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It is a comparatively easy matter to coat platinum electrodes with platinum black by electrolytic deposition of the metal from a platinizing solution.

This bulletin contains two parts. The first part gives a short theoretical overview while more details are offered in the Metrohm Monograph Conductometry. The second, practice-oriented part deals with the following subjects:Conductivity measurements in general; Determination of the cell constant; Determination of the temperature coefficient; Conductivity measurement in water samples; TDS – Total Dissolved Solids; Conductometric titrations;

The determination of the physical and chemical parameters as electrical conductivity, pH value, p and m value (alkalinity), chloride content, the calcium and magnesium hardness, the total hardness, as well as fluoride content are necessary for evaluating the water quality. This bulletin describes how to determine the above mentioned parameters in a single analytical run.Further important parameters in water analysis are the permanganate index (PMI) and the chemical oxygen deman (COD). Therefore, this Bulletin additionally describes the fully automated determination of the PMI according to EN ISO 8467 as well as the determination of the COD according to DIN 38409-44.

This Bulletin gives a survey of standard methods from the field of water analysis. You will also find the analytical instruments required for the respective determinations and references to the corresponding Metrohm Application Bulletins and Application Notes. The following parameters are dealt with: electrical conductivity, pH value, fluoride, ammonium and Kjeldahl nitrogen, anions and cations by means of ion chromatography, heavy metals by means of voltammetry, chemical oxygen demand (COD), water hardness, free chlorine as well as a few other water constituents.

This Bulletin describes the automatic measurement of conductivity in water samples with low electrical conductivity in accordance with USP<645>. Conductivity measurement is demonstrated on the example of ultrapure water, which is used, among other things, to produce injection solutions in the pharmaceutical sector.

The TitrIC flex I system is used for the fully automatic analysis of water samples using direct measurement, titration, and ion chromatography. The following parameters are determined within a very short time: temperature, conductivity, pH, alkalinity, water hardness, and in parallel, the concentrations of individual anions. Further Metrohm instruments can be incorporated in the existing system at any time and used to measure additional parameters. This Application Bulletin describes in detail the installation instructions for the TitrIC flex I system.

The TitrIC flex II system is used for the fully automatic analysis of water samples using direct measurement, titration, and ion chromatography. The following parameters are determined within a very short time: temperature, conductivity, pH, acid capacity, and in parallel, the concentrations of individual anions and cations with the resulting water hardness and ion balance. Further Metrohm instruments can be incorporated in the existing system at any time and used to measure additional parameters. This Application Bulletin describes in detail the installation instructions for the TitrIC flex II system.

The main components of a battery are the positive and negative electrodes, together with the electrolyte, which provides only the ionic conductivity. The most common electrolytes are in the liquid state. Therefore, a separator is needed to provide a physical separation between the electrodes. The separator is soaked with electrolyte. The MacMullin number is a parameter used to determine the quality of a separator, in terms of ionic conductivity, when soaked with an electrolyte. The MacMullin number can be calculated, using the results of data fitting of two EIS experiments and the geometric factors of the measurement cells. In this application note, a commercial electrolyte is employed, together with a porous filter, used as a separator.

In this application note, we demonstrate how to determine the binary diffusion coefficient of a commercial liquid binary lithium ion battery electrolyte based on a galvanostatic pulse polarization method.

This application note presents the experimental details and an overview of the most important findings from the EIS and CV experiment to study the structure of a model solid electrolyte interface forming on a planar glassy carbon electrode in contact with a typical organic battery electrolyte.

In this application note, we demonstrate how to determine the through-plane tortuosity τ of a commercial lithium ion battery cathode material with known porosity and coating thickness, based on the electrochemical impedance spectroscopy (EIS) method.

In this application note, we demonstrate how to determine the lithium ion transference number of a commercial liquid binary lithium ion battery electrolyte, based on the very-low-frequency electrochemical impedance spectroscopy (VLF-EIS) method.

Corrosion of metals is a problem seriously affecting not only many industrial sectors, but also private life, resulting in enormous costs. In this application note, the results gained during electrochemical corrosion studies on different metals are compared to literature data.

