高效液相色谱全轮廓指纹图谱结合化学计量学区分不同地区的紫苏叶

利用高效液相色谱全轮廓指纹图谱结合化学计量学方法对不同栽培地区的紫苏叶样品(共84个)进行区分。全轮廓色谱数据经自适应迭代加权最小二乘法(airPLS)和相关优化翘曲法(COW)校正后,基线和保留时间漂移现象均得到明显改善。经预处理后的色谱数据采用主成分分析(PCA)进行解析,结果表明不同来源的样品能按其特性各自聚为一类;而分段间隔压缩变量后的色谱数据经主成分分析处理可得到与全轮廓色谱数据为输入变量时相一致的结果。此外,偏最小二乘判别分析(PLS-DA)对于紫苏叶样品分类的识别能力和预报能力分别为92.8%和89.6%。     

The recognition of similarities in trace elements content in medicinal plants using MLP and RBF neural networks

The objective of the paper was to verify if the content of some elements provides enough information for proper classification of the medicinal plant raw materials. Such information could be helpful in standardization process of herbal products. Four elements—zinc, copper, lead and cadmium were determined using inverse voltammetry in commercially available medicinal herbal raw materials. Initially, principal component analysis (PCA) was employed to investigate the relationships among the analyzed trace elements. In the next stage of the study, two different types of feed-forward artificial neural networks (FANNs)—multilayer perceptron (MLP) and radial basis function (RBF) were applied. The concentrations of the elements were used as input variables to neural networks models, which were to recognize the taxonomy of the plant and the anatomical part it originated from. Although full recognition of the samples with use of FANNs on the basis of some trace elements content was not achieved, it was possible to identify two elements—cadmium and lead as the most important in the classification analysis of medicinal plants.     

Radiocesium contamination in soil due to the Chernobyl accident

Three different cereal cultivated fields (rice, maize/wheat, wheat/barley) were selected and soil samples were collected in order to study the behaviour of the radiocesium deposited over the crops after the Chernobyl accident fall-out (April 1986) together with its distribution at different ground depths. For each field, soil samples were removed during the sowing (Oct–Nov '86), in Spring (Apr '87) and during the harvest time (Jun–Sept '87). The⁴⁰K concentration and stable potassium content in soil was also evaluated by nuclear spectrometry and by atomic absorption spectrometry. Beside soil sample measurements, the cultivated cereals produced in the 1986 harvest (rice, maize, wheat) were analyzed to evaluate the deposited contamination, and in order to evaluate the contamination during the growth and naturation we also analyzed whole plants (roots, stalks, grains) of the cultivated cereals (rice, wheat, barley) in 1987. Results are presented and discussed.     

Influence of Different Microplastic Forms on pH and Mobility of Cu2+ and Pb2+ in Soil

Microplastics, due to their surface properties, porosity and electrostatic interactions have a high affinity for cations sorption from the aqueous phase. As soil is a complex matrix, interactions between microplastics, soil constituents and heavy metals (HM) may modify the soil microenvironment for heavy metal mobilization/immobilization processes. In order to better understand the problem, three commonly found forms of microplastics in soil (fibers, fragments and microbeads) were mixed with Cu²⁺- or Pb²⁺-contaminated soil and incubated at 22 °C for 180 days. In soil samples pH and the content of water and acid exchangeable species of metals were analyzed. The results of this study showed that the presence of microplastics in HM-contaminated soil affected metal speciation, increasing the amount of easily exchangeable and potentially bioavailable forms of Cu²⁺ or Pb²⁺ in the tested soil. Soil pH also increased, confirming that microplastic particles affect soil properties relevant to the sorption/desorption process of metal cations. Overall, the smallest microplastic particles (≤1 mm), such as fibers or glitter microbeads, had a greater impact on the change in the sorption and desorption conditions of metals in tested soil than larger particles. The findings of our study show that microplastic form, shape and size should be considered as important factors that influence the soil properties and mobility of heavy metals in soil.     

