Ratio Of Sodium Dodecyl Sulfate Research Articles

Effect of surfactant compounding on the wettability of talcum powder

AbstractTalcum powder is one of the leading causes of pneumoconiosis, adding compound surfactants to the dust removal process can significantly increase the effectiveness of the dust removal. Therefore, it is of great significance to study the effect of compound surfactants on the wettability of talcum powder. This paper focuses on the ability of compound surfactants to increase the wettability of talcum powder surface by using Materials Studio 8.0. The simulation results were analyzed from the water adsorbed amount, interaction energy, and water molecule concentration profile. Combined with the experimental data of contact angle, the optimal surfactant compounding method was obtained. The simulation results revealed that stable adsorption structures can be formed by the compound of anionic and nonionic surfactants, which can reduce the electrostatic repulsion between anionic surfactants effectively and promote the directional arrangement of nonionic surfactants on the talcum powder surface. When the molar ratio of sodium dodecyl sulfate (SDS) and Polysorbate 80 was 0.4:0.6, the amount of absorbed water reached 113, which is better than monomers and other compound surfactants. The contact angle experiment results indicated a consistent variation law with the simulation results. The contact angle decreased from 68.48° to 19.84° using the compounding method mentioned above, which has the optimum wetting effect among the four compounding methods. The research results will provide a reference for the application of compound surfactants in talcum powder dustproof work.

Using mixture experimental design to study the effect of phosphating bath formulation on the properties of magnesium substrate

PurposeThis paper aims to achieve phosphating via optimal features of Mg metal as a suitable base coating, which is considered for other properties such as barrier properties against the passage of several factors.Design/methodology/approachIn this research, in the phosphate bath, immersion time, temperature and the content of sodium nitrite as an accelerator were changed.FindingsAs a result, increasing the immersion time of AZ31 Mg alloy samples in the phosphating bath as well as increasing the ratio of sodium dodecyl sulfate (SDS) concentration to sodium nitrite concentration in the phosphating bath formulation increase the mass of phosphating formed per unit area of the Mg alloy. The results of the scanning electron microscope test showed phosphating is not completely formed in short immersion times, which is a thin and uneven layer.Research limitations/implicationsMg and its alloys are sensitive to galvanic corrosion, which would lead to generating several holes in the metal. As such, it causes a decrease in mechanical stability as well as an unfavorable appearance.Practical implicationsMg is used in several industries such as automobile and computer parts, mobile phones, astronaut compounds, sports goods and home appliances.Social implicationsNevertheless, Mg has high chemical reactivity, so an oxide-hydroxide layer is formed on its surface, which has a harmful effect on the adhesion and uniformity of the coating applied on Mg.Originality/valueBy increasing the ratio of SDS concentration to sodium nitrite concentration in the phosphating bath, the corrosion resistance of the phosphating increases.

Size-tunable CaCO3@n-eicosane phase-change microcapsules for thermal energy storage

Phase-change materials can store and release tremendous amounts of latent heat energy in a single storage unit, and they have become a promising candidate for building comfort temperature regulation with a significant energy-saving effect. In this study, we developed a novel type of size-tunable phase-change microcapsules for high-efficient thermal management and temperature regulation in buildings. The phase-change microcapsules were based on an n-eicosane core and a CaCO3 shell and fabricated using an emulsion-templated self-assembly interfacial precipitation method. Their sizes were controlled through regulating the surfactant concentration, resulting in a desired capsule size as well as a well-defined core-shell microstructure and a regular spherical morphology. When the mass ratio of sodium dodecyl sulfate to sulfobetaine varied from 3/2 to 1/1 in the mixed surfactant system, the resultant phase-change microcapsules exhibited a tunable diameter from 740 nm to 1.54 µm together with a significant increase in latent-heat capacity from 100 to 131.5 J/g. The application investigation of the obtained microcapsules in building thermal regulation was performed through incorporating microcapsule samples into cement, employing the resultant cement composites as building envelopes for a model house. The cement composites presented a good ability to regulate the indoor temperature of the model house thanks to the thermal energy storage and latent heat release of the phase-change microcapsules. The model house coated with the cement composites on the roof exhibited a maximum indoor temperature of 47 °C after subjected to the simulated sunlight radiation for 4 h, leading to a decrease in indoor temperature by 5 °C compared to the model house with pure cement. With a rational combination of the phase-change microcapsules and cement, this study provides a promising approach to passive and efficient comfort temperature regulation for green energy-saving building applications.

