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History of Metrohm IC – Part 3

History of Metrohm IC – Part 3

Part 3 of this series on the history of ion chromatography development at Metrohm focuses on the near past, from the mid 2000s until a few years ago. Here, sequential suppression was introduced, making analysis even more sensitive with the removal of baseline disturbances from the chromatogram. In the rest of this blog post, I cover the 4th and 5th instrument generations, presenting professional, flexible, intelligent ion chromatography from Metrohm to the world.

Have you read the other parts in this series? If not, find them here to understand the history of IC development at Metrohm over the past few decades.

«An IC system so smart that it can make logical decisions on its own? For example, diluting samples automatically, if the concentration of your target analyte is too high and results would fall outside the calibrated range?»

Dr. Markus Läubli, R&D Ion Chromatography, Metrohm AG

«This is exactly what the 850 Professional IC and MagIC Net™ software can do. In fact, our Professional IC system takes care of the liquid handling & sample preparation with hardly any work required from the user!»

Dr. Andrea Wille, Manager Competence Center Ion Chromatography, Metrohm AG

2005: Sequential suppression is introduced

Sequential suppression was introduced in 2005 to overcome issues that arise from using chemical suppression alone.

In chemical suppression (using the packed bed Metrohm Suppressor Module, MSM), the dissociated carbonic acid from carbon dioxide attributes a background conductivity of approximately 15 µS/cm. This yields in relatively large water dips as well as system peaks (from carbonate). Depending on the carbonate concentration, the system peak may interefere with other peaks of interest in the chromatogram.

Furthermore, the pH in a peak changes due to the increasing concentration of H+, as e.g. chloride is eluted as HCl. This pH change induces a decreasing baseline as the hydrogen carbonate—carbonic acid equilibrium is pushed towards development of carbonic acid. The effect is schematically illustrated in Figure 1.

Here, the calculated baseline is marked with the straight red line, but the real baseline shows small negative deviations under the analyte peaks. This negative peak area is not taken into account for the quantification of the respective analyte. This and other effects result in a deviation from the linearity of the calibration curve. In most cases it is therefore recommended to apply a quadratic curve fit.

Figure 1. Chromatogram with chemical suppression. The blue area is not taken in to account in the quantification. Negative peaks: real baseline due to pH change.

Download our free poster: Sequential suppression for conductivity detection in ion chromatography. The poster describes how different suppressors (MSM and MCS) work and mentions possible applications. 

Sequential suppression for anions

The term «sequential suppression» represents the combination of chemical suppression and CO2 suppression. The Metrohm CO2 Suppressor (MCS) removes CO2 from the eluent (mobile phase) after chemical suppression, but before detection. This shifts the equilibrium from hydrogen carbonate towards dissolved CO2. Applying sequential suppression therefore reduces the background conductivity to < 1 µS/cm, corresponding to ultrapure water itself.

As an effect of sequential suppression, the water dip as well as the system peak (carbonate peak) is reduced dramatically. The former allows easier integration of the early eluting peaks (Fig. 2), e.g. fluoride. The latter reduces the interference and disturbance of peaks of interest. Using the MCS in combination with the MSM, there are no negative baseline peaks present in the chromatogram, and the linearity is improved. Nevertheless, it is still recommended to apply a quadratic curve fit when calibrating a concentration range of one or more orders of magnitude.

Figure 2. Overlay of a chromatogram of standard anions with chemical suppression (MSM alone, blue) and a chromatogram of the same standard, but while applying sequential suppression (MSM + MCS, red). The water dip (1, injection peak) and the system peak (2, carbonate peak) are no longer present with sequential suppression.

Here you can find a selection of free application notes for download using sequential suppression for both anions and cations.

4th generation: Intelligent ion chromatography – 2007

The fourth generation of Metrohm ion chromatography was introduced in 2007, bringing with it a higher level of detection data handling and finally adding intelligence to the IC instruments.

After the introduction of the 850 Professional IC series in 2007, the respective compact versions (881 Compact IC pro and 882 Compact IC plus) were launched in 2009 (Figure 3), offering IC systems for all kinds of laboratories and sample throughput needs. The 883 Basic IC plus followed shortly after this as well in 2009 (Fig. 3).

Figure 3. New additions to the Metrohm IC family (left to right): The 850 Professional IC, 881 Compact IC pro, 882 Compact IC plus, and 883 Basic IC plus.

Aside from general improvements on the hardware modules, the conductivity detector was switched from analog to digital. The previous iteration consisted of a stand-alone detector block and an electronic unit, which was able to cover the full signal range of conductivity for IC. However, it was required to select a dedicated measuring range and an optimal full-scale (e.g., 20 µS/V) for the best signal quality.

