Aplikacje

Compared to the classical Epton titration, potentiometrically indicated two-phase titrations using organic-solvent-resistant Surfactrodes can be easily automated and require no toxic and environmentally hazardous chloroform. Even challenging matrices such as fats and oils in bath oils and hair conditioners or strong oxidizing agents in washing powder and industrial cleaners do not interfere with the titration of the ionic surfactants. Results obtained show excellent agreement to those of the Epton titration. Irrespective of the matrix, relative standard deviations of threefold determinations are all below 2.1%. While the Surfactrode Resistant is mainly used for oil-containing formulations, the Surfactrode Refill is ideal for washing powders and soaps. Both electrodes excel by their ruggedness and allow the rapid and precise determination of anionic and cationic surfactants.

The titrimetric determination of nonionic surfactants on the basis of polyoxyethylene adducts (POE adducts) is described in the Bulletin. The basis for the determination is the transfer of the nonionic surfactant into a pseudo-cation compound and its precipitation titration with sodium tetraphenylborate (Na-TPB). The NIO electrode is used for the indication of the potentiometric titration. This Bulletin describes determinations in raw products, formulations and wastewater and draws attention to special features, possibilities, limits and disruptions.

Anionic surfactants can be titrated with cationic surfactants and vice-versa. The Bulletin describes a multitude of substances that can be determined in this fashion and specifies the respective working conditions and parameters. In contrast to the classic two-phase titration in accordance with Epton, the titration with the anionic and cationic surfactants electrodes can be performed without chloroform. Furthermore, the equivalence point of the titration is difficult to determine in some cases with the Epton method and the titration cannot be automated.In many cases, a surfactant ISE is a remedy that is both environmentally friendly and suitable here. It was developed specially for application with potentiometrically indicated surfactant determinations.

The two potentiometric titration methods described here allow the determination of the content of commercial betaine solutions. Neither method is suitable for determining the betaine content of formulations. The possibilities and limits of both methods are described and distinctive features and possible sources of interference are mentioned. The Bulletin explains the most important theoretical principles and is intended to help users to develop their own product-specific titration methods.

The present Bulletin offers an overview of the multitude of surfactants and pharmaceuticals that can be determined with potentiometric titration. Metrohm provides five different surfactant electrodes for indicating the titration endpoint: the Ionic Surfactant, the High Sense, the Surfactrode Resistant, the Surfactrode Refill and the NIO Surfactant electrode. The manufacture of the respective titrants and their titer determination are described in detail. In addition to this, the Bulletin contains a tabular overview of more than 170 proven applications from the area of surfactant and pharmaceutical analysis. This guideline leads you reliably to your destination: At a glance you can see from the table which surfactant electrode and which titrant are optimally suitable for your product.

On the basis of a multitude of practical examples, this Bulletin describes the potentiometric two-phase titration of ionic surfactants in raw materials and many other formulations.Two surfactant electrodes – the Surfactrode Resistant and the Surfactrode Refill – make it possible to perform this type of surfactant titration, analogous to the classic "Epton titration", with a high degree of automation. The achieved results correlate very well with those of Epton titration. The toxic, carcinogenic and environmentally hazardous chloroform can be replaced by other solvents such as methyl iosbutyl ketone or n-hexane.

Two-phase titration with potentiometric indication is a universal method for the determination of ionic surfactants in detergents. The results obtained are comparable to those with the classic two-phase titration in accordance with Epton (mixed indicator system disulfine blue / dimidium bromide). The present Bulletin addresses various parameters that could have an influence on potentiometric surfactant titration. The information provided makes it possible for the user to determine precisely the anionic surfactant content in practically all formulations.

This Application Bulletin describes methods for checking the condition of electrodes for surfactant titration. For testing electrodes used for ionic surfactant titration (Ionic Surfactant electrodes), sodium dodecyl sulfate (SDS) is determined using TEGO®trant. Conversely, for testing electrodes used for cationic surfactant titration (Cationic Surfactant electrodes), TEGO®trant is titrated with SDS.For non-ionic surfactant electrodes (NIO surfactant electrode), PEG 1000 is titrated with sodium tetraphenylborate (STPB).For testing Surfactrode Resistant and Surfactrode Refill electrodes, titrations of SDS with TEGO®trant are performed. Suitable criteria for the test are the height of the potential jump and the shape of the titration curve.Key word: NaPh4B

Determination of a nonionic surfactant of the alkyl propylene oxide derivative type in commercial mixtures containing anionic surfactants.

Standardisation of sodium tetraphenylborate (NaTPB) solution for the determination of potassium and for nonionicsurfactants.

Determination of sodium lauryl ether sulfate surfactants.

Standardization of cetyl pyridinium chloride solutions for use as a cationic surfactant titrant in the determination ofanionic surfactants such as sodium lauryl ether sulfate.

This Application Note outlines the determination of total acidic active surface sites in zeolites with thermometric titration.

This Application Note shows that the parameter of surface basicity of zeolites can be measured by thermometric titration.

