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An uncomplicated and sensitive kinetic spectrofluorometric method was developed for the simultaneous analysis of sibutramine, indapamide, and hydrochlorothiazide commonly found in weight-reducing health foods. The mentioned compounds were oxidized by cerium(IV) ammonium sulfate dissolved in an acidic solution. The kinetic-fluorescence spectrum of the produced cerium(III) was recorded between 0 and 600 s reaction time at the excitation wavelength of 250 nm. It was found that the fluorescence intensity was proportional to the concentration of the compounds, and their linear ranges were 0.005–0.12, 0.03–1.44 and 0.01–0.20 μg mL−1; the corresponding detection limits were 1.6, 8.3 and 6.0 ng mL−1 for sibutramine, indapamide and hydrochlorothiazide, respectively. The measured three- and two-way data of the mixtures were processed by chemometrics (included methods: parallel factor analysis (PARAFAC), partial least squares (PLS), principal component regression (PCR), and radial basis function-artificial neural network (RBF-ANN)). The proposed method was applied for the simultaneous determination of the analytes in weight-reducing food samples, and the results were comparable with those from the reference HPLC method.

A novel kinetic spectrophotometric method was developed for the simultaneous determination of caffeine, theobromine and theophylline in food samples. This method was based on the different kinetic characteristics between the reactions of analytes with cerium sulphate in sulphuric acid and the associated change in absorbance at 320 nm. Experimental conditions, the effects of sulphuric acid, cerium sulphate and temperature, were optimised. Linear ranges (0.4–8.4 μg mL −1 ) for all three analytes were established, and the limits of detection were: 0.30 μg mL −1 (caffeine), 0.33 μg mL −1 (theobromine) and 0.16 μg mL −1 (theophylline). The recorded data were processed by partial least squares and artificial neural network, and the developed mathematical models were then used for prediction. The proposed, novel method was applied to determine the analytes in commercial food samples, and there were no significant differences between the results from the proposed method and those obtained by high-performance liquid chromatography.

The interaction of graphene oxide (GO), a medicinal drug (10-hydroxy camptothecin (HCPT)), and bovine serum albumin (BSA) was investigated with the aim of developing a method for the analysis of serum albumin proteins. It was demonstrated that HCPT could be readily loaded onto GO via the π–π stacking interaction, and the delivery of HCPT to BSA was improved in the presence of GO; this, in turn, facilitated the binding interaction of HCPT and BSA. Chemometrics methods, multivariate curve resolution-alternating least squares (MCR-ALS) and parallel factor analysis (PARAFAC), were applied to resolve spectral data, and this assisted in the elucidation of the above interaction. GO was found to enhance the fluorescence response of HCPT to BSA, and thus, a low cost fluorescence bio-sensing platform was developed for fluorescence-enhanced detection of BSA based on GO. The satisfactory analytical performance of this biosensor for BSA was attributed to the structure and electronic properties of GO.

The binding interaction of bovine serum albumin (BSA) with dopamine was studied by different spectroscopic techniques, and a fluorescence quenching mechanism was associated with this process. Estimated thermodynamic parameters indicated the presence of hydrogen bonding and van der Walls forces between dopamine and BSA. The microenvironment of the protein-binding site was studied by the synchronous fluorescence, FT-TR, and three-way fluorescence techniques in the presence of dopamine, and changes in conformation were indicated within the binding cavity. This study provides useful information on the transportation and distribution of dopamine in proteins.

A reliable method for simultaneous determination of three antibiotic drugs (levofloxacin, gatifloxacin and lomefloxacin) by differential pulse stripping voltammetry (DPSV) in Britton–Robinson buffer (pH 7.96) was presented. The method is based on adsorptive accumulation of the antibacterial drugs on a hanging mercury dropping electrode (HMDE), followed by the reduction of the adsorptive species by the technique of DPSV. Optimal conditions, the deposition time of 80 s, the deposition potential of −1250 mV, and the scan rate of 25 mV/s, were obtained. The linear concentration ranges of 0.010–0.080 μg/mL were obtained for all these three antibiotic drugs, while the detection limits were 2.38, 3.20 and 1.60 ng/mL for levofloxacin, gatifloxacin and lomefloxacin, respectively. In this work, chemometrics methods, such as classical least squares (CLS), partial least squares (PLS), principle component regression (PCR) and radial basis function-artificial neural networks (RBF-ANN), were used to quantitatively resolve the overlapping signals. It was found that PCR gave the best results with total relative prediction error (RPE T ) of 7.71%. The proposed method was applied to determine these three drugs in several commercial food samples with spiked method and yielded satisfactory recoveries.

