Introductory remarks

Separate terms to distinguish the matrix between the cells that grow in vitro and the matrix that separates and surrounds cells in the living body are being proposed. The currently used designations: pericellular, extracellular, or intercellular matrix should be used only for the substance produced by cells in vitro (cultures). The well organized, highly specific, and stable structure with significant topographic variations between the cells of living tissues and organs should be called biological matrix or briefly as biomatrix. My experiments published in the early 1940s on plant cell walls illustrate some similarities between biomatrix of animal tissues and plant cell wall. When cells of plant epithelial membranes undergo plasmolysis, the space between the contracting cell and cellulose cell wall is filled with filaments called Hechtian filaments or strands. With silver impregnation, these filaments become a fibrous network, filling the space between the cell wall and the contracting plasma (cell) membrane. A similar extracellular fibrous network has been described earlier after silver impregnation in some animal tissues. I interpreted my finding that a pectin-like polysaccharide in the cell wall biomatrix and hyaluronan, the only polysaccharide present in the biomatrix of animal tissues, are responsible for this fibrous network artifact.     

Thermodynamic networks

Continuity matrices have been developed for matter, energy and entropy networks. The advantages of this approach are the increased generality and compactness developed by the set of three matrix equations. A simple power plant system or network is analyzed using the matrix method.     

Effect of plant matrix and fluid ethanol concentration on supercritical fluid extraction efficiency of schisandrin derivatives

An investigation of the effect of plant matrix on the supercritical fluid extraction efficiency of five schisandrin derivatives is reported, exhibiting a great difference with respect to extraction efficiency depending on the matrix. Pure supercritical CO2 at 60 degrees C and 34.0 MPa cannot fully recover schisandrin derivatives from the leaves as much as from the other matrices. Only 36.9% of these compounds are extracted from leaves of Schisandra chinensis by supercritical CO2 in comparison with organic solvent extraction. However, more than 80% of schisandrin derivatives are obtained from both stem and fruit parts. Ethanol addition also shows a different effect depending on plant matrix; that is, CO2 modified with 10% ethanol could enhance the yield of schisandrin derivatives from leaves by four times when compared with that of pure CO2, but it has little effect on both stems and fruits.     

Determination of arsenic in plant samples by inductively coupled plasma atomic emission spectrometry with ultrasonic nebulization: a complex problem

Under well-defined conditions, the analysis of most trace elements by inductively coupled plasma atomic emission spectrometry with ultrasonic nebulization (ICP-AES-USN) leads to accurate results for environmental matrices usually studied. Due to differences in matrix composition between standards and samples, ICP-AES-USN determinations of arsenic are interfered with by changes that take place mainly within the desolvation stage of the USN device. In this work, effects of plant matrices on the determination of As in six arsenic species have been investigated. Firstly, interferences were simulated by measuring analyte (species) signals in solutions containing variable concentrations of the main matrix elements encountered in mineralized plant samples (K, Ca, Mg, P and Na). Secondly, the influence of real plant matrices on emission signals of arsenic species was also studied. In this case, the observed effects were different than for individual matrix elements considered separately: Ca and Mg always present in real samples efficiently compensate the undesirable effects. Validation of this statement has been performed using mineralized plant reference materials. In addition, ICP-AES-USN results have been compared with those obtained by Zeeman electrothermal atomic absorption spectrometry.     

