A general chemiluminescence method for the determination of surfactants based on its quenching effect on the luminol-NaIO4-cyclodextrin reaction

Here we report that all types of surfactant could be simply and sensitively determined, by directly quenching the chemiluminescence (CL) between luminol and NaIO4 in a basic solution containing one polyhydroxyl compound such as cyclodextrin (CD), glucose or glycerol. This specific quenching effect was attributed to the change of the microenvironment of the CL reaction, caused by the addition of various surfactants. Based on this fact, the potential use of this CL reaction was exemplified by the cationic surfactant CTMAB, anionic surfactant SDS and non-ionic surfactant Triton X-100. It was found that the measurable range of CTMAB, SDS and Triton X-100 were 4.0 x 10(-6)-4.0 x 10(-4) M by using a basic CD-luminol-NaIO4 CL reaction. With our simple setup, CTMAB, SDS and Triton X-100 were detectable at a concentration as low as 2 microM. Overall, this new CL reaction is quite promising for the post-column determination of surfactant mixtures.     

Fluorimetric determination of anionic surfactants by extraction as safranine-T ion-pairs

A simple and rapid method is proposed for the spectrofluorimetric determination of anionic surfactants. It is based on formation of an ion-pair at pH 2 with safranine-T and its subsequent extraction into chloroform. Fluorescence intensity is increased by a factor of about 5 with respect to that of the reagent. The calibration graph is linear in the concentration range 0.015–0.40 mg l^?1 dodecyl sulfate; the relative standard deviation is 5.6% at 0.22 ml l^?1 surfactant. The method is applied to determine anionic surfactants in city waste-waters, giving recoveries close to 100%.     

Estimation of non-ionic, surface-active substances in aqueous solutions by means of the Controlled Growth Mercury Electrode

In this paper, a quick and simple tensammetric method of estimation of non-ionic surfactants (NS) in aqueous solutions is proposed. The method makes use of the variation in the differential capacity of double layer in relation to the time of accumulation (C(d)-t(acc)) of non-ionic surfactants at the hanging mercury drop electrode, generated by a single, very quick opening of the valve. Under such conditions, the capacity current measured at the potential of maximum adsorption diminishes with accumulation time of non-ionic surfactants. The proposed method, which was verified for model surfactant (Triton X-100), may also be applied in the determination of other NS. Modifications in construction of the CGME electrode and its improved metrological parameters played an important role in the presented procedure. In addition, other measurements were performed using standard electrochemical techniques, whereby current-time and differential capacity-potential curves were recorded. Satisfactory results were obtained in the determination of Triton X-100 in the range from 0.05 to 20 mg L(-1) (R.S.D.=6%, recovery=94-103%, r=0.999, DL=0.15 mg L(-1)). Applicability of the method was presented using the water samples from Bia?ka and Dunajec rivers, from which NS were removed by addition of fumed silica.     

Determination of aceclofenac using adsorptive stripping voltammetric techniques on conventional and surfactant chemically modified carbon paste electrodes

An electroanalytical method for determination of the anti-inflammatory agent aceclofenac at the ppb level using adsorptive stripping voltammetric techniques on conventional and surfactant chemically modified electrodes is developed. In this electroanalytical study a process of aceclofenac adsorption on carbon particles has been identified. In order to improve the aceclofenac determination, a chemical modification of the carbon paste was carried out employing several hydrophobic substances such as phospholipid and fatty acids, as well as several surfactants such as the non-ionic Triton X-100 and Triton X-405 and anionic sodium dodecyl sulfate. The influence of parameters such as pH, preconcentration time, carbon Nujol ratio, surfactant carbon ratio, potential scan rate, etc., on sensitivity of the method were widely studied. The proposed method was applied to the determination of the active compound in tablets.     

Disposable Nafion-modified micro-fabricated bismuth-film sensors for voltammetric stripping analysis of trace metals in the presence of surfactants

This work is a study of the analytical utility of Nafion-modified microfabricated bismuth film electrodes (BiFEs) for the determination of Pb(II) and Cd(II) by anodic stripping voltammetry (ASV) in the presence of surfactants. Micro-fabricated BiFEs were prepared by depositing a thin film of bismuth on the surface of a silicon substrate by sputtering while the two-dimensional geometry of the final sensors was defined by photolithography. The BiFEs were further drop-coated with a Nafion film. These devices were applied to the determination of Pb(II) and Cd(II) by square wave ASV (SWASV) in the presence of Triton X-100 (a non-ionic surfactant), cetyltrimethylammonium bromide (CTAB) (a cationic surfactant) and sodium dodecyl sulphate (SDS) (an anionic surfactant). It was found that the presence of Nafion afforded an increase in sensitivity and the tolerance against surfactants but these properties were severely influenced by both the thickness of the Nafion film and the nature of the interfering surfactant. Using a Nafion of 0.4 μm thickness and 120 s of preconcentration, the repeatability (expressed as the % relative standard deviation on the same sensor (n = 8)) at the 20 μg l⁻¹ level was 3.8% for Pb(II) and 3.1% for Cd(II) and the limits of detection were 0.5 μg l⁻¹ for Cd(II) and Pb(II). The sensors were applied to Cd(II) and Pb(II) determination in a certified lake-water sample.     

