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The newest results in the chromatographic analysis of synthetic and natural fungicides present in biological and environmental matrices are collected and critically evaluated. Examples of the employment of gas chromatography, liquid chromatographic technologies, such as thin-layer chromatography and high-performance liquid chromatographic methods as well as electrically driven systems are presented. The advantages and disasdvantages of the various chromatographic technologies are briefly discussed and the efficacies of the methodologies are compared., (Copyright © 2011 John Wiley & Sons, Ltd.)

The growth response of 25 Trichoderma strains to 26 alkanols and 7 other organic solvents was examined in vitro. The sensitivity of strains considerably varied depending on their taxonomic position, thus the strains of Longibrachiatum section proved to be more tolerant than those of Pachybasium and Trichoderma sections. Significant relationship was revealed between structure of C1 -C24 alkanols and their growth inhibitory effect to Trichodermas, both efficacy and selectivity of C1 -C3 and C14 -C24 alkanols failed off the C9 -C11 alkanols. The non-alkanol solvents tested were non-toxic. The C8 -C11 alkanols used in agricultural practices exhibited noticeable toxicity to all Trichoderma strains, therefore pesticidal preparations containing these alkanols cannot be used simultaneously with Trichoderma based biopreparations., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The quantitative relationship between the TLC retention parameters of 28 short peptides and their physicochemical characteristics was calculated using linear regression analysis. It was established that surface parameters exert a significant impact on the retention of peptides and the ratio of non-polar surface area/polar surface area exerts the highest influence on the retention. This result may be due to the fact that peptides turn towards the apolar surface of the stationary phase with their non-polar substructures while the polar molecular parts point into the hydrophilic mobile phase.

The new applications of various chromatographic techniques such as gas-liquid chromatography, high-performance liquid chromatography and electrophoretic methods employed for the analysis in macro- and micro-components in vegetable oils and dairy products are compiled and critically evaluated. The employment of these methods for authenticity tests and traceability is discussed., (Copyright 2005 John Wiley & Sons, Ltd.)

The interaction of free amino acids with the corn protein zein was studied by thin-layer chromatography carried out on cellulose layers covered with zein and the effect of pH and salts on the strength of interaction was elucidated. Only the binding of Arg, His, Lys, Orn and Trp to zein was verified, other amino acids were not retained. Retention of Arg, His, Lys and Orn decreased linearly with increasing concentration of salts the mobile phase indicating the hydrophilic character of amino acid-zein interaction. Both alkaline and acidic pH influenced the strength of binding. Principal component analysis indicated the different character of the influence of pH and salts on the interaction. The results suggest that these amino acid residues may account for the binding of other peptides and proteins to zein.

The more recent methods for the removal of synthetic dyes from waters and wastewater are complied. The various methods of removal such as adsorption on various sorbents, chemical decomposition by oxidation, photodegradation, and microbiological decoloration, employing activated sludge, pure cultures and microbe consortiums are described. The advantages and disadvantages of the various methods are discussed and their efficacies are compared.

The newest results in the use of various extraction techniques and chromatographic methods such as gas-liquid and high-performance liquid chromatography used for the assessment of herbicide residues in various matrices have been compiled and critically evaluated. Practical employments in water and soil research, environmental protection, clinical and food chemistry are presented.

The retention time of 22 barbituric acid derivatives was measured on a narrow-bore porous graphitized carbon (PGC) column using water-dioxane mixtures as mobile phases. The capacity factor (k), theoretical plate number (N), and asymmetry factor (AF) were calculated for each solute in each mobile phase. The relationships between chromatographic characteristics and physicochemical parameters of solutes were elucidated by stepwise regression analysis (SRA). SRA indicated that the binding of barbiturates to the PGC surface is of mixed character electrostatic and apolar interactive forces are equally involved. Sterical correspondence between the surface of the stationary phase and the solutes also exert a significant influence on the retention behavior.

