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A high throughput automated system was developed to determine pH of culture media using a pH module equipped with an external flow cell. A custom septum-piercing, vented needle was developed to accommodate the shape and size of the customer sample vials. For this application, both accurate and precise pH measurements were required. The data presented in this document was collected by a customer as a part of their validation process and was provided for use with their consent.

Halides interfere with most determinations of mercury or silver. However, if mercury or silver is titrated with sulfide ions, extremely insoluble sulfides are formed.A simple method is described that allows the direct titration of mercury(II) or silver(I) compounds in the presence of halides. The potentiometric titration takes place under alkaline conditions using thioacetamide as the titrant after formation of the EDTA complex.Organic compounds that are insoluble in alkaline EDTA can also be titrated after a Schoeniger digestion.

This Application Bulletin provides information regarding the MATi 10 (Metrohm Automated Titration) system. MATi 10 is a completely configured system for automatic volumetric Karl Fischer titration with which the water content in liquid and solid samples can be determined. Up to 24 samples can be analyzed directly in 75 mL titration vessels. The samples are weighed into the titration vessels and covered with an aluminum foil. This prevents falsification of the water content.

The present Application Bulletin contains NIR applications and feasibility studies for NIRSystems devices in the chemical industry. Qualitative and quantitative analyses of a wide variety of samples are part of this bulletin. Each application describes the instrument that was originally used for the analysis, as well as the system recommended for the analysis and the results that were achieved thereby.

MATi 11 (MATi = Metrohm Automated Titration) is a completely configured system for water content determination in solid or liquid samples using automated volumetric Karl Fischer titration. It contains a Polytron PT 1300 D for the homogenization of the samples. Up to 53 samples are analyzed directly in 120 mL titration beakers. The samples are weighed in the titration beaker and sealed with aluminum foil and a foil holder so that they neither lose nor absorb water.

Eco Titrators provide the capability to send PC/LIMS reports directly to a PC. This feature is mainly used to transfer data to an external LIMS system or to simply store the data in a digitally on the PC. Additionally, it is possible to control the Eco Titrator by RS232 commands if the connection is set up according to the procedure described below.The data transfer from the Eco Titrator to a PC can be done by a software- or a hardware-based option. Additional accessories are needed for the hardware-based option whereas for the software-based option two additional softwares must be installed. Both solutions are described in this document.

Determination of sodium, ammonium, potassium, calcium, and magnesium in betaine using cation chromatography with direct conductivity detection.

Determination of lithium, sodium, ammonium, zinc, potassium, magnesium, and calcium impurities in syringe filters using cation chromatography with direct conductivity detection.

Chipped wood and sawdust may be used in production of feed e.g., for ruminants. Melamine, a raw material for resins in wood adhesives, is limited to be used in feed. Therefore, the melamine concentration in sawdust has to be analyzed. Melamine determined after ion chromatographic separation with UV/VIS detection.

The mass transport characteristics of the diffusion controlled oxidation and reduction of the ferri/ferro cyanide couple was studied using the Autolab RDE with a low noise liquid Hg contact.

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.

Convolution voltammetry consists essentially of a voltammetric, chronoamperometric, or chronocoulometric experiment followed by a mathematical transformation - convolution. Using a convolution method, the effect of the decrease of the concentration gradient can be eliminated from the total response of the electrode. This application note explains how the convolution in NOVA works.

Capacitors are electronic components necessary for the success of the electronics industry. They have also become essential components of both electric and hybrid vehicles. Electrochemical tests, such as potentiostatic cyclic voltammetry, are used to check the performance of capacitors. VIONIC powered by INTELLO can perform both staircase and linear cyclic voltammetries (CV). This Application Note gives a comparison between the linear and the staircase potentiostatic cyclic voltammetries and highlights the necessity of using the linear CV to best study the performance of capacitors.

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.

The operational behavior of a fuel cell stack is usually evaluated by determining the polarization and power density curves of the cell. These curves provide a quick characterization of the stack performance and an assessment of its optimal operating conditions (temperature, humidity, electrocatalyst, ion-exchange membrane).

Determination of bicarbonate and carbonate in a mixture by sequential thermometric titrations.

Automated determination of the zirconium content of zirconium acetate, as well as other zirconium compounds which can be rendered soluble as zirconium acetate.