Spectroscopic investigations on the binding of ammonium salt of 8-anilino-1-naphthalene sulfonic acid with non-ionic surfactant micelles in aqueous media

The anionic dye 8-anilino-1-napthalensulfonic acid ammonium salt, or ANS, was used as a fluorescent probe to investigate the behaviour of dye-surfactant interactions in aqueous solutions of Triton X-100 and the Brij and polyoxyethylene tridecyl ether (POE TDE) series of polyoxyethylene non-ionic surfactants. The fluorescence behaviour of the dye with the non-ionic surfactants was examined in micellar media. The concentration of surfactant was kept well above the cmc to investigate the interaction of the dye with surfactant micelles. In this investigation, the relative fluorescence enhancements, binding constants of the dye to the surfactant micelles and aggregation numbers of the micelles were determined, from the analysis of spectroscopic data.     

AGGREGATION CHARACTERISTICS OF LASER DYE RHODAMINE 6G IN AQUEOUS SURFACTANT SOLUTIONS

Abstract— –The role of surfactants as deaggregating agents for the laser dyes is investigated by spectrophotometry using Rhodamine 6G as a representative. A method to estimate the fraction of dye present as monomer, dimer and as a monomer-surfactant (monomer or micelle) complex is described. It is shown that among the surfactants, cetyl trimethyl ammonium bromide, Triton X-100, sodium lauryl sulfate (SLS) and potassium oleate, the anionic ones are the most effective in suppressing the aggregation of Rhodamine 6G. While the non-ionic surfactant is found to be effective only above its critical micellar concentration, the cationic surfactant has no effect on aggregation. The optimum concentration of SLS needed for suppression of dye-dimers is estimated.     

Chemiluminescence determination of surfactant Triton X-100 in environmental water with luminol-hydrogen peroxide system

Background  

The rapid, simple determination of surfactants in environmental samples is essential because of the extensive use and its potential as contaminants. We describe a simple, rapid chemiluminescence method for the direct determination of the non-ionic surfactant Triton X-100 (polyethylene glycol tert-octylphenyl ether) in environmental water samples. The optimized experimental conditions were selected, and the mechanism of the Luminol-H₂O₂-Triton X-100 chemiluminesence system was also studied.     

Preparation of Stable Miniemulsions of Poly(2-ethyl hexyl acrylate-co-vinyl acetate)

Summary: This paper presents the results of the preparation of miniemulsions as well as the subsequent copolymerizations of 2-ethyl hexyl acrylate and vinyl acetate. The miniemulsions were prepared using a mixture of an anionic and a non-ionic surfactant. Sodium dodecyl sulfate (SDS) was used as the anionic surfactant and two non-ionic surfactants were studied: Triton X-405 and Disponil A3065. The miniemulsions prepared with a 90/10 mol.-% Disponil A3065 were able to reach a kinetically-stable state to yield latexes with 43 wt.-% solids content with a maximum change in the number of particles (N_p) with respect to the number of droplets (N_d) of ∼6%. A 2³ factorial design was then used to discern the influence of monomer, chain transfer agent and surfactant concentration on the droplet size distribution (DSD) and particle size distribution (PSD). Pressure-sensitive adhesive (PSA) properties were also examined.     

Spectrophotometric determination of nonionic surfactants by flow injection analysis utilizing ion-pair extraction and an improved phase separator

The proposed flow-injection determination of nonionic surfactants of the general type RO(CH₂CH₂O)nH (where R is an alkyl or alkylphenyl group and n is the number of moles of oxyethylene group) is based on extraction of the colored ion-pair product formed between the nonionic surfactant and the regent tetrabromophenolphthalein ethyl ester potassium salt (TBPE-K). The complex is extracted into 1,2-dichloroethane and measured at 609 nm. A new phase separator is described. Triton X-100 is used as a model compounds, for which response is linear in the range 2–60 mg l^?1. Precision of the method is excellent with a relative standard deviation of <1.0%. The sensitivity of the method depends on the type of surfactant examined.     

Effect of Surfactants and Ionic Strength on Dissociation of Hydrochlorides of Phenothiazine Derivatives

Abstract

A study of the effect of the anionic surfactant dodecyl sulfate, the cationic surfactant carbethoxypentadecyl trimethyl ammonium bromide (Septonex), nonionic surfactant p-octyl phenyl polyoxyethylene (Triton X-100), and a strong electrolyte (KBr) on the dissociation of the hydrochlorides of two derivatives of phenothiazine (diethazine and fluphenazine) was made. It was found that sodium dodecyl sulfate increases the pKa value, whereas Septonex and Triton X-100 decrease this value. The presence of KBr suppresses the effect of the surfactants. A new method for the potentiometric determination of fluphenazine in an aqueous medium was proposed.     