The new simple, cost effective and well performing differential pulse stripping voltammetry method for the simultaneous determination of antibiotics – oxytetracycline, tetracycline and chlorotetracycline was researched and developed. It depends on the reduction of these compounds at a hanging mercury drop electrode. The samples were extracted from (i) spiked animal feed, and (ii) fresh fish muscle dosed with the drugs. The voltammograms from the drug mixture produced complex, overlapping profiles, and chemometrics methods were applied for calibration modelling. The analytical linear ranges were within 0.02–0.18 μg mL −1 and the corresponding LODs were 3–5 μg L −1 for the three analytes. These values compare well with those from the HPLC and fluorescence methods in the literature. The % relative prediction errors from the verification trials were between 4% and 9% with % Recoveries being 103–107. Also, the % Recoveries of the antibiotics from animal feeds as measured by the new method were comparable with those from the HPLC analysis (85%), i.e. the method is highly competitive, especially as a screening approach.

This paper describes a kinetic spectrophotometric method for simultaneous determination of three cephalosporin antibiotics, cephradine, cefaclor and cefixime, with the aid of chemometrics. The method relies on their oxidation with KMnO4 to produce green manganate with different kinetic rates in alkaline medium. The proposed method was successfully applied to a pharmacokinetic study of three cephalosporin antibiotics in rabbit plasma via intravenous injections. The results indicated that the amount of cephradine, cefaclor and cefixime were reduced rapidly in rabbit blood, showing clear dose-dependency and the half-life of cefixime (160 min) was longer than those of cephradine (60 min) and cefaclor (60 min).

The binding interaction of the terazosin hydrochloride and prazosin hydrochloride with bovine serum albumin (BSA) was studied by spectrofluorimetry. Both of these two compounds quenched the fluorescence of BSA. The thermodynamic parameters (ΔH 0, ΔS 0 and ΔG 0) obtained from the fluorescence data measured at two different temperatures showed that the binding of terazosin hydrochloride to BSA involved hydrogen bonds and that of prazosin hydrochloride to BSA involved hydrophobic and electrostatic interactions. In this work, the competitive interaction of the terazosin hydrochloride and prazosin hydrochloride with BSA was studied by three-way excitation-emission fluorescence with the aid of parallel factor analysis (PARAFAC).

The interaction of quercetin, which is a bioflavonoid, with bovine serum albumin (BSA) was investigated under pseudo-physiological conditions by the application of UV-vis spectrometry, spectrofluorimetry and cyclic voltammetry (CV). These studies indicated a cooperative interaction between the quercetin-BSA complex and warfarin, which produced a ternary complex, quercetin-BSA-warfarin. It was found that both quercetin and warfarin were located in site I. However, the spectra of these three components overlapped and the chemometrics method - multivariate curve resolution-alternating least squares (MCR-ALS) was applied to resolve the spectra. The resolved spectra of quercetin-BSA and warfarin agreed well with their measured spectra, and importantly, the spectrum of the quercetin-BSA-warfarin complex was extracted. These results allowed the rationalization of the behaviour of the overlapping spectra. At lower concentrations ([warfarin]

A novel voltammetric method for simultaneous determination of the glucocorticoid residues prednisone, prednisolone, and dexamethasone was developed. All three compounds were reduced at a mercury electrode in a Britton–Robinson buffer (pH 3.78), and well-defined voltammetric waves were observed. However, the voltammograms of these three compounds overlapped seriously and showed nonlinear character, and thus, it was difficult to analyze the compounds individually in their mixtures. In this work, two chemometrics methods, principal component regression (PCR) and partial least squares (PLS), were applied to resolve the overlapped voltammograms, and the calibration models were established for simultaneous determination of these compounds. Under the optimum experimental conditions, the limits of detection (LOD) were 5.6, 8.3, and 16.8 µg l−1 for prednisone, prednisolone, and dexamethasone, respectively. The proposed method was also applied for the determination of these glucocorticoid residues in the r...

A kinetic spectrophotometric method with aid of chemometrics is proposed for the simultaneous determination of norfloxacin and rifampicin in mixtures. The proposed method was applied for the simultaneous determination of these two compounds in pharmaceutical formulation and human urine samples, and the results obtained are similar to those obtained by high performance liquid chromatography.