The newest achievements in the application of miscellaneous liquid chromatographic techniques such as size-exclusion, ion-exchange and reversed-phase high-performance liquid chromatography, and thin-layer chromatography for the elucidation of the various aspects of the binding of ligands to proteins are compiled and briefly discussed. Examples of employment in pharmaceutical and clinical chemistry, drug design, enzyme kinetic studies and environmental protection are presented., (Copyright 2003 John Wiley & Sons, Ltd.)

The effect of the addition of the nonionic surfactant tributylphenyltetraethoxylate to culture media on pH and extracellular protein content, and on production of beta-glucosidase, xylanase, laccase, and manganese-dependent and -independent peroxidases by the edible fungus Pleurotus ostreatus was determined. The relationship between fermentation parameters and concentration of surfactant was assessed by multiple linear regression analysis, and the similarities and differences among the fermentation parameters were elucidated by principal component analysis. Calculations proved that except for xylanase all other cultivation parameters were significantly influenced by the surfactant, with the effect higher at higher surfactant concentrations. Surfactant increased the production of beta-glucosidase and inhibited laccase and manganese-dependent and -independent peroxidase activities.

The growth inhibitory effect of 30 synthetic dyes on 22 bacteria (test organisms) belonging to various taxonomic groups was determined. The strength (potency) and selectivity of the biological effect were separated by the spectral mapping technique, reducing the dimensionality of the selectivity maps to two by the nonlinear mapping technique. The relationship between biological effect and physicochemical parameters of dyes was elucidated by stepwise regression analysis. It has been established that the strength of the effect of anthracene and trityl derivatives was higher than that of azobenzene dyes and significantly depended on the hydrophobicity of the compound. The selectivity of the effect also depended on hydrophobicity and on the nonpolar unsaturated surface area of the dyes. Gram negative and Gram positive bacteria differed in the strength and selectivity of their response to dyes indicating the marked impact of the taxonomical position on the response. Contrary to other multivariate mathematical statistical methods biological activity may be divided by SPM into potency and selectivity values, therefore, application of the technique in future QSAR studies is highly recommended.

The strength and the character of the binding of 14 organic solvents to the corn protein zein in distilled water and in various salt solutions were determined by preparing zein-coated carbon stationary phase and by measuring the retention characteristics of solvents on a high-performance liquid chromatographic column filled with this stationary phase. The relationship between the physicochemical parameters and binding characteristics of solvents was elucidated by principal component analysis. It was established that various interactive forces are involved in the binding of solvent to the protein, suggesting a mixed binding mechanism. Binding characteristics are equally influenced by the molecular hydrophobicity and by the polarity parameters of the solvent. Coordination numbers, ionization, and lattice energies of the monovalent cations significantly influenced the various aspects of the binding of organic solvents to zein.

The influence of pH and the concentration of sodium chloride on the strength and selectivity of the interaction of twelve 8-substituted-2'-deoxyadenosine and sixteen 5-substituted-2'-deoxyuridine derivatives with gamma-cyclodextrin (GCD) have been studied by the spectral mapping technique (SPM). The potency values of the spectral map were regarded as indicators of the capability of antisense nucleosides and GCD to interact simultaneously taking into consideration all relevant data. It has been established that the strength of interaction is highest in acetic and lowest in alkaline solutions, and the selectivities of acidic, alkaline and salt solutions are markedly different. The length of hydrophobic alkyl substituents in antisense molecules influenced both the strength and selectivity of the interaction. The character of the base structure affected only the selectivity., (Copyright 2003 Elsevier Science B.V.)

The interaction of 16 ring-substituted phenols and anilines with the corn protein zein was studied by reversed-phase high-performance liquid chromatography by preparing silica- and alumina-based stationary phases coated with various concentrations of zein. The relationship between the strength of interaction and the physicochemical parameters of solutes was elucidated by principal component analysis followed by the nonlinear mapping technique. The binding of each phenol and aniline derivative to zein has been demonstrated. It was established that the electrostatical parameters of solutes exert the highest influence on the interaction and the involvement of hydrophobic binding forces is of secondary importance. The binding characteristics of phenol and aniline derivatives were different.

