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Analytica Chimica Acta (v.576, #1)

Editorial Board (pp. co1).

Contents (pp. vii-viii).

Calendar of forthcoming meetings (pp. n1).

Editorial Board (pp. co1).

Contents (pp. vii-viii).

Preface by Ching-Erh Lin (pp. 1-1).

Continuous multi-element (Cu, Mn, Ni, Se) monitoring in saline and cell suspension using on-line microdialysis coupled with simultaneous electrothermal atomic absorption spectrometry by Wei-Chang Tseng; Po-Hua Chen; Tong-Shung Tsay; Bai-Hsiun Chen; Yeou-Lih Huang (pp. 2-8).

We have developed a microdialysis sampling technique coupled on-line with simultaneous electrothermal atomic absorption spectrometry (SIMAAS) for the continuous monitoring of copper (Cu), manganese (Mn), nickel (Ni), and selenium (Se) in saline solutions and in cell suspensions. These trace elements are considered to be those associated most significantly with oxidative stress in biological systems. We employed ultrapure saline (0.9% NaCl) as the perfusate and, thus, the dialysate samples contained a high concentration of salt in the matrix. The use of modifiers [Pd coupled with Mg(NO₃)₂] prevented the target elements from undergoing evaporation at a pyrolysis temperature of 1200°C, a process that effectively eliminated interference from NaCl. The excellent linearity, detection limits, and precision of the SIMAAS technique allowed the Cu, Mn, Ni, and Se concentrations to be determined in saline. For the on-line microdialysis–SIMAAS system, the ultrapure saline was perfused at a flow rate of 1μL/min. The probe recoveries of Cu, Mn, Ni, and Se in saline were 57.9, 65.0, 65.5, and 67.9%, respectively. A standard saline solution was measured continuously by the on-line system to ensure long-term stability; each measurement fell within a range of two standard deviations. We determined the on-line spiked recoveries of Cu, Mn, Ni, and Se (101.3, 88.8, 91.3, and 98.5%, respectively) by adding a spiking standard into the stirred saline. The spiked recoveries (Cu, 37.5%; Mn, 3.8%; Ni, 71.1%; Se, 33.8%) were also determined through on-line spiking of a standard into the stirred cell suspension; these values demonstrate that Cu, Mn, and Se were depleted in the cell suspension, but Ni was not. The use of this on-line microdialysis–SIMAAS system permitted the in situ, dynamic, and continuous monitoring of Cu, Mn, Ni, and Se in cell suspensions at a temporal resolution of 20min.

Keywords: Microdialysis; SIMAAS; Copper; Manganese; Nickel; Selenium

Interlaboratory study to improve the quality of trace element determinations in rainwater by Sathrugnan Karthikeyan; Rajasekhar Balasubramanian (pp. 9-16).

This is the first publication which describes the development of a reference material (RM) for the determination of 11 trace elements (Cu, Pb, Mn, Ni, Zn, Fe, Cd, Co, V, As and Al) in rainwater at microgram per liter concentrations. An interlaboratory comparison study for the determination of trace elements in rainwater was carried out for material performance studies to establish analyte concentrations with a stated uncertainty. Fifteen reputed laboratories from Asia, Europe and North America participated in the study. These laboratories used their regular in-house methods to analyze the rainwater samples. The aim of this study is to establish concentration levels of trace elements in rainwater based on interlaboratory study results. Details of the production, homogeneity and stability of the reference sample are given in this article. The organization of the study and the quality assurance measures undertaken at the organizer's laboratory are described. The analytical results obtained from individual laboratories and the analytical methods used for the determination of trace elements in rainwater are discussed. Based on the results obtained from the intercomparison study, certified values as well as informative values are assigned to the 11 trace elements in rainwater.

Keywords: Abbreviations; AAS; atomic absorption spectrometry; DPASV; differential pulse anodic stripping voltametry; GFAAS; graphite furnace atomic absorption spectrometry; HDME; hanging drop mercury electrode; HG-AFS; hydride generation atomic fluorescence spectrometry; IC; ion chromatography; ICP-AES; inductively coupled plasma atomic emission spectrometry; ICP-MS; inductively coupled plasma mass spectrometry; ILS; interlaboratory study; TXRF; total internal reflectance X-ray fluorescenceInterlaboratory study; Trace elements; Reference materials; Quality control; Rainwater

Interlaboratory study to improve the quality of trace element determinations in rainwater by Sathrugnan Karthikeyan; Rajasekhar Balasubramanian (pp. 9-16).