Determination of zinc in foods by fluorescence spectroscopy in micellar media

The effect of cationic [cetyltrimethylammonium bromide (CTAB), Zephiramine], non-ionic (Triton X-100, Brij-35) and anionic (sodium lauryl sulphate) surfactant micelles on the fluorescence intensity of the zinc 5,7-dichloro-2-methylquinolin-8-ol chelate is described. In Brij-35 or CTAB micellar media, the fluorescence is about 25 times greater than that obtained in ethanol-water. The relationship between fluorescence intensity and experimental variables was studied in order to develop a procedure for the fluorimetric determination of zinc. Linear calibration graphs were obtained in the ranges 3–100 and 50–400 ng Zn ml^?1. The detection limit is 3 ng ml^?1. The method was successfully applied to the determination of zinc in food samples and drinking waters.     

Tensammetry with accumulation on the hanging mercury drop electrode : Part 3. The behaviour of triton X-100 in mixtures with PEG-9000

The behaviour of Triton X-100, which can be present in monomeric or associated form, and its mixtures with PEG-9000, which does not undergo association, is described. The tensammetric curve of Triton X-100 alone shows one or two peaks at negative potentials, depending on the concentration of Triton X-100, i.e., on the presence of associated forms. For <2 mg l^?1, there is one broad peak, related to monomers of Triton X-100. The calibration plot for this peak is sigmoidal but its rising section (0.05–0.20 mg l^?1) is approximately linear. The calibration curve of the second, much narrower, peak related to associated forms of Triton X-100, grows parabolically with increasing concentration of Triton X-100. The behaviour of a mixture of PEG-9000 with a larger amount of Triton X-100 is similar to the behaviour of a model mixture of components with sufficiently different properties (e.g., PEG 1500/PEG 9000). The peak for PEG-9000, the stronger surfactant, is relatively less affected by a large amount of Triton X-100. Even this effect can be decreased by using a suitable preconcentration potential (?1.45 V vs. SCE) so that PEG-9000 can be determined in the presence of a 1000-fold amount of Triton X-100. Both peaks of Triton X-100 are greatly decreased by the presence of PEG-9000 and the broad peak can be completely suppressed. Triton X-100 cannot be determined accurately in the presence of unknown amounts of PEG-9000.     

Sensitive spectrofluorimetric determination of zinc at ultra-trace levels

An ultra-trace method based on the reaction of zinc with salicylthiocarbohydrazone (SATCH) and Triton X-100 as a non-ionic surfactant was developed for the fluorimetric determination of zinc at the picogram level. The reaction is carried out in the pH range 4.4–4.7 in an aqueous ethanolic medium [52% (v/v) ethanol]. The influence of the reaction variables is discussed. The detection limit is 10 pg ml^?1 and the range of application is 0.01–500 μg l^?1, with an optimum range of 0.04–400 μg l^?1. The relative standard deviations are 0.68% (0.01–0.1 μg l^?1 of zinc), 0.41% (0.1–1.0 μg l^?1 of zinc), 0.64% (1–10 μg l^?1 of zinc), 0.82% (10–100 μg l^?1 of zinc) and 0.15% (100–500 μg l^?1 of zinc). The method is highly sensitive and selective in the presence of Cd^II and Hg^II. The effect of interferences from other metal ions and anions was studied; the masking action is discussed. The advantages of the proposed method include its high sensitivity, simplicity and selectivity.     

Determination of antihyperglycemic drugs in nanomolar concentration levels by micellar electrokinetic chromatography with non-ionic surfactant

A method for the separation of six selected antihyperglycemic (antidiabetic) drugs (tolbutamide, gliclazide, glimepiride, glibenclamide, repaglinide, and glipizide) was developed with use of micellar electrokinetic chromatography. Two non-ionic poly(ethylene glycol)-based surfactants Genapol X-080 and Triton X-114 (reduced) were studied as neutral pseudostationary phases. High alkaline pH 10.0 was used to obtain negative charges of separated antidiabetic drugs and non-ionic surfactants were employed for selectivity alteration. Both non-ionic surfactants provided good selectivity at concentration 0.2% (v/v) in sodium borate buffer and the separation of six drugs was obtained within 5 min. An on-line preconcentration method based on reversed electrode polarity switching was employed for the determination of antihyperglycemic drugs in blood serum after acetonitrile protein precipitation. The limits of detection ranged from 20.8 nmol L⁻¹ for tolbutamide to 6.5 nmol L⁻¹ for glibenclamide, respectively.     