The strength and the character of the binding of 12 organic solvents to the corn protein zein was determined by preparing zein-coated carbon stationary phase and by measuring the retention of solvents on a high-performance liquid chromatographic column filled with this stationary phase. The relationship between the physicochemical parameters and binding characteristics of solvents was elucidated by principal component analysis. Various interactive forces are involved in the binding of solvent to the protein. The strength of the binding is dominantly influenced by the molecular hydrophobicity while the Gaussian or non-Gaussian distribution of the adsorption strength is markedly dependent on the polarity parameters of the solvent. Sterical correspondences exerted considerable influence on each binding parameter.

The lipophilicities of 18 ring-substituted phenol and aniline derivatives are determined on alumina and silica thin-layer chromatographic supports impregnated with 2.5 and 10% (v/v) paraffin oil in n-hexane using a mixture of water-methanol as the mobile phases. The effect of calculated physicochemical parameters and chromatographic conditions on the retention is elucidated by stepwise regression analyis. It is established that the degree of impregnation exerts a greater impact on the retention than the character of the support. Not only the calculated lipophilicity but also various sterical and polarity parameters significantly influence the retention, indicating the involvement of factors other than hydrophobic forces in the retention mechanism.

The newest results concerning the biological activity and environmental fate of anionic surfactants are collected and critically evaluated. The chemical and physicochemical parameters related to the biological activity and the field of application are briefly discussed. Examples on the effect of anionic surfactants on the cell membranes, on the activity of enzymes, on the binding to various proteins and to other cell components and on their human toxicity are presented and the possible mode of action is elucidated. The sources of environmental pollution caused by anionic surfactants are listed and the methods developed for their removal from liquid, semiliquid and solid matrices are collected. Both the beneficial and adversary effects of anionic surfactants on the environment are reported and critically discussed. It was concluded that the role of anionic surfactants in the environment is ambiguous: they can cause serous environmental pollution with toxic effect on living organisms; otherwise, they can promote the decomposition and/or removal of other inorganic and organic pollutants from the environment. The relationship between their chemical structure, physicochemical parameters, biological activity and environmental impact is notwell understood. A considerable number of data are needed for the development of new anionic surfactants and for the successful application of the existing ones to reduce the adversary and to promote beneficial effects.

The effect of ascorbic acid, light, and storage on the stability of the pigments beta-carotene and capsanthin in red pepper (Capsicum annuum) powder has been elucidated by determining the amount of pigment in samples treated by various concentrations of ascorbic acid. Determination of pigment concentration has been performed after different storage times using high-performance liquid chromatography. The dependence of the concentration of pigments on the concentration of ascorbic acid, presence of light and the storage time has been assessed by stepwise regression analysis. The concentration of pigments decreased at longer storage time and increased at higher concentration of ascorbic acid, beta-carotene being more sensitive towards storage time and concentration of ascorbic acid than capsanthin. Interaction between the effects of light and storage time, and light and concentration of ascorbic acid has been established.

The newest results in the use of miscellaneous mass spectrometric detection methods in various chromatographic techniques are compiled and critically evaluated. Examples of application in clinical chemistry, health care, and in the analysis of pharmaceuticals, environmental pollutants, foods and food products are given. The benefits and drawbacks of MS detection are discussed, and future trends are briefly discussed., (Copyright 2002 John Wiley & Sons, Ltd.)