Summary Physico-chemical properties of surface water and groundwater samples from some developing countries have been subjected to multivariate analyses by the non-parametric multi-criteria decision-making methods, PROMETHEE and GAIA. Complete ranking information necessary to select one source of water in preference to all others was obtained, and this enabled relationships between the physico-chemical properties and water quality to be assessed. Thus, the ranking of the quality of the water bodies was found to be strongly dependent on the total dissolved solid, phosphate, sulfate, ammonia–nitrogen, calcium, iron, chloride, magnesium, zinc, nitrate and fluoride contents of the waters. However, potassium, manganese and zinc composition showed the least influence in differentiating the water bodies. To model and predict the water quality influencing parameters, partial least squares analyses were carried out on a matrix made up of the results of water quality assessment studies carried out in Nigeria, Papua New Guinea, Egypt, Thailand and India/Pakistan. The results showed that the total dissolved solid, calcium, sulfate, sodium and chloride contents can be used to predict a wide range of physico-chemical characteristics of water. The potential implications of these observations on the financial and opportunity costs associated with elaborate water quality monitoring are discussed.

The interactions of salicylic acid (SL) and two different site markers (warfarin for site I and ibuprofen for site II) with bovine serum albumin (BSA) in pH 7.4 Tris–HCl buffer have been investigated with the use of spectrofluorimetry. An equilibrium solution of BSA and SA was titrated separately with the two markers. This initial work showed that the binding of SL with BSA could be quite complex, and that there was probably a competitive interaction occurring between ibuprofen and SL. However, the spectral results were difficult to interpret clearly for the interaction of warfarin and SL in similar circumstances. To extract more information from the resolution of fluorescence excitation-emission spectra, the contour plots of the fluorescence spectra indicated that the optimal excitation wavelengths for BSA, SL, warfarin and ibuprofen were different, and were found to be at 278, 295, 306 and 218 nm, respectively. The spectral information was arranged into three-way excitation-emission fluorescence matrix (EEM) stack arrays, and was submitted for analysis by the parallel factor analysis (PARAFAC) algorithm. Firstly, it was demonstrated that the estimated excitation and emission spectral responses for SL, BSA and the site markers, warfarin and ibuprofen, agreed well with the measured spectra. Then, the interpretation of the plots of simultaneously extracted (by PARAFAC) equilibrium concentrations for the above four reactants, showed that: (i) the SL primarily appears to bind in site I but at a different location from the high-affinity binding site (HAS) for warfarin, and the interaction partially overlaps with the low-affinity binding site (LAS) for warfarin. (ii) The SL may have two LAS—one in site II where the HAS for ibuprofen is located, and the other in site I at the LAS for ibuprofen. Thus, application of the PARAFAC method for the study of competitive interaction of SL and BSA with the aid of two different site markers has extracted information unobtainable by traditional methods such as the Scatchard plot, and provided useful means of data visualization.

Anti-bacterial drugs such as sulfonamides and trimethoprim, are commonly used in medical and veterinary applications. The tablets often contain mixtures of drugs such as sulfadiazine, sulfadimidine, sulfamethoxazole, sulfanilamide and trimethoprim. Thus, a simple, rapid and inexpensive method for the simultaneous determination of these drugs was researched and developed with the aid of chemometrics methods comparing the classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS) models. UV-spectra were collected in the 200–350 nm range from a set of samples containing aqueous ethanolic solutions (pH = 9.9) of drug mixtures prepared from the above compounds with the aid of an orthogonal array design. Initial studies of the UV-spectra of the individual compounds showed that satisfactory linear regression calibration models could be constructed in the concentration range of approximately 1.0–24.0 mg l− 1 for all compounds with LOD values in the range of ca. 0.2–1.0 mg l− 1 for each of the five drugs. These studies also indicated the significant spectral overlap of the UV- spectra of the drugs showing the need for chemometrics modeling for simultaneous analysis of the mixtures. Calibration models for the three multivariate methods were constructed with the use of the raw and derivative spectral data sets. These were verified with the aid of UV-spectral data obtained from a separately prepared set of drug mixture samples. The %RPE values for analysis of the individual drugs in mixtures were in the range of 2–10 with %Recoveries being close to 100 for the PCR and PLS models while the CLS method performed relatively poorly. The four PCR and the PLS models constructed could not be distinguished on prediction performance for practical purposes, and the PCR calibration based on the raw data matrix was utilised to illustrate successfully the application of the proposed method for analysis of the drugs in commonly available pharmaceutical tablets.

