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The importance of titrations in pharmaceutical analysis

The importance of titrations in pharmaceutical analysis

If you are in the pharmaceutical industry and wonder if a conversion from a manual titration to an automated titration is suitable for your work, this blog post should give you all the answers you need.

I will cover the following topics in this article (click to go directly to the topic):

Applicability of modern titration methods in pharmaceutical analysis

Perhaps you have already heard or read about automated titration and its benefits in comparison to manual titration, but are now wondering whether those guidelines are also applicable to pharmaceutical analysis.

Getting straight to the point: Yes, it is true that many USP monographs as well as USP General Chapter <541> Titrimetry still refer to the manual visual endpoint titration. But there’s good news! USP-NF General Notices and Requirements Section 6.30 states:

As long as the alternative method is fully validated and you can prove that both methods are equivalent, you are allowed to use alternative methods.

Since titration still plays an important role in pharmaceutical analytical procedures and processes, Metrohm offers a variety of applications for innumerous API monographs of the United States Pharmacopeia as well as pharmacopeia-compliant analytical instruments.

Automated titration procedure

Have you wondered about how to perform the procedure of an automated titration—how does it differ from a manual titration? Working with a pharmacopeia compliant analytical instrument from Metrohm is not so different:

 

  1. Titrant is added with an automated piston buret that safely controls the delivery of titrant to a precise level.
  2. The sample is homogenized with a stirrer.
  3. The electrode detects the titration endpoint, removing subjectivity of color changes.
  4. Results are automatically calculated and displayed allowing no room for human error.
Figure 1. Anatomy of an automatic titrator.

As shown in Figure 1, an automated titration procedure mainly consists of four steps. These steps are repeated until the end of the titration (Figure 2).

In addition, all Metrohm devices that run with proprietary tiamo® or OMNIS® software are 21 CFR Part 11 compliant meeting all ALCOA+ requirements. Thanks to improvements in productivity, accuracy, and precision, the human influence on analysis is reduced to a minimum.

Figure 2. The titration cycle illustrating the different steps in an automated titration procedure.

If you are wondering how to transfer a manual titration to automated titration, then check out our earlier blog posts on this topic. Also, download our free white paper comparing manual and automated titration.

Choice of electrodes for pharmaceutical titrations

For autotitration, either an electrode or a photometric sensor is used to detect the point of a sample analyte neutralization. Metrohm offers a wide range of different electrodes for titrations that are extremely suitable for various pharmaceutical applications. The electrode choice depends on the type of reaction, the sample, and the titrant used.

Download our free brochure to learn more.

If you want to know more about how endpoints are recognized using electrodes or photometric sensors, read our previous blog post to find out how the endpoint is determined during an autotitration.

Maybe you are not quite sure which is the best electrode for your application. Therefore, Table 1 shows an interactive electrode guide for different pharmaceutical titrations.

Type of titration Electrode Close-up view Pharma Application / API

Aqueous acid/base titrations

e.g. titrant is NaOH or HCl

phenolphthalein indicator

Combined pH electrode with reference electrolyte c(KCl) = 3 mol/L

e.g. Ecotrode Plus, Unitrode

Water-soluble acidic and basic active pharmaceutical ingredients (API) and excipients

API: Benzbromaron, Potassium carbonate, Potassium bicarbonate

Non-aqueous acid/base titrations

e.g. solvent is organic or glacial acetic acid

crystal violet indicator

Combined pH electrode with alcoholic reference electrolyte LiCl in EtOH

e.g. Solvotrode easyClean

Water-insoluble weak acids and bases

Assay of API

Acid value (free fatty acids)

API: Caffeine, Ketoconazole

Redox titrations

e.g. titrant is sodium thiosulfate

starch indicator

Pt metal electrode

e.g. combined Pt ring electrode, Pt Titrode

 

Antibiotic assays

Peroxide value in fats and oils

API: Captropril, Paracetamol, Sulfonamide

Precipitation titrations

e.g. titrant is silver nitrate

ferric ammonium sulfate indicator

Ag metal electrode

e.g. combined Ag ring electrode, Ag Titrode

Chloride content in pharmaceutical products

Iodide in oral solutions

API: Dimenhydrinate

Complexometric titrations

e.g. titrant is EDTA

hydroxy naphthol blue indicator

Ion-selective electrode

e.g. combined calcium-selective electrode with polymer membrane

Calcium content in pharmaceutical products

API: Calcium succinate

Photometric titration

e.g. titrant is EDTA

Eriochrome black T indicator

Photometric sensor

e.g. Optrode

Assay of various metal salts in APIs

API: Chondroitin sulfate, Bismuth nitrate, Zinc sulfate

Table 1. Electrode guide for pharmaceutical titrations.

To help you select the best electrode for your titrations, we have prepared a poster for you to easily find the perfect electrode for USP monographs. Additionally, you will find information about proper sensor maintenance and storage.

If you prefer, the Metrohm Electrode Finder is even easier to use. Select the reaction type and application area of your titration and we will present you with the best solution.

As documentation and traceability are critical for the pharmaceutical industry, Metrohm has developed fully digital electrodes, called «dTrodes». These dTrodes automatically store important sensor data, such as article number and serial number, calibration data and history, working life, and the calibration validity period on an integrated memory chip.