The ASTM standard G100 is an electrochemical method to test localized corrosion of aluminum 3003-H14 and other alloys. A cyclic galvanostatic staircase polarization (galvanostaircase) is composed of an upward and a downward scan. The potential values at the end of each step are collected and linearly fitted, and the potential values at zero current are found.

A reference electrode has a stable and well-defined electrochemical potential (at constant temperature), against which the applied or measured potentials in an electrochemical cell are referred. A good reference electrode is therefore stable and non-polarizable. In other words, the potential of such an electrode will remain stable in the used environment and also upon the passage of a small current. This application note lists the most used reference electrodes, together with their range of use.

When current flows through an electrochemical cell, a potential drop between the RE and the WE occurs. This voltage drop is influenced by the electrolyte conductivity, the distance between the reference and the working electrodes, and the magnitude of the current. This application note gives a basic explanation of the Ohmic drop, its causes and the impact on measurements.

This application note describes three different measurement methods of the ohmic drop and the ohmic resistance presented. Current interrupt and positive feedback are fast methods, but care is necessary for their use in order to avoid data misinterpretation or damage to the setup. EIS, on the other hand, is a more reliable method to determine the ohmic resistance. The ohmic drop can be compensated by the potentiostat during the measurement, or a mathematical correction can be applied to the data.

The relative permittivity εr, also known as dielectric constant, is of great importance in materials characterization. It can be defined as the ratio between the amount of electrical energy stored in a material and the amount of electrical energy stored in a vacuum. One of the easiest way to obtain the relative permittivity is to calculate it from capacitance values. In this Application Note, five techniques to retrieve capacity values have been compared.

In order to calculate the conductivity of an electrolyte, the cell constant of the cell must be known. The combination of the Metrohm Autolab PGSTAT204 equipped with the FRA32M module in combination with the Autolab Microcell HC setup was used for the determination of the conductivity cell constants of TSC1600 temperature controlled electrochemical cell.

The proton conductivity of membranes made of a proton conductive material is an essential quantity to be determined. In this application note, we present the results of an exemplary study of σDC(T) determined by impedance spectroscopy for a novel solid proton conductor in its dry state.

In the application note AN-EIS-004 on equivalent circuit models, an overview of the different circuit elements that are used to build an equivalent circuit model was given. After identifying a suitable model for the system under investigation, the next step in the data analysis is estimation of the model parameters. This is done by the non-linear regression of the model to the data. Most impedance systems come with a data-fitting program. In this application note, the way NOVA is uses to fit the data is shown.

In this application note, the advantage of recording the raw time domain data for each individual frequency during an electrochemical impedance measurement is described.

Electrochemical impedance spectroscopy (EIS) is a powerful technique which provides information about the processes occurring at the electrode-electrolyte interface. The data collected with EIS are modeled with a suitable electrical equivalent circuit. The fitting procedure will change the values of the parameters until the mathematical function matches the experimental data within a certain margin of error. In this Application Note, some suggestions are given in order to get acceptable initial parameters and to perform an accurate fitting.

In this application note, a combination of PGSTAT and electronic load is use to perform electrochemical impedance spectroscopy in a fuel cell operating at high currents.

In the food industry, it is essential to determine and monitor certain quality parameters to guarantee consistency. This is especially important for liquid dairy products, which are subject to a strict cold chain. Both the dissolved oxygen (DO) and the pH value have proven to be reliable quality criteria. Oxygen shortens the shelf life and influences the product quality (e.g., nutritional value, color, and flavor). The DO content depends on the salinity in the sample, which is automatically calculated and corrected by the 914 pH/DO/Conductometer during the parallel conductivity measurement. Acidity is another important characteristic to measure that can be checked easily using the pH value. With the 914 pH/DO/Conductometer, all important quality criteria can be monitored with one device.

