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Performance of a novel analytical method for complex samples, based on combined or fused high-performance liquid chromatography (HPLC) and Fourier transform infrared spectroscopy (FT-IR) data, was compared with that based on measurements from either of the techniques. The analytes were different varieties of Radix Paeoniae (Shaoyao), traditional Chinese medicines (TCM), from various regions. When the HPLC and FT-IR datasets (L and R) were separately submitted to either PCA or several supervised classification and prediction methods, the recognition rates were unsatisfactory. Thus, the potential of combined data of these two techniques was investigated, and two statistical methods for reducing the dimensions of the fused data were developed based on: (i) four PCs from the L and R matrices, and (ii) selection of optimum variables by the genetic algorithm-partial least squares (GA-PLS). PCA of these two fused sets indicated improved discrimination of the different sample clusters. Subsequent application of the supervised classification and prediction methods—linear discriminant analysis (LDA), least squares-support vector machine (LS-SVM), and radial basis function neural network (RBF-ANN)—indicated significantly higher recognition rates. Thus, the best discrimination of the complex Shaoyao TCM samples on the basis of their variety and geographical origin, was obtained with the use of non-linear RBF-ANN and LS-SVP models.

The interaction of aspirin and ibuprofen with bovine serum albumin (BSA) was studied by spectrofluorimetry under simulated physiological conditions. Both aspirin and ibuprofen quenched the intrinsic fluorescence of BSA and the binding ratios obtained were 2 : 1 for aspirin-BSA and 3 : 1 for ibuprofen-BSA interactions, respectively. The thermodynamic parameters (ΔH, ΔS and ΔG) obtained from the fluorescence spectroscopy data showed that the binding of aspirin to BSA involved van der Waals interactions and hydrogen bonds. Competitive experiments using warfarin and diazepam as site markers indicated that aspirin was mainly located in the hydrophobic pocket of site II of the protein as well as to a small extent in site I. Furthermore, the competitive interaction of the aspirin and ibuprofen with BSA, which was studied with the use of the three-way excitation-emission fluorescence spectra and a parallel factor analysis (PARAFAC) chemometrics method, showed that the competitive effect of ibuprofen was stronger than that of aspirin, i.e. the former molecule replaced the aspirin from the aspirin-BSA complex.

A new kinetic spectrophotometric method for simultaneous determination of chlortetracycline, tetracycline and oxytetracycline in real samples has been researched and developed. The method was based on the kinetic reaction involving the oxidation of the drugs by alkaline potassium permanganate at 40 °C. After the addition of these drugs, an increasing absorbance at 526 nm and a decreasing absorbance at 608 nm caused by manganate and permanganate, respectively, were observed. The three-way kinetic-spectral data in the 325–725 nm range from 0 to 360 s were collected and applied to build chemometrics models. The plot of absorbance versus concentration was rectilinear over the 0.05–0.75 µg mL−1 range for chlortetracycline and tetracycline, and 0.02–0.34 µg mL−1 for oxytetracycline, with the limit of detection of 0.013, 0.015 and 0.011 µg mL−1, respectively. The experimental conditions were carefully investigated to optimize the development and stability of the color products (potassium manganate). The proposed method was successfully applied to the simultaneous determination of tetracyclines (TCs) in feed and muscle samples, and the results showed satisfactory agreement with those from of the HPLC method.

Beta-agonists such as ractopamine (RAC) and clenbuterol (CLEN), have similar effects as anabolic steroids i.e. they promote growth of muscular tissue and reduce body fat. They have been used successfully with animals and humans but have also been banned in many countries principally, because of their serious side effects. However, their illegal use persists. Thus, their interaction with biomolecules such as bovine serum albumin (BSA) is of significance, especially the co-operative reaction of mixed ligands with the protein. Fluorescence and UV-vis spectra of complex mixtures of individual ligands, binary and ternary complexes with BSA resulted in significantly overlapping spectral profiles. Qualitative and quantitative information about the various complex ligand-protein species formed, was obtained with the resolution of the excitation-emission fluorescence three-way data matrices by chemometrics methods-MCR-ALS and PARAFAC. Individual spectra of the ligands, their binary complexes with BSA and their ternary complexes were extracted, and quantitative concentration profiles for each species in a particular interaction were constructed. Such analyses made it possible to interpret the role and behaviour of each reaction component. It was found that both ligands, RAC and CLEN, bound co-operatively in site I of the BSA. This was confirmed with the use of site markers such as warfarin (site I) and ibuprofen (site II). However, CLEN formed a 1:1 CLEN-BSA complex, while RAC formed a 2:1 RAC(2)-BSA binary species. Interestingly, when CLEN or RAC was added to RAC(2)-BSA or CLEN-BSA, respectively, ternary complexes were produced such as RAC(2)-BSA-CLEN. Significantly, the presence of the second ligand in such an interaction in excess, appeared to increase the affinity of the added ligand for BSA. This may have consequences on the amount of steroid required to achieve a desired tissue growth effect.