The new IC Conductivity Detector for 850 Professional IC instruments consisted of only the «detector block» itself. The complete electronics were now integrated within the thermostated detector block. Besides the digital data acquisition capability, this significantly improves the signal stability which yields in an extremely low noise level. The digital detector could now handle the full conductivity range without the need for any range or full-scale settings.

MagIC Net, the new fully in-house developed software for both hardware control and data handling, brought many enhanced features and capabilities to the world of Professional IC (Figure 4). Here, «Intelligent IC» was born. Intelligent IC stands for the automatic recognition of most of the hardware components, e.g., the high pressure pump, the separation column, etc. This information is stored in every determination, allowing users full system traceability for each analysis.

Figure 4. MagIC Net software for the full hardware control and data handling of Metrohm IC instruments.

MagIC Net also brought forth many special control functions enabling sophisticated Inline Sample Preparation and automatic calibration techniques. Logical decisions are available, allowing analysts to perform logical dilutions for example. Here, the logical decision-making software decides whether an analysis is a standard, a QC standard, or a sample. After the chromatographic run, the results can be tested for concentrations out of the calibration range. When such outliers are found, MagIC Net calculates new dilution factors and automatically re-runs the samples with the new values. At the end, perfect results are available for all analytes without manual redilution and re-injection.

5th generation: Modular flexibility arrives – 2013

The fifth generation of Metrohm ion chromatography arrived with an upgrade to the Professional IC system allowing even more application capabilities. The 940 Professional IC Vario and the 930 Compact IC Flex were introduced in 2013 (Figure 5).

Figure 5. The Metrohm 940 Professional IC Vario (left) and the 930 Compact IC Flex (right), developed with flexibility in mind.

These instruments were followed in quick succession by the 942 Extension Modules Vario as well as the stand-alone 945 Professional Detector with conductivity and/or amperometric detection options to further broaden application suitability.

The 941 Eluent Production Module, also introduced in 2013, enabled the continuous preparation of all types of eluents via dilution of concentrated mobile phase constituents. Commercial as well as homemade concentrates may be applied. Therefore, the eluent production is not reduced to standard or costly eluents.

Figure 6. Ultimate modularity for the laboratory – mix and match modules: the Metrohm 940 Professional IC Vario TWO/ChS set up for AnCat analysis, containing 2 IC Conductivity Detectors, sitting atop two 942 Extension Modules Vario LQH and a 941 Eluent Production Module.

Intelligent IC: Not only limited to the laboratory

After the introduction of the new MagIC Net software for IC analysis, an updated version of the Metrohm IC process analyzer from Metrohm Process Analytics was also developed and launched. In 2016, the Process IC ONE and Process IC TWO were introduced, only differing in the amount of measurement channels and detectors (Figure 7). These process analyzers were built using the 940 Professional IC Vario series with the same functionality for the laboratory, in a rugged housing suitable for harsh industrial conditions.

The use of various MISP techniques (Metrohm Inline Sample Preparation) such as Inline Ultrafiltration and Inline Dilution, along with nine configurable wet part modules for further sample conditioning, integrated eluent production, and the possibility to connect one system to up to 20 process points for time-saving sequential analysis at multiple areas inside of a plant further expanded the application capabilities beyond what any lab instrument could offer. The use of liquid level sensors and integrated alarms for leakages and out-of-specification data results in maximum analyzer uptime due to reduced maintenance intervals.

Figure 7. The Metrohm Process IC TWO configured for AnCat analysis, with optional PURELAB® flex 5/6 from ELGA®, a pressureless inline ultrapure water feed.

Are you interested in ion chromatography applications for industrial process analysis and optimization? Did you know that you can also monitor the air quality indoors as well as in the environment with these products? Check out our selection of FREE Process Application Notes (PANs) for IC:

What’s next?

After the mid 2010s, more focus was given to the development of hyphenated techniques to support IC as part of a comprehensive analytical solution for more difficult sample matrices and analytes. In the next installment, I will discuss TitrIC, VoltIC, Combustion IC (CIC), and more, as well as what is on the horizon for the process analysis world. Stay tuned, and don’t forget to subscribe to the blog!

Visit our website

to find out more about Metrohm Inline Sample Preparation (MISP)

Post written by Dr. Markus Läubli, Manager Marketing Support IC at Metrohm International Headquarters, Herisau, Switzerland.

Forewarned is Forearmed: Error and risk minimization in process analysis – Part 3

Forewarned is Forearmed: Error and risk minimization in process analysis – Part 3

In the course of life, each of us learns to trust our gut feelings or our experiences to avoid situations that seem dangerous or risky. You quite literally sense potential dangers with an uneasy feeling. Who hasn’t painfully learned that touching a hot stove top isn’t a good idea? Or who voluntarily goes outside during a tornado?