Dye-sensitized solar cells (DSC) are currently subject of intense research in the framework of renewable energies as a low-cost photovoltaic (PV) device. To characterize photovoltaic devices, two additional frequency domain methods can be used, based on the modulation of the light intensity. These two methods are Intensity modulated photovoltage spectroscopy (IMVS): measurement of the transfer function between the modulated light intensity and the generated AC voltage, and Intensity modulated photocurrent spectroscopy (IMPS): measurement of the transfer function between the modulated light intensity and the generated AC current.This Application Note illustrates the use of the Metrohm Autolab PGSTAT302N equipped with a FRA32M module, in combination with the Autolab Optical Bench kit to perform IMVS and IMPS characterization of photovoltaic devices.

The TitrIC flex II system is the perfect combination of titration, direct measurement, and ion chromatography for fully automated analysis of all key parameters. These include pH, conductivity, hardness, anions, cations, as well as the calculation of the ion balance: comprehensive water analysis from one system.

The automated system Basic water analysis determines conductivity, pH value, and alkalinity in all kind of water samples. The high degree of automation (e.g., automated sample addition, automated calibration as well as automated titer and cell constant determination) minimizes errors and guarantees an outstanding reproducibility.

In this application note, a fully automated system is presented which allows the determination of several parameters according to various standards within one analysis. These include conductivity (ISO 7888, EN 27888, ASTM D1125, EPA 120.1), the pH value (EN ISO 10523, ASTM D1293, EPA 150.1), alkalinity (EN ISO 9963, ASTM D1067, EPA 310.1), and Ca/Mg content (ISO 6059, ASTM D1126, EPA 130.2). Additionally, the system transfers the required sample volume into an external titration vessel for the analysis, reducing manual sample preparation. Furthermore, all sensors can be automatically calibrated and the titer of each titrant can also be determined.

In this application note, a fully automated system is presented which allows the determination of several parameters according to various standards within one analysis. These include conductivity (ISO 7888, EN 27888, ASTM D1125, EPA 120.1), pH value (EN ISO 10523, ASTM D1293, EPA 150.1), alkalinity (EN ISO 9963, ASTM D1067, EPA 310.1), and chloride content (ISO 9297, ASTM D512, EPA 325.3). Additionally the system transfers the required volume of sample into an external titration vessel, further reducing manual sample preparation. Furthermore, all sensors can be calibrated automatically and the titer of each titrant can also be determined.

In this application note, a fully automated system is presented which allows the determination of several parameters according to various standards within one analysis. These include conductivity (ISO 7888, EN 27888, ASTM D1125, EPA 120.1), pH value (EN ISO 10523, ASTM D1293, EPA 150.1), alkalinity (EN ISO 9963, ASTM D1067, EPA 310.1), Ca/Mg (ISO 6059, ASTM D1126, EPA 130.2), and chloride (ISO 9297, ASTM D512, EPA 325.3). Additionally the system transfers the required volume of sample into external titration vessels for the different analyses, reducing manual sample preparation. Furthermore, all sensors can be automatically calibrated and the titer of each titrant can also be determined.

Ethanol, bio-ethanol and biofuel (E85) are increasingly used as substitutes for petroleum-based fuels. During storage, they often come into contact with metallic substrates or surfaces, e.g., in barrels, tanks, or other containers. Excessive concentrations of ions in the stored fuel promotes corrosion. Monitoring the total concentration of the ions present in the fuel matrix should be the first step of an effective anti-corrosion strategy.An easy, fast, and cost-effective method to determine the total amount of ions is by measuring the electrical conductivity according to DIN 15938.

Finishing and coating procedures are used primarily for the purpose of modifying the surface of a workpiece – while retaining certain surface properties. To this end the surface is either chemically modified or coated with a material that exhibits the desired properties. This article describes the use of process analyzers in several typical applications for surface finishing and coating.

The rapid growth of the Earth's population has led to massive increases in the consumption of energy and resources and in the production of consumer products and chemicals. It is estimated that 17 million chemical compounds are currently on the market, of which 100,000 are produced on a large industrial scale. Many of these enter the environment. This leads to a demand for sensitive analytical procedures and high-performance analytical instruments.pH value, conductivity and oxygen requirement are important characteristics in water and soil analysis. The first two of these can be determined rapidly; for the third, the titration that is used is also the one used in numerous single determinations. This article describes several important standard-compliant determinations in water and soil analysis.