Colloidochemical Processes in the Biotechnology of Heavy Metal Removal from the Soil

The sorption processes of uranium(VI), copper, cobalt, and strontium by the native soil were studied. It was shown that, by their ability to be accumulated by the podsolized soil, these metals are arranged in the following sequence: U(VI) > Cu > Co > Sr. This selectivity sequence is retained during the sorption of metals from mixed solutions containing their equimolar concentrations. The possibility of the leaching of the studied metals from the contaminated soil by Basillus cereusVKM 4368 metal-resistant culture was demonstrated using glucose and sodium acetate as the sources of carbon and energy. In the first case, 90–99% of heavy metals was extracted from the soil as water-soluble citrate complexes. In the second case (during the metabolism of acetate by bacteria), the removal of heavy metals from the soil as hydroxide–carbonate precipitates and complexes was equal to 80–90%. Sedimentation of particles in the soil suspension is accelerated considerably after the treatment by the metal-resistant culture.     

Urease–glutamic dehydrogenase biosensor for screening heavy metals in water and soil samples

A screen-printed three-electrode amperometric biosensor based on urease and the nicotinamide adenine dinucleotide hydrogen (NADH)–glutamic dehydrogenase system was developed and applied to the screening of heavy metals in environmental samples. The development of an amperometric sensor for the monitoring of urease activity was feasible by coupling the urea breakdown reaction catalysed by urease to the reductive ammination of ketoglutarate catalysed by glutamic dehydrogenase (GLDH). The ammonia provided by the urea conversion is required for the conversion of ketoglutarate to glutamate with the concomitant oxidation of the NADH cofactor. NADH oxidation is monitored amperometrically at 0.3 V (vs. Ag/AgCl) after urease immobilization onto the screen-printed three-electrode configuration. Immobilization of urease on the surface of screen-printed electrodes was performed by entrapment in alginate gel and adsorption on the electrode in a nafion film. Low sensitivity to inactivation by metals was recorded after urease entrapment in alginate gel with detection limits of 2.9 and 29.8 mg L^–1 for Hg(II) and Cu(II), respectively. The use of the negatively charged nafion film created a more concentrated environment of cations in proximity to the enzyme, thus enhancing the urease inhibition when compared to gel entrapment. The calculated detection limits were 63.6 and 55.3 g L^–1 for Hg(II) and Cu(II), respectively, and 4.3 mg L^–1 for Cd(II). A significant urease inactivation was recorded in the presence of trace amounts of metals (g L^–1) when the enzyme was used free in solution. Analysis of water and soil samples with the developed nafion-based sensor produced inhibition on urease activity according to their metal contents. The obtained results were in agreement with the standard methods employed for sample analysis. Nevertheless, the use of the amperometric assay (with free urease) proved more feasible for the screening of trace amounts of metals in polluted samples.     

Application of exploratory data analysis for the characterization of tubular wells of the North of Brazil

Roraima is located in the extreme North of Brazil, in the Western Amazon Region. The groundwater has an important role in the public supply of potable water on the Roraima State. The objective of this work is the application of PCA (Principal Component Analysis) and HCA (Hierarchical Cluster Analysis) for the characterisation of tubular wells of the Roraima State, as regards physical–chemical composition of water. The parameters analyzed in laboratory were the following ones: pH, electric conductivity, Total Hardness, Total Alkalinity, Bicarbonate, Calcium, Potassium, Magnesium, Nitrate, Chloride, Total Iron. The physical–chemical analyses, were carried out during the months of September and October 2000 (winter, period of rains). The laboratory analysis was performed using classical methods (titrimetry and uv–visible spectroscopy), the samples were processed in agreement with the Standard Methods for Examination of Water and Wastewater.The physical–chemical analyses, were accomplished in September and October 2000. In physical–chemical terms, the groundwater samples analyzed do not indicate any restriction to human consumption and the two chemometric methods of exploratory data analysis: PCA and HCA are efficient for the discrimination of bicarbonated (tubular wells locateds in the South of the Roraima State) and not bicarbonated (tubular wells locateds in the North of Roraima) groundwater.     