While humans can rely on their intuition and learned patterns to avoid dangers or use protective strategies, this is far more complicated with electronic systems or machines. All components of a system must be in a permanently safe state. Failures and malfunctions of individual components can have devastating consequences for production processes and the safety of the operators.

An example of this is the Seveso disaster in 1976, in which highly toxic dioxin TCDD escaped as a result of an uncontrolled reaction, and sustainably poisoned flora and fauna. With regard to other major chemical accidents, the European Seveso III Directive then came into force in 2012 to control major accident hazards to prevent major accidents.

Have you read Part 1 and Part 2 of our «Advantages of PAT (Process Analytical Technology)» series? If not, find them here!

Recognize, master, and avoid errors

Process engineering systems that are operated continuously contain countless components that can wear out or fail during their life cycle. However, if the measuring, control, or regulating circuit is affected, failures can cause immense damage. Under no circumstances should humans nor the environment be exposed to any kind of danger. For this reason, the functional safety of the components must be guaranteed, and their risk and hazard potential must be analyzed in detail.

The service life of mechanical components can be evaluated by observing mechanical wear and tear. However, the aging behavior of electronic components is difficult to assess. A unit of measure that makes risk reduction and thus functional safety quantifiable is the so-called «Safety Integrity Level» (SIL). 

The following procedure is followed:

  1.   Risk analysis
  2.   Realization of risk reduction
  3.   Evidence that the realized risk reduction corresponds at least to the required risk reduction

«Process analysis systems are part of the entire safety cycle of a manufacturing plant and therefore only one component whose risk of malfunctions and failures must be considered in an assessment.»

Risk assessmentA process is considered safe if the current risk has been reduced below the level of the tolerable risk. If safety is ensured by technical measures, one speaks of functional safety.

Significance for process analysis systems

Errors can happen anywhere, and can never be completely excluded. To minimize possible errors, it is therefore necessary to estimate the risk of occurrence and the damage to be expected from it as part of a risk analysis. A distinction must be made here between systematic and random errors.

Systematic errors are potentially avoidable and are caused, for example, by software errors or configuration deficiencies. Accordingly, they already exist during or prior to commissioning.

In contrast, random errors are potentially difficult to avoid because they occur arbitrarily. Nevertheless, the error rate or failure probability can be determined statistically and experimentally.

Random errors usually result from the hardware and occur during operation. Ultimately, systematic errors should be avoided, and random errors should be mastered to ensure trouble-free functionality.

Process analysis systems are the link between manual laboratory analysis and the industrial process. In applications where continuous and fully automatic monitoring of critical parameters is required, process analyzers are indispensable. Due to the different analysis conditions in the laboratory and directly in the process, there are some challenges when transferring the measurement technology from the lab to the process. The decisive factors are the working and environmental conditions (e.g., high temperatures, corrosive atmospheres, moisture, dust, or potentially explosive environments) which the process analyzers have to meet regarding their design, construction materials, and reliability of the components. The analyzer automatically and continuously transmits system and diagnostic data to prevent hardware or software components from failing through preventive measures. This significantly reduces the chance of random errors occurring.

General process analyzer setup

a) Analyzer Setup

Process analyzers have been specially developed for use in harsh and aggressive industrial environments. The IP66 protected housing is divided into two parts, and consists of separate wet and electronic parts. The electronics part contains all components relevant to control and operate the process analyzer. Modular components like burettes, valves, pumps, sampling systems, titration vessels, and electrodes can be found in the analyzer wet part. Representative samples can thus be taken from the process measuring point several meters away. The analysis procedure, the methods to be used, and method calculations are freely programmable.

A touchscreen with intuitive menu navigation allows easy operation, so that production processes can be optimized at any time. The course of the measurement is graphically represented and documented over the entire determination, so that the analysis process is completely controlled. The measurement results can be generated 24/7 and allow close and fully automatic monitoring of the process. Limits, alarms, or results are reliably transferred to the process control system.

When operating the analyzer, there is a risk that software errors can lead to failures. In order to recognize this with foresight, the system delivers self-diagnostic procedures as soon as it is powered on and also during operation. This includes, e.g., checking pumps and burettes, checking for leaks, or checking the communication between the I/O controller, the human interface, and the respective analysis module.

b) Sensors

The central component of a process analyzer is the measurement technique in use. In the case of sensors or electrodes, there are several requirements such as chemical resistance, ease of maintenance, robustness, or precision which they must meet. The safety-related risk arises from the possibility if measurement sensors fail due to aging, or if they become damaged and subsequently deliver incorrect measurement results.