Conclusion

Metrohm is your qualified partner for all chemical and pharmaceutical analysis concerns and for analytical method validation.

In addition to full compliance with official directives, Metrohm instruments and applications comply with many of the quality control and product approval test methods cited in pharmacopoeias. Discover the solutions Metrohm offers the pharmaceutical industry (and you in particular!) for ensuring the quality and safety of your products.

Learn even more about the practical aspects of modern titration in our monograph and visit our Webinar Center for informative videos.

Need a reason to switch

from manual to automated titration?

How about FIVE?

Post written by Doris Hoffmann, Product Manager Titration at Metrohm International Headquarters, Herisau, Switzerland.

NIR spectroscopy in the polymer industry: The ideal tool for QC and product screening – Part 1

NIR spectroscopy in the polymer industry: The ideal tool for QC and product screening – Part 1

Undoubtedly, there is a trend nowadays towards stricter quality assurance and quality control in production processes, such as in the polymer industry. At the same time, this trend is accompanied by a stronger focus on cost-saving and time-efficient methods so that performing more testing will not automatically result in higher costs. 

Major driving factors for companies to voluntarily implement more testing and quality practices include: 

  • Cost pressure. Testing can reveal out-of-specification products, allowing production to be stopped in plenty of time, eliminating excess manufacturing costs.
  • Increased competition. Quality practices provide a competitive edge and can be used as a marketing tool to raise brand value.
  • Scarcity of resources. Qualified staff are difficult to find; therefore, checks that can be carried out by non-specialists are invaluable.

Near-infrared (NIR) spectroscopy is an analytical method that addresses the above drivers and is particularly suited for making quality control more efficient and cost-effective as shown in this article. A short overview of NIRS is presented, followed by application examples for the quality control of polymers, concluding with indications and examples regarding how polymer producing and processing companies can benefit from the utilization of NIRS.

NIR technology overview

The interaction between light and matter is a well-known process—just recall the last time your skin was sunburned. Depending on the applied light intensity and energy, the interaction can be destructive (as with a sunburn) or harmless (like radio waves). Light used in spectroscopic methods is typically not described by the applied energy, but in many cases by the wavelength or wavenumbers.

A NIR spectrometer such as the Metrohm DS2500 Polymer Analyzer measures this interaction between light and matter to generate spectra as displayed in Figure 1. NIRS is especially sensitive to the presence of certain functional groups including -CH, -NH, -OH, and -SH. Therefore, NIR spectroscopy is an ideal method to quantify chemical parameters like water content (moisture), hydroxyl value, acid number, and amine content, just to name a few. Furthermore, the interaction is also dependent upon the matrix of the sample itself, which allows the detection of physical and rheological parameters like density, intrinsic viscosity, and melt flow rate.

Figure 1. Nylon and polyethylene spectra resulting from the interaction of NIR light with the respective samples.

All this information is contained in just one spectrum, making this method suitable for quick multiparameter analysis. Solid samples, such as powders, are secured within an appropriate container or vial (Figure 2a) then placed as-is on the analyzer. Heterogeneous samples, such as polymer pellets, can be analyzed using larger measurement cups (Figure 2b).

Figure 2. Solid sample placement for NIR spectra measurement. A) Direct measurement of powders in a vial. B) Large heterogeneous sample such as pellets can be analyzed using large sample cups.

Learn more about the DS2500 Polymer Analyzer on our website!

The measuring mode is referred to as «diffuse reflection», generally an appropriate procedure for analyzing granules, fibers, flakes, and both coarse and fine powders. For diffuse reflection (Figure 3), the NIR light comes from below the sample, penetrating and interacting with it, while being partially absorbed. Unabsorbed NIR light reflects to the detector. In less than 1 minute, the measurement is completed, and the results are displayed.

Figure 3. Schematic display of the light path interacting with a sample during diffuse reflection.

The procedure to obtain NIR spectra already highlights two major advantages of NIR spectroscopy: simplicity regarding sample measurement and speed.

  • Fast technique with results in less than a minute.
  • No sample preparation required – measure sample as-is.
  • Low cost per sample – no chemicals or solvents needed.
  • Environmentally friendly technique – no waste generated.
  • Non-destructive – precious samples can be reused after analysis.
  • Easy to operate – inexperienced users are immediately successful.
Read our previous blog posts to learn more about NIRS as a secondary technique.

What kinds of polymer manufacturers in the production chain might benefit from using NIR spectroscopy?

Figure 4 illustrates the individual production steps from the plastic producer, via plastic compounder and plastic converter to the plastic parts producer. The first step in which near-infrared lab instruments can be used is when pure polymers are produced, and their purity requires confirmation. NIRS is also a very useful technique for the next step, when polymers are compounded into products to be used for further processing. 

Figure 4. Simplified illustration of the polymer production chain.

A plastic part producer, typically an injection molding or extrusion company, assesses the quality of the received polymer batches. In many cases, the certificate from the supplier is trusted without any further verification. However, a rapidly growing number of companies that create products for the medical industry or that produce parts of high value or in high quantities have started to assess the important rheological quality parameters of each polymer batch before using it for injection molding or extrusion. Feeding an out-of-specification polymer to the production process leads to costly standstill of the equipment and its time-consuming cleaning.