Studies on electrochemical behaviors of acyclovir and its voltammetric determination with nano-structured film electrode by Fang Wang; Lin Chen; Xiaoxia Chen; Shengshui Hu (pp. 17-22).

A multi-wall carbon nanotubes (MWNTs)-dihexadecyl hydrogen phosphate (DHP) film-coated glassy carbon electrode (GCE) was fabricated, and the electrochemical behaviors of acyclovir on the MWNTs-DHP film-coated GCE were investigated by using cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and chronocoulometry (CC). The oxidation peak current of acyclovir increased significantly and the peak potential shifted negatively at the MWNTs-DHP film-modified GCE, compared with that at a bare GCE. The results showed that this nano-structured film electrode exhibited excellent enhancement effects on the electrochemical oxidation of acyclovir. Consequently, a simple and sensitive electroanalytical method was developed for the determination of acyclovir. The oxidation peak current was proportional to the concentration of acyclovir from 8.0×10⁻⁸ to 1.0×10⁻⁵mol/L. The detection limit was about 3.0×10⁻⁸mol/L for 60s accumulation at 0.00V. The proposed method was demonstrated by using acyclovir tablets and the result was satisfying.

Keywords: Acyclovir; Multi-walled carbon nanotubes (MWNTs); Chemically modified electrodes (CMEs); Voltammetry; Glassy carbon electrode (GCE); Nano-structured film

Studies on electrochemical behaviors of acyclovir and its voltammetric determination with nano-structured film electrode by Fang Wang; Lin Chen; Xiaoxia Chen; Shengshui Hu (pp. 17-22).

Keywords: Acyclovir; Multi-walled carbon nanotubes (MWNTs); Chemically modified electrodes (CMEs); Voltammetry; Glassy carbon electrode (GCE); Nano-structured film

Microwave assisted sample preparation for determining water-soluble fraction of trace elements in urban airborne particulate matter: Evaluation of bioavailability by Sathrugnan Karthikeyan; Umid Man Joshi; Rajasekhar Balasubramanian (pp. 23-30).

The feasibility of using two different microwave-based sample preparation methods was investigated to determine the total and water-soluble trace metal fraction in airborne particulate matter. The extraction techniques were then applied to urban particulate matter of different sizes in order to evaluate their bioavailability of associated trace metals. While a combination of HNO₃–HF–H₂O₂ was used for the total trace metal fraction of particulate matter, water was employed for the microwave-assisted extraction of water-soluble trace metal fractions. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for the analysis of trace elements. The experimental protocol for the microwave assisted digestion was established using two different SRMs (1648, urban particulate matter and 1649a, urban dust). In the case of water-soluble trace metal fraction, the quantities extracted from the SRMs were compared between ultrasonic and microwave-assisted extractions, and there was a good agreement between the two extraction methods. Blanks values and limits of detection (LODs) for total and water-soluble trace metal concentrations were determined for three different filter substrates (Teflon, Zeflour, and Quartz). Subsequently, the proposed digestion method was evaluated for its extraction efficiency with these filter substrates. Finally, the real-world application of the proposed microwave-based sample preparation methods was demonstrated by analyzing trace elements in airborne particulate samples collected from different outdoor environments in Singapore. The solubility of 11 trace elements detected in the particulate samples is quantified.

Keywords: Trace metals; Aerosols; Extraction; Air pollution; Airborne particulate matter

Development of new cleanup method of polychlorinated dibenzo- p-dioxins/dibenzofurans in fish by freezing-lipid filtration by Yun Gyong Ahn; Jungju Seo; Jeoung Hwa Shin; Jeehyeong Khim; Jongki Hong (pp. 31-36).

Freezing-lipid filtration as a new method has been developed for the rapid determination of polychlorinated dibenzo- p-dioxins/dibenzofurans (PCDDs/Fs) in biological samples. This method can effectively reduce the time of sample pretreatment, labor and amount of solvents compared with conventional methods. By freezing-lipid filtration procedure, about 90% of lipids in extract could be removed without any significant loss of PCDD/Fs. For further cleanup of extracts after freezing-lipid filtration, automatic parallel LC columns including silica gel, alumina and carbon columns were applied. During automatic parallel LC columns cleanup, most of co-extracted interferences such as residue lipids and fatty acids could be eliminated and dioxins could be separated from many other dioxin-like congeners such as polychlorinated biphenyls by this procedure. The extracts after cleanup were analyzed by high-resolution gas chromatography (HRGC)/high-resolution mass spectrometry (HRMS) using an isotope dilution method. The average recoveries and relative standard deviation (R.S.D.) of 17 native congeners in the spiked fish samples at 8–80pg/g ( n=3) were ranged between 85.3 and 117.2% and 5.7–20.3%, respectively.