Failure of the electrode, contamination, or damage must be reported immediately. With online analysis systems, the analysis is performed in an external measuring cell. In addition, recurring calibration and conditioning routines are predefined and are performed automatically. The status of the electrode is continuously monitored by the system.

Between measurements, the electrode is immersed in a membrane-friendly storage solution that prevents drying out and at the same time regenerates the swelling layer. The electrode is therefore always ready for use and does not have to be removed from the process for maintenance. This enables reliable process control even under harsh industrial conditions.

c) Analysis

Process analyzers must be able to handle samples for analysis over a wide concentration range (from % down to trace levels) without causing carry-over or cross-sensitivity issues. In many cases, different samples from several measuring points are determined in parallel in one system using different analysis techniques. The sample preparation (e.g., filtering, diluting, or wet chemical digestion) must be just as reliable and smooth as the fully automatic transfer of results to the process control system so that a quick response is possible.

Potential dangers for the entire system can be caused by incorrect measurement results. In order to minimize the risk, a detector is used to notify the system of the presence of sample in the vessel. The testing of the initial potential of the analysis or titration curves / color development in photometric measurements are diagnostic data that are continuously recorded and interpreted. Results can be verified by reference analysis or their plausibility can be clarified using standard and check solutions.

Detect errors before they arise

The risk assessment procedures that are carried out in the context of a SIL classification for process engineering plants are ultimately based on mathematical calculations. However, in the 24/7 operation of a plant, random errors can never be completely excluded. Residual risk always remains. Therefore, the importance of preventive maintenance activities is growing immensely in order to avoid hardware and software failures during operation.

A regular check of the process analyzer and its diagnostic data is the basic requirement for permanent, trouble-free operation. With tailor-made maintenance and service concepts, the analyzer is supported by certified service engineers over the entire life cycle. Regular maintenance plans, application support, calibration, or performance certificates, repairs, and original spare parts as well as proper commissioning are just a few examples.

Advantages of preventive maintenance from Metrohm Process Analytics

  • Preservation of your investment
  • Minimized risk of failure
  • Reliable measurement results
  • Calculable costs
  • Original spare parts
  • Fast repair
  • Remote Support

In addition, transparent communication between the process control system and the analyzer is also relevant in the context of digitalization. The collection of performance data from the analyzer to assess the state of the control system is only one component. The continuous monitoring of relevant system components enables conclusions to be drawn about any necessary maintenance work, which ideally should be carried out at regular intervals. The question arises as to how the collected data is interpreted and how quickly it is necessary to intervene. Software care packages help to test the software according to the manufacturer’s specifications, to perform data backup and software maintenance.

«Remote support is particularly important in times when you cannot always be on site.»

In real emergency situations in which rapid error analysis is required, manufacturers can easily support the operator remotely using remote maintenance solutions. The system availability is increased, expensive failures and downtimes are avoided, and the optimal performance of the analyzer is ensured.

Read what our customers have to say!

We have supported customers even in the most unlikely of places⁠—from the production floor to the desert and even on active ships!

Post written by Dr. Kerstin Dreblow, Product Manager Wet Chemical Process Analyzers, Deutsche Metrohm Prozessanalytik (Germany).

History of Metrohm IC – Part 2

History of Metrohm IC – Part 2

In the second part of our series behind the development of high quality ion chromatography instrumentation at Metrohm, I will cover the mid 1990s until the mid 2000s. During this time, Metrohm focused on modular IC, lowering background suppression, as well as bringing further robust detection methods on to the market.

Did you miss Part 1? Click here to read the first part of our series on the history of ion chromatography at Metrohm:

«The 1990‘s. People start to care about the environment. Authorities impose quantitative limits on the presence of many substances, most of which must be detected down to trace levels. Metrohm builds the perfect tool for this: the 761 Compact IC.»

Dr. Helwig Schäfer, retired Head of R&D Ion Chromatography, Metrohm AG

2nd generation: The modular IC system – 1996

While the Labograph was soon replaced by integrators (initially with integrators and later on by PC-based integration tools), the conductivity detector stood unbeaten for a long period. Improvements to the system setup, as well as additional liquid handling tools and automation capabilities yielded the second generation of Metrohm IC: the modular system.

At the same time, the initial patents on chemical suppression were about to expire, allowing the possibility to begin the development of the Metrohm Suppressor Module.

Metrohm Suppressor Module (MSM)

The idea for the MSM is based on the suppression column as described in the paper by Small, Stevens, and Baumann [1]. Its main purpose is to remove the eluent conductivity after the separation and prior to the conductivity detection. Thus, the eluent needs to be convertible to water by ion exchange.

