (Chemical College, Beijing, P.R. China) designed a stainless-steel flow cell with ZnSe as the window material for construction of a CO2 laser induced photoacoustic detector for gas chromatography (GC).Two-dimensional GC was used for the analysis of selenomethionine in complex mixtures of the hydrolytic products of proteins in selenium-enriched mushrooms by Bingjiu Xu (Beijing Medical University, Beijing, P.R. China). Qiang Gu (Hua Feng Nutrition Factory, Wuxi, P.R. China) used GC for determining trans-10-hydroxy-2-decenoic acid, which was claimed to have an anticancer effect, in a popular Chinese tonic Royal Jelly. Weixi Yao (Dionex Corporation, Sunnyvale, CA, USA) reviewed the recent development of capillary electrophoresis (CE) and the important criteria for comparison of different CE apparatus. David T.Mao (J & W Scientific) discussed ways of solving problems associated with the use of capillary gel electrophoresis (CGE) . One approach is the development of replaceable polymerhetworks as the sieving media to avoid contamination carried from previous analysis. Weixi Yao (Research Centre for Eco-environmental Science, Beijing, P.R. China) and Eugene Lo Wei (Dionex Corporation) reviewed supercritical fluid chromatography (SFC) and supercritical fluid extraction (SFE) techniques. It is possible to use SFE to separate carcinogenic benzo[a]anthran- cene (BaA) and benzo[j]fluoranthene (BjF) from their isom- ers chrysene and benzo[k]fluoranthene (BkF) , respectively, the last two being of low toxicity. Fullerenes Several speakers presented work on fullerenes and their fluorinated derivatives.Wenkuan Zhao (Wuhan University) reported the preparation of a dark red-brown liquid consisting of Cm-C, by extraction of a black graphitic soot, which was produced by arcing in a vacuum using boiling benzene in a Soxhlet extractor. Chromatographic separation and mass spectrometry (MS) , 13C nuclear magnetic resonance spectros- copy (NMR) and Fourier transform infrared (FTIR) spec- trometric identification were reported. Yiliang Sun (Peking University, Beijing, P.R. China) reported the chromato- graphic analysis of fullerenes in the toluene extract of the soot produced by contact-arc vaporization of a graphite rod. Besides Cm and C7,,, a small amount of some higher fullerenes probably also existed.Rongsheng Sheng (Wuhan University) used surface-enhanced Raman spectra (SERS) for studying the symmetry of C6,, prepared in their laboratory. They claimed that the symmetry of Cm adsorbed onto the silver mirror was changed and adopted a more ellipsoidal shape and Cm was unstable under laser radiation. Yi Wu (Institute of Microchemistry, Beijing, P.R. China) reported the field desorption (FD) mass spectra of Cm, C70 and fluorinated fullerene C60F60.62N ANALYST, MAY 1993, VOL. 118 Spectroscopy A number of new spectroscopic techniques along with some traditional ones attracted the attention of delegates. Xihui Luo (Fushun Research Institute of Petroleum & Petrochem- icals, Fushun, P.R. China) reported the use of positron annihilation spectroscopy for chemical analysis (PASCA) for studying the catalysts used in petrochemical industries.As PASCA is based on the chemical probes, positrons and ortho-positroniums, which can react chemically with the active sites on a catalyst surface it should be a powerful complement to electron spectroscopy for chemical analysis (ESCA) and extended X-ray absorption fine structure spec- troscopy (EXAFS), which are based on physical phenomena. By using PASCA, a method for explaining the essential features of the surface of alumina was formulated. The interaction between metal and its supported material and formation of metal support interaction complex were found. Meisheng Zhou (National University of Singapore, Singa- pore) described construction and calibration of her interesting apparatus for photopyroelectric spectroscopy (PPES) .When a metal is coated with a polymer layer, and the temperature of metal-polymer interface increases due to non-radiative relax- ation processes following optical absorption, the polarized film aligns its polar constituent crystallites along the temperat- ure gradient field, thus producing a net dipole moment, which results in a pyroelectric voltage. The PPES based on this phenomena was used for identification and characterization of the electrode surface coating. Yongfa Zhu (Tsinghua Univer- sity, Beijing, P.R. China) reported the method for calculation of chemical shift in Auger electron spectroscopy by XPS (X-ray photoelectron spectroscopy) binding energy. He used this technique to study surface reaction of oxygen on zinc, Ti/Si interface reaction and the structure of lubrication films.H. C. Kang (National University of Singapore) studied the reconstruction of platinum and gold films on 11oPd using Auger electron spectroscopy and low-energy electron diffrac- tion (LEED). In a Plenary Lecture, Guo-Qin Xu (National University of Singapore) reported his studies on alkali overlayers and their oxides supported on 1olRu using high- resolution