Using a test mixture consisting of standard proteins (cytochrome c, chymotrypsinogen A, hen egg albumin, bovine serum albumin, aldolase, catalase and ferritin) and synthetic polypeptides (polylysine, polyaspartic, polyglutamic acid and polyproline) it was revealed that using sodium dodecyl sulfate (SDS) as background electrolyte modifier at acid pH (2.5) allows selective separation of highly positively charged polypeptides (polylysine) provided that their relative molecular mass is sufficiently low (3300 Da). The altered elution sequence of standard proteins as compared to a separation done without SDS may help their identification. Addition of Pluronic F127 offers clear-cut separations of standard proteins up to a relative molecular mass of 5 x 10(4) Da and allows to reveal protein/polypeptide microheterogeneity where applicable. None of the systems tested is suitable for the separation of acidic polypeptides and polyproline.

The production of beta-glucosidase by the ligninolytic fungus Pleurotus ostreatus has been studied in different culture media containing agro-industrial wastes. The enzyme is purified by anion-exchange chromatography, the molecular mass and isoelectric point of purified beta-glucosidase are measured by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing and the stability and kinetic parameters of the enzyme assessed by spectrophotometry. It has been established that the retention time, molecular mass and isoelectric point of the enzyme depend on the composition of the culture media while the activity and stability of beta-glucosidases of different origin were very similar. The combined chromatographic and electrophoretic methods have proved to be suitable techniques for the purification and characterisation of the beta-glucosidases produced by the ligninolytic fungus Pleurotus ostreatus in different culture media.

The effect of light, storage time and temperature on the decomposition rate of monomeric anthocyanin pigments extracted from skins of grape (Vitis vinifera var. Red globe) was determined by reversed-phase high-performance liquid chromatography (RP-HPLC). The impact of various storage conditions on the pigment stability was assessed by stepwise regression analysis. RP-HPLC separated well the five anthocyanins identified and proved the presence of other unidentified pigments at lower concentrations. Stepwise regression analysis confirmed that the overall decomposition rate of monomeric anthocyanins, peonidin-3-glucoside and malvidin-3-glucoside significantly depended on the time and temperature of storage, the effect of storage time being the most important. The presence or absence of light exerted a negligible impact on the decomposition rate.

Multiwavelength spectrometry and reversed-phase high-performance liquid chromatography have been employed for the study of the effect of reduced glutathione and storage time on the pigments of paprika powders. The evaluation of the data by principal component analysis and cluster analysis proved that the storage time exerts the highest effect of the decomposition rate of pigments. The stability of some pigment fractions was modified in the presence of reduced glutathione. However, the effect was of secondary importance. Multiwavelength spectrometry combined with HPLC can be successfully used for the study of the stability of pigments of paprika powder.

The retention time of 16 peptides was determined on polyethylene-coated alumina stationary phase using mixtures of acetonitrile (MeCN) and acidic and basic phosphate buffers as mobile phases. The majority of peptides showed nonlinear retention behaviour, their retention decreased with increasing concentration of MeCN in the lower concentration range, reached a minimum and increased again with increasing concentration of MeCN in the higher concentration range. Quadratic equations described well the atypical retention behaviour of peptides, the significance level being always over 95%. Principal component analysis indicated that the steric parameters of peptides exerted the highest influence on their retention on polyethylene-coated alumina stationary phase.

The activity of manganese-dependent and manganese-independent peroxidases produced by Pleurotus ostreatus in culture media composed of agro-residues was measured by visible spectrophotometry. The overall enzyme activity and its selectivity were separated by using spectral mapping technique followed by nonlinear mapping. The relationships between the parameters of enzyme production and the composition of culture media and fermentation time was assessed by stepwise regression analysis. Calculations proved that the addition of extract of straw to the culture media significantly decreased the overall production of both enzymes, whereas the selectivity of enzyme production was influenced by amount of potato extract and the concentration of total sugar in the culture media. Enzyme activity depended quadratically on the fermentation time.

The newest achievements in the use of various liquid chromatographic techniques such as adsorption and reversed-phase thin-layer chromatography and HPLC employed for the separation and quantitative determination of terpenoid-based color substances in foods and food products are reviewed. The techniques applied for the analysis of individual pigments and pigments classes are surveyed and critically evaluated. Future trends in the separation and identification of pigments in foods and food products are delineated.