In the case of anion chromatography, sodium hydroxide is an example of such a candidate. By replacing sodium by a proton through ion exchange, the eluent is converted to water alone. The authors applied a suppressor column of opposite charge (compared to the analytical column) after the analytical column [1].

The Metrohm Suppressor Module.

As with all things, suppressor columns do have a couple of disadvantages. They have to be externally regenerated on occasion. Depending on the amount of cations already bound to the suppressor column, its separation and ion-exclusion behavior is modified. This leads to changes in retention times of the ions, especially regarding the carbonate peak, which shifts quite strongly and interferes with other peaks of interest. On the other hand, one of the most positive points of suppressor columns is their ruggedness.

Metrohm was looking for solutions to the disadvantages without compromising the ruggedness of this column-based approach.

To overcome the shifting retention time over the usage of suppressor columns, the dimensions of the column were reduced dramatically. This yielded in a small cartridge-like compartment. The exchanger capacity needed to stay high enough for running, minimally, one single chromatogram. Under the precondition that only one chromatogram is suppressed with a single suppressor compartment, in this way all determinations have exactly the same conditions and no retention time shifts can occur.

Now it was required to regenerate the suppressor compartment prior to the next sample injection. Here, the idea of a rotating unit with three compartments was born. 

All three compartments are connected to a liquid stream: i.e. unit 1 suppresses the eluent conductivity in the analytical stream, unit 2 is being regenerated with acid, and unit 3 is rinsed (acid-free) with ultrapure water or with the detector effluent (now known as STREAM). Prior to each injection, the MSM rotor is switched by one position. In this way, each injection uses its own freshly regenerated and rinsed suppressor unit.

The final suppression setup was launched as the 753 Suppressor Module in 1996 together with the modular system consisting of the 732 Conductivity Detector, 709 IC Pump, 733 IC Separation Center, and the 766 IC Sample Processor plus further liquid handling modules. Together with IC Net, the PC-based data acquisition and handling software, full automation of the ion chromatographic system was available

The Metrohm 753 Suppressor Module. 
Modular IC at Metrohm, circa 1996.

While modular IC was extremely flexible and opened up possibilities for a high grade of automation opportunities, it also was quite complex for straightforward, everyday applications.

This routine IC required for general users was introduced in 1999 as the first all-in-one ion chromatograph – the 761 Compact IC. It was the ideal instrument to run standard applications on directly due to the integration of all basic components required for IC analysis. These included: IC pump, injector, Metrohm Suppressor Module with peristaltic pump for regeneration (when required) and rinsing and the conductivity detector. The 761 Compact IC was the first instrument available in only a metal-free version.

The Metrohm 761 Compact IC. 

IC with built-in amperometric detection

The initial 641 VA Detector and its successor the 791 Amperometric Detector were electronic high-performance instruments requiring a quite high level of knowledge in electrochemistry. Handling and maintenance were not easy tasks, however, analysts which were familiar with these products were extremely happy.

The Metrohm 641 VA Detector and its successor, the 791 Amperometric Detector.

By then, setting voltages manually, as well as compensating the background with potentiometers was outdated. Therefore, Metrohm introduced the 817 Bioscan in 2001.

The Metrohm 817 Bioscan.

It was based on the concept of Compact IC. The 817 Bioscan consisted of the amperometric detector used mainly for Pulsed Amperometric Detection (PAD) applications, a built-in column oven, the 812 Valve Unit (injector), and the 709 IC pump. This was Metrohm’s entry to the analysis of sugars.

The 791 Amperometric Detector (introduced in 1998 as the successor of the of the 641 VA Detector), was still dedicated for use as the ideal detector for applications applying DC amperometric detection.

3rd generation: Advanced Modular IC – 2003

In 2003, Metrohm introduced the «Advanced Modular IC» system, featuring the same modularity and remote control concept as the previous «Modular IC», but with improved capabilities added to the individual modules. Both the data acquisition and remote control were still managed by the IC Net software.

Around the same time period, the 811 Online IC was developed, as a more suitable instrument for the harsh environmental conditions of industrial production processes. Weighing in at approximately 450 kg, this heavyweight was built with a top-of-the-line Metrohm modular IC system and was controlled by IC Net software, coming in two versions: single channel as well as a dual channel version to measure both anions and cations. This process analyzer was combined with a modular wet part setup, which allowed the use of various modules (e.g., 10-way sampling valve or tubing pump), so the IC could be fully customized to meet customer requirements for any application.