Metal-organic compounds are commonly used in organic chemistry, for example as Grignard reagents or as strong bases (e.g., butyl lithium compounds). The knowledge of the exact content of reactive species allows to better plan the required amounts for reactions preventing the waste of material or too low yields.This Application Note describes the analysis of metal organics by thermometric titration using 2-butanol as titrant. Due to the strongly exothermic nature of the reaction between 2-butanol with metal-organic compounds, a fast and quantitative analysis of these substances is possible.

Tartaric Sulfuric Anodizing (TSA) is an established technique for corrosion protection in the aerospace industry. It is an alternative to the environmentally harmful chromic anodizing process. As such, a method to monitor the levels of sulfuric acid and tartaric acid in TSA plating baths is required. Potentiometric titration methods have been developed, and are widely used across the industry. Their disadvantage is that two titrations with different electrodes and solvents are required.In this Application Note, an alternative method is presented, where the concentration of both acids is determined in sequence using a thermometric sensor. Compared to potentiometric titration, thermometric titration is faster and more convenient (no sensor maintenance required). On a fully automated system, the determination of both parameters takes about 7 minutes.

The water content of coal dust is determined according to Karl Fischer. Because of the low water content of the voluminous sample, the oven method (nitrogen, 270 °C) and coulometric titration have to be used.

Determination of the water content of liquid ammonia according to Karl Fischer after absorption of the water in ethylene glycol.

Large sample sizes can lead to subtraction of too high blank values. This Application Note describes the calculation of a relative blank and thus helps to improve the accuracy of the method.

The vaping and electronic cigarette industries are growing. The mixtures used in these products are usually called e-liquid, e-fluid, or e-juice. Toensure the quality of these e-liquids, testing the most important parameters is required. One important quality control parameter is water or moisture content.Water/moisture content determination by Karl Fischer titration (KFT) is an established and reliable procedure. Compared to other methods the advantages of KFT are its accuracy, speed, and selectivity. For high water content samples, such as e-liquids, volumetric KFT is the method of choice.In this Application Note a system for the fast and reliable determination of the water content in E-liquids is presented. This fully automated system performs the analysis including system preparation, blank, titer, and sample determination completely unattended. Hence, the workload of the operator is reduced to only weighing in the sample and placing the sealed sample vessels on the system.

Determination of diethylamine and trimethylamine using cation chromatography with MS detection.

Chromate (Cr(VI)) is considered toxic and potentially carcinogenic, which is why its concentrations in children's toys should be kept as low as possible. The EU directive 2009/48/EC defines limit values for the migration of chromate from children's toys. The hydrochloric-acid-containing migration solution is diluted with a buffer. 2000 μL of this solution are injected automatically using intelligent preconcentration technology and matrix elimination. Detection takes place via ICP/MS.

Near-infrared spectroscopy (NIRS) was used as an analysis method for quality control of aqueous xanthan gum solutions. Quantitative models for the determination of optical density, glucose, and xanthan gum were developed, enabling fast and reliable quality control.

This Application Note describes a fast method for the simultaneous quantification of nicotine and glycerin in liquid mixtures used for electronic cigarettes. With visible near infrared spectroscopy (VIS-NIRS), results are available without sample preparation, thus making VIS-NIRS highly suited for fast quality control.

The quantification of residual moisture in lyophilized pharmaceutical peptides is an important measure for quality control in the pharmaceutical industry. For development purposes, such measurements are necessary and routinely performed during stability studies and to optimize the freeze-drying process (lyophilization). Currently, Karl Fischer titration is widely used for moisture determination in routine analysis. However, this method is time consuming and destroys the sample during analysis. This Application Note shows that near-infrared spectroscopy (NIRS) is a fast, reagentless, non-destructive method to determine moisture content in lyophilized pharmaceutical products.

This Application Note shows the determination of glucose and galactose in a 2% solution of lactose. The separation is achieved on a Hamilton RCX-30 - 250/4.6 applying pulsed amperometric detection (PAD) at a gold electrode. Instrument control, data acquisition, and data handling is done by Empower 3.0 using the Metrohm IC Driver 2.0 for Empower.

This Process Application Note presents a way to closely monitor multiple parameters simultaneously during the dioctyl terephthalate production process with near-infrared spectroscopy.