Here, a quick pre-check of the starting polymer material used in the process would be ideal to avoid such risks and potential downtime. For this purpose, NIRS is the ideal solution because it is fast, has low running costs, and can be operated by personnel without any extensive chemical education.

When the final part is created at the end of the production process, it can also be subjected to NIR spectroscopic investigations for quality control. This is useful for assessing the homogeneity or thickness of bottles or sheets of material, for example.

What kinds of polymer applications and parameters are possible with NIRS in general?

In principle, NIRS analysis is more suitable for measuring bulk materials and not for trace analysis. Furthermore, polymer samples should contain no more than 3% carbon black and a reference method should be available. When complying with these prerequisites, NIR spectroscopy can be used as a fast and cost-saving alternative measurement technology.

Metrohm Application Bulletin 414 describes several applications for the polymer industry that can be carried out with the aid of NIRS instruments. This document contains analyses of a wide range of parameters in a very large array of samples.

Examples for use of NIR spectroscopy for selected polymers are indicated in Table 1.

Table 1. Examples for use of NIRS for selected polymers.
Polymer type Parameter Conventional analysis method Advantage of using NIRS Related NIRS application note
Polyethylene (HDPE/LDPE) Density Densimeter Results within 30 seconds AN-NIR-003
AN-NIR-081
Melt Flow Index MFI apparatus

Time-saving

No cleaning of equipment

AN-NIR-083
Polypropylene (PP) Melt Flow Index MFI apparatus

Time-saving

No cleaning of equipment

AN-NIR-004
AN-NIR-082
AN-NIR-083
Polyamide (PA) Intrinsic Viscosity Ubbelohde viscosimeter

No time-consuming dissolution in hazardous chemicals

No waste

Cost savings

AN-NIR-005
AN-NIR-060
COOH, NH2, Moisture Titration

Time & cost savings

No chemicals needed

No chemically educated operator needed

AN-NIR-077
Polyethylene terephthalate (PET) Intrinsic Viscosity Ubbelohde viscosimeter

No time-consuming dissolution in hazardous chemicals

No waste

Cost savings

AN-NIR-023
Acid number Titration

Time & cost savings

No chemicals needed

No chemically educated operator needed

Isophtalic acid HPLC

No eluent solvents needed

Time & cost savings

No chemically educated operator needed

Polyurethane (PU) OH of polyols Titration

Time & cost savings

No chemicals needed

No chemically educated operator needed

AN-NIR-006
AN-NIR-007
Isocyanate content Titration AN-NIR-035
AN-NIR-065
AN-NIR-068
Polyvinyl Alcohol (PVA) Degree of alcoholysis Titration

Time & cost savings

No chemicals needed

No chemically educated operator needed

AN-NIR-076
Silicone Rubber Vinyl content Gas Chromatography

Time & cost savings

No chemicals needed

No chemically educated operator needed

AN-NIR-084
Polyvinylidene Chloride (PVDC) Sheet thickness Weighing

Time-saving

Reduced user error risk

AN-NIR-092

Save up to 90% on running costs with NIRS

Underestimation of quality control processes is one of the major factors leading to internal and external product failure, which have been reported to cause a loss of turnover between 10–30%. As a result, many different norms are put in place to support manufacturers with their QC process. However, time to result and the associated costs for chemicals can be quite excessive, leading many companies to implement near-infrared spectroscopy in their QC process.

Our free white paper illustrates the potential of NIRS and displays cost saving potentials up to 90%.

Future installments in this series

This article is only a general overview of the use of NIR spectroscopy as the ideal QC tool for the polymer industry. Future installments will be dedicated to the most commonly produced and commercially important polymers and will include much more detailed information. These polymers are:

 

  • Polyethylene and Polypropylene (PE & PP)
  • Polyethylene Phthalate (PET)
  • Polyamide (PA)
  • Polyols and Isocyanates to produce Polyurethane (PU)

For more information

About spectroscopy solutions provided by Metrohm, visit our website!

We offer NIRS for lab, NIRS for process, as well as Raman solutions

Post written by Wim Guns, International Sales Support Spectroscopy at Metrohm International Headquarters, Herisau, Switzerland.

Developing the electrochemical sensors of your dreams

Developing the electrochemical sensors of your dreams

«Measurement is the first step that leads to control and ultimately to improvement. If you can’t measure something, you can’t understand it. If you can’t understand it, you can’t control it. If you can’t control it, you can’t improve it.»
H. James Harrington

 

The statement above relates very well to the demand to measure more and more about our lives—one option available to achieve this improvement is through the development of electrochemical sensors. Sensor manufacturing is in high demand and is expected to grow exponentially in the coming years.

Everything around us gives valuable information, including the chance to discover and the ability to know how we need to act. Developing sensors opens up new opportunities to develop and customize powerful and accurate solutions for specific applications in multiple fields, as well as being able to monitor different parameters outside the laboratory on the spot.

Electrochemical sensors and biosensors that are developed in small sensor strips allow for many measurement and monitoring possibilities. Sensors with new strategies have evolved by working with new materials, substrates, and formats that improve their accuracy, miniaturization, and portability in response to new analytical paradigms in various markets.

Why are electrochemical sensors needed?

Electrochemical sensors are a sensitive, fast, accurate, and cost-effective solution for point-of-care measurements. Such characteristics make these solutions suitable for integration into various monitoring or automation systems which, combined with a data communication structure, can generate considerable advances in the field of biosensing, creating new and important possibilities for the market as practical and future-proof solutions.