Trace analysis of metals in plant samples with inductively coupled plasma – mass spectrometry

An analytical method for the quantitative determination of Al, Ti, V, Cr, Co, Ni, Cu, Zn, Mo, Cd, Ti and Pb in plant samples by ICP-MS has been developed. Spectral interferences, plant matrix effects, precision and accuracy are discussed. Results are demonstrated for selected samples concerned with the mass balance of heavy metals after utilization of non-food vegetable materials in a power plant. Received: 7 January 1997 / Revised: 2 June 1997 / Accepted: 18 June 1997     

Growth Processes due to Reactions in Swellable Cellular Matrixes

In matrix reactions in swellable cellular matrixes, the solids formed are oriented in space and arranged in the form of cells in strong three-dimensional growth processes. Open-cell, flexible, elastic polyurethanes have a particularly good matrix action. The principle is of general validity, and can be realized with a wide variety of matrixes and reaction types. The dimensional changes, which are always symmetrical, are largely determined by the chemical constitution of the matrix, segment structure, degree of crosslinking, and solvation and hydration behavior. One-component reactions having high rates give sigmoid growth curves and exhibit parallels with growth curves of plant cell walls containing cellulose.     

A novel approach to identify plant parasitic nematodes using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Plant parasitic nematodes are difficult to identify because different species are morphologically similar, and this makes their control more difficult. The aim of this work was to develop a rapid, simple method to identify plant parasitic nematodes, based on analysis of protein profiles of nematodes generated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). Two methods have been used: grinding and direct analysis of intact nematodes. Both methods were standardised using the nematode Anguina tritici (wheat seed-gall nematode) as a model. Development of the approach involved optimisation of experimental parameters to generate reproducible diagnostic protein profiles for plant parasitic nematodes. With alpha-cyano-4-hydroxycinnamic acid (CHCA) as the matrix, the most effective solvent extraction was with 90% acetone. With sinapinic acid (SA) as matrix, 90% ethanol was most effective. When intact nematodes were analysed directly by mixing with the matrix solution, 40 min extraction with CHCA matrix solution generated the best protein profiles. The standardised methods were applied to analyse the seed-gall nematodes A. tritici and A. funesta and to the root-knot nematode, Meloidogyne javanica, which infects many horticultural crops. Typical protein profiles and diagnostic peaks were identified for these nematode species and for mixtures of Anguina species. The results provide 'proof-of-concept' that these nematode species can be identified by protein profiling using MALDI-TOFMS. This new approach could be extended to identify other plant and non-plant parasitic nematodes.     

Matrix effects during trace element analysis in plant samples by inductively coupled plasma atomic emission spectrometry with axial view configuration and pneumatic nebulizer

Plant sample matrix effects have been investigated during trace element analysis by inductively coupled plasma atomic emission spectrometry with axial view and pneumatic nebulizer. Eight elements often analyzed in environmental samples were studied: As, Cd, Co, Cr, Cu, Ni, Pb and Se. To simulate the effects caused by digested plant samples, the spectral line profiles of analytes were measured on solutions containing various concentrations of elements encountered in plant matrix such as K, Ca and Mg. Depressions in the emission intensities occurred and were more dramatic with high concentrations of the concomitant species. The inter-element effects were found to be caused by the matrix amount entering into the central channel of the plasma. In fact, energy consumed for droplets desolvation and particles of salts vaporization leads to lower plasma temperatures and produce changes in excitation mechanisms. Ion emissions were especially affected. The matrix effects can be removed using a high generator power (1.4 kW) and a moderate uptake flow rate of solution into the plasma (pump speed: 15 rev./min). The use of the natural plant sample led to the same conclusions. These operating conditions decreased the sensitivity but routine analyses of the plant material could be carried out.     

Determination of perchlorate at parts-per-billion levels in plants by ion chromatography

A method for the analysis of perchlorate in plants was developed, based on dry weight, and applied to the analysis of plant organs, foodstuffs, and plant products. The method reduced greatly the ionic interferences in water extracts of plant materials. The high background conductivity, due to the plant matrix, was reduced sufficiently to allow quantitation of perchlorate with little or no matrix interference. Ion chromatography (IC) on a microbore AS16 anion-exchange column and a conductivity detector was used for separation and detection of perchlorate from the ionic plant extract. The extract was heated to precipitate proteins, centrifuged, exposed to alumina, and filtered through a cartridge filled with divinylbenzene to yield a water clear extract for IC analysis, even from highly colored solutions. Heating the extract and treatment with alumina reduced substantially the ionic content of the extracts without loss of perchlorate.     