This paper presents a study undertaken to evaluate site suitability for sewage effluent renovation based on physico-chemical characteristics of the soil. The results obtained showed that as the soil becomes acidic, the phosphorus concentration in the soil reduces accordingly. The chloride ion concentration was found to be a reliable indicator for evaluating the soil capacity to remove nitrogen. A high cation exchange capacity (CEC) can enhance the renovation of sewage effluent. Soils with high quartz content had a low CEC with high organic matter content (OM) being able to compensate. Therefore, an understanding of the micro-nutrients in the soil, organic matter content and chloride ion concentration are important. To facilitate a multi-variate approach for site selection, multicriteria decision-making (MCDM) methods, PROMETHEE and GAIA, were applied for analysis of a sequence of three matrices consisting of 8, 16, and 48 soil site objects, respectively, and seven soil property parameters. Matrix models and the interpretation of results are discussed in detail. From these analyses, PROMETHEE II net outranking flows, ϕ , found that two sites were always among the top three ranks of the three matrix models, which suggested that they were the most suitable for sewage effluent renovation. The criteria CEC and OM, were particularly important for the selection of these better sites, but pH and Cl − attributes discriminated the weaker performing sites from the better ones; as well the PO 4 3− and the NH 3 –N criteria were in general opposition to CEC, OM, pH and Cl − but were much less effective as discriminators. Consideration of net outranking flows suggested an approach method for the selection of other possibly suitable sites for sewage effluent renovation.

A voltammetric method, aided by chemometrics, was developed for the simultaneous determination of paracetamol and phenobarbital in pharmaceuticals. Both of these analytes gave well‐defined oxidation peaks in the Britton–Robinson buffer (pH 5.72) when analyzed by differential pulse‐stripping voltammetry (DPSV) at a glassy carbon electrode. The experimental conditions were optimized: 200 mV—deposition potential, 160 s—deposition time, 4 mV—increment potential, 50 mV—amplitude, and 60 ms—pulse width. Under these selected conditions, the oxidation current had a linear relationship with concentration of paracetamol [ranges: 0.09–0.93 mg l−1 (r 2 = 0.999) and 0.9–11.7 mg l−1 (r 2 = 0.999)], and phenobarbital [1.0–22.0 mg l−1 (r 2 = 0.999)]. Due to the overlapping voltammograms from the two analytes, two chemometrics methods, partial least squares (PLS), and principal component regression (PCR), were used for building calibration models from voltammograms of mixtures. These models were applied for predi...

This paper reviews the synthesis and the absorbing properties of the wide variety of porous sorbent materials that have been studied for application in the removal of organics, particularly in the area of oil spill cleanup. The discussion is especially focused on hydrophobic silica aerogels, zeolites, organoclays and natural sorbents many of which have been demonstrated to exhibit (or show potential to exhibit) excellent oil absorption properties. The areas for further development of some of these materials are identified.

The voltammetric behavior of antipsychotic drugs, such as, chlorpromazine hydrochloride and promethazine hydrochloride has been investigated at a glassy carbon electrode in Britton–Robinson buffer of pH 9. It was found by applying the differential pulse stripping voltammetry (DPSV) that both chlorpromazine hydrochloride and promethazine hydrochloride had well formed oxidation voltammetric waves, with the peak potential for chlorpromazine hydrochloride at 620 mV, and for the two peaks of promethazine hydrochloride at 444 and 668 mV. The calibrations were linear for chlorpromazine hydrochloride and promethazine hydrochloride in the concentration ranges of 0.05–1.2 and 0.1–1 mg l−1, respectively. However, the voltammetric peaks of these two drugs, seriously overlap and it is difficult to determine them individually from a response of a drug mixture. In this work, a method for the simultaneous determination of these two drugs is proposed, and is based on their oxidation at the glassy carbon electrode. The interpretation of the complex voltammograms is achieved with the aid of chemometric methods, such as, classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS). The proposed method was applied to determine these two drugs in a set of synthetic mixtures and blood samples, and in general, satisfactory results were obtained.

The degradation of poly(ethylene oxide) (PEO) by electrolysis was investigated in an aqueous chloride or bromide medium adjusted to pH 6.5 at 25°C. The degradation was monitored by the reduction in viscosity of the reaction system. The PEO was degraded more readily by electrolysis in the presence of halide ion than in their absence. The degradability of PEO increased with an increase in halide ion concentration under a constant current and the degradation in a chloride solution is easier than that in a bromide solution. The initiation mechanism of PEO degradation is discussed; a hypohalide ion is generated during electrolysis in the presence of a halide ion, and the hydroxyl radical may be generated from this ion. This radical abstracts a hydrogen atom from the polymer to form polymer alkyl radical, and further cause chain scission.