The latest advances in the miniaturization of electrochemical sensors is another reason for their growing use and popularity. These portable and simple formats are geared towards the end user—technical and non-technical—to obtain results in their daily work. This makes electrochemistry very attractive to anyone thinking of taking an idea or research to the next level and commercializing their findings.

This progress makes the development of electrochemical sensors one of the most active areas of analytical electrochemistry. These sensors are capable of providing information with superior features such as: real-time data generation, disposability, high accuracy, or wide-range linearity that make these small sensor strips an advanced alternative to conventional, bulky and expensive analytical instruments.

Multiple possibilities for production of electrochemical sensors

Your dream sensor is now possible thanks to expert manufacturing from Metrohm DropSens that allows customization and production according to your required quantity and specifications. Using an innovative and experienced production process, large quantities of customized sensors can be produced while maintaining high product quality and scalability stability as well as an attractive price-performance ratio.

Optimized design

Metrohm DropSens R&D experts understand the application concept in depth. The engineering and design departments assist in the development process to implement a final prototype, always finding a solution in which all specifications converge.

 

Custom-made solutions

The development of these sensors allows their miniaturization while at the same time allowing the possibility of modifications in terms of spatial distribution, shape, area, substrate, or the use of a wide range of materials, to name just a few. In addition, flexible sensors, textile sensors, biosensors or other types of solutions can be manufactured to suit the biochemical and electronic process needs of each individual application.

 

 Manufacture on demand

Take advantage of this capacity to produce custom-made electrochemical sensors on demand efficiently and quickly, regardless of the quantity ordered, meeting future needs without ever running out of supply.

 

High performance market-ready solutions

Be the first to bring a sensor to market, avoiding long processes and an abundance of partners. Count on the fast and professional manufacturing capability from a company positioned directly in the launch and production of electrochemical sensors to the market.

 

The highest quality standards

Production is carried out with the highest quality materials, printing, and finishing. In addition, the solutions are approved by quality management systems, which allows the highest levels of reliability and stability to be achieved in each product, guaranteeing its scalability.

From small-scale prototyping to large-scale sensor production, Metrohm DropSens offers support throughout the entire process: initial conceptualization, in-depth prototype design, and helping to achieve results that meet your goals.

This expert manufacturing is backed by the global support of Metrohm’s extensive worldwide network of partners. With more than 75 years of experience, Metrohm offers the highest standards of product and service quality, providing all you need for chemical analysis support.

Sensors for infinite uses

Progress and improvement cannot be adequately defined without the use of sensors. Everything can be measured (and usually quantified), which gives many opportunities to grow. State-of-the-art sensors based on the most recent scientific accomplishments excel in their customer-friendliness, allowing sensors to become part of everyday life as they are accessible to more people. Furthermore, the development of these decentralized devices can leverage R&D in many different industry sectors by addressing their specific applications and needs, giving them the option to reach the market.

The measurement of human health, pollution, information about foods and beverages, environmental analysis, water contamination, illicit drugs, or viruses, among other things, can be performed with electrochemical techniques and solutions. Sensors also play a fundamental role in industrial sectors such as agriculture and livestock farming, being able to measure an infinite number of parameters applicable to their improvement and development.

Another aspect to be taken into account regarding the development and growth of relevant sectors is the capacity of sensors for continuous electrochemical monitoring of different biomarkers. Combined with automated wireless data communication systems, this has represented a considerable advance in the field of biosensing towards new market possibilities.

Certified by ISO 13485 for the manufacture of sensors for medical devices

In the clinical setting, point-of-care (POC) testing dominates as an end-user application. The main areas of development focus especially on POCs for home monitoring of chronic diseases and POC testing of infectious pathologies, among others.

The COVID-19 pandemic, caused by a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has posed a threat to global public health. Therefore, the development of a rapid, accurate, and easy-to-apply diagnostic system for the detection of the virus has become crucial to control the outbreak of infection and monitor the progression of the disease. 

Metrohm DropSens manufactures electrochemical sensors under ISO 13485 certification, which attests to the ability to provide production that consistently meets customer and regulatory requirements applicable to medical devices and related services.

The sectors of medical and diagnostic services are driven by a strong interest in rapid point-of-care testing and monitoring devices. In addition, the integration of biosensors into medical diagnostic equipment will offer endless opportunities for the market for prevention and control of the spread of disease.

Moreover, the proliferation of biosensors employing electrochemical sensing technology has been gaining ground due to the strong demand for rapid and non-invasive POC applications. These are market-ready sensors that can be used by anyone.

Electrochemical test strips are a suitable canvas and format for the creation of a motorized diagnostic and testing system in this area and can provide a solution to these new analytical paradigms. The development of non-invasive sensors for decentralized and continuous monitoring has received a great deal of attention from researchers in different industries for painless analysis of important health parameters.

These are extraordinary times for sensor development

We constantly look for ways to mark our progress, and having the ability to measure parameters is one way to achieve this. The development of electrochemical sensors opens up a wealth of possibilities, and thanks to the customization and mass production capabilities of Metrohm DropSens, you will be able to produce high quality electrochemical devices that are tailored to specific applications. This production process is designed to meet the long-standing market demand for end-user-oriented sensor solutions with features such as: portability, wireless functionality, and simple usability without any loss in measurement accuracy.

