Applications

This Application Note shows the selectivity of the Metrosep C Supp 1 - 250/4.0 column for alkyl and ethanol amines in addition to standard cations under isocratic conditions. Quantification takes place using conductivity detection following sequential suppression.

This White Paper compares the two most commonly used technologies in near-infrared spectroscopy: Predispersive monochromator technology and Fourier transformation technology. In addition to measurement speeds and captured spectral ranges, the noise levels and the signal-noise ratios associated with them are also contrasted with one another.

This white paper presents six technical tips that you should consider before taking a pH measurement.

With significant global viral outbreaks becoming the norm rather than generational outliers, it is imperative that fast, sensitive, and cost-effective testing is available to the masses. Screen-printed electrodes (SPEs) allow rapid, widespread testing of populations for infectious disease, without the need of skilled personnel or burdensome equipment in the field. The possibility of point-of-care (POC) testing with SPEs has been exhibited in several recent studies. Metrohm DropSens combines high production capabilites of custom-made SPEs with a valid ISO 13485 certification "Manufacturing of sensors for medical devices", meaning testing procedures developed on these SPEs can be reliably scaled up for larger operations, with easier regulatory approval for commercialization.

Electrochemical measurements utilizing a rotating cylinder electrode (RCE) are widely used in industrial corrosion applications when simulation of realistic pipe conditions are necessary in a lab environment. This white paper allows further insight into the particularities and parameters which govern the electrochemical measurements, in particular measurements performed in turbulent flow conditions, and shows a complete picture of the best practice use of this technique. The annexes provide an overview and short explanation of the parameters and laws specific to the fluid behavior in electrochemical cells with RCE.

Ion chromatography mass spectrometry (IC-MS) is a powerful tool that can handle many challenging analytical tasks which cannot be performed adequately by IC alone. IC-MS is a robust, sensitive, and selective technique used for the determination of polar contaminants like inorganic anions, organic acids, haloacetic acids, oxyhalides, or alkali and alkaline earth metals. After separation of the sample components via IC, mass selective detection guarantees peak identity with low detection limits. The inclusion of automated Metrohm Inline Sample Preparation (MISP) allows not only water samples, but also chemicals, organic solvents, or post-explosion residues to be readily analyzed without need for extensive manual laboratory work. This White Paper explains the benefits of IC-MS over IC in certain cases, the hyphenation of IC and different MS systems, as well as related norms and standards.

In this White Paper, details of the electronic (PGSTAT) and electrochemical cell grounding are presented together with the necessity of using a floating PGSTAT for different application and experimental examples. Due to the wide variation of experimental requirements and kinds of electrochemical cells, the use of an electrochemical instrument with a selectable floating feature (such as VIONIC) which brings additional versatility to the user is recommended.

This White Paper will walk you through the selection process of ion chromatography as the best analytical tool in the product development of a cell-based gene therapy.

This work was carried out with a Metrosep C 2 - 150 separation column, the following eluent parameters being investigated: nitric, tartaric, citric and oxalic acid concentration and concentration of the complexing anion of dipicolinic acid (DPA). The aim was to determine the effect of these parameters plus that of the column temperature on the retention times of alkali metals, alkaline earth metals, ammonium and amines using ion exchange chromatography with non-suppressed conductivity detection. Due to similar affinities for the ion exchange column, transition metals are difficult to separate with the classical nitric, tartaric, citric and oxalic acid eluents. Partial complexation with the dipicolinate ligand significantly shortens the retention times and improves the separation efficiency. However, too strong complexation results in a rapid passage through the column and thus in a complete loss of separation. Apart from a change in the elution order of magnesium and calcium at high DPA concentrations, other non-amine cations are only slightly affected by the eluent composition. Irrespective of the tartaric acid and nitric acid concentration in the eluent, an increase in column temperature shortens the retention times and slightly improves the peak symmetries of organic amine cations, particularly in the case of the trimethylamine cation. In contrast, an increase in column temperature in the presence of DPA concentrations exceeding 0.02 mmol/L increases the retention time of the transition metals. Depending on the separation problem, variation of the pH value, the use of a complexing agent and/or an increase in column temperature are powerful tools for broadening the scope of cation chromatography.

This article demonstrates the utility of portable Raman spectroscopy as a versatile tool for process analytical technology (PAT) for raw material identification, in-situ monitoring of reactions in developing active pharmaceutical ingredients (APIs), and for real-time process monitoring. Raw material identification is done for verification of starting materials as required by PIC/S and cGMP, and can be readily done with handheld Raman. Portable Raman systems allow users to make measurements to bring process understanding and also provide proof of concept for the Raman measurements to be implemented in pilot plants or large-scale production sites. For known reactions which are repetitively performed or for continuous online process monitoring of reactions, Raman provides a convenient solution for process understanding and the basis for process control.