Tensiometry and FTIR study of the synergy in mixed SDS:DDAO surfactant solutions at varying pH

The interactions between a model anionic and amphoteric surfactant pair in aqueous solution are examined as a function of composition, at floating and fixed pH, employing a combination of tensiometry, regular solution theory analysis, and FTIR spectroscopy. An extensive series of pure and mixed ratios of sodium dodecyl sulfate (SDS) and N,N-dimethyldodecylamine N-oxide (DDAO), ranging from 0.0016 to 100 mM, yielding 77 data points below and above the critical micelle concentrations (CMC), is investigated. Compared to either pure surfactant solutions, the CMC of mixed SDS:DDAO solutions is found to decrease by up to 20-fold, and the surface tension (γ) at CMC down to ≃ 23 mN/m. At all concentrations, the most prominent effects are observed at equimolar SDS:DDAO ratios. Further, the pH of mixed micellar solutions is found to increase with respect to the pure surfactant solutions (from ≃ 7 up to ≃ 9.5), which is attributed to the enhanced protonation of DDAO in the presence of SDS, and supported by FTIR frequency shifts of isolated O‒H stretching vibrations. Vibrational responses from CH2 stretching of the methylene tails, and the S‒O stretching modes for the sulfate headgroups indicate strong lateral interaction and enhanced packing between SDS and DDAO. From regular solution theory analysis of tensiometry data, the molecular interaction parameters are found to have a larger magnitude (i.e., more negative) at the interface as compared to within micelles. At fixed solution pH, a decrease from pH 9.5 to 7.5 results in minimal changes in both interfacial and micellar parameters, indicating the intrinsic origin of these pairwise interactions. Overall, our findings demonstrate a pronounced synergistic interaction between SDS and DDAO, arising from diminished electrostatic and steric repulsions in, respectively, SDS and DDAO, accompanied by enhanced lateral surfactant packing.

EVALUATION OF THE INFLUENCE OF A VARYING MOLAR RATIO OF SODIUM DODECYL SULFATE TO WHEY PROTEIN ISOLATE ON THE STABILITY OF THE WHEY PROTEIN EMULSIONS

In combination with the Lumifuge centrifugation and Zeta potential apparatuses, the influence of a varying molar ratio of Sodium Dodecyl Sulfate (SDS) to Whey Protein Isolate (WPI) on the stability of the whey protein emulsions at pH 4 and pH 5.5 is observed. Two whey protein stabilized emulsions were prepared by homogenizing 20 wt. % soybean oil and 80 wt. % whey protein solutions (0.5 wt.% whey protein in buffer, pH 4 and pH 5.5) at room temperature.By observation, the droplets are weakly flocculated at a ratio of SDS to whey protein of 256. This shows that there is a strong electrostatic repulsion between the emulsion droplets if much surfactant is adsorbed to the protein molecules, which prevents them from aggregating. The magnitude of the measured zeta potentials explained the stability of the emulsion at pH 4 as well as the emulsion at pH 5.5 is ensured at SDS to whey protein ratio equal to 256. The results of the transmission profile by Lumifuge separation analyzer at different time and at 3000 rpm (1200 g) elucidated that the stability of the whey protein emulsion at pH 4 and 5.5 is obtained upon dilution with SDS-WPI ratio of 256.

Optimization of a soft degumming process of crude rapeseed oil—Changes in its antioxidant capacity

A modified soft degumming process of crude rapeseed oil for maximizing phospholipid removal and minimizing losses of antioxidants was proposed and optimized by response surface methodology. The effects of water volume, degumming time, and concentration ratio of sodium dodecyl sulfate to disodium ethylenediaminetetraacetate on the concentration of phospholipids and phenolics and antioxidant capacity of oils were evaluated. The soft degumming process removed phospholipids from the crude oil (94.9–98.7%) more effectively than industrial acid degumming (95.3%). Moreover, rapeseed oils revealed high phenolic content (20.0–22.1mg sinapic acid (SA)/100g) and antioxidant capacity, as determined by ferric-reducing antioxidant power (FRAP=301–328μmol Trolox equivalent (TE)/100g), 2,2-diphenyl-1-picrylhydrazyl (DPPH=528–739μmol TE/100g), and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS=1300–1505μmol TE/100g) methods.The predicted optimum water volume (11.5mL), time (19.7min), and concentration ratio of sodium dodecyl sulfate to disodium ethylenediaminetetraacetate (=1) resulted in total phospholipids=67mg/kg, phenolics=20.8mg SA/100g, FRAP=313μmol TE/100g, DPPH=617μmol TE/100g, and ABTS=1346μmol TE/100g.Replacement of industrial acid degumming by the proposed soft degumming can improve the stability of rapeseed oil with potent antioxidant capacity.