Electrochemical sensors, based on small sensor strips, are now simpler, smarter, more user-oriented, and cheaper than conventional electrodes, which rely on cleaning or recovery tasks and have lower reproducibility in many areas of analysis. These devices are also characterized by the ability to acquire data in real time, which, combined with portability and ubiquitous availability, makes them practical and powerful tools for measurement purposes. In addition, they can provide an alternative solution for applications where complexity is involved, as they can be developed to adapt to infinite specifications.

Electrochemical sensors guarantee optimum quality, excellent measuring accuracy, and use perfectly bonded materials, prints, and substrates. They can be developed in various formats and are reproducible on flexible or even wearable materials, always maintaining good conductivity and preserving the correct alignment of the different sensor elements in all cases.

Metrohm DropSens is able to produce these electrochemical sensors in large quantities on a customized basis while still maintaining all the benefits and features scaled up from the customer-developed application. This is possible while guaranteeing market-ready production, an efficient price-performance ratio, and no risk of stock-outs – always with continuous global and specialized support service. Contact us to make your dream sensor a reality!

Dream of your sensor

and together we will make it true

Post written by Belén Castedo González, Marketing Communication at Metrohm DropSens, Oviedo (Asturias), Spain.

Decarbonizing chemical processes with Thor

Decarbonizing chemical processes with Thor

The chemical manufacturing industry consumes approximately 10% of the energy produced worldwide and is responsible for more than 5% of global carbon emissions. Nearly all chemicals are synthesized using thermal energy generated by fossil fuel combustion, leading to the significant carbon footprint from this sector. What if there was a way to reduce the carbon footprint without requiring significant amounts of energy or high costs? That is where the 2021 Metrohm Young Chemist Award winner, Ryan Jansonius, comes in.

Ryan Jansonius is a Ph.D. candidate at the University of British Columbia and a co-founder of ThorTech. He received his BSc (Hons) in Chemistry from the University of Calgary in 2016. He then went on to work at the Automotive Fuel Cell Cooperation, a subsidiary of Ford and Daimler, developing ion exchange membranes for hydrogen fuel cell vehicles. His research in the Berlinguette group at UBC has centered around developing technologies that use inexpensive and abundant renewable electricity to drive otherwise environmentally costly chemical transformations. ThorTech is bringing to market a unique membrane reactor technology that uses water and electricity to hydrogenate molecules relevant to the biofuel, pharmaceutical, and specialty chemical industries.

The Metrohm Young Chemist Award

Metrohm values the spirit of innovation and believes in the value of novel research performed by pioneering young scientists. At Metrohm USA, the tradition of holding a yearly contest for early career researchers has gone on for nearly a decade! Every year, between 50 and 75 entries are received to try and win a grand prize of $10,000 USD.

A panel of judges from inside and outside of the company reviews the submissions and scores the applicants’ responses to the questions on the application. Finalists are then asked a series of follow up questions from the judges and asked to summarize their role in the work and its future potential. A winner is chosen, who then presents their research at PITTCON. Watch Ryan’s presentation at PITTCON 2021 below!

Past winners of the MYCA  have gone on to continue their research and broaden their horizons using the prize money to do things they otherwise would have had to pass on.

Learn more about the Metrohm Young Chemist Award here! Applicants do not have to use Metrohm instrumentation to be considered, and it plays no part in winner selection.

Decarbonizing the chemical industry

Ryan’s doctoral research at UBC focuses on finding ways to decarbonize chemical manufacturing. The production of fuels, plastics, fertilizers, pharmaceuticals, and specialty chemicals consumes a significant amount of energy and is responsible for 5% of all greenhouse gas emissions. By developing ways to produce these useful chemicals using only abundant feedstocks and renewable electricity, there is an opportunity to offset these emissions.

To decarbonize chemical processes, Ryan and his group are developing a reactor that can use renewable electricity to drive chemical reactions that would otherwise require fossil fuel inputs. The type of reaction they are targeting is called «hydrogenation», and it is used in about 25% of all chemical manufacturing across several industries. Hydrogenation is a simple chemical process where hydrogen atoms are added to an unsaturated chemical feedstock.

Normally, this requires high pressure, high temperature hydrogen gas to achieve, which is extremely dangerous to handle. Conventional technology requires capital intensive hydrogenation plants for this purpose and has not changed for nearly a century.

The reactor, called «Thor», produces hydrogen through the electrolysis of water, which then passes through a thin membrane and hydrogenates an organic feedstock. What makes Thor unique is the use of a palladium membrane as a cathode, hydrogen-selective membrane, and hydrogenation catalyst simultaneously. This architecture enables the electrolysis to proceed in aqueous electrolyte while hydrogenation is mediated in organic solvent. Both reactions proceed efficiently as a result.

Team Thor (left to right): Ryan Jansonius, Natalie LeSage, Roxanna Delima, Mia Stankovic. Not pictured: Arthur Fink, Camden Hunt, Aoxue Huang, and Aiko Kurimoto. The technological innovation is defined by the large number of female group members, as shown by their lead authorship on several peer-reviewed articles (listed at the bottom of the page).