photoemission spectroscopy and thermal desorp- tion. By using these techniques, it was observed that upon the exposure of oxygen to potassium overlayer, the initial oxidation occurred in the ‘bulk’ layer, not the surface layer as expected. Tsutomu Fukasawa (Yamanashi University, Japan) reported the use of an X-ray diffraction technique for speciation and quantification of inorganic compounds, in particular the characterization of airborne particulates from Tokyo, Japan, and Sichuan, P.R.China. He claimed that some new compounds with a high-lead content, which were isostructural with potassium lead chromates, were found. Yang Lu (Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing, P.R. China) showed a special software program NOMCSDP for routine analysis of organic molecules, especially natural organic compounds, by using X-ray diffraction methods. Guangzhong Tu (Beijing Institute of Microchemistry) used NMR for analysis of liquorice, a well known traditional drug in China. The structure of squasapoge- no1 extracted from liquorice was identified as olean-11,13( 18)- diene-3,22-diol.Proton NMR was used by Yong-Cheng Hing (Tsinghua University) for identification of the viper venom components, which were used for treating thrombosis and atrophic gastritis. Xiao-Yuan Li (Hong Kong University of Science and Technology, Hong Kong) gave an informative Plenary Lecture on the use of resonance Raman spectroscopy (RRS) and related Raman techniques for studying the structure and dynamics of metalloporphyrins, which are the prosthetic group of haemproteins. Rongsheng Sheng (Wuhan University) reported the in situ SERS of 5,10,15,2O-tetra-(4- trimethylammoniumpheny1)porphyrin at a silver electrode. The use of IR photoacoustic spectroscopy for analysis of fibrous samples such as acrylic, wool and ramie was reported by Xueguang Shao (Chinese University of Science and Technology, Hefei, P.R.China). Fluorescence Fluorescence and related methods were the subject of a number of presentations. Yaoqun Li (Xiamen University, Xiamen, P.R. China) derived an equation for calculating the wavelength position of solvent Raman scatter appearing on constant-wavelength synchronous fluorescence spectra. Longdi Li (Tsinghua University) studied the room tempera- ture phosphorescence of 6-coumarinsulfonyl chloride as a labelling reagent for amino acids. Zhujun Zhang (Shaanxi Normal University, Xi’an, P.R. China) discussed the new approaches to solid surface chemiluminescence (SSCL). By using foaming plastic as the solid support, a method for determining 0.1-10 pg of gold was developed for ore and steel analysis. Zhang also reported a fibre-optic biosensor for 0.1-10 pg ml-1 of lactic acid by covalently coupling lactate oxidase and horseradish peroxidase to 3-aminopropyl porosity silica via glutaraldehyde and attaching the silica to the end of fibre-optic handle. Yuanbao Zhu (Hunan University, Chang- sha, P.R.China) reported the design of two fibre-optic sensors for ammonia. The membranes contained a neutral carrier for ammonium ion and a lipophilic pH indicator. Kemin Wang (Hunan University) reported an optical sensing membrane containing dinaphthyl-20-crown-6 and ETH5294 as the neutral carrier and lipophilic pH indicator, respectively. The membrane was sensitive to primary amine drugs. Micellization Micelle-sensitized spectrophotometry and fluorimetry was studied by a number of investigators. Yong-Xi Zheng (Tsing- hua University) proposed a new mechanism for the sensitizing effect of cetyltrimethylammonium on the absorbance and fluorescence of the Zr-morin complex.A sensitive method for determination of Ru was reported by Zuting Pan (Wuhan University) using 01, p, y ,&te trakis(4- trime thylammonium- pheny1)porphyrin and dodecylbenzenesulfonate. The micelli- zation behaviour of the steroidal surfactant sodium deoxy- cholate was studied using fluorescent probe, optical rotation and conductivity measurements by Yunbao Jiang (Xiamen University). New Reagents A number of new analytical reagents were reported: 2,4- dimethoxyphenylfluorone (Jinduan Zhao, China University of Geosciences, Wuhan, P. R. China), 4-formacylbenzene- diazoaminoazobenzene (Yinglu He, China University of Geosciences) , rneso-tetra(4-methoxy-3-sulfonatophenyl)por- phine (Yushou Chen, Fuzhou University, Fuzhou, P.R.China), 5-(6-bromobenzothiazole-2-azo)-8-aminoquinoline, diantipyryl-o-chlorophenylmethane (Qiheng Xu, Yunnan University, Kunming, P.R. China), 2,3,7-trihydroxy-9-lyral- 6-fluorone (Xianchun Li, Jiangxi Normal University, Nan- chang, P.R. China), 9-(3,5-dibromo-4-amino)phenylfluorone and other derivatives of phenylfluorone (Huashan Zhang, Wuhan University), 1-(4-antipyriny1)-3-(4-nitrophenyl)- triazene (Bin Xu, Hubei Normal University, Huangshi, P.R. China). Atomic Spectrometry Some new techniques for atomic spectrometry were presented at the symposium. Benli Huang (Xiamen University) des- cribed in his Plenary Lecture a simple and compact nebulizer- hydride generator system for simultaneous determination of hydride forming elements