The retention behaviour of seven monotetrazolium and nine ditetrazolium salts was studied in seven different mobile phases on alumina and impregnated alumina stationary phases. The strength and selectivity of the components of mobile phases were separately calculated by the spectral mapping technique. It was established that tetrahydrofuran (THF) has the highest solvent strength while the differences among ethanol, 1-propanol, 2-propanol and dioxane were relatively low. The selectivity of THF was also considerably different from those of other solvents. Hydrophobicity and electronic parameters were equally involved in the retention strength and selectivity of tetrazolium salts, indicating the mixed character of their interaction with the alumina stationary phase., (Copyright 2001 John Wiley & Sons, Ltd.)

Depository effects in slowly metabolised proteins, typically glycation or the estimation of products arising from the reaction of unsaturated long-chain-fatty acid metabolites (possessing aldehydic groups) are very difficult to assess owing to their extremely low concentration in the protein matrix. In order to reveal such alterations we applied deep enzymatic fragmentation resulting in a set of small peptides, which, if modified, are likely to change their electrophoretic properties and can be visualised on the resulting profile. Peptide maps of collagen (a mixture of collagen types I and III digested by bacterial collagenase) were applied as the model protein structure for detecting the nonenzymatic posttranslational changes originating during various physiological conditions like high fructose diet and hypertriglyceridemic state. Capillary electrophoresis in acidic media (sodium phosphate buffer, pH 2.5) was used as the separation method capable of (partial) separation of over 60 peptide peaks. Two to 13 changes were revealed in the profiles obtained reflecting the physiological conditions of the animals tested. Combination of peptide profiling with subsequent t-test evaluation of individual peak areas and principal component analysis based on cumulative peak areas of individual sections of the electropherograms allowed to determine in which section (part) of the electropherogram the physiological state indicating changes occurred. Simultaneously it was possible to reveal the qualitative differences between the four physiological regimes investigated (i.e., which regime affects the collagen molecules most and which affects them least). The approach can be used as guidance for targeted preseparation of the very complex peptide mixture.

The interaction between low molecular-mass homopeptides and mixtures of nonionic and anionic surfactants has been assessed by using reversed-phase thin-layer chromatography. The relative strength of interaction for mixtures of sodium dodecylsulfate and tridecylalcohol diglycolate (GNX) at the molar ratios of 8:2, 6:4, 4:6 and 2:8 has been calculated and its relationship with the physicochemical parameters (number of amino acid units, hydrophobicity, side chain bulkiness, electronic characteristics) of peptides has been computed by stepwise regression analysis. Each peptide interacted with each surfactant mixture the strength of interaction markedly depending on both the character of the peptide and the composition of the surfactant mixture. The hydrophobicity and electronic properties of the amino acid units exerted the highest influence on the strength of interaction at the highest concentration of the nonionic surfactant (GNX) whereas the number of amino acid units in the peptide molecule and the bulkiness of the amino acid side chain governed the strength of interaction at the lowest concentration of GNX.

The colour pigments of five chili powders of different origins were separated and quantified by reversed-phase high-performance liquid chromatography (RP-HPLC). The similarities and dissimilarities of pigment composition of chili powders were elucidated by principal component analysis (PCA). RP-HPLC separated 50-100 pigment fractions depending on the detection wavelength and on the origin of chili powder. It was found that the pigment composition of chili powders from Malaysia and China and from India and Pakistan show marked similarities while the composition of colour pigments of chili powder from Thailand was different. It was further established that the chromatograms are similar in the first 5-35 min of development, they are highly different between 35 and 75 min and moderately different at the end of the chromatograms. It was concluded that RP-HPLC followed by PCA can be successfully used for the identification of chili powders according to the composition of their colour pigments.