This process circumvents the use of fossil-derived H2, and the natural gas heaters required for conventional thermochemical hydrogenation reactors used industrially today. The ultimate goal is to use Thor to produce renewable diesel, pharmaceuticals, and a host of bio-derived specialty chemicals in a way that is cleaner, safer, and more cost-effective than conventional methods.

The legend of Thor(Tech)

Where did the name «Thor» originate?

Studying the palladium-hydrogen system led the Berlinguette research group to develop the Thor reactor in 2018. The inventor of the technology, Rebecca Sherbo (currently a postdoctoral fellow at Harvard), came up with this idea after studying the bizarre hydrogen absorption properties of palladium. The first setup and proof of concept was a tandem hydrogenation oxidation reactor. Now, instead of the paired electrolysis method they use water hydrolysis as a hydrogen source, but kept the great name to remind them of the history.

What is ThorTech? Ryan and his research team explain their project in a nutshell:

Earlier iterations of the prototype reactor developed by Ryan’s research group at UBC.

Potential commercial impact of greener technology

Thor solves key challenges with conventional hydrogenation methods by using water as a hydrogen source. Therefore, pressurized H2 gas is no longer required, which is challenging to handle and store. The reactivity of hydrogen atoms delivered to the organic feedstock in the reactor is on the order of hundreds of atmospheres. Hydrogen sourced from water can therefore be used to hydrogenate organic molecules without the use of dangerous reagents or high temperatures. Using electricity as the only energy input also enables the device to be carbon neutral if is coupled to a renewable electricity source.

A close-up view of the Thor benchtop reactor.
An expanded view of the internal parts in the flow cell.

Why choose Metrohm?

So, why choose Metrohm over other providers? I asked Ryan about his experiences with our line of potentiostats for his doctoral research in the Berlinguette lab group at UBC.

«All of the potentiostats that we use are Metrohm potentiostats in the lab. The only piece of fancy equipment or scientific equipment we need to run it [Thor] is a potentiostat. We have one big multichannel potentiostat with five or six individual channels in it, and we run all of our reactions off of that.»

Ryan Jansonius

MYCA 2021 Winner and Ph.D. Candidate, University of British Columbia

Learn more about Metrohm’s electrochemical instruments on our website!

A Metrohm Autolab Multichannel instrument. Each channel is a separate potentiostat/galvanostat module, allowing you to perform up to twelve measurements on just as many individual electrochemical cells.

«The thing that sets them apart from other potentiostats I’ve used is that the user interface is really good. The Metrohm software has a lot of default procedures and makes making custom procedures almost brainless, which is great.

You want to use your brain for the hard stuff, not the “set up the instrument” stuff.»

Ryan Jansonius

MYCA 2021 Winner and Ph.D. Candidate, University of British Columbia

We wholeheartedly agree! For more information about potentiostats from Metrohm Autolab, visit the website.

The next steps

The Thor team is currently working to develop membranes that use less palladium, designing flow cells to increase reaction rates and efficiency, and screening catalysts that enable a broader scope of feedstocks to be hydrogenated in Thor.

Dr. Aiko Kurimoto, a postdoctoral fellow on the Thor team has shown that depositing thin layers of different catalysts on the palladium cathode leads to substantially higher reactivities. This work was published in Angewandte Chemie (2021).

Of course, the COVID-19 pandemic has influenced research activities across the globe, and it is no different for our Metrohm Young Chemist Award winner. After spending nearly six months outside of the lab, social distancing measures made it difficult for Ryan to finish up his doctoral work. If an experiment failed, an entire week of work could be lost because of the need to stagger attendance. Ultimately, the team moved to a larger unoccupied space close by in order to continue their work.

How will the MYCA prize money be used?

After completing his doctorate, Ryan had planned to put all efforts into his start-up company ThorTech based on the research he contributed to. However, the transition from graduate researcher to start-up co-founder is quite an expensive one.

«It [the prize] couldn’t have come at a better time! I’m just now starting to appreciate how expensive transitioning [to industry] is.»

Ryan Jansonius

MYCA 2021 Winner and Ph.D. Candidate, University of British Columbia

He wants to take some time off to work on the company before investment capital comes in, and the prize money will be instrumental to help him do this. Additionally, a bit of rest and recharge is needed after finishing his degree!

Ryan defends his Ph.D. at the University of British Columbia in May 2021, and we wish him the very best of luck. To learn more about the research of Ryan and his team, selected peer-reviewed literature is provided below.

Selected literature for further reading:

  • Sherbo, R.S.; Delima, R.S.; Chiykowski, V.A.; et al. Complete electron economy by pairing electrolysis with hydrogenation. Nat. Catal. 2018, 1, 501–507. https://doi.org/10.1038/s41929-018-0083-8

    This is the first article published on the Thor reactor.

  • Sherbo, R.S.; Kurimoto, A.; Brown, C.M.; et al. Efficient Electrocatalytic Hydrogenation with a Palladium Membrane Reactor. JACS 2019, 141, 7815–782. https://doi.org/10.1021/jacs.9b01442

    Thor enables ~65% more energy efficient hydrogenation reactions than can be achieved using normal electrochemical hydrogenation methods.

  • Delima, R.S.; Sherbo, R.S.; Dvorak, D.J.; et al. Supported palladium membrane reactor architecture for electrocatalytic hydrogenation. J. Mater. Chem. A 2019, 7, 26586–26595. https://doi.org/10.1039/c9ta07957b

    This article describes a design for palladium membranes that uses 25x less palladium than conventional Pd foils.