Keywords: Polychlorinated dibenzo-; p; -dioxins/dibenzofurans (PCDDs/Fs); Fish; Freezing-lipid filtration; Automatic parallel LC; HRGC/HRMS

Treatment of colored effluent of the textile industry in Bangladesh using zinc chloride treated indigenous activated carbons by Mohammad Mainul Karim; Ajoy Kumar Das; Sang Hak Lee (pp. 37-42).

The adsorption of colored compounds from the textile dyeing effluents of Bangladesh on granulated activated carbons produced from indigenous vegetable sources by chemical activation with zinc chloride was studied. The most important parameters in chemical activation were found be the chemical ratio of ZnCl₂ to feed (3:1), carbonization temperature (450–465°C) and activation time (80min). The adsorbances at 511nm (red effluent) and 615nm (blue effluent) were used for color estimation. It is established that at optimum temperature (50°C), time of contact (30–40min) and adsorbent loading (2gl⁻¹), activated carbons developed from Segun saw-dust and water hyacinth showed substantial capability to remove coloring materials from the effluents. It is observed that adsorption of reactive dyes by all sorts of activated carbons is higher than disperse dyes. It is explained that activated carbon, because of its acidic nature, can better adsorb reactive dye particles containing large number of nitrogen sites and –SO₃Na group in their structure. The use of carbons would be economical, as saw-dust and water hyacinth are waste products and abundant in Bangladesh.

Keywords: Activated carbon; Tube furnace; Carbonization; Bangladesh; Effluent

Treatment of colored effluent of the textile industry in Bangladesh using zinc chloride treated indigenous activated carbons by Mohammad Mainul Karim; Ajoy Kumar Das; Sang Hak Lee (pp. 37-42).

Keywords: Activated carbon; Tube furnace; Carbonization; Bangladesh; Effluent

Analysis of volatile compounds emitted from fresh Syringa oblata flowers in different florescence by headspace solid-phase microextraction–gas chromatography–mass spectrometry by Zu-Guang Li; Maw-Rong Lee; De-Long Shen (pp. 43-49).

In this study, a simple and solvent-free method was developed for determination of the volatile compounds from fresh flowers of Syringa oblata using headspace solid-phase microextraction and gas chromatography–mass spectrometry. The SPME parameters were studied, the optimum conditions of a 65μm polydimethylsiloxan/divinylbenezene (PDMS/DVB), extraction temperature of 25°C and extraction time of 30min were obtained and applied to extraction of the volatile compounds emitted from fresh flowers of S. oblata. The volatile compounds released from fresh flowers of S. oblata were separated and identified by GC–MS. Lilac aldehyde A, lilac aldehyde B, lilac aldehyde C, lilac aldehyde D, lilac alcohol A, lilac alcohol B, lilac alcohol C, lilac alcohol D, α-pinene, sabinene, β-pinene, myrcene,d-limonene, eucalyptol, cis-ocimene, benzaldehyde, terpinolene, linalool, benzene acetaldehyde, α-terpineol, p-methoxyanisole, p-anisaldehyde, ( Z, E)-α-farnesene and ( E, E)-α-farnesene were the most abundant volatiles released from fresh flowers of S. oblata var. alba. The relative contents of main volatile fragrance were found to be different in emissions from two varieties of S. oblata flowers (white or purple in color). The four isomers of lilac alcohol and four isomer lilac aldehyde were the characteristic components of the scent of fresh flowers of S. oblata. The main volatile fragrance from fresh flowers of S. oblata var. alba in different florescence ((A) flower buds; (B) at the early stage of flower blooming; (C) during the flower blooming; (D) at the end of flower blooming; (E) senescence) were studied in this paper. The results demonstrated that headspace SPME–GC–MS is a simple, rapid and solvent-free method suitable for analysis of volatile compounds emitted from fresh flowers of S. oblata in different florescence.

Keywords: Syringa oblata; Solid-phase microextraction (SPME); Gas chromatography–mass spectrometry (GC–MS); Volatile compounds

Enantiomeric quantification of ( S)-(+)-methamphetamine in urine by an immunoaffinity column and liquid chromatography–electrospray-mass spectrometry by Ahai C. Lua; Yenny Sutono; Tsong-Yung Chou (pp. 50-54).