Evaluating Tannins and Flavonoids from Traditionally Used Medicinal Plants with Biofilm Inhibitory Effects against MRGN E. coli

In the search for alternative treatment options for infections with multi-resistant germs, traditionally used medicinal plants are currently being examined more intensively. In this study, the antimicrobial and anti-biofilm activities of 14 herbal drugs were investigated. Nine of the tested drugs were traditionally used in Europe for treatment of local infections. For comparison, another five drugs monographed in the European Pharmacopoeia were used. Additionally, the total tannin and flavonoid contents of all tested drugs were analyzed. HPLC fingerprints were recorded to obtain further insights into the components of the extracts. The aim of the study was to identify herbal drugs that might be useable for treatment of infectious diseases, even with multidrug resistant E. coli, and to correlate the antimicrobial activity with the total content of tannins and flavonoids. The agar diffusion test and anti-biofilm assay were used to evaluate the antimicrobial potential of different extracts from the plants. Colorimetric methods (from European Pharmacopeia) were used for determination of total tannins and flavonoids. The direct antimicrobial activity of most of the tested extracts was low to moderate. The anti-biofilm activity was found to be down to 10 µg mL⁻¹ for some extracts. Tannin contents between 2.2% and 10.4% of dry weight and total flavonoid contents between 0.1% and 1.6% were found. Correlation analysis indicates that the antimicrobial and the anti-biofilm activity is significantly (p < 0.05) dependent on tannin content, but not on flavonoid content. The data analysis revealed that tannin-rich herbal drugs inhibit pathogens in different ways. Thus, some of the tested herbal drugs might be useable for local infections with multi-resistant biofilm-forming pathogens. For some of the tested drugs, this is the first report about anti-biofilm activity, as well as total tannin and flavonoid content.     

Orthogonal projection (OP) technique applied to pattern recognition of fingerprints of the herbal medicine houttuynia cordata Thunb. and its final injection products

It is a crucial issue to determine the origins of herbal medicinal materials and identify the quality grades and fakes of their final products collected from different pharmaceutical corporations. Pattern recognition technique may assist the manufacturers to achieve this purpose and effectively control the quality of their products. In this work, a widely used method in chemometrics, orthogonal projection (OP) technique, was applied to discrimination analysis and identification of fingerprints of the herbal medicine houttuynia cordata Thunb. (HCT) and its final injection products. The advantages of the OP technique are clearly shown after comparing with the conventional methods such as principal component analysis (PCA), Mahalanobis distance (MD), and similarity comparison method (SCM). Three different sources of medicinal material HCT and its final injection products from six different manufacturers were studied under 'sixfold', 'threefold' and 'threefold-bis' cross-validation procedures. The good performance of the proposed method in determination and identification of unknown samples shows it could be a powerful tool for quality control in herbal medicine production and other related research fields.     

Use of atomic absorption spectrometry for the determination of metals in sediments in south-west Louisiana

The relatively recent introduction of atomic absorption spectrometry has produced a rapid and relatively inexpensive method for the determination of metal concentrations in a wide variety of samples. One such application is in the determination of metal concentrations in soils and sediments. Soils and sediments represent concentrated reservoirs for these metals that serve as sinks for introduced trace metals or can become environmental sources. The coastal zone of Louisiana provides a ‘living laboratory’ to investigate the mechanisms of transport, deposition, and dissolution of trace metals into this fragile environment. Investigations done in the coastal zone have found trace metals tend to concentrate near pollution inputs and sources and have not migrated to or significantly impacted the coastal zone of Louisiana. Common trace metals determined and their range of concentrations in coastal soil and sediments are chromium (10–30 ppm), copper (10–25 ppm), iron (0.6–2.1%), manganese (200–600 ppm), nickel (6–20 ppm), lead (8–20 ppm), and zinc (30–55 ppm).     

Determination of pyrimethanil and kresoxim-methyl in soils by headspace solid-phase microextraction and gas chromatography-mass spectrometry

A method using headspace solid-phase microextraction (HS-SPME) then gas chromatography–mass spectrometry with selected ion monitoring (GC–MS, SIM) has been developed for determination of trace amounts of the fungicides pyrimethanil and kresoxim-methyl in soil and humic materials. Both fungicides were extracted on to a fused-silica fibre coated with 85 m polyacrylate (PA). Response-surface methodology was used to optimise the experimental conditions. For soil samples the linear dynamic range of application was 0.004–1.000 g g^–1 for pyrimethanil and 0.013–1.000 g g^–1 for kresoxim-methyl. The detection limits were 0.001 g g^–1 and 0.004 g g^–1 for pyrimethanil and kresoxim-methyl, respectively. HP-SPME–GC–MS analysis was highly reproducible—relative standard deviations (RSD) were between 6.7 and 12.2%. The method was validated by analysis of spiked matrix samples and used to investigate the presence of pyrimethanil and kresoxim-methyl above the detection limits in soil and humic materials.     