  • Jansonius, R.P.; Kurimoto, A.; Marelli, A.M.; et al. Hydrogenation without H2 Using a Palladium Membrane Flow Cell. Cell Reports Physical Science, 2020, 1, 100105. https://doi.org/10.1016/j.xcrp.2020.100105

    This article shows a designed and validated scalable flow cell architecture, enabling 15x faster, and 2x more efficient hydrogenation reactions.

  • Huang, A.; Cao, Y.; Delima, R.S.; et al. Electrolysis Can Be Used to Resolve Hydrogenation Pathways at Palladium Surfaces in a Membrane Reactor. JACS Au 2021, 1, 336-343. https://doi.org/10.1021/jacsau.0c00051

    Thor can also be used to resolve complex reaction mechanisms by depositing nanoparticles on the surface of the membrane.

Post written by Dr. Alyson Lanciki, Scientific Editor at Metrohm International Headquarters, Herisau, Switzerland.

Special thanks go to Ryan Jansonius for taking the time before his doctoral defense to contribute to this article.

Fire and ice: discovering volcanic eruptions with ion chromatography

Fire and ice: discovering volcanic eruptions with ion chromatography

Some answers lie deep beneath the ice, waiting to be discovered.

Performing environmental chemistry research has taken me to the most remote places on Earth. In my doctoral studies, I was fortunate enough to handle samples from the South Pole and to perform my own research in Greenland, and later in Antarctica for my post-doc. What were we searching for, that took us to the middle of nowhere?

Volcanic eruptions are pretty unpredictable. Among the more active and aesthetic volcanoes with lava flows are Mount Etna in Catania (Italy), Kilauea on the large island of Hawaii (USA), and more recently Mount Fagradalsfjall in Iceland. When smaller events occur, people travel from all over to view this natural wonder. However, not all eruptions are equal…

Depending on a number of factors including the height of the eruption plume and the composition of the emissions, volcanic events can have quite a significant effect on the global climate. The Volcanic Explosivity Index (VEI) is a logarithmic scale used to measure the explosivity value of volcanic eruptions and categorize them from 0 (effusive) to 8 (mega-colossal). The largest of these events in the past century was the 1991 Pinatubo eruption in the Philippines (VEI 6, colossal). The cloud column reached high into the stratosphere, ejecting huge amounts of aerosols and gases, including sulfur dioxide (SO2) that scatter and absorb sunlight. This led to a measured global cooling effect for nearly two years after the eruption ended. Images of cloudless days at noon during this time showed a flat white hazy sky, indicative of the scattering effect of high-altitude sulfur aerosols.

Other large volcanic eruptions have led to periods of famine as well as enlightenment. It is said that the fantastic skies resulting from Krakatoa in 1883 (VEI 6, colossal) inspired Edvard Munch to paint his well-known masterpiece The Scream. If you’re familiar with Frankenstein, you can thank Mary Shelley for writing it during the wintry «year without a summer» in 1816, a result of the eruption of Mount Tambora (VEI 7, super-colossal).

Solving a mystery at the ends of the Earth

This cold period has been studied at length by several research groups and methodologies. In fact, the preceding decade had been found to be abnormally cool, however no record of another volcanic eruption was immediately apparent. Ultimately, it was pristine ice that held the clue that solved this mystery, and many others.

The sulfur dioxide emitted during volcanic eruptions is oxidized to sulfuric acid aerosols in the atmosphere, and depending on the height they reach, they can reside for days or even up to years. The deposition of volcanic sulfate on the polar ice sheets of Antarctica and Greenland preserves a record of eruptions via the continuous accumulation of snow in these areas. Therefore, records of volcanic activity can be found in polar ice cores by measuring the amount of sulfate. A fantastic way to determine sulfate, along with other a suite of major anions and cations in aqueous samples even at trace levels is with ion chromatography (IC).

The author holding a 1-meter long ice core drilled in Summit Camp, Greenland (left) and Dome Concordia, Antarctica (right).

Of course, gases can also be measured as they are trapped in the spaces between snowflakes, which are then compacted into firn and subsequently locked into the ice sheet. However, the time resolution for this is not fine enough for such volcanic measurements, nor is the volume of gas large enough to make an accurate estimate of the volcanic origin.

Gases trapped in the ice can be measured with special instrumentation and give insight into the prehistoric atmosphere.

Drilling ice cores for ion analysis is not a simple business. The logistics are staggering – getting both the field equipment and properly trained personnel to the middle of the ice sheet takes a sophisticated transportation network and cannot follow a strict schedule because Mother Nature plays by her own rules.

A complete medical checkup is necessary from top to bottom, as medical facilities can be rudimentary at best. This includes bloodwork, heart monitoring, full dental x-rays, and more (depending on your age and gender). It can take several days to evacuate a hurt or sick person to a proper hospital and therefore being in good health with an up-to-date medical record is part of being prepared for this type of remote work.

Equipment must be shipped to the site weeks or months in advance, often left at the mercy of the elements before being assembled again. Hopefully, everything works. If not, you must be very resourceful because there are no regular shipments and replacement parts are difficult to come by.