The degradation of azo dyes such as Orange I_??_IV was investigated in an electrolyte solution containing chloride or bromide ions as halide ions with electrolysis. In the presence of halide ions, the electrolyzed degradation was accomplished because of the generated electrophilic halonium ions as active species with electrolysis that involve initial attack at azo groups. It was presumed that these degradations were due to the molecular structure of dyes relating to the existence of azo-hydrazone equilibria in hydroxyazo dyes and electron-donating group in aminoazo dyes. In the case of an electrolyte solution containing chloride ion, the degradation of dyes was significantly influenced by the pH of this electrolyte and decrease with rising pH. The ability of degradation with electrolysis was larger in bromide ion than that in chloride ion and the pH of electrolyte had no influence on the degradation in the case of bromide ion, compared with chloride ion.

Interactions between the anti-carcinogens, bendamustine (BDM) and dexamethasone (DXM), with bovine serum albumin (BSA) were investigated with the use of fluorescence and UV–vis spectroscopies under pseudo-physiological conditions (Tris–HCl buffer, pH 7.4). The static mechanism was responsible for the fluorescence quenching during the interactions; the binding formation constant of the BSA–BDM complex and the binding number were 5.14 × 105 L mol−1 and 1.0, respectively. Spectroscopic studies for the formation of BDM–BSA complex were interpreted with the use of multivariate curve resolution – alternating least squares (MCR–ALS), which supported the complex formation. The BSA samples treated with site markers (warfarin – site I and ibuprofen – site II) were reacted separately with BDM and DXM; while both anti-carcinogens bound to site I, the binding constants suggested that DXM formed a more stable complex. Relative concentration profiles and the fluorescence spectra associated with BDM, DXM and BSA, were recovered simultaneously from the full fluorescence excitation–emission data with the use of the parallel factor analysis (PARAFAC) method. The results confirmed that on addition of DXM to the BDM–BSA complex, the BDM was replaced and the DXM–BSA complex formed; free BDM was released. This finding may have consequences for the transport of these drugs during any anti-cancer treatment.

A spectrophotometric method for the simultaneous determination of the important pharmaceuticals, pefloxacin and its structurally similar metabolite, norfloxacin, is described for the first time. The analysis is based on the monitoring of a kinetic spectrophotometric reaction of the two analytes with potassium permanganate as the oxidant. The measurement of the reaction process followed the absorbance decrease of potassium permanganate at 526 nm, and the accompanying increase of the product, potassium manganate, at 608 nm. It was essential to use multivariate calibrations to overcome severe spectral overlaps and similarities in reaction kinetics. Calibration curves for the individual analytes showed linear relationships over the concentration ranges of 1.0-11.5 mg L(-1) at 526 and 608 nm for pefloxacin, and 0.15-1.8 mg L(-1) at 526 and 608 nm for norfloxacin. Various multivariate calibration models were applied, at the two analytical wavelengths, for the simultaneous prediction of the two analytes including classical least squares (CLS), principal component regression (PCR), partial least squares (PLS), radial basis function-artificial neural network (RBF-ANN) and principal component-radial basis function-artificial neural network (PC-RBF-ANN). PLS and PC-RBF-ANN calibrations with the data collected at 526 nm, were the preferred methods--%RPE(T) approximately 5, and LODs for pefloxacin and norfloxacin of 0.36 and 0.06 mg L(-1), respectively. Then, the proposed method was applied successfully for the simultaneous determination of pefloxacin and norfloxacin present in pharmaceutical and human plasma samples. The results compared well with those from the alternative analysis by HPLC.

A linear sweep stripping voltammetric (LSSV) method has been researched and developed for simultaneous quantitative determination of mixtures of three antibiotic drugs, ofloxacin, norfloxacin and ciprofloxacin. It relies on reductive reaction of the antibiotics at a mercury electrode in a Britton–Robinson buffer (pH 3.78). The voltammograms of these three compounds overlap strongly, and show non-linear character. Thus, it is difficult to analyse the compounds individually in their mixtures. In this work, chemometrics methods such as classical least squares (CLS), principal component regression (PCR), partial least squares (PLS) and radial basis function-artificial neural networks (RBF-ANN) were applied for the simultaneous determination of these compounds. The prediction performance of the calibration models constructed on the basis of these methods was compared. It was shown that satisfactory quantitative results were obtained with the use of the RBF-ANN calibration model relative prediction error (RPE T ) of 8.1% and an average recovery of 101%. This method is able to accommodate non-linear data quite well. The proposed analytical method based on LSSV was applied for the analysis of ofloxacin, norfloxacin and ciprofloxacin antibiotics in bird feedstuffs and their spiked samples, as well as in eye drops with satisfactory results.

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.

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.