Application of isotope-dilution laser ablation ICP–MS for direct determination of Pu concentrations in soils at pg g<Superscript>−1</Superscript> levels

The methods available for determination of environmental contamination by plutonium at ultra-trace levels require labor-consuming sample preparation including matrix removal and plutonium extraction in both nuclear spectroscopy and mass spectrometry. In this work, laser-ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) was applied for direct analysis of Pu in soil and sediment samples. Application of a LINA-Spark-Atomizer system (a modified laser ablation system providing high ablation rates) coupled with a sector-field ICP–MS resulted in detection limits as low as 3×10^–13 g g^–1 for Pu isotopes in soil samples containing uranium at a concentration of a few g g^–1. The isotope dilution (ID) technique was used for quantification, which compensated for matrix effects in LA–ICP–MS. Interferences by UH⁺ and PbO₂⁺ ions and by the peak tail of ²³⁸U⁺ ions were reduced or separated by use of dry plasma conditions and a mass resolution of 4000, respectively. No other effects affecting measurement accuracy, except sample inhomogeneity, were revealed. Comparison of results obtained for three contaminated soil samples by use of -spectrometry, ICP–MS with sample decomposition, and LA–ICP–IDMS showed, in general, satisfactory agreement of the different methods. The specific activity of ^239+240Pu (9.8±3.0 mBq g^–1) calculated from LA–ICP–IDMS analysis of SRM NIST 4357 coincided well with the certified value of 10.4±0.2 mBq g^–1. However, the precision of LA–ICP–MS for determination of plutonium in inhomogeneous samples, i.e. if "hot" particles are present, is limited. As far as we are aware this paper reports the lowest detection limits and element concentrations yet measured in direct LA–ICP–MS analysis of environmental samples.Sergei F. Boulyga is on leave from The Radiation Physics and Chemistry Problems Institute, 220109 Sosny, Minsk, Belarus.     

Extraction of local anaesthetics from human blood by direct immersion-solid phase micro extraction (SPME)

Summary Local anaesthetics have been shown to be extractable from human whole blood samples by direct immersion (DI)-solid phase micro extraction (SPME). After deproteinization with perchloric acid, the pH of the clear supernatants of human whole blood samples containing the drugs were adjusted to about 7 with 10 M NaOH in the presence of NaCl; a polydimethylsiloxanecoated SPME fiber was then immersed directly into the sample solution to allow adsorption of the drugs before capillary gas chromatography (GC) with flame ionization detection. The DI-SPME for 1-mL whole blood gave peaks for all the drugs; only a small amount of background noise appeared and this gave no problems in the detection of the drugs. Recoveries of the ten drugs from human whole blood was 0.74–19.7 %. The calibration curves for seven drugs showed linearity in the range of 0.25–12 g mL^–1 whole blood, with detection limits of 54–158 ng mL^–1.     

Discrimination of Ganoderma lucidum according to geographical origin with near infrared diffuse reflectance spectroscopy and pattern recognition techniques

A rapid and nondestructive near infrared (NIR) method combined with chemometrics was used to discriminate Ganoderma lucidum according to cultivation area. Raw, first, and second derivative NIR spectra were compared to develop a robust classification rule. The chemical properties of G. lucidum samples were also investigated to find out the difference between samples from six varied origins. It could be found that the amount of polysaccharides and triterpenoid saponins in G. lucidum samples was considerably different based on cultivation area. These differences make NIR spectroscopic method viable. Principal component analysis (PCA), discriminant partial least-squares (DPLS) and discriminant analysis (DA) were applied to classify the geographical origins of those samples. The results showed that excellent classification could be obtained after optimizing spectral pre-treatment. For the discriminating of samples from three different provinces, DPLS provided 100% correct classifications. Moreover, for samples from six different locations, the correct classifications of the calibration as well as the validation data set were 96.6% using the DA method after the SNV first derivative spectral pre-treatment. Overall, NIR diffuse reflectance spectroscopy using pattern recognition was shown to have significant potential as a rapid and accurate method for the identification of herbal medicines.     