and monohydride forming ones.The sensitivity for the hydride forming elements was substan-ANALYST, MAY 1993, VOL. 118 63N tially improved. Hydride generation was also studied by Li Zhang (Perkin-Elmer, Norwalk, CT, USA). The matrix effect in inductively coupled plasma atomic emission spectrometry (ICP-AES) was studied by Zhanxia Zhan (Zhongshan Uni- versity, Guangzhou, P.R. China) using an optical-fibre probe to sample the spatial position of plasma and constructing the three-dimensional spatial distribution of electron densities in the presence of different elements. Li-Ching Tian (Nanjing University) combined a movable sampling device with a pulsed laser to eliminate the effect of inhomogeneity of powdered solid geological samples in ICP-AES.Zucheng Jiang (Wuhan University) studied the use of a poly(tetra- fluoroethylene) slurry fluorinating reagent in electrothermal vaporization (ETV) in ICP-AES to avoid the formation of refractory carbides by converting the analytes into their corresponding halides. The detection limit was improved by 1-2 orders of magnitude compared with the conventional ETV procedure. The advantage of an end-on viewing ICP for AES has been recalled and re-evaluated for its suitability to ICP-AES coupled with a charge-injection device as the mass detector. Pengyuan Yang (Xiamen University) reported his latest work using an end-on viewing ICP-AES instrument with D.Nygaard (Baird Corporation, Bedford, MA, USA). Jianshi Ren (Institute of Metal Research, Shenyang, P.R. China) studied the cathode sputtering of alloys in glow discharge lamp and showed the hyperbolic relationship between the sputtering rate and concentration of constituents of these alloys. Xiaobin Zeng (Wuhan University) studied the high-temperature reaction of A1 compounds on a graphite substrate for elucidation of their interference on the determi- nation of precious metals by electrothermal atomic absorption spectrometry (ETAAS). Gongke Li (Zhongshan University) studied the characteristic mass for many elements under standardized conditions for absolute analysis by ETAAS. A correction factor was defined to account for the effect of experimental parameters.Electroanalysis The electroanalytical chemistry section was one of the largest sections of the symposium. In his Plenary Lecture, Hong Gao (Nanjing University) reviewed the systematic study of oscillo- graphite analysis undertaken by his group and gave a comprehensive classification of different methods. The improved oscillographic chronopotentiometry, for instance, changes the incision of the dEldt versus E curve into a very sharp peak with a height directly proportional to the concen- tration of sought-for species. Ultramicroelectrodes have been the subject of many investigations for their ability to offer dramatic improvement in the quality of electrochemical data. The theory of these ultramicroelectrodes was studied by Zuxun Zhan and Hongyuan Chen (Nanjing University).Chen derived the current equations of single sweep and first-, second- and third-order differential voltammetry at ultramic- rodisc electrodes. Li Jiang (University of Oxford, Oxford, UK) reported the fabrication of a microelectrode array on silicon substrates with individual elements of from 0.3 to 5 pm dimensions by photolithography and electron beam litho- graphy. The arrays retained the advantages of single ultra- microelectrodes while substantially increasing the current response. Jinyuan Mo (Zhongshan University) reported a series of advances in cyclic staircase pulse voltammetry (CSPV), which improved the symmetry of the waveform of square-wave voltammetry. In the middle of each staircase step of cyclic scan a pulse is superimposed. The currents are measured at both the advancing and following edge of each pulse. After addition the forward and reverse charging currents are eliminated.The theoretical equations of CSPV for different types of electrode reactions were derived by Mo. In his Plenary Lecture, Ying-Sing Fung (University of Hong Kong, Hong Kong) described the theoretical equation derived and verified by him for the transient current response at planar electrodes for a reversible electrode reaction in steady-flow system. Jem-Mau Lo (Tsinghua University, Hsinchu, Taiwan) combined differential-pulse anodic stripping voltammetry with a preconcentration extraction procedure for determina- tion of 0.1 pg 1-1 of metal in sea-water. Shaojun Dong (Changchun Institute of Applied Chemistry, Changchun, P.R. China) reviewed her recent research in designing chemically modified electrodes. The enzyme sensors for glucose, alcohol, lactate and malate with mediators and improved sensitivity and selectivity were reported.Some porphyrin derivatives were synthesized as a kind of artificial enzyme for biosensor design. The ion transfer at the liquid liquid interfaces of membranes containing some newly syn- thesized bis-crown ethers were studied by Jinyao Yin (Beijing Research Institute of Chemical Engineering & Metallurgy, Beijing, P.R. China) for design and characterization