The 811 Online IC (2001) and its successor, the 821 Compact Online IC (2002).

Due to the success of the 811 Online IC, in 2002 a smaller version was introduced: the 821 Compact Online IC. It was commonly referred to as the «little brother» due to its lighter weight and reduced size.

In 2005, the 861 Advanced Compact IC was introduced to the laboratory world, and in the same year the 844 UV/VIS Compact IC was placed on the market. This was both the first Metrohm UV/VIS IC as well as the first all-in-one UV/VIS ion chromatograph. It was dedicated to direct as well as post-column reaction applications with photometric detection. The 844 UV/VIS Compact IC was complementary to the Bischoff Lambda 1010, used in modular systems as an optional optical detector.

The Metrohm 844 UV/VIS Compact IC (front view).
The Metrohm 844 UV/VIS Compact IC (inside view).

What’s next?

In Part 3, I will continue into the later 2000s and beyond, covering the evolution of sequential suppression (the combination of chemical suppression and CO2 suppression) in addition to the 4th and 5th generations of Metrohm ion chromatography.

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Download our free White Paper for more information about suppression

When HPLC fails: IC in food, water, and pharmaceutical analysis

Reference

[1] Small, H.; Stevens, T.S.; W.C. Baumann. Novel ion exchange chromatographic method using conductimetric detection. Anal. Chem. 1975, 47 (11), 1801–1809. https://doi.org/10.1021/ac60361a017

Post written by Dr. Markus Läubli, Manager Marketing Support IC at Metrohm International Headquarters, Herisau, Switzerland.

Making a better beer with chemistry

Making a better beer with chemistry

Lager or ale? Pale ale or stout? Specialty beer, or basic draft? This week, to celebrate the International Beer Day on Friday, August 7th, I have chosen to write about a subject near and dear to me: how to make a better beer! Like many others, at the beginning of my adult life, I enjoyed the beverage without giving much thought to the vast array of styles and how they differed, beyond the obvious visual and gustatory senses. However, as a chemist with many chemist friends, I was introduced at several points to the world of homebrewing. Eventually, I succumbed.

Back in 2014, my husband and I bought all of the accessories to brew 25 liters (~6.5 gallons) of our own beer at a time. The entire process is controlled by us, from designing a recipe and milling the grains to sanitizing and bottling the finished product. We enjoy being able to develop the exact bitterness, sweetness, mouthfeel, and alcohol content for each batch we brew.

Over the years we have become more serious about this hobby by optimizing the procedure and making various improvements to the setup – including building our own temperature-controlled fermentation fridge managed by software. However, without an automated system, we occasionally run into issues with reproducibility between batches when using the same recipe. This is an issue that every brewer can relate to, no matter the size of their operation.

Working for Metrohm since 2013 has allowed me to have access to different analytical instrumentation in order to check certain quality attributes (e.g., strike water composition, mash pH, bitterness). However, Metrohm can provide much more to those working in the brewing industry. Keep reading to discover how we have improved analysis at the largest brewery in Switzerland.

Are you looking for applications in alcoholic beverages? Check out this selection of FREE Application Notes from Metrohm:

Lagers vs. Ales

There are two primary classes of beer: lagers and ales. The major contrast between the two is the type of yeast used for the fermentation process. Lagers must be fermented at colder temperatures, which lends crisp flavors and low ester formation. However, colder processes take longer, and so fermentation steps can last for some months. Ales have a much more sweet and fruity palate of flavors and are much easier to create than lagers, as the fermentation takes place at warmer temperatures and happens at a much faster rate.

Comparison between the fermentation of lagers and ales.

Diving a bit deeper, there are several styles of beer, from light pilsners and pale ales to porters and black imperial stouts. The variety of colors and flavors depend mostly on the grains used during the mash, which is the initial process of soaking the milled grains at a specific temperature (or range) to modify the starches and sugars for the yeast to be able to digest. The strain of yeast also contributes to the final flavor, whether it is dry, fruity, or even sour. Taking good care of the yeast is one of the most important parts of creating a great tasting beer.