A method using an immunoaffinity column (IAC) and liquid chromatography–electrospray ionization mass spectrometry (LC/MS) for on-line detecting the presence of MA in the effluent was developed for the quantitative and enantiomeric determination of ( S)-(+)-methamphetamine (d-MA) in urine. The IAC was made in our laboratory and utilized in the LC/MS to simultaneously extract and separate enantiomers of MA from urine samples. An aqueous ammonium acetate buffer was used as the mobile phase. Urine samples were spiked with racemic deuterated methamphetamine (MA-d₁₄) as internal standard (IS), filtered through a membrane, and injected into the LC/MS without any further pre-treatment. Protonated molecular ion of MA and MA-d₁₄ ( m/ z 150 and 164) were isolated and further fragmented, the respective product ions, m/ z 119 and 130, were collected for quantitative determination. This is an improvement of our previous method (A.C. Lua, Tsong-Yung Chou, J. Chromatogr. A 967 (2002) 191). In the previous method, MA was separated with HPLC, the efflux was fractionated and each fraction was either determined with an immunoassay or GC/MS. Monitoring of MA in the efflux is tedious and time consuming. Urine samples spiked with different concentrations ofd-MA were measured by this method. A linear relationship exists in the 150–1050ng/mL range, and the detection limit (defined as signal-to-noise ratio 3) ofd-MA was determined to be 18ng/mL. The linearity of the method ford-MA can be described by the equation ( Y=1.415×10⁻³ X+0.034, correlation coefficient: r²=0.999). Within run, accuracy and precision ( n=6, relative error: −7.2 to +4.0% and relative standard deviation: 3.8–9.3%) of the method are fairly good.

Keywords: Immunoaffinity column; Enantiomeric separation; LC/MS; Methamphetamine

Urinary polyamines and N-acetylated polyamines in four patients with Alzheimer's disease as their N-ethoxycarbonyl- N-pentafluoropropionyl derivatives by gas chromatography–mass spectrometry in selected ion monitoring mode by Man-Jeong Paik; Sunmie Lee; Kyung-Hea Cho; Kyoung-Rae Kim (pp. 55-60).

Simultaneous determination of putrescine, cadaverine, spermidine, spermine, N¹-acetylputrescine, N¹-acetylcadaverine, N¹-acetylspermidine, N⁸-acetylspermidine and N¹-acetylspermine in aqueous samples was achieved as their N-ethoxycarbonyl- N-pentafluoropropionyl derivatives by gas chromatography–mass spectrometry (GC–MS) in selected ion monitoring (SIM) mode. The overall GC–SIM–MS method was linear ( r≥0.9987), repetitive (% relative standard deviation=1.3–6.4), and accurate (% relative error=−2.1–8.6). As compared to normal subjects, the levels of putrescine, N¹-acetylspermine and spermine were significantly elevated while the levels of N¹-acetylputrescine, N¹-acetylcadaverine and N¹-acetylspermidine were markedly reduced in all four Alzheimer's disease (AD) patients. When star symbol plotting was applied to the normalized levels of nine polyamines relative to the corresponding normal mean values, each star pattern of the AD patients was deformed, thus being readily distinguishable from the nonagon shape of the normal group average.

Keywords: Urinary polyamines; Ethoxycarbonylation; Pentafluoropropionylation; GC–SIM–MS; Alzheimer's disease; Star pattern recognition

Combination of liquid-phase hollow fiber membrane microextraction with gas chromatography-negative chemical ionization mass spectrometry for the determination of dichlorophenol isomers in water and urine by Bin-Wei Lai; Bo-Min Liu; Pradip K Malik; Hui-Fen Wu (pp. 61-66).

A method for the determination of trace amount of dichlorophenol isomers in urine samples using the combination of liquid-phase hollow fiber microextraction (LPME-HF) with gas chromatography-negative chemical ionization mass spectrometry (GC–NCI-MS) has been demonstrated. The method has been optimized with respect to several parameters including the effects of negative chemical ionization (NCI) reagent pressure, the hollow fiber length, extraction time, stirring rate, sample pH and salt concentration for the determination of dichlorophenol isomers in water. The correlation coefficient ( r²) of the calibration curves for 2,5-dichlorophenol, 2,3-dichlorophenol, 2,6-dichlorophenol, 3,5-dichlorophenol and 3,4-dichlorophenol were 0.988, 0.981, 0.985, 0.971 and 0.994, respectively. The average recovery rates for 2,5-dichlorophenol, 2,3-dichlorophenol, 2,6-dichlorophenol, 3,5-dichlorophenol and 3,4-dichlorophenol were 0.97, 0.93, 0.96, 0.95 and 0.95, respectively ( n=3 for each dichlorophenol) indicate that the methodology is feasible for the determination of trace amounts of dichlorophenol isomers in water and urine samples. Limits of detection (LOD) have been found to be in the range of 5–20ng/ml. In addition, differentiation of the five dichlorophenol isomers is an easy task using the current approach of combining LPME-HF with NCI-GC–MS technique since they exhibit different NCI spectra.