The interaction of 12 phenoxyacetic acid derivatives with human and serum albumin as well as with egg albumin was studied by charge-transfer reversed-phase (RP) thin-layer chromatography (TLC) and the relative strength of interaction was calculated. Each phenoxyacetic acid derivative interacted with human and bovine serum albumins whereas no interaction was observed with egg albumin. Stepwise regression analysis proved that the lipophilicity of the derivatives exert a significant impact on their capacity to bind to serum albumins. This result supports the hypothesis that the binding of phenoxyacetic acid derivatives to albumins may involve hydrophobic forces occurring between the corresponding apolar substructures of these derivatives and the amino acid side chains.

The interaction of 12 substituted phenol, three aminophenol and four substituted aniline derivatives with the corn protein zein was studied on zein-coated silica and alumina stationary phases by high-performance liquid chromatography using bidistilled water as mobile phase. Solutes were eluted from the zein-coated supports with different retention times indicating that they bind to the protein with different forces. They were more strongly retained on silica-based than on alumina-based support proving that the original adsorptive character of the support remains even after impregnation. The retention of solutes on both zein-coated stationary phases significantly depended on the steric and electronic parameters of solutes and was independent of the calculated and measured lipophilicity parameters, indicating that hydrophobic forces are not included in the interaction of zein with these class of solutes. It has been concluded that the interaction is governed by steric and electrostatic forces.

The relative strength of interaction between anionic (SDS) and nonionic surfactant (octaethoxylated oleyl alcohol, GEN) and homologous series of peptides was determined by reversed-phase thin-layer chromatography (RP-TLC) carried out on alumina layers impregnated with paraffin oil. The relative strength of interaction was calculated and was correlated with the physicochemical parameters of peptides. It was established that each peptide interacted with both surfactants and with their mixture (1:1, m/m). The relative strength of interaction depended on the number of amino acid units in the peptide, side chain bulk and electronic properties and hydrophobicity of the amino acids. The impact of individual parameters highly depended on the character of surfactant. The data prove that the retention order of peptides can be modified by adding different surfactants and surfactant mixtures to the mobile phase resulting in improved separation.

A spectral mapping technique (SPM) was employed for separating the strength and selectivity of the retention of 41 barbituric acid derivatives and 5 organic modifiers on a porous graphitized carbon column (PGC). The potency values calculated by SPM were considered to be indicators of the capacity of drugs to bind to the surface of PGC and the capacity of organic modifiers to remove the drugs from the surface. The dimensionality of the multidimensional selectivity maps was reduced to two by a nonlinear mapping technique. Calculations indicated that molecular lipophilicity plays a negligible role in the strength and selectivity of retention, proving that the retention mechanism of PGC deviates from those of traditional reversed-phase stationary phases. Sterical and electronic parameters exerted the highest influence on the retention, emphasizing the importance of the polar interaction and the sterical correspondence between the surface of PGC and the solute molecules.

The interaction of twelve 8-substituted-2'-deoxyadenosine and seventeen 5-substituted-2'-deoxyuridine derivatives (antisense nucleosides) with cyclomalto-octaose (GCD) was determined by charge-transfer chromatography and the relative strength of the interaction was calculated. The majority of antisense nucleosides (14 deoxyuridine and 11 deoxyadenosine derivatives) interacted with GCD, which probably led to inclusion complex formation. Stepwise regression analysis proved that the strength of interaction was related to the length of the apolar alkyl chain of substituents and the bulkiness of the nucleoside ring structure. The effect of double or triple bonds in the chain was negligible.

The colour pigments of Trichoderma harzianum fermentation broth were separated and the main fractions were tentatively identified by reversed-phase thin-layer chromatography-Fourier transform infrared spectroscopy (RP-TLC-FT-IR), RP-HPLC-diode array detection and RP-HPLC-MS. It was established that the multistep gradient elution developed for RP-TLC separation of pigments can be successfully used as a pilot method for the rational design of gradient elution in RP-HPLC for the separation of the same pigments. FT-IR and MS measurements were unable to identify the exact chemical structures of the main pigment fractions, the presence of OH, =CH and C=O (RP-TLC-FT-IR) and OH and NH, substructures (RP-HPLC-MS) was confirmed. It was assumed that the main pigment fractions are oxidation polymers originating from monomer molecules containing polar substructures and double bonds in the alkyl chain which are liable for oxidation during the aerobic fermentation process.