Application of microbial alkaloid prodigiosin as a potent matrix for the MALDI mass spectrometry analysis of low-molecular-weight plant antioxidants

Microbial alkaloid prodigiosin is proposed as a new effective matrix for the analysis of low-molecular- weight plant antioxidants by MALDI mass spectrometry in the negative ion detection mode. It is demonstrated that the physicochemical characteristics of prodigiosin, such as ability to activate ionization/ desorption of analyte, high absorption coefficient at the working wavelengths of lasers, good solubility in solvents used for analytes, uniformity of crystallization on the target, stability under working conditions, and the absence of interfering peaks of fragment and cluster ions, are consistent with the recommendations for effective matrices. Prodigiosin as a matrix ensures the high-resolution detection of various plant antioxidants in complex mixtures. The obtained mass spectra of flavonoid aglycones were characterized by high quality (signal-to-noise ratio higher than 10³) and reproducibility. The use of prodigiosin for analyzing a complex preparation of plant antioxidants ensures the simultaneous recording and interpretation of more than two dozens of ions corresponding to various antioxidants with the molecular weights of 100–500 Da.     

Efficiency Of L'vov Platform And Ascorbic Acid Modifier For Reduction Of Interferences In The Analysis Of Plant Samples For Pb,T1, Sb,Cd, Ni AND Cr BY ET-AAS

Abstract

The interferences encountered in trace metal analysis of plant media by ET-AAS are described. The atomization of Cd, Cr and Ni are weakly perturbed by the plant matrix elements and no corrections have been investigated. For Pb, T1 and Sb a drastic slope reduction of the working curve is observed, which drastically reduces sensitivity. These perturbations are minimized by the L'vov platform technology, the efficiency of which has been tested with four commercially available ET-AAS systems. Matrix modification by ascorbic acid may be also efficient.     

Recent advances in application and progress of advanced materials as adsorbents in sample preparation for plant growth regulators

Plant growth regulators are a class of physiologically active substances that could modify or regulate basic physiological processes in the plant and defense against abiotic and biotic stresses, including natural plant growth regulators and synthetic ones. Different from natural plant growth regulators with low content and high cost of extraction in plants, synthetic ones can be produced in large-scale production and widely used in agriculture for increasing and securing yield and quality of the harvested produce. However, like pesticides, the abuse of plant growth regulators will have negative impacts on human beings. Therefore, it is important to monitor plant growth regulators residues. Due to the low concentration of plant growth regulators and complex matrices of food, it is necessary to isolate and extract plant growth regulators by appropriate adsorbents in sample preparation for obtaining satisfactory results. In the last decade, several advanced materials as adsorbents have shown superiority in sample preparation. This review briefly introduces the recent application and progress of advanced materials as adsorbents in sample preparation for extraction of plant growth regulators from the complex matrix. In the end, the challenge and outlook about the extraction of plant growth regulators of these advanced adsorbents in sample preparation are presented.     

固相萃取-色谱/质谱技术在油菜素内酯分析中的研究进展

油菜素内酯(brassinosteroids,BRs)是一类重要的植物激素,参与调节植物的各个生理过程.确定BRs在不同植物组织中的含量有利于进一步了解其作用机制.由于此类激素内源含量极低、植物基质复杂等原因,BRs的定量分析面临较大挑战.固相萃取及其衍生方法(固相微萃取、磁性固相萃取等)以及色谱-质谱技术的发展,能显...     

Strategies for the identification of non-polar toxicants in aqueous environmental samples using toxicity-based fractionation and gas chromatography-mass spectrometry.