A DRIFT method for collecting spectra from dye mixtures (50 - 500 ng) extracted from small textile samples (2 mm yarn) is outlined. Results of experiments using library search routines for matching of IR spectra of simple (< 5 components) dye mixtures indicate that matches can be distinguished satisfactorily, however, with complex (8 - 14 components) dye mixture matching of duplicate spectra is less well defined. The application of principal component analysis for matching and discrimination of small dye extracts from a worn garment suggests that this is a useful approach and can add to the TLC information about the sample.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Three commonly used fluoroquinolone antibiotics (norfloxacin (NFX), ofloxacin (OFX) and lomefloxacin (LMFX)) were used as examples of molecules which can interact with a biomacromolecule, such as DNA, separately or in a mixture. Such interactions were investigated with the use of UV and Synchronous Fluorescence Spectroscopy (SFS). Equilibrium binding (K(ap)) and Stern-Volmer equilibrium (K(SV)) constants were extracted from these two types of spectra from interactions of DNA with single fluoroquinolones. The values of these equilibrium constants were relatively low, and this suggested that the DNA groove was the likely binding site. The complex SFS profiles obtained from the interactions of the DNA with the drug analyte mixtures were resolved, with the use of the curve resolution method, parallel factor (PARAFAC) analysis, into spectra of individual drugs. From these spectra, the (K(SV)) values for the individual analytes in the mixture were obtained. Also extracted were the concentrations of the individual quinolones as a function of concentration of the DNA. From a comparison of the equilibrium constants for the individual drug-DNA interaction with those obtained from the interaction with the drugs in a mixture, it was found that the binding strength of a single analyte to DNA was LMFXNFXOFX, but when the drug mixture was involved, this order was reversed. Importantly, it was also found that the equilibrium uptake of the drugs OFX and NFX was higher than from single drug-DNA experiments; the concentrations of LMFX did not change significantly. These observations collectively suggested that the binding of NFX and OFX to DNA is synergistically affected and that they probably share similar binding sites, while the LMFX was bound to a different site. This new important qualitative and quantitative information, which can now act as a springboard for more complex and deeper studies of the apparent synergistic effects of drug interactions with biomacromolecules, could only be obtained by the combination of three-way array SFS measurements and their interpretation by a chemometrics curve resolution method such as PARAFAC.

Rice breeders are involved in developing new varieties for a diverse range of production environments to increase average yields. Interpretation of performance of several varieties evaluated in a broad range of environments is usually affected by variety × environment interactions. Application of multivariate analyses, especially multi-criteria decision making (MCDM) methods in variety × environment interaction studies can benefit interpretation of yield performance and adaptation of varieties in response to different environments. The case study discussed in this paper highlights the significant advantages of using MCDM methods to overcome constraints imposed by having to investigate a large number of variables inherent in such analysis. The grain yield of 13 rice varieties with varying characteristics, grown in 4 different regions in southern New South Wales (NSW), Australia, during the 2000–06 growing seasons was analysed using classification techniques and preference ranking organization method for enrichment evaluation (PROMETHEE) analysis. Significant variety × environment interaction was found to influence the yield performance of individual varieties across a range of environmental conditions. Classification of environments and geometrical analysis for interactive aid (GAIA) plot of PROMETHEE analysis identified the Murrumbidgee Irrigation Area (MIA) and Coleambally Irrigation Area (CIA) as higher yielding regions compared with the Eastern Murray Valley (EMV) and Western Murray Valley (WMV). Turbid water and cold weather conditions are suggested to explain the lower yield obtained in the WMV environment. In terms of varieties, Amaroo and Opus were identified as widely adaptable to most of the environments, while Jarrah was the least adaptable. Illabong can be considered as best adapted to the EMV or WMV regions, while Paragon and Reiziq can be regarded as best adapted to the MIA and CIA regions. Partial and complete ranking showed the interrelationships between the varieties for their yield performance and adaptation across all environments. Amaroo, Illabong, and Opus were ranked as the most preferred varieties, while Koshihikari, Kyeema, and Jarrah were ranked as the least preferred ones. Partial pre-order with 13 classes from PROMETHEE I analysis identified varieties with similar characteristics and aided the selection of suitable alternative varieties. The outcomes from the analyses reported here allow rice varieties or genotypes to be rated for yield stability for a specific or a range of different environments.