Examination of flotation behavior of metal ions for process water remediation

Solutions containing low concentrations of heavy metal could be produced from any industrial processes and it is important to remove these ions from aqueous solution due to environmental regulations. In this paper, ion flotation method is employed to remove metal ions such as copper, lead, zinc, cadmium and nickel from aqueous solution. Firstly, several parameters such as pH, concentration and type of surfactants were investigated along with copper. After, ion flotation was tested on multiple ions individually and collectively, in different type of flotation machines. The best conditions were found as pH9, with 1:1 ratio of sodium dodecyl sulfate and metal concentration, 20mg/L each metal concentration, 3min flotation time. After flotation the remaining solution contained 0.5mg/L Cu, 2.5mg/L Pb, 2.6mg/L Ni, 3.4mg/L Cd, 1.5mg/L Zn. Ion flotation method can be used to clean process waters produced in flotation plants containing low metal concentrations. The overall method is suggested to remediate process waters generated flotation plants.

(Invited) Establishing Thermodynamically-Stable Surfactant Structures Around Single Wall Carbon Nanotubes

The high surface area of single-walled carbon nanotubes (SWCNTs) dictates that the interface with their surroundings is important in determining their properties or functionality. For example, the interface of SWCNTs with their surroundings is important to their application in polymer composites, devices, drug delivery, bioimaging and biosensing. Understanding and ultimately controlling these surface layers is important because of its influence on reactivity, adsorption of pollutants, and interaction with biological materials. SWCNT interfaces are often altered with surfactants to improve their dispersion in aqueous suspensions. While the surfactant surrounding the nanotube provides many benefits, the inability to alter or control this interface often limits the performance or functionality of the nanotube. A lack of information on the effect of the surrounding environment on SWCNT properties further complicates the development of processes to control these interfaces. Our group has focused on characterizing and controlling SWCNT interfaces. The ability to reorganize the surfactant structure surrounding SWCNTs is achieved through both chemical and mechanical manipulations. The goal is to learn how to control these structures around SWCNTs to influence their interaction with biological materials and other surfaces. For example, the surfactant orientation on the SWCNT surface plays an important role in their separation by nearly any method. Using our understanding of the surfactant structure surrounding SWCNTs, we have achieved high-fidelity separations based on selective desorption with a single elution profile in a single hydrogel-packed column. The selective desorption of a wide range of single-chirality (n,m) fractions only occurs once a specific ratio of sodium dodecyl sulfate (SDS)/sodium deoxycholate (DOC) co-surfactant solution is used. High-purity fractions of small diameter nanotubes are obtained at this ratio even with long elution times, different total co-surfactant concentrations, and moderate temperature changes. The elution of only one (n,m) type at a specific co-surfactant ratio while other types are exposed to more surfactant suggests that each (n,m) type forms a thermodynamically-stable surfactant structure in the co-surfactant solution. These thermodynamic equilibrium states result in entropy-driven desorption at specific co-surfactant ratios, enabling high-fidelity separations of a single (n,m) type in a single column. Although the differences between the co-surfactant ratios needed to separate two (n,m) species can sometimes be very small, the separation can be improved at higher co-surfactant concentrations at the same ratio. The elution order is nearly identical to the order of separation in the aqueous two-phase extraction, suggesting that the same processes are occurring regardless of the method used to separate the SWCNTs. The structure of the surfactant or other molecules around the SWCNTs is also shown to have important implications in toxicology and drug delivery.

Selective Desorption of Multiple High-Purity SWCNT Fractions from Hydrogels through Co-Surfactant Modulation

The post-synthetic separation of single walled carbon nanotubes (SWCNTs) has been studied with great interest in the past decade. While high-fidelity separations of SWCNTs by their (n,m) type have been demonstrated, a simple, high-throughput method is still desired. Our previous work has highlighted the importance of surfactant structure along SWCNT sidewalls in the separation mechanism. Here we report the selective desorption of a wide range of single-chirality (n,m) fractions in a single hydrogel-packed column. High-purity fractions of (n,m) nanotubes are obtained with high yield once a specific ratio of sodium dodecyl sulfate (SDS)/sodium deoxycholate (DOC) co-surfactant solution is used. The differences between the co-surfactant ratios needed to separate two (n,m) species can sometime be very small. The separation can be obtained under a wide variety of co-surfactant background concentrations. However, better separations are achieved at higher background concentrations.