Toxicity-based fractionation is a useful tool for the isolation and identification of non-polar organic compounds that are present at toxic concentrations in aqueous environmental samples. Methods for isolating such toxicants from the aqueous sample matrix and techniques for fractionating the compounds for the purpose of reducing the complexity of the sample matrix and thus facilitating identification are evaluated. Strategies for analyzing gas chromatographic-mass spectrometric data and confirming toxicant identification are presented. Studies that use toxicity-based fractionation for identifying the cause of toxicity in aqueous environmental samples such as municipal and industrial wastewater treatment plant effluents and ambient waters are discussed.     

Review of adsorptive stripping voltammetric methods for cobalt determination in the presence of a zinc matrix

Different polarographic and voltammetric methods for the determination of Co in the presence of a large excess of zinc are reviewed. Adsorptive stripping voltammetry with in-situ matrix exchange and catalytic adsorptive stripping voltammetric methods are recommended for monitoring Co traces in zinc plant electrolyte. The principles of the catalytic adsorptive stripping voltammetric methods for Co determination are presented. The correct selection of the investigated supporting electrolytes, enabling the monitoring of Co traces in a zinc plant electrolyte by means of catalytic adsorptive methods is also discussed. The catalytic adsorptive voltammetric procedures offer the possibility of the determination of Co or Co and Ni traces in metallic zinc and zinc salts.     

油菜素甾醇激素分析的研究进展

油菜素甾醇是一类具有高生理活性的甾体激素,在植物中含量低,所在基体复杂。目前,要实现该激素的高效分离和准确定量分析仍存在很大的困难。本文综述了油菜素甾醇样品前处理方法及其分析检测技术的研究进展。共引用文献49篇。     

Thin-layer chromatography in food and agricultural analysis

The TLC analysis of agricultural products, foods, beverages, and plant constituents is reviewed for the period from mid-1995 to mid-1999. Techniques and applications for a wide range of analyte and sample matrix types are covered, with specification of the particular layers, mobile phases, detection methods, and quantification conditions in many cases.     

Non-dispersive systems in atomic fluorescence spectroscopy—III : Scattering by particles and its correction in practical analysis

In the determination of trace metals in sample solutions containing high concentrations of matrix material, the usefulness of the atomic fluorescence technique may be limited by the scatter signal from particulate matter in the flame. The nature and extent of this phenomenon are investigated and various methods of correction for it are discussed. These methods are applied in several practical analyses of high-purity metals, plant materials and soil samples.     

Carotene location in processed food samples measured by cryo In-SEM Raman

Cryo In-SEM Raman has been used for the first time to localise carotene compounds in a food matrix. Raman spectra of lycopene and β-carotene have been obtained from sampling oil droplets and plant cell structures visualised with cryo-SEM in tomato and carrot based emulsions containing 5% oil. It was possible to identify the carotenoids in both the oil droplets and the cell walls. Furthermore our results gave some indication that the carotenoids were in the non-crystalline state. It has been suggested that a higher amount of carotenes solubilised into the oil phase of the food matrix would lead to a higher bioaccessibility, thus understanding the effect of processing conditions on micronutrients distribution in a food matrix might help the design of plant based food products with a better nutritional quality. This shows improved structural characterisation of the cryo-SEM with the molecular sensitivity of Raman spectroscopy as a promising approach for complex biological problems.     

Statistical Model for Organic Chromatographic Trace Analysis of Complex Samples. A Case Study: Plant Extracts

Abstract

The use of pooled plant extracts is described in the estimation of matrix interference in HPLC (UV and EC) determinations of organic compounds in plant extracts. An extract from freeze dried leaves of 134 different plant species was used for this purpose. It was split in different subgroups with solid extraction clean-up procedures. UV, EC and chromatographic data of the subgroups were used in the calculation of minimum concentrations of organic compounds which are still accurately determinable in plant samples with HPLC methods. The UV and/or EC characteristics of the compound must be known. The contribution of the solid phase extraction procedures and of the analytical system to the selectivity of the method can be estimated. Information is also supplied which allows rapid comparison of the selectivity of the UV and EC (single, or dual parallel) detectors for the determination of a specified compound.