Keywords: LPME-HF; NCI; GC–MS

Piezoelectric quartz crystal sensor for rapid analysis of pirimicarb residues using molecularly imprinted polymers as recognition elements by Hui Sun; Yingsing Fung (pp. 67-76).

A new piezoelectric quartz crystal (PQC) sensor using molecularly imprinted polymer (MIP) as sensing material has been developed for fast and onsite determination of pirimicarb in contaminated vegetables. Three MIPs particles have been prepared by conventional bulk polymerization (MIP-B) and precipitation polymerization in either acetonitrile (MIP-P1) or chloroform (MIP-P2). MIP-P2, with uniform spherical shape and mean diameter at about 50nm, has shown the best performance as the sensing material for PQC sensor. The sensor fabricated with MIP-P2 can achieve a steady-state response within 5min, a very short response time as compared to MIPs-coated PQC sensor reported in the literature. The sensor developed exhibits good selectivity (low response to those pesticides with similar structures to pirimicarb, such as atrazine, carbaryl, carbofuran and aldicarb) and high sensitivity to pirimicarb with a linear working range from 5.0×10⁻⁶ to 4.7×10⁻³molL⁻¹ (following a regression equation ( r=0.9988) of −Δ F=0.552+1.79×10⁶C), a repeatability (R.S.D., n=5) of 4.3% and a detection limit ( S/ N=3, n=5) of 5×10⁻⁷molL⁻¹. The MIP-coated PQC sensor developed is shown to provide a sensitive and fast method for onsite determination of pirimicarb in aqueous extract from contaminated vegetables with satisfactory recoveries from 96 to 103% and repeatability (R.S.D., n=5) from 4.6 to 7.1% at pirimicarb concentrations ranging from 8.0×10⁻⁶ to 2.0×10⁻⁴molL⁻¹.

Keywords: Piezoelectric quartz crystal; Pirimicarb; Molecularly imprinted polymers; Pesticide residues; Chemical sensor; Precipitation polymerization

Piezoelectric quartz crystal sensor for rapid analysis of pirimicarb residues using molecularly imprinted polymers as recognition elements by Hui Sun; Yingsing Fung (pp. 67-76).

Keywords: Piezoelectric quartz crystal; Pirimicarb; Molecularly imprinted polymers; Pesticide residues; Chemical sensor; Precipitation polymerization

Surface plasmon resonance immunosensor for histamine based on an indirect competitive immunoreaction by Yan Li; Masatoshi Kobayashi; Koji Furui; Nobuaki Soh; Koji Nakano; Toshihiko Imato (pp. 77-83).

The use of a surface plasmon resonance immunosensor for the analysis of histamine (β-imidazole ethylamine) is described. The method is based on an indirect competitive reaction of an anti-histamine antibody in a sample solution with histamine immobilized on a sensor chip and with histamine in the sample solution. A sensor chip immobilized with histamine was prepared using a self-assembly monolayer of 11-mercaptoundecanoic acid (11-MUA) as an anchor membrane, followed by an amino-coupling reaction with histamine after activation of the 11-MUA layer on the sensor chip by treatment with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-hydroxysuccinimide. The sensor chip can be reused, after regeneration with a 10mM HCl solution, which dissociates the anti-histamine antibody complex from histamine on the sensor chip. The affinity constants for the immunocomplex of the anti-histamine antibody with histamine in the solution and for that of the anti-histamine antibody with histamine immobilized on the sensor chip were calculated to be 1.5×10⁷ and 7.2×10⁵M⁻¹, respectively, by assuming a Langmuir-type adsorption of the anti-histamine antibody to histamine immobilized on the sensor chip. The detection limit of the method was determined to be 3ppb.