of K+ and pH sensors. Shouzhuo Yao (Hunan University) discussed the design and theory of piezoelectric sensors in the liquid phase. An immunosensor was reported by Guoli Shen (Hunan University) for a-fetoprotein, which is an important index for clinical diagnosis of liver cancer. C hemome trics Chemometrics were the subject of a series of presentations.The author of this report gave a Plenary Lecture entitled ‘Analytical chemometrics: theory and methodology of chem- ical measurement’. The development of analytical chemo- metrics including analytical information theory, theories of sampling, analytical detection, calibration, etc., stimulated formulation of a sound mathematical theory of chemical measurement, which should play an important role in the development of modern analytical chemistry. Zhenpu Wang (Nanjing Institute of Chemical Technology, Nanjing, P.R. China) made a comparison of different chemometric methods for multivariate calibration in FTIR analysis using Monte Carlo simulation.The Monte Carlo simulation was also used for studying the nebulization and evaporation process in ICP-AES by Jianguo Zheng (Zhongshan University). Bo Deng (Tsinghua University, Beijing) used the fuzzy orthogo- nal design for the optimization of ETAAS. Yaoguang Wang (Fuzhou University) combined Kalman filtering with fast Fourier transform smoothing and a standard additions method to resolve overlapping neopolarographic peaks. The Kalman filtering method was also used for photodiode-ICP-AES for the determination of trace ytterbium in vanadium by Xiaoguo Ma (Zhongshan University). Jian Fan (Zhongnan University of Technology, Changsha, P.R. China) reported the simul- taneous indirect determination of anions using their interfer- ence effect on the atomic absorption of calcium.The data were analysed by the partial least squares (PLS) method. Spline smoothing was used by Jinyuan Mo (Zhongshan University) for step voltammetry data treatment. Tianming Yang (Zhongnan College for Minority Nationalities, Wuhan, P.R. China) reported the experiment of using pattern recognition for carcinoma diagnosis by using the trace element content of patient’s hair as feature variables. Zheng Li (Shanghai Institute of Organic Chemistry, Shanghai, P.R. China) used neural networks for prediction of furnace lining durability in some industrial plants. Applications The problem-oriented applications of various analytical methods focused on environmental chemistry and life science. Jiunn-Guang Lo (Tsinghua University, Hsinchu, Taiwan) gave an informative Plenary Lecture on trace gas analysis in connection with the CATS programme (Climate and Air- quality Taiwan Station) for studying long-term air quality change and their impact on the climate of Taiwan.Xiaobai Xu64N ANALYST, MAY 1993, VOL. 118 (Research Centre for Eco-environmental Sciences) discussed the analytical aspects of a series of papers on polycyclic aromatic hydrocarbons and some recently discovered environ- mental carcinogens and mutagens. The variation of iron and molybdenum concentration in the sea-water during the red tide (RT) was studied by Xiuhuan Yang (Zhongshan Univer- sity) by using Zeeman-effect background corrected ETAAS. The iron concentration within the RT area was relatively high, decreasing rapidly in the course of RT and rising again after the disappearance of RT.On the contrary, the molybdenum concentration first decreased, then rose gradually and sus- tained for 1-2 d after the disappearance of RT. Tonghui Zhou (Institute of Materia Medica, Beijing) gave a Plenary Lecture on the use of rat liver microsomes for in vitro metabolic studies of drugs. Erik Lund (Huddinge University Hospital, Hud- dinge, Sweden) studied the mechanism of peroxidation of cholesterol into monooxygenated products by lipoxygenase system. He also reported the analysis of the ginseng G155 extract. The optimized procedure with alkaline hydrolysis was found to produce 20-s-protopanaxadiol and 20-s-protopanax- atriol from ginsenosides with about 80% yield. Te-Hsien Lin (School of Technology for Medical Sciences, Kaohsiung Medical College, Kaohsiung, Taiwan) measured lipid peroxi- dation in tissues and body fluid of mercury intoxicated rats to study the molecular mechanism of cell injury in acute HgC12 poisoning. Conclusion Space does not permit the description of many excellent presentations. The symposium was well organized and managed, the absence of a language barrier and the friendly atmosphere throughout prompted optimum interaction between the delegates. An interdisciplinary symposium of this kind has the advantage of the cross-fertilization that occurs when people dealing with various aspects of analytical chemistry come together and discuss diverse ways of looking at similar problems. The diversity and depth of study reported was truly impressive. The next Huayi Symposium on Analy- tical Chemistry will take place in Guangzhou, China, in 1995. Ru-Qin Yu Department of Chemistry and Chemical Engineering, Hunan University, Changsha 41 0082, Peoples Republic of China