Ink is a complex mixture that, along with numerous additives, is comprised mainly of solvent, dye, water and surfactant. Vis-NIR spectroscopy is outstandingly suitable for providing rapid and reliable determinations of constituents in the context of quality controls. This Application Note describes the determination of diethylene glycol (DEG), water, dye and surfactant.

Near-infrared spectroscopy (NIRS) was used in a preliminary study as a fast and accurate method for the quantification of different preservatives and active ingredients in liquid shampoo. This Application Note shows how this analytical method allows the simultaneous determination of several constituents in shampoo in a single measurement.

Determination of sodium laureth sulfate (SLES), cocamidopropyl betaine (CABP), cocamidopropylamine oxide (CAW), cocamide diethanolamine (DEA), and carbopol in shampoo is a cost- and time-intensive process due to the use of large volumes of chemicals per analysis. This application note demonstrates that the DS2500 Solid Analyzer operating in the visible and near-infrared spectral region (Vis-NIR) provides a cost-efficient and fast solution for a simultaneous determination these parameters in shampoo. With no sample preparation or chemicals needed, Vis-NIR spectroscopy allows for the complete analysis in less than a minute.

Rapid quality control for toothpaste is achieved by Metrohm`s Vis-NIR analyzers. Vis-NIR technology offers significant advantages compared to standard reference analysis. It is a cost effective and safe method because no hazardous chemicals are used.

Liquid laundry detergents contain fabric softeners, bleachers, surfactants, as well as enzymes. Among these compounds, surfactant is the most important one for the cleaning effect, as it reduces the surface tension of the liquid.The quantification of surfactant is still often performed using primary methods such as two-phase potentiometric titration. However, prior to the analysis, time consuming sample preparation steps like dilution and pH adjustment are necessary. In contrast, Visible-Near Infrared Spectroscopy works without any sample preparation steps at all, saving time and costs, and avoiding chemical waste.

Determination of anionic surfactants in shower lotions and shampoos by potentiometric titration with TEGO®trant A100 using the «Ionic Surfactant» electrode.

Determination of anionic surfactants in a nickel plating bath by potentiometric titration with TEGO®trant A100 using the «Ionic Surfactant» electrode.

Determination of cationic surfactants in hair conditioner by potentiometric titration with dioctyl sodium sulfosuccinate using the «Ionic Surfactant electrode.

Determination of the cationic surfactant «cetrimide» in an antiseptic disinfectant by potentiometric titration with sodium dodecyl sulfate using the «Ionic Surfactant» electrode.

This application note shows a reliable way to determine the content of non-ionic surfactants in liquid cleaning solutions by potentiometric titration.

Determination of nonionic surfactants in compact washing powders by potentiometric titration with sodium tetraphenylborate using the NIO surfactant electrode.

Determination of the soap content of soap noodles by potentiometric titration with TEGO®trant A100 using the «Ionic Surfactant» electrode.

Determination of soaps and anionic surfactants in washing powder by potentiometric two-phase titration with TEGO®trant A100 using the «Surfactrode Resistant» electrode.

Determination of anionic surfactants in shower oil by potentiometric two-phase titration with TEGO®trant A100 using the «Surfactrode Resistant» electrode.

Determination of cationic surfactants in a household cleaner by potentiometric two-phase titration with sodium dodecylsulfate using the «Surfactrode Resistant» electrode.

This application note describes the determination of nonylphenol ethoxylate by potentiometric titration with sodium tetraphenylborate using the NIO surfactant electrode.

Due to its price and wide availability, the anionic surfactant sodium lauryl sulfate (SLS; SDS) can be found in many detergents as an emulsifier or as a fat solvent e.g., in cleaning or cosmetic products. To avoid causing severe dry skin and hair, and thus skin irritation, regulations in many countries have restricted the sodium lauryl sulfate concentration in ready-to-use products to a range between 0.05–2.5% SLS. To control the concentration of SLS in different products, a titration is carried out with TEGO® trant A100 and the Optrode. The evaluation is done automatically by means of a software, leading to reliable and reproducible results.

Determination of lauryl ether sulfate (LAES) by potentiometric/turbidimetric titration with TEGO®trant A100 using the 610 nm Spectrode.

Tallow amine ethoxylates are toxic to aquatic life, and therefore their use is restricted. This Application Note explains an approach to determine these non-ionic surfactants potentiometrically.

This application note shows how coconut oil ethoxylates can be determined via potentiometric titration.

Alkyl glycosides, alkyl maltosides and compounds with polyoxyethylene groups (POE) are numbered among the nonionic surfactants. These surfactants can be analyzed by standard titration with TEGO®trant following derivatization – in this case following sulfonation.

Anionic surfactants represent, by volume, the most important group of surfactants used in cleaning products. The potentiometric two-phase titration is a universal method for the accurate and fast determination of them. Using the Surfactrode Refill, the anionic surfactants are determined by potentiometric titration with hyamine as titrant.