Keywords: Surface plasmon resonance sensor; Histamine; Competitive immunoassay; Allergy substances

Use of β-cyclodextrin bonded phase with s-triazine moiety in the spacer for separation of aromatic carboxylic acid isomers by high-performance liquid chromatography by Chen-Hsing Lin; Chih-Yu Chen; Shu-Wen Chang; Jong-Chang Wu; Ching-Erh Lin (pp. 84-90).

The separation and retention behavior of five aromatic carboxylic acid isomers was investigated by means of high-performance liquid chromatography (HPLC) using a β-cyclodextrin bonded phase with s-triazine ring in the spacer. The influence of mobile phase pH on the retention was examined. The presence of s-triazine moiety in the spacer enhances greatly the selectivity of the isomers of aromatic carboxylic acids. Baseline separations of the five aromatic carboxylic acid isomers were achieved. In particular, the isomers of toluic, aminobenzoic, nitrobenzoic and hydroxybenzoic acid were successfully and effectively separated. The chromatographic results indicate that, in addition to inclusion complexation, π–π interaction and hydrogen bonding interaction between the bonded phase and analytes play significant roles in the retention of these acid isomers. Different elution orders were observed for these acidic solutes with different substituents. Possible retention mechanisms are discussed.

Keywords: High-performance liquid chromatography; Cyclodextrin bonded phase; Retention mechanism; Aromatic carboxylic acids; s; -Triazine

Measurement of non-methane hydrocarbons in Taipei city and their impact on ozone formation in relation to air quality by Ben-Zen Wu; Chih-Chung Chang; Usha Sree; KongHwa Chiu; Jiunn-Guang Lo (pp. 91-99).

Air pollutants data from semi-continuous measurements at multiple sampling sites in Taipei metropolitan area of Taiwan was obtained by collecting air samples in canisters. The hydrocarbon composition was determined by using GC/MS and GC/FID. The air samples were pre-concentrated onto glass beads prior to separation by PLOT and DB-1 columns of GC. The method showed detection limit of <1ppb and relative standard deviation in the range of 5–30% for different compounds. Aromatic hydrocarbons (toluene, benzene, etc.) and aliphatic hydrocarbons (ethylene, acetylene, propane, etc.) were correlated primarily to determine the source of emission. The estimated hydrocarbons were ranked according to their abundance and photochemical reactivity. The criteria pollutants, ozone and NO₂ were measured by UV-differential optical absorption spectroscopy (UV-DOAS), and were utilized to determine the relative importance of non-methane hydrocarbons (NMHC) and significant contribution of NO₂ in limiting ozone formation. The obtained results suggest that ozone formation in Taipei city is probably limited by the supply of non-methane hydrocarbons. The concentration profile of targeted pollutants was compared to other metropolitan areas to determine air quality and the pollutant sources.

Keywords: NMHC; Benzene; Toluene; Ozone; GC/MS; FID; UV-DOAS

Sampling and analysis of volatile organics emitted from wastewater treatment plant and drain system of an industrial science park by Ben-Zen Wu; Tien-Zhi Feng; Usha Sree; Kong-Hwa Chiu; Jiunn-Guang Lo (pp. 100-111).

Volatile organic compounds (VOCs) were monitored in the different sections of a wastewater treatment plant (WWTP), the outlet of both the WWTP and rainfall water, and the downstream of the WWTP joining the river in the area or vicinity of an industrial science park located in Hsinchu, Taiwan. Levels of VOCs were determined by collecting air samples over several sampling points and analyzed using gas chromatography. Among VOCs identified in the drainage and effluent system in each season, acetone, isopropanol (IPA) and dimethyl sulfide (DMS) were the major emission species and maximum concentrations were 400.4, 22.8 and 641.2ppbv, respectively. The ambient air and wastewater sample analysis from neighboring wastewater streams identified pollutants being discharged from unaccounted sources other than the industrial park. According to the 24h semi-continuous monitoring data (27/7/2002–29/7/2002), the total VOC concentration was an average of 93ppbv (acetone contributed ∼78%) with a dramatic variation during the day and night. The emission rate of measured VOCs estimated using fixed box model projected an average of 2–4μgm⁻²h⁻¹) during the day and 9–17μgm⁻²h⁻¹ during the night. In addition, the isopleth maps show that the acetone and DMS emissions influence adversely the nearby residential area located at less than 100m downwind from the plant. Eventually, based on this study, an on-line monitoring and alerting system could be built for a long-term performance, and with regular information on the varying pollutants over time construction of a green strategy and creation of a sustainable environment can be achieved.