Brewing terminology

  • Malting: process of germinating and kilning barley to produce usable sugars in the grain
  • Milling: act of grinding the grains to increase surface area and optimize extraction of sugars
  • Mashing: releasing malt sugars by soaking the milled grains in (hot) water, providing wort
  • Wort: the solution of extracted grain sugars
  • Lautering: process of clarifying wort after mashing
  • Sparging: rinsing the used grains to extract the last amount of malt sugars
  • Boiling: clarified wort is boiled, accomplishing sterilization (hops are added in this step)
  • Cooling: wort must be cooled well below body temperature (37 °C) as quickly as possible to avoid infection
  • Pitching: prepared yeast (dry or slurry) is added to the cooled brewed wort, oxygen is introduced
  • Fermenting: the process whereby yeast consumes simple sugars and excretes ethanol and CO2 as major products

Ingredients for a proper beer

These days, beer can contain several different ingredients and still adhere to a style. Barley, oats, wheat, rye, fruit, honey, spices, hops, yeast, water, and more are all components of our contemporary beer culture. However, in Bavaria during the 1500’s, the rules were much more strict. A purity law known as the Reinheitsgebot (1516) stated that beer must only be produced with water, barley, and hops. Any other adjuncts were not allowed, which meant that other grains such as rye and wheat were forbidden to be used in the brewing process. We all know how seriously the Germans take their beer – you only need to visit the Oktoberfest once to understand!

Determination of the bitterness compounds in hops, known as «alpha acids», can be easily determined with Metrohm instrumentation. Check out our brochure for more information:

You may have noticed that yeast was not one of the few ingredients mentioned in the purity law, however it was still essential for the brewing process. The yeast was just harvested at the end of each batch and added into the next, and its propagation from the fermentation process always ensured there was enough at the end each time. Ensuring the health of the yeast is integral to fermentation and the quality of the final product. With proper nutrients, oxygen levels, stable temperatures, and a supply of simple digestible sugars, alcohol contents up to 25% (and even beyond) can be achieved with some yeast strains without distillation (through heating or freezing, as for eisbocks).

Improved quality with analytical testing

Good beers do not make themselves. For larger brewing operations, which rely on consistency in quality and flavor between large batch volumes as well as across different countries, comprehensive analytical testing is the key to success.

Metrohm is well-equipped for this task, offering many solutions for breweries large and small.

Don’t take it from me – listen to one of our customers, Jules Wyss, manager of the Quality Assurance laboratory at Feldschlösschen brewery, the largest brewery in Switzerland.

«I have decided to go with Metrohm, because they are the only ones who are up to such a job at all. They share with us their huge know-how.

I can’t think of any other supplier who would have been able to help me in the same way

Jules Wyss

Manager Quality Assurance Laboratory, Feldschlösschen Getränke AG

Previous solutions failed

For a long time, Jules determined the quality parameters in his beer samples using separate analysis systems: a titrator, HPLC system, alcohol measuring device, and a density meter. These separate measurements involved a huge amount of work: not only the analyses themselves, but also the documentation and archiving of the results all had to be handled separately. Furthermore, Jules often had to contend with unreliable results – depending on the measurement procedure, he had to analyze one sample up to three times in order to obtain an accurate result.

A tailor-made system for Feldschlösschen

Jules’ close collaboration with Metrohm has produced a system that takes care of the majority of the necessary measurements. According to Jules, the system can determine around 90% of the parameters he needs to measure. Jules’ new analysis system combines various analysis techniques: ion chromatography and titration from Metrohm as well as alcohol, density, and color measurement from another manufacturer. They are all controlled by the tiamo titration software. This means that bitterness, citric acid, pH value, alcohol content, density, and color can all be determined by executing a single method in tiamo.

Measurement of the overall water quality as well as downstream analysis of the sanitization process on the bottling line is also possible with Metrohm’s line of Process Analysis instrumentation.

Integrated analytical systems with automated capabilities allow for a «plug and play» determination of a variety of quality parameters for QA/QC analysts in the brewing industry. Sample analysis is streamlined and simplified, and throughput is increased via the automation of time-consuming preparative and data collection steps, which also reduces the chance of human error.

Something to celebrate: The Metrohm 6-pack (2018)

In 2018, Metrohm celebrated its 75 year Jubilee. At this time, I decided to combine my experience as a laboratory analyst as well as a marketing manager to brew a series of six different styles of beer for the company, as a giveaway for customers of our Metrohm Process Analytics brand, for whom I worked at the time. Each batch was brewed to contain precisely 7.5% ABV (alcohol by volume), to resonate with the 75 year anniversary. The array of ales was designed to appeal to a broad audience, featuring a stout, porter, brown ale, red ale, hefeweizen, and an India pale ale (IPA). Each style requires different actions especially during the mashing process, based on the type of grains used and the desired outcome (e.g., flavor balance, mouthfeel, alcohol content).

Bespoke bottle caps featuring the Metrohm logo.
The 6 styles of beers brewed as a special customer giveaway to celebrate the Metrohm 75 year Jubilee.