Rice samples were obtained from the Red River region and some other parts of Vietnam as well as from Yanco, Australia. These samples were analysed for 14 elements (P, K, Mg, Ca, Mn, Zn, Fe, Cu, Al, Na, Ni, As, Mo and Cd) by ICP-AES, ICP-MS and FAAS as described in Part 1. This data matrix was then submitted to multivariate data analysis by principal component analysis to investigate the influences of environmental and crop cultivation variables on the elemental content of rice. Results revealed that geographical location, grain variety, seasons and soil conditions are the most likely significant factors causing changes in the elemental content between the rice samples. To assess rice quality according to its elemental content and physio-biological properties, a multicriteria decision making method (PROMETHEE) was applied. With the Vietnamese rice, the sticky rice appeared to contain somewhat higher levels of nutritionally significant elements such as P, K and Mg than the non-sticky rice. Also, rice samples grown during the wet season have better levels of nutritionally significant mineral elements than those of the dry season, but in general, the wet season seemed to provide better overall elemental and physio-biological rice quality.

Uptakes of chromium(III), copper(II), iron(II), nickel(II) and zinc(II) by wool were determined by inductively coupled plasma atomic emission and flame atomic absorption spectrometry. The order of uptakes at 100 °C for these metal ions was found to be CuII≫ ZnII > CrIII > FeII > NiII. Further, the metal ion-treated wool samples were submitted to Fourier transform infrared spectrometric analysis, which was facilitated by chemometric methods (principal components analysis, soft independent modelling of class analogies and fuzzy clustering). This revealed the order of structure modification at the carboxyl group as a result of metal ion–wool interactions to be CrIII > CuII≫ ZnII > FeII≈ NiII. The difference between the above two rank orders suggests that relatively large uptakes do not necessarily lead to the most significant structurally interactive effects in wool keratin.

A simple and rapid method for the simultaneous polarographic determination of pyrazine and its methyl derivatives (up to four components) has been developed. The potential was scanned from –600 to – 1000 mV by differential-pulse polarography. A solution containing a phosphate—citric acid buffer and a potassium chloride supporting electrolyte (pH 4.8; l= 0.5 mol l–1) was used. Under these conditions, high measurement sensitivities for the pyrazines were achieved. The pulse amplitude, scan rate and the time interval were –50 mV, –10 mV s–1 and 600 ms, respectively. However, because of severe overlap of the polarograms for pyrazines under these conditions, the Kalman filter method was used for the determination and curve resolution of individual components. In contrast to conventional implementation of the Kalman filter, a measurement function derived from a known set of mixed pyrazines was found to yield the best results in this work.

The application of scanning densitometry to the analysis of dyes extracted from transferred fibers is examined. The Camag high-performance thin-layer chromatography (HPTLC)/thin-layer chromatography (TLC) scanner can provide all of the information normally available from visual examination of the TLC plates. The position, color, and relative proportions of the various components are obtained in a semiquantitative form. The instrument can provide useful data in both the visible and fluorescence modes with greater sensitivity than is available from visual observations. The potential of the instrument for examination of dyes from pale-colored fibers is demonstrated. The data obtained are objective and do not suffer from the variations that can occur when using subjective visual observations.

The potential of using a combination of normal and reverse phase thin-layer chromatography for the comparison of disperse, acid, and reactive dyes extracted from textile fibers of forensic science origin was examined. For disperse and acid dyes, the use of a normal silica gel and a reverse phase system was shown to provide a pair of systems of low correlation. In contrast, the use of two silica gel systems provided a pair of highly correlated systems that possibly offered little more additional information than a single system. A suitable reverse phase system for the separation of reactive dyes was not found. The various pairs of silica gel systems tested for reactive dyes were all shown to be highly correlated.