Although the process of building, validating and using a method is well-defined through software, the robustness of the method is dependent on proper practice of sampling, validation, and method maintenance. In this document, we will detail the recommended practices for using the multivariate method with NanoRam-1064. These practices are recommended for end users who are in the pharmaceutical environment, and can expand to other industries as well. This document aims to serve as a general reference for NanoRam-1064 users who would like to build an SOP for method development, validation and implementation.

This Bulletin provides an overview of the potentiometric titer determination of current titrants. Many publications only describe methods with color indicators. However, the titration conditions chosen for the titer determination should resemble those used for the actual analysis as closely as possible. The tables contain suitable titrimetric standard substances and electrodes for selected titrants as well as additional information. Following this, an example is given to show what an SOP for a titer determination could look like.

The sample preparation for ion chromatography is divided into steps which should generally be implemented to preserve the column and into steps which should be performed to obtain an improved chromatogram. The goal is to have the test substance in ionic form in solution without the presence of interfering substances.

Lithium-ion batteries must be completely free of water (concentration of H2O < 20 mg/kg), because water reacts with the conducting salt, e.g., LiPF6, to form hydrofluoric acid.The water content of several materials used in lithium ion batteries can be determined reliably and precisely by coulometric Karl-Fischer titration. In this Application Bulletin the determination for the following materials is described:raw materials for the manufacture of lithium-ion batteries (e.g., solvents for electrolytes, carbon black/graphite); electrode coating preparations (slurry) for anode and cathode coating; the coated anode and cathode foils as well as in separator foil and in the combined material; electrolytes for lithium-ion batteries;

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;

This Bulletin, using practical examples, indicates how the user can achieve optimum pH measurements. As this Bulletin is intended for actual practice, the fundamentals - which can be found in numerous books and publications - are treated only briefly.

Standardization of barium acetate titrant used in the determination of sulfate in phosphoric acid. The same procedure is applied if barium chloride is chosen as the titrant.

Combustion ion chromatography (CIC) measures AOX (adsorbable organically bound halogens, i.e., AOCl, AOBr, AOI) and AOF as well as CIC AOX(Cl) according to DIN 38409-59 and ISO/DIS 18127.

The use of an appropriate full scale together with the zero function of the 732 IC Detector minimizes baseline noise dramatically. Much lower detection limits are achieved.

Determination of mono-, di-, and trimethanolamine (MMA, DMA, TMA respectively), in the presence of lithium, sodium, ammonium, potassium, magnesium, cesium, calcium, and strontium using cation chromatography with direct conductivity detection.

Determination of traces of methylamine, isopropylamine diethylethanolamine, and diethylamine in the presence of lithium, sodium, ammonium, potassium, magnesium, and calcium using cation chromatography with direct conductivity detection.

Long-term determination of standard cations with automatic inline eluent preparation using Dosino and Level Control instruments and cation chromatography with direct conductivity detection.

Determination of monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) in the presence of lithium, sodium, ammonium, potassium, calcium, and magnesium using cation chromatography with direct conductivity detection.

The Metrosep C 6 columns have a higher capacity than those of the Metrosep C 4. The present Application Note describes the exceptional separating efficiency for standard cations with the three Metrosep C 6 column lengths available. The outstanding sodium-ammonia separation is particularly noteworthy.

The column temperature influences the duration of the cation separation on the high-performance Metrosep C 6 - 150/4.0 column. The retention times of lithium, sodium, ammonium, magnesium, and calcium remain practically constant with increasing column temperature, whereas those of potassium, strontium, and barium are considerably shortened. This means that the temperature can be used to reduce analysis time considerably on the Metrosep C 6 - 150/4.0.

Automatic dilution reduces manual work and improves the reproducibility and accuracy of the results. So far, the Inline Dilution Technique (MIDT) has been tested in a range of max. 1:100. Using a dedicated sample needle this range is enlarged significantly. This AN shows the performance of an Inline Dilution with a factor of 1:2000 as well as a comparison of manual and inline dilution for a dilution factor of 1:1000.

Ammonia determination via NH3 ISE requires precise calibration. Details on this are provided by the present Application Note.

The new DIN draft standard 38407-53 outlines TFA analysis in water using direct injection LC-MS/MS, enabling quantification from 0.1–3.0 μg/L as shown in this Application Note.

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.