Keywords: Hi-tech industry; Wastewater; Ambient air; Volatile organics; Acetone

Differentiation of herbs linked to “Chinese herb nephropathy�? from the liquid chromatographic determination of aristolochic acids by Wan Chan; Ka Man Hui; Wing Tat Poon; Kim Chung Lee; Zongwei Cai (pp. 112-116).

A HPLC method was developed and applied to analyze aristolochic acids (AA-I and AA-II) in Chinese medicinal herbs. The herb samples were extracted by using ultrasonication with the extraction efficiency of better than 82%. Extracts were then filtered and injected onto a C18 column eluting under a gradient program using methanol and water-containing 0.5% acetic acid. The method with the detection limits of 1.33ng for AA-I and 7.29ng for AA-II per injection was successfully applied for the analysis of traditional Chinese medicine (TCM) and related products and differentiation of Chinese medicinal herbs that have previously been misused and caused toxicological effects. The developed protocol provided an example that analysis of selected component markers could serve for health security and quality control of TCM consumption.

Keywords: Aristolochic acids; Chinese herbal medicine; HPLC; Chinese herb nephropathy

Differentiation of herbs linked to “Chinese herb nephropathy” from the liquid chromatographic determination of aristolochic acids by Wan Chan; Ka Man Hui; Wing Tat Poon; Kim Chung Lee; Zongwei Cai (pp. 112-116).

Keywords: Aristolochic acids; Chinese herbal medicine; HPLC; Chinese herb nephropathy

Sol–gel monolithic anion-exchange column for capillary electrochromatography by Tai-Ahn Lin; Guan-Yi Li; Lai-Kwan Chau (pp. 117-123).

A single-step approach has been used to prepare a monolithic electrochromatographic column by sol–gel processing of an organofunctional silicon alkoxide precursor that contains a propyl- N, N, N-trimethylammonium group. We have found that the time of adding the porogen, poly(ethylene glycol), during the sol–gel reaction affected the separation performance. Since the surface charge of this material is switchable in sign upon manipulation of solution pH, the direction and magnitude of the electroosmotic flow (EOF) can be controlled by adjusting the pH of the running electrolyte. By controlling the direction of the EOF from cathode to anode, inorganic anions can be separated in a short time. Because of the quaternary ammonium functional group, the resulting material is anion exchangeable. Interestingly, the anion-exchange selectivity of inorganic anions on this column changes with solution pH or applied voltage. The column shows excellent run to run reproducibility (R.S.D.<0.4%), good day to day reproducibility (R.S.D.<4%), and reasonable column to column reproducibility (R.S.D.<9%).

Keywords: Capillary electrochromatography; Monolithic column; Sol–gel; Anion-exchange

Sol–gel monolithic anion-exchange column for capillary electrochromatography by Tai-Ahn Lin; Guan-Yi Li; Lai-Kwan Chau (pp. 117-123).

Keywords: Capillary electrochromatography; Monolithic column; Sol–gel; Anion-exchange

Simultaneous determination ofl-ascorbic acid, ascorbic acid-2-phosphate magnesium salt, and ascorbic acid-6-palmitate in commercial cosmetics by micellar electrokinetic capillary electrophoresis by Chun-Chi Wang; Shou-Mei Wu (pp. 124-129).

l-Ascorbic acid (LAA) can be used as a whitening agent in cosmetics. Because of its instability, some more stable derivatives have been developed to control melanin production, such as ascorbic acid-2-phosphate magnesium salt (AAPM) and ascorbic acid-6-palmitate (AA6P). To assess the quality of cosmetics, a micellar electrokinetic capillary electrophoresis technique (MEKC) was established for simultaneous analysis of AA and its two derivatives. Separation was performed with 10mM borate (pH 9.5) containing 50mM sodium dodecyl sulfate (SDS) at 20kV. The detection wavelength was 265nm. Several parameters, including borate concentration, buffer pH, and SDS level, were investigated. On method validation, calibration curves were linear over a concentration range of 150.0–1000.0μM for LAA and 200.0–1000.0μM for AAPM and AA6P. For intraday and interday analysis, relative standard deviation and relative errors were all less than 3%. Limits of detection were 70μM for AAPM and AA6P, and 50μM for LAA. All recoveries were greater than 95%. This method was applied to quality control of commercial cosmetics.

Keywords: l; -Ascorbic acid; Ascorbic acid-2-phosphate magnesium salt; Ascorbic acid-6-palmitate; Cosmetics; MEKC

Attenuated total reflection Fourier transform infrared spectra of faceted diamonds by Pimthong Thongnopkun; Sanong Ekgasit (pp. 130-135).

Attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy has been employed for characterization of faceted diamonds. ATR spectra of round brilliant cut natural diamonds of ∼0.1ct were observed with excellent spectral quality. The mirror-flat spectrum of the table facet enables a good contact to the ATR crystal with a minimal applied pressure. The observed ATR spectra agreed very well with the diffuse reflectance and transflectance spectra. The detailed spectral information in the one-phonon region of diamonds with high nitrogen impurities can be clearly observed in the ATR spectra but those in the diffuse reflectance and transflectance spectra were obscured by the saturated absorption. The strong evanescent field under the ATR condition enables spectral acquisition of a thin film on the mirror-flat surface of the faceted diamonds. The spectral signatures of this thin film were not observable in the diffuse reflectance or the transflectance spectra.

Keywords: Faceted diamond; Diamond; Infrared spectroscopy; ATR FT-IR spectroscopy; Diffuse reflectance; Transflectance; Evanescent field

Attenuated total reflection Fourier transform infrared spectra of faceted diamonds by Pimthong Thongnopkun; Sanong Ekgasit (pp. 130-135).

Keywords: Faceted diamond; Diamond; Infrared spectroscopy; ATR FT-IR spectroscopy; Diffuse reflectance; Transflectance; Evanescent field

Analysis of salicylic acid based on the fluorescence enhancement of the As(III)–salicylic acid system by Mohammad Mainul Karim; Hwa Suk Lee; Young Sun Kim; Hyun Sook Bae; Sang Hak Lee (pp. 136-139).

A new, simple and sensitive spectrofluorimetric method for the determination of salicylic acid ( λ_ex=315nm, λ_em=408nm) using As(III) as a sensitizing reagent has been investigated by measuring the increase of fluorescence intensity of salicylic acid due to the complexation of As(III)–salicylic acid in presence of sodium dodecyl sulfate (SDS) 10⁻³M. Under optimum conditions, a significant relationship was obtained between the fluorescence intensity and salicylic acid concentration. A linear calibration curve was obtained in the range 13.8–13812μgl⁻¹ with product-moment correlation coefficient ( R) 0.99985 and detection limit 4.2μgl⁻¹. The R.S.D. is 2.35% ( n=5).The method was applied successfully to the determination of salicylic acid in human serum.

Keywords: Fluorescence; Salicylic acid; Arsenic; Serum

Distribution characteristics of methamphetamine and amphetamine in urine and hair specimens collected from alleged methamphetamine users in northern Taiwan by Sheng-Meng Wang; Chih-Che Lin; Tien-Lai Li; Chun-Yao Shih; Yun-Seng Giang; Ray H. Liu (pp. 140-146).

This study was conducted to better understand the distribution characteristics of methamphetamine and amphetamine in urine and hair specimens collected from alleged methamphetamine users in the local population. It is anticipated that the data hereby obtained will be helpful to the interpretation of the time and pattern of drug use. Eight alleged methamphetamine-using arrestees from Keelung Police Department (north of Taipei, Taiwan) consented to contribute both urine and hair specimens. Each arrestee contributed seven urine specimens collected at 0, 12, 24, 48, 72, 96, and 120h, respectively, after the arrest. Hair specimens were cut into 2-cm sections. The limits of detection and quantitation of the urine protocol were 40 and 50ng/mL, respectively, for both amphetamine and methamphetamine, while the corresponding limits of detection and quantitation for the hair protocol were 0.8 and 1.0ng/mg, respectively. The concentration variations of methamphetamine and amphetamine in the urine specimens exhibited three distinct patterns: (a) continuous decrease in the analytes’ concentrations for specimens collected at hours 0–120; (b) increase in the analytes’ concentrations in specimens collected at hours 0–12, followed by decrease; (c) increase in analytes’ concentrations in specimens collected at later times. Together with the amphetamine/methamphetamine concentration ratios found in these urine specimens, the observed trends in the changes of the analytes’ concentrations are helpful for the interpretation on the time of drug use. Unlike urine specimens, amphetamine/methamphetamine concentration ratios in various hair specimens and hair sections remain relatively constant.

Keywords: Gas chromatography–mass spectrometry (GC–MS); Amphetamine; Methamphetamine; Drug testing; Hair drug analysis; Drug distribution

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Analytica Chimica Acta (v.576, #1)

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Analytica Chimica Acta (v.576, #1)