Preparation of high-strength microporous phenolic open-cell foams with physical foaming method

A series of high-strength and highly microporous phenolic open-cell foams modified by different epoxy resins were fabricated using physical foaming method. The new compound emulsifiers consisting of anionic and nonionic surfactants were physical blended at high speed with modified resols, foaming agent, and mixed acid curing agent. The modified synthesis of epoxy-modified phenol-formaldehyde (PF) resin was conducted via the etherification mechanism. In order to verify the occurrence of etherification mechanism by co-reaction between resole methylol, hydroxyl group, and ring-opening epoxy group and to characterize the structure successfully, Fourier transform infrared spectroscopy, carbon-13 (13C) and proton nuclear magnetic resonance (1H NMR) had been used to characterize the structure successfully. The phase of resols and curing behavior were characterized. Fabricated foams were characterized for cellular, water absorption, apparent density, and mechanical and thermal properties. The results show epoxy modified resol demonstrated single uniform phase. The open-cell micropore structure revealed by scanning electron microscopy (SEM) demonstrates that smaller and more homogeneous cells existed with increasing dosage of epoxy. When the content of epoxy increased from 0 wt% to 10 wt%, the thermal conductivity, water absorption, and porosity of PF gradually increased. The highest open-cell porosity reached up to 90.959%. The differential scanning calorimetry and gel time data demonstrated that modified resols exhibited less gel time and lower endothermic and curing exothermic heat. Anionic surfactant, sodium dodecyl sulfonate, which was better compatible with resol, promoted the formation of open cells and produced good homogeneous and moderate micropores. In addition, the high-strength open-cell PF possessed excellent filterable and separation performance and absorbency. The porous micropore structure controlled by the content of epoxy resin and the ratio of sodium dodecyl sulfate /Tween80 greatly improved the mechanical strengths of PF.

Split Application of Potassium Improves Yield and End‐Use Quality of Winter Wheat

Many studies have investigated the effects of basal K fertilization on the yield and quality of wheat (Triticum aestivum L.). However, less is known about the influence of the split application of K on yield, size distribution of protein fractions, and quality of wheat. Field studies were conducted in two successive seasons (2010/2011 and 2011/2012) using four winter wheat cultivars, Jimai 20, Gaocheng 8901, Yannong 19, and Jinan 17, and three regimes of K fertilization (K0: no K fertilization; KB: basal K fertilization of 120 kg ha−1; KS: basal K fertilization of 60 kg ha−1 plus topdressing of 60 kg ha−1 at jointing). The yield and its components, protein composition, dough‐mixing properties, and bread‐making quality were determined after harvesting. On average, the KS treatments had a yield advantage over KB treatments mainly resulting from higher kernel weight. The KS treatments improved wheat quality resulted in increased glutenin/gliadin ratio, higher polymerization index (the ratio of sodium dodecyl sulfate to insoluble glutenin in total glutenin), and larger glutenin macropolymer (GMP) particles compared to KB fertilization. No differences in the content of crude protein and wet gluten were found between the KS and KB treatments. Dough development time, stability time, and loaf volume were positively correlated with the glutenin/gliadin ratio, polymerization index, and average size of the GMP, respectively. These results suggest that KS can improve the yield and end‐use quality of winter wheat.

Fabrication and Characterization of Electrodeposited Ni–SiC–h/BN Composite Coatings

Ni–SiC–h/BN composite materials were prepared by electrodeposition technique with the dispersion of SiC (10 g/L) and h/BN nanosheets (10 g/L) in a nickel sulfamate electrolytic bath. Different ratio of sodium dodecyl sulfate (SDS) and cetyltrymethyl ammonium bromide (CTAB) surfactants were used to evaluate the effect of surfactants on the properties of the electrodeposited composite coatings. The coating samples were characterized by scanning electron microscopy, X-ray diffraction, Vickers microhardness test, scratch and tribology tests. The results revealed that the co-deposition of nanoparticles was significantly influenced by surfactants during electrodeposition process. Pyramidal or polyhedral nickel crystallites were observed at higher ratio of SDS/CTAB while smaller oval grains with refined surface morphologies were obtained at lower ratio of SDS/CTAB surfactants. In addition, wt% of particles co-deposition was increased, and Vickers microhardness, wear and coefficient of friction of the electrodeposited composite coatings were improved at increased CTAB and decreased SDS contents in the electrolyte during electrodeposition process.