The performance of reversed-phase thin-layer (RP-TLC) and reversed-phase high-performance liquid chromatography (RP-HPLC) was compared for the separation and determination of the colour pigments of chili (Capsicum frutescens) powder using a wide variety of eluent systems. No separation of pigments was achieved in RP-TLC, however, it was established that tetrahydrofuran shows an unusually high solvent strength. RP-HPLC using water-methanol-acetonitrile gradient elution separated the chili pigments in many fractions. Diode array detection (DAD) indicated that yellow pigments are eluted earlier than the red ones and chili powder contains more yellow pigments than common paprika powders. It was established that the very different absorption spectra of pigments make the use of DAD necessary.

Silica gel, aluminium oxide, diatomaceous earth, polyamide, cyano, diol and amino plates have been tested for their capacity to separate the color pigments of six chili powders of different origin by both adsorption and reversed-phase thin-layer chromatography. The plates were evaluated at 340 and 440 nm wavelengths. Best separation of color pigments was obtained on impregnated diatomaceous earth layer using acetone-water 17:3 v/v eluent. It was found that the pigment composition of chili powders showed marked differences. Principal component analysis employed for the classification of the chili powders according to their pigment composition indicated that these differences can be used for the determination of the similarity or dissimilarity of the chili powders.

The adsorption and desorption capacities of 11 different solid-phase extraction sorbents were tested for the preconcenration of pigments of various Hungarian red wines. The concentrates were evaluated by multiwavelengh spectrophotometry combined with a spectral mapping technique (SPM) and by reversed-phase high-performance liquid chromatography. The highest (10-fold) concentration of pigments was achieved on octadecylsilica sorbent. It can be used five times without losing adsorption and desorption characteristics. SPM indicated that multiwavelength spectrophotometry can be employed for the differentiation of red wines. Comparison of the chromatograms of pigments with and without preconcentration showed that preconcentration makes possible the separation and detection of pigments present in low concentration in red wines.

The efficiency of microwave-assisted extraction (MAE) for the extraction of colour pigments from paprika (Capsicum annuum) powders was evaluated using 30 extracting solvent mixtures. The separation efficacy and selectivity of MAE was carried out using a spectral mapping technique and the relationship between the efficacy and selectivity of extraction and the physicochemical parameters of solvent mixtures was calculated by stepwise regression analysis. The calculation results were verified experimentally by the separation of pigment fractions by high-performance liquid chromatography. It was established that both the efficacy and selectivity of MAE depend significantly on the dielectric constant of the extraction solvent mixture.

The newest results in the application of various liquid chromatographic techniques for the analysis of natural pigments in pure state and in complicated matrices are compiled. The methods employed for the separation and quantitative determination of the different pigment classes (flavonoids, coumarins, chlorophylls, etc.) are described and critically evaluated. The future trends are briefly discussed., (Copyright 2000 John Wiley & Sons, Ltd.)

The soluble color pigments of raisin are separated by reversed-phase thin-layer chromatography (TLC), and the capacity of TLC-Fourier transform infrared (FTIR) with both on-line and off-line coupling is assessed for the identification of the main fraction. TLC has also been used as a pilot technique for the development of a gradient elution method for the separation of pigments by high-performance liquid chromatography (HPLC). On-line TLC-FTIR cannot be used for identification because of the strong adsorbance of the stationary phase. Off-line TLC-FTIR combined with the retention behavior of the main pigment fraction indicates that it is a polymer, caramel-like compound composed of erythrose and fructose monomers. Baseline separation of pigments is achieved by HPLC using TLC as a pilot method.