Surfactant-sensitized post-column reaction with xylenol orange for the determination of lanthanides by ion chromatography

The presence of the cationic surfactants cetylpyridinium chloride and hexadecyltrimethylammonium bromide in an alkaline 40% methanol medium was found to enhance sensitivity when xylenol orange is employed as the post-column reaction reagent for the determination of lanthanides by dynamic ion chromatography. Detection of individual lanthanides was carried out at 618 nm after separation by cation-exchange chromatography with gradient elution on a C₁₈ column. The eluent was -hydroxyisobutyric acid-sodium octanesulfonate, pH 3.8. Sensitivity enhancements by factors of three to six, compared with xylenol orange alone, were achieved at a cationic surfactant concentration of 2.4 mM. The calibration response was linear in the 0.05 to 5 μg ml⁻¹ analyte concentration range. Limits of detection below 3 ng were obtained for all the natural lanthanides and lanthanum. No sensitivity enhancement effects were observed with anionic (sodium dodecyl sulfate) and non-ionic (Triton X-100) surfactants under the conditions tested.     

Understanding surfactant aided aqueous dispersion of multi-walled carbon nanotubes

Dispersions of multi-walled carbon nanotubes (MWNTs) assisted by surfactant adsorption were prepared for a number of ionic and non-ionic surfactants including sodium 4-dodecylbenzenesulfonate (NaDDBS), hexadecyl(trimethyl)azanium bromide (CTAB), sodium dodecane-1-sulfonate (SDS), Pluronic? F68, Pluronic? F127, and Triton? X-100 to examine the effects of nanotube diameter, surfactant concentration, and pH on nanotube dispersability. Nanotube diameter was found to be an important role in surfactant adsorption rendering single-walled carbon nanotube studies as unreliable in predicting MWNT dispersive behavior. Similar to other reports, increasing surfactant concentrations resulted in a solubility plateau. Quantification of nanotube solubility at these plateaus demonstrated that CTAB is the best surfactant for MWNTs at neutral pH conditions. Deviations from neutral pH demonstrated negligible influence on non-ionic surfactant adsorption. In contrast, both cationic and anionic surfactants were found to be poor dispersing aids for highly acidic solutions while, CTAB remained a good surfactant under strongly basic conditions. These pH dependent results were explained in the context of nanotube surface ionization and Debye length variation.     

浊点萃取-分光光度法测定自来水及酒类样品中的痕量铁

利用非离子表面活性剂TritonX-100在温度高于其浊点时形成相分离行为,建立了浊点萃取-分光光度法测定痕量铁的新方法,探讨优化了以KSCN为显色剂,TritonX-100浊点萃取富集痕量铁的实验条件.研究发现:加入正辛醇可使TritonX-100的浊点降低约30℃,有利于萃取实验的进行;同时,加入的正辛醇与TritonX-100对痕量铁起到了协同萃取作用.在优化了的实验条件下,进行了痕量铁的分析,检出限为0.02mg·L-1,加标回收率为97.4%～101.6%,应用于自来水及酒类样品中痕量铁的测定,结果满意.     

Cloud point extraction and spectrophotometric determination of codeine in pharmaceutical and biological samples

Cloud point extraction process using non-ionic surfactant, Triton X-114, to extract codeine from aqueous solution was investigated. The method was based on the extraction of codeine and bromothymol blue from acetate buffer media to surfactantrich phase and formed a charge transfer-ion pair complex. The extracted surfactant-rich phase was diluted with ethanol and its absorbance was measured at 430 nm. The effect of different variables such as pH, Triton X-114 concentration, cloud point temperature and time was established. The calibration graph was linear in a wide range of 100–700 ng ml^?1 of codeine with r = 0.998 (n = 7). The detection limit based on three times standard deviation of the blank (3s) was 4.6 ng ml^?1 and relative standard deviation (R.S.D) is 2.15% for 500 ng ml^?1 codeine (n = 5). The proposed method was applied to the determination of codeine in acetaminophen codeine tablets and blood samples.     

Selective determination of Triton-type non-ionic surfactants in different samples by on-line clean-up and FIA

Summary A FIA method is proposed for the determination of non-ionic surfactants, applying spectrophotometric detection. The method is based on the formation of a surfactant-K⁺-picrate adduct and subsequent extraction into 1,2-dichloroethane. The method can handle samples containing large excesses of ionic and amphoteric surfactants, which are retained on ion-exchange columns inserted in the flow system. Beer's law is obeyed at 380 nm in the 0.02–1.2 mg·l^–1 range for Triton-type non-ionic surfactants (X-100, X-405 and WR-1339). Relative standard deviation (n=10) is 0.3% at the 0.5 mg·l^–1 level. The method has been applied to several samples and its applicability evaluated by ANOVA statistical comparison with two other methods.