Worldwide, milk and dairy products are vital sources for human nutrition. A major component and energy source in dairy products is lactose. To efficiently metabolize lactose, the enzyme lactase is indispensable. However, globally nearly 70% of the population is lactose intolerant and they have difficulties to digest lactose. Lactose malabsorption leads to numerous gastrointestinal and extra-intestinal symptoms and other complaints with varying extents. Therefore, consumers rely on accurate food labels and for manufacturers appropriate sensitive analytical techniques are a must to comply with these demands. Ion chromatography with pulsed amperometric detection (IC-PAD) enables the determination of very low lactose contents. Validation according to AOAC requirements shows the high sensitivity and reliability of this method as a routine analysis.

Determination of fluoride, hypophosphite, chlorite, bromate, chloride, nitrite, bromide, chlorate, nitrate, phosphite, phosphate, sulfate, and iodide using anion chromatography with conductivity detection after chemical suppression.

Speciation analysis is an important tool in analytical chemistry giving information about the quantitative distribution of different oxidation states of one and the same metal ion. The speciation of iron(II) and iron(III) (Fe 2+/Fe 3+) is achieved by ion chromatographic separation of their anionic dipicolinic acid complexes. Afterwards, post-column reaction with 4-(2-)pyridylazo-resorcinol (PAR) allows VIS detection at 510 nm.

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.

The ASTM B825 is used to determine the corrosion and tarnish film on metal surfaces. This is achieved by using the so-called cathodic reduction method. With the help of a Metrohm Autolab PGSTAT302N and a Metrohm Autolab 1 L corrosion cell, a procedure to replicate the ASTM B825 is shown.

This application explains ohmic iR drop in electrochemical cells, its causes, and strategies to minimize its impact for accurate and reliable potential measurements.

A fuel cell is an electrochemical energy conversion device that produces electricity and heat by electrochemically combining a fuel (typically hydrogen) and an oxidant (typically oxygen). The higher efficiency also results in much lower carbon dioxide emissions and negligible amounts of SOx and NOx (when reformed fuel is used) compared with fossil fuel-based technologies for the same power output.

The use of impedance measurements on fuel cells under load makes it possible to study the influence of the different fuel cell elements on the behavior and (if detectable) on the ageing of the fuel cell. To perform high current density measurements, the Autolab systems can be connected to a third party electronic load. This extends the measurable range of the instrument by several current decades.

The Metrohm 858 Professional Sample Processor is a robotic liquid handling system capable of handling large series of samples automatically. This instrument provides a platform that can be directly controlled by the NOVA software and combined with the Autolab potentiostat/galvanostat for automated high-throughput electrochemical measurements.

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.

This application introduces two tools (current interrupt and positive feedback) that measure and compensate for up to 90% of the ohmic iR drop, a common error in electrochemistry.

To improve the performance of electrochemical energy storage devices like batteries and supercapacitors, one can focus on enhancing the ion conductivity (ƠDC) of the electrolyte. It is a common method for obtaining ƠDC values of different electrolyte systems, to carry out electrochemical impedance spectroscopy (EIS) experiments, at different temperatures, in a 2-electrode setup.

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.

Electrochemical impedance spectroscopy (EIS) is a widely used multidisciplinary technique for characterizing the behavior of complex electrochemical systems. EIS is employed in the study of a range of complex systems including batteries, catalysis, and corrosion processes. This Application Note focuses on the basic principles of EIS measurements.

Many different configurations are made possible when using two-, three-, or four-electrode cell setups in research. Depending on the experimental requirements, one setup may be preferred over another. Therefore, the proper electrode arrangements for these three situations are defined in this Application Note. As an example, the potential at the counter electrode is measured during the platinum oxidation in acidic media, with the second sense (S2) of VIONIC powered by INTELLO. Since dissolved Pt in solution could bias the results, it is important to be able to monitor the potential of the counter electrode.

This Application Note discusses differential capacity analysis (DCA) and its impact on enhancing battery performance, with a focus on using the INTELLO platform.

This Application Note presents DPV as a sensitive, selective method for detecting heavy metals in water, detailing setup, parameters, and advantages over other techniques.

Spectroelectrochemical experiments not only provide outstanding qualitative information about samples, but also offer other quantitative data that can be considered when performing analyses. A single set of experiments allows analysts to obtain two calibration curves: one with the electrochemical data and another with the spectroscopic information. The concentration of tested samples is calculated by using both curves, confirming the obtained results by two different routes. In this Application Note, comparison between electrochemical and spectroscopic determinations demonstrates that the two methods measure uric acid (UA) indistinctively, with close agreement of the calculated values with empirical data.

Alamar Blue is monitored with fluorescence spectroelectrochemistry during its irreversible reduction to resorufin and further reversible reduction to dihydroresorufin.

Mercury can be determined in alkali media using back titration with zinc sulfate. Eriochrome black T is used as the indicator for this procedure. The Optrode is used for indication at a wavelength of 502 nm.

This Application Note shows the automatic pH adjustment of a mixture of acetonitrile, water and amine using a Metrohm titrator.