Using a Metrohm Ion Chromatograph, I analyzed my home tap water for concentrations of major cations and anions to ensure no extra salts were needed to adjust it prior to mashing. After some of the beers were prepared, I tested my colleagues at Metrohm International Headquarters in the IC department, to see if they could determine the difference between two bottles with different ingredients:

Overlaid chromatograms from IC organic acid analysis highlighting the differences between 2 styles of the Metrohm 75 year Jubilee beers.

The IC analysis of organic acids and anions showed a clear difference between the beers, allowing them to determine which sample corresponded to which style, since I did not label them prior to shipping the bottles for analysis. As the milk stout contained added lactose, this peak was very pronounced and a perfect indicator to use.

Metrohm ion chromatography, along with titration, NIRS, and other techniques, allows for reliable, comprehensive beer analysis for all.

In conclusion, I wish you a very happy International Beer Day this Friday. Hopefully this article has illuminated the various ways that beer and other alcoholic beverages can be analytically tested for quality control parameters and more  fast, easy, and reliably with Metrohm instrumentation.

For more information about the beer quality parameters measured at Feldschlösschen brewery, take a look at our article: «In the kingdom of beer The largest brewery in Switzerland gets a made-to-measure system». Cheers!

Read the full article:

«In the kingdom of beer – The largest brewery in Switzerland gets a made-to-measure system»

Post written by Dr. Alyson Lanciki, Scientific Editor (and «chief brewing officer») at Metrohm International Headquarters, Herisau, Switzerland.

History of Metrohm IC – Part 1

History of Metrohm IC – Part 1

Ion chromatography (IC) has been a part of the Metrohm portfolio of analytical chemical instrumentation since 1987, and in that span of 33 years, several new and exciting developments have been introduced challenging the limits of what IC can do. From simple setups for academic laboratories, to hyphenated techniques (e.g., IC-ICP-MS) broadening the capabilities of chemical analysis – we’ve done it! This week, I would like to begin to unveil the history of this analytical method at Metrohm and how it has changed over the intervening decades.

«The mid-1980‘s. Our mission: develop an affordable ion chromatograph with a minimal footprint, simple to use, providing outstanding measurements.»

Walter Terzer, R&D Ion Chromatography, Metrohm AG

«The 690 Ion Chromatograph was engineered for people without a PhD in chemistry, too. And it was so rugged that quite a few 690 IC’s are used even today. Most importantly: At the time, it cost only half as much as our competitor’s product!»

Dr. Markus Läubli, R&D Ion Chromatography, Metrohm AG

The beginning: 1980’s

Ion chromatography was added to the Metrohm portfolio in 1987, broadening our span of techniques, which at the time only included titration, meters, voltammetry, and the Rancimat. IC, already a couple of years on the market, was seen on one hand as a very interesting method, but on the other hand also as a very complex and expensive technology.

The increasing viability of IC for previously typical titration applications guided Metrohm to focus on this method.

The Metrohm 636 Titroprocessor.

Development of the conductivity detector

Conductivity is the most common detection technique used with ion chromatography. Conductivity is the inherent sum parameter of all ions in aqueous solution. As ion chromatography is performed using aqueous solutions such as eluents (i.e. the mobile phase) and samples, conductivity is the essential detection mode.

You can see how this is measured in the video below. Other detection techniques can be used as well, but typically are applicable only in special cases.

The modernized, compact, and intelligent Metrohm IC Conductivity Detector.

In the early 1980s, the method of IC began to compete for market share with titration. Based on positive experiences with the amperometric detector (641 VA Detector, introduced in 1980, and originally sold as an HPLC detector) and Metrohm’s competence in conductivity measurement, this led to the idea to develop a conductivity detector in a similar manner. A prerequisite for the project was the availability of separation columns (stationary phase) which allowed analysts to reach detection limits of 1 mg/L (or lower) of the standard anions.

The Metrohm 641 VA Detector.

In 1984, a test was run on an initial setup consisting of a single-piston HPLC pump, a 6-port injector, commercially available IC separation columns, a conductivity detector, and a chart recorder (586 Labograph). This test proved that the 1 mg/L limit could be reached, and thus the project of developing an official Metrohm conductivity detector began.

At that time, chemical suppression introduced by Small, Stevens, and Baumann [1] was patented and not available. However, non-suppressed conductivity detection described by Gjerde, Schmuckler, and Fritz [2] was seen as a viable alternative. When measurement of low concentrations of ions in solution was necessary, the very small chromatographic peaks plus the high conductivity background from the mobile phase (eluent) created a challenge, and special requirements for the conductivity detector had to be taken into account. The most critical of these was the temperature coefficient of the conductivity, which is typically around 2%/°C. This requires maintaining an extremely stable temperature during the measurement.

During the initial development phase it was found that, aside from bulk measurement, platinum was not the best