Boarding passes given to polar support staff leaving from Christchurch, New Zealand to McMurdo Station (USA) in Antarctica.

Ice cores obtained from polar areas and other remote places have been used for decades to analyze and reconstruct past events. Many considerations must be made regarding where to drill, how deep to go, and so on. The geographic location is of critical importance for several reasons including avoiding contamination from anthropogenic emissions, but also for its annual snowfall accumulation rate, proximity to volcanoes and even to other living beings (like penguin colonies, in the Antarctic).

Remote drill site based outside and upwind of Summit Camp, Greenland.

A fine resolution record of sulfate from ice cores drilled in Greenland and Antarctica has led to the discovery of previously unknown volcanic events. Ion chromatography with a dual channel system allows the simultaneous measurement of cations and anions from the same sample. When dealing with such critical samples and small volumes, this is a huge benefit for complete record keeping purposes. With the addition of automatic sample preparation like Metrohm Inline Ultrafiltration or Inline Dilution, human error is eliminated with a robust, time-saving analysis method.

Over the past two decades, the time resolution for data from ice core analysis has increased significantly. Conductivity used to be the measurement of choice to determine large volcanic events in ice cores, as it is difficult to see (unaided) the deposits of tephra from many eruptions, contrary to what you may think. The conductivity of sulfuric acid is higher than that of water, but conductivity is a sum parameter and does not disclose exactly what components are in the sample.

Tephra layers deposited by a volcanic eruption in Iceland.

Even when IC began to build traction in this space, the sample sizes did not allow researchers to determine monthly variations, but yearly approximations. This meant that any smaller sulfate peaks could have been overlooked. Researchers have tried to overcome this by matching records from ice cores around the globe to estimate the size, origin, and climatic impact of past volcanoes. Unfortunately, when the drill site is located close to active volcanism (as is the case with Greenland, downwind from Iceland), even smaller eruptions can seem to have an oversized effect.

Drilling into the ice always requires keeping track of the top and bottom ends of each meter!

The enhanced time resolution now possible with more sophisticated sample preparation (i.e. continuous flow setups for sample melting without contamination) for small volume IC injection allows for more accurate dating of volcanic eruptions without other apparent historical records.

Selected data from a drilled ice core, measured by IC. Trace analysis is necessary due to the low concentrations of ionic species deposited in remote locations. Annual layer counting was possible here, as shown with the yearly variations in several measured analytes. Grey bars represent the summer season.

Depending on the annual snowfall at the drill site and the depth of the core drilled, it can be possible to determine which month in a given year the deposition of sulfate from a volcanic eruption occurred.

This information, combined with other data (e.g., deposition length) helps pinpoint the circulation of the eruption plume and estimate the global impact. Aside from this, other data can be gained by measuring the isotopic composition of the deposited sulfate to determine the height of the eruption cloud (a more accurate method to confirm stratospheric eruptions), but that is beyond the scope of this article.

Storing hundreds of meters of ice cores during a summer research campaign in Antarctica.
Summers at Dome Concordia are not balmy, as shown in the temperature data (-54.3 °C wind chill!).

Using ion chromatography, it is possible even in the field to accurately determine the depth where specific volcanic events of interest lie in the ice. Then several ice cores can be drilled in the same location to procure a larger volume of ice to perform more detailed analyses.

My ice core research laboratory in Antarctica. Left: Metrohm IC working around the clock in the warm lab. Right: the ice core sample processing area in the cold lab (kept at -20 °C).

To solve this particular mystery, it was the combination of matching the same sulfate peak measured via IC in ice cores from both polar regions along with confirming the stratospheric nature of the eruption that led to the discovery of a previously unrecorded volcanic event in the tropics around the year 1809 C.E.

Transporting insulated ice cores back home for further research takes the cooperation of scientists, camp support staff, and the government. If flying, the entire flight must be kept cold to ensure the integrity of the ice. Any unlucky person catching a ride on a cold-deck flight must bundle up!

Cold period was extended by a second volcanic eruption

In fact, the stratospheric Tambora eruption in 1815 was already preceded by another huge climate-impacting event in the tropics just a few years before. This combination led to one of the coldest periods in the past 500 years. The data obtained by IC measurements of ice cores was instrumental in this discovery, and many more in the past few years.

Leaving the Antarctic continent can happen in a number of ways: by boat, military aircraft, or a plane. I was lucky enough to catch a first class ride on a government plane, with the added bonus of having a very interesting flight plan on screen.

High impact data

Other new volcanic eruptions have been discovered in the ice core record as the analytical technology improves. Their eruption dates can also be more accurately determined, helping to explain which of them had a climatic impact or not. This information helps to improve the accuracy of climate models, as the high altitude sulfate aerosols resulting from large eruptions reflect the sun and cause long periods of global cooling. It is for this reason that some groups have proposed a form of geoengineering where controlled amounts of sulfur gases are injected high into the atmosphere to mimic the effects of a stratospheric eruption.

In conclusion

I hope that this brief summary of a niche of environmental research with ion chromatography has piqued your interest! Maybe the inspiration of knowing that such roles exist will push other young scientists to pursue a similar career path. Chemistry education does not always have to happen indoors!

Robust ion chromatography solutions

Metrohm has what you need!

Post written by Dr. Alyson Lanciki, Scientific Editor at Metrohm International Headquarters, Herisau, Switzerland.