Synthesis and aqueous solution properties of hydrophobically modified polyacrylamide

ABSTRACTHydrophobically modified polyacrylamide (HMPAM) is synthesized by a free radical micellar polymerization method with low amounts of anionic long‐chain alkyl, sodium 9‐(and 10)‐acrylamidostearate (NaAAS), which is derived from a renewable resource material, oleic acid. In this progress, the molar ratio of Sodium dodecyl sulfate (SDS) to NaAAS is adjusted, so polymers with different lengths of the hydrophobic blocks (NH = 3 and NH = 6) are obtained. The copolymers are characterized by 1H NMR, and the polymer weight and polydispersity are determined by gel permeation chromatography. The solution behaviors of the copolymers are studied as functions of concentrations, pH, and added electrolytes by steady‐flow and oscillatory experiments. The viscosities of these HMPAMs increase enormously above the critical concentration (c*). The sample with longer hydrophobic blocks exhibits better thickening effect. The rheological behaviors of aqueous solutions of HMPAMs are also investigated at different pH and brine environments. Low pH or the presence of brine promotes the intramolecular associating of hydrophobes for the both copolymers in semidilute solutions. The introduction of ionizable carboxylic group on the long hydrophobic side chain significantly influences the aggregation behaviors of the copolymers, leading to unique solution behaviors of the poly(AAm/NaAAS) copolymers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40754.

Synthesis of Manganese Oxide Nanocompounds for Electrodes in Electrochemical Capacitors

Nanocrystals of Mn3O4 with different shapes and size under 100 nm were prepared using normal micelles as templates. Modifying the solution conditions allowed the authors to control the particle shape. The key factors to control the nanostructure of particles are the interactions between micelles and Mn+2 ions and the molar ratio of sodium dodecylsulfate (SDS)/Mn. When the molar ratio of SDS/Mn was relatively high, nanoparticles acquire the micelle shape, and when the molar ratio was relatively low, a transition from spherical to cylindrical micelles is predicted by the packing parameter and results in rod-shaped nanocrystals. All the samples obtained show pseudocapacitive behavior.

Factorial experimental design on synthesis of functional core/shell polymeric nanoparticles via differential microemulsion polymerization

AbstractFunctionalized core/shell nanoparticles of the co‐polymer of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) could be polymerized by differential microemulsion polymerization, using a small amount of surfactant (the weight ratio of sodium dodecyl sulfate (SDS)/monomer is 1 : 24). The core/shell nanoparticles have a high conversion, high molecular weight, and small particle size (25–30 nm). The statistical analysis indicated that SDS, water, and the interactionbetween SDS and water have a significant positive interaction between the MMA conversion to form the core nanoparticles. For the core‐shell polymer, [GMA], [GMA]*[SDS], and [GMA]* [water] have significant negative effects on conversion; whereas [SDS] and [water], [SDS]*[water] and [GMA]*[SDS]*[water] have positive effects on the conversion to form core/shell nanoparticles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Hybrid emulsifiers enhancing polymerization stabilities and properties of pressure sensitive adhesives

AbstractIn this study, a series of (anionic and nonionic) emulsifiers were investigated to prepare acrylic pressure sensitive adhesives (PSA) with core‐shell structure by semicontinuous emulsion polymerization. The cloud point of different emulsifiers was characterized to explain the emulsifier effects on the emulsification ability. It was interestingly found that the hybrid emulsifiers (anionic coupling with nonionic) with optimized compositions could enhance the stability of emulsion system and improve the properties of PSA compared with the mono‐emulsifier. The stability of emulsion polymerization, the appearance of the emulsion system and the properties of PSA were studied in details by changing the proportion and the content of hybrid emulsifiers. When the ratio of sodium dodecyl sulfate (SDS: anionic emulsifier) to polyoxyethylene alkyl phenyl ether (OP‐10: nonionic emulsifier) reached 2 : 1, the content of hybrid emulsifiers reached 3 wt % and the reaction temperature was around 80°C, a better emulsion system was obtained in terms of comprehensive properties. At this condition, the synthesized PSA demonstrated the good holding power and 180° peel strength properties with fair tacky property, which was promising for industrial applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Removal characteristics of metal cations and their mixtures using micellar-enhanced ultrafiltration