The planarity and smoothness of silicon wafers are fundamental to manufacture optimal semiconductor devices, and Chemical Mechanical Planarization (CMP) is the most common technology used to achieve ultra-flat surfaces. A slurry is used for this purpose, composed of deionized water, a colloidal silicon or alumina liquid dispersion, and hydrogen peroxide, which has to be constantly monitored at all times.Online monitoring of the CMP process is necessary to avoid chemical waste and enhance wafer production yields. Metrohm Process Analytics can measure not only the H2O2 concentration, but also pH, conductivity, and temperature using the multipurpose 2060 Process Analyzer.

Rapid inline monitoring of the major SC1/SC2 bath constituents is possible with reagent-free near-infrared spectroscopy, e.g., the 2060 The NIR-R Analyzer.

Many electrochemical methods have been developed but are traditionally limited to aqueous media. Raman spectroelectrochemistry in organic solutions is an interesting alternative, but developing new EC-SERS procedures is still required. This Application Note demonstrates that the electrochemical activation of gold and silver electrodes enables the detection of dyes and pesticides in organic media.

Determination of chloride, nitrite, nitrate, and sulfate in betaine using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride and sulfate in an electrolyte used in sensors for transcutaneous CO2 measurement using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, acetate, formate, chloride, nitrite, nitrate, phosphate, and sulfate impurities in syringe filters using anion chromatography with conductivity detection after sequential suppression.

Determination of fluoride, formate, chloride, nitrite, bromide, nitrate, sulfate, oxalate, and molybdate in a coolant using anion chromatography with conductivity detection after chemical suppression and Metrohm Inline Dialysis.

Ionic liquids, also denominated as «designer solvents», are organic salts that are liquid at low temperatures. They are powerful solvents, conduct the electric current, and are therefore used in many applications. Anions, in particular halogenides, are common byproducts in the manufacturing of ionic liquids. Therefore, their concentration has to be controlled.

Determination of the iron content of iron powder by potentiometric titration with potassium dichromate using the Pt-Titrode.

The vaping and electronic cigarette industries have grown impressively in the past decade. The mixtures used in these products are usually called «e-liquid», «e-fluid», or «e-juice». To ensure the quality of these e-liquids, testing the most important quality parameters, such as nicotine content, is required. Nicotine in tobacco is usually determined by gas chromatography or liquid chromatography. Aqueous acid base titration is a much more affordable alternative for this determination. As e-liquids do not contain other components which might interfere with the titration, the aqueous acid base titration presented in this Application Note can be applied for nicotine determination. This method is an affordable and reliable way to determine the nicotine content in e-liquids and their nicotine starting material, ensuring the quality of these products.

Determination of iodate, chlorite, bromate, and nitrite using suppressed anion chromatography with UV/VIS detection after post-column reaction.

Chromate (Cr(VI)) is regarded as being carcinogenic, mutagenic and damaging to DNA, which is why Cr(VI) concentrations are to be kept as low as possible. The EU Toy Safety Directive 2018/725 defines migration limit values for the release of chromate from toys. The "HCl migration solutions" are diluted with a buffer before 2,000 µL are injected via Metrohm intelligent Preconcentration Technique with Matrix Elimination (MiPCT-ME). Determination is performed with VIS detection following derivatization with diphenylcarbazide.

Hexavalent chromium (Cr(VI)) is regarded as being toxic and potentially carcinogenic. Its concentration in drinking water should therefore be kept as low as possible. The determination of Cr(VI) is performed using ion chromatography. The separation takes place on the Metrosep A Supp 10 - 250/2.0 separation column. The presence of Cr(VI) is determined photometrically following post-column reaction (PCR) with diphenylcarbazide.

Germanium can be determined by adsorptive stripping voltammetry (AdSV) at the HMDE using acetate buffer as supporting electrolyte and catechol as complexing agent.

The concentration of Pd in an activator bath is determined by polarography in ammonium chloride electrolyte.

Ion chromatography is a precise and reliable method for the determination of hexavalent chromium in children's toys. Thanks to preconcentration and Inline Matrix Elimination, the method is equally suitable for trace analysis pursuant to the new European Standard DIN EN 71, Part 3. Furthermore, the method is impressive not only because of its high degree of automation but also because of its accuracy and precision.

Chromate is allergenic, carcinogenic and extremely toxic. It is therefore subject to strict monitoring. It is present in different concentrations in drinking water, toys, textiles, leather and many other materials. Metrohm has developed various methods for ion chromatographic determination of chromium(VI) which, thanks to Inline Sample Preparation, are suitable for a variety of matrices and concentration ranges – from ng/L to mg/L.