Chromatographic fingerprinting and related chemometric techniques for quality control of traditional Chinese medicines

Development of chromatographic fingerprint (CF) and related chemometric methods and their applications to quality control of traditional Chinese medicines (TCMs) were discussed. CF is essentially a kind of quality control method for TCMs (or Chinese herbal medicines). Also, it is a quality‐relevant‐data high‐throughput and integral tool to explore chemically the complexity of TCMs. With the help of chemometrics, some difficulties in evaluation and analysis of CFs, such as calculation of information content, peak alignment, pattern analysis, deconvolution of overlapping peaks, etc. could be well solved. To further explore TCMs synergic quality, intensive study of CF coupled with chemometrics will create the possibility to achieve the aim to reveal the working mechanisms of TCMs and to further control and strengthen TCMs' intrinsic quality in a comprehensive manner.     

Consecutive thin-layer chromatographic separation of Au(III), Pt(IV), Pd(II) and large amounts of associated base metals

Summary The TLC system composed of ECTEOLA-cellulose and 2.5 mol/l HCl–2.5 mol/l NaCl–0.6% (w/v) H₂O₂ solution allows consecutive separations of Au(III), Pt(IV), Pd(II) and a number of associated base metals such as Cr(III), Mn(II), Fe(III), Co(II) Ni(II), Cu(II), Mg, Ca, Ba, Al, Bi(III), Pb(II), Zn(II) and Ag(I) coexisting in an extremely wide range of amounts and ratios, to be conducted completely in a single run. The effectiveness of the present system is verified by applying it to various synthesized samples containing the three noble metals and one of the base metals, Pt-metal powder and two kinds of Au-alloys.     

THM PyGC–MS of wood fragment and vegetable fibre forensic samples

Wood fragments and vegetable fibres were investigated using thermally assisted hydrolysis and methylation with pyrolysis gas chromatography–mass spectrometry (THM PyGC–MS). Multiple ion chromatography was used to decrease the interference from cellulosic peaks, and to obtain greater resolution between the lignin peaks. Forty-four wood samples were analysed using THM PyGC–MS. The wood fragments were able to be differentiated into angiosperms (hardwoods) and gymnosperms (softwoods) using principle component analysis (PCA), hierarchical cluster analysis (HCA), and the ratio of syringyl to guaiacyl lignin fragments (S/G ratio). PCA and HCA also differentiated several Monterey pine samples from the rest of the gymnosperms, primarily by the presence of β-pinene, an extractive compound. Other gymnosperm species and the individual angiosperm species were unable to be differentiated. A pilot study investigating the use of THM PyGC–MS for the analysis of vegetable fibres in forensic science found that the fibre types tended to group into two clusters, with one containing cotton, hemp and linen; and the other consisting of hessian, sisal, jute and coir. The seagrass sample was able to be differentiated from both groups. These groups were well separated using PCA, HCA and by the ratio of cinnamyl phenolic derivatives to guaiacyl lignin derivatives (C/G ratio). Some grouping of each fibre type was evident within each cluster, however the separation between the clusters was insufficient to differentiate them using these statistical techniques. THM PyGC–MS of vegetable fibres showed some potential for future use in forensic science.     

Statistical Evaluation of Bioavailability of Metals to Grapes Growing in Contaminated Vineyard Soils using Single Extractants

This article describes the statistical evaluation of concentrations of Cd, Co, Cr, Cu, Fe, Mn. Ni, Pb. Zn, Ca. and Mg metals determined in twenty-two grape and corresponding soil samples from around a zinc smelter in Kayseri. Turkey. In the analyses of soil samples. three different extraetants. 0.1 M HCl in 0.025 M H₂SO₄, 1 M NH₄OAc, and aqua regia (1HNO₃ + 3HCl), were used to extract and determine the leachable metal contents which are acid soluble, exchangeable, and total. respectively. A mixture of HNO₃ and HCIO₄ was used to dissolve grape samples. The determinations of metals were performed by flame atomic absorption spectrometry (FAAS). The analytical data were evaluated by using principal component analysis (PCA). hierarchial cluster analysis (HCA), correlation analysis (CA), and enrichment factors (EF). The relationship between the grapemetal and soil-extractable-metal concentrations was examined to evaluate the bioavailability of metals in soil to grape samples. As a consequence of statistical evaluations. Cd, Pb, Zn. Mn. and Fe labile levels in soil were related to total grape-metal contents indicating the method’s suitability for bioavailability studies in polluted soil–plant systems.