Divalent ions were removed by ultrafiltration of anionic surfactant solution and the removal characteristics in single and mixed systems were investigated. The removal efficiency was >95% when the ratio of sodium dodecyl sulfate (SDS) to metal ions (S/M ratio) was >10. In single metal systems, the removal efficiency of each metal ion was almost the same. In the mixture, however, there was slight difference (ca. 1–2%) of removal efficiency and the order was Cd2+>Cu2+>Co2+≈Zn2+. As S/M ratio increased, the difference in removal efficiency diminished. To explain the difference of removal efficiency in a mixture, complexation of divalent metal ion with counterion was considered. The distribution of complexed form of each metal ion was calculated, but it did not coincide with the experimental results. Further research will be necessary for a clear explanation.

Glycine Derived Polymerizable Cosurfactant in the Synthesis of Functionalized Poly(butyl acrylate) Nanolatexes

The approach of employing N-glycinylmaleamic acid (NGMA) as an efficient cosurfactant to provide microemulsion polymerization of butyl acrylate using a weight ratio of sodium dodecyl sulfate (SDS)/butyl acrylate (BA) at <or=1.5, which is lower than that employed in previous experiments, has been demonstrated. The narrow polydispersity index at 1.36-1.48 of poly(butyl acrylate) copolymers from investigated microemulsion polymerization reactions evidences the promotion of a controlled polymerization reaction, in contrast to the solution polymerization method generating polymers with higher polydispersity index at 3.15-4.23. The enhanced incorporation of NGMA at approximately 0.35 m in the copolymer demonstrates the merits of the proximity effect enabled in the microemulsion polymerization reaction. The incorporation of NGMA promotes rigidity of the polymer chain as suggested by a higher Tg of -16.8 degrees C for the copolymer in comparison to that of the poly(butyl acrylate) homopolymer.

Investigations of capacitance for sodium dodecyl sulfate/benzyl alcohol/H 2O microemulsion

With an increase of benzyl alcohol (BA) content at constant weight ratio of Sodium dodecyl sulfate (SDS) to water, the system capacitance first increases to a maximum in the rod-like micellar region and then decreases in the spherical micellar region. And the differential capacitance remains almost unchanged in the rod-like micellar region and decreases in the spherical micellar region. At constant weight ratio of SDS to BA, neither the system capacitance nor the differential capacitance changes much in the bicontinuous microemulsion (the mixed region of oil in water (O/W) and water in oil (W/O) microemulsion), but both decrease quickly in the oil in water microemulsion (O/W) region with the addition of water content. The variation of capacitance corresponds to the structural transformation of the SDS/BA/H 2O system.

Simultaneous Determination of Trace Ofloxacin, Ciprofloxacin, and Sparfloxacin by Micelle TLC-Fluorimetry

The method of simultaneous determination of ofloxacin (OFLX), ciproflxacin (CPLX), and sparfloxacin (SPLX) by thin-layer chromatography is established, with micelle solutions as mobile phases. It is found that the optimum molar ratio of sodium dodecyl sulfate (SDS) to ethylene diamine tetraacetic acid is 0.01:0.1. On the polyamide thin-layer sheet, OFLX, CPLX, and SPLX are separated from each other, and the corresponding Rf values are 0.72, 0.55, and 0.32, respectively. The fluorescence spots are scanned with a spectrodensitometer at the excitation wavelength of 282 nm. The cut-off filter is set at 400 nm. The detection limits are 2 x 10(-6) mol/L for OFLX, 1.5 x 10(-6) mol/L for CPLX, and 1.6 x 10(-6) mol/L for SPLX, and the respective linear ranges correspondingly fell in the concentration of 1 x 10(-5) to 4 x 10(-4) mol/L for OFLX, 1 x 10(-5) to 4.5 x 10(-4) mol/L for CPLX, and 1 x 10(-5) to 4.2 x 10(-4) mol/L for SPLX. For all the three components, the relative standard deviations are in the range of 1.12-5.82%, and the recoveries are found to be 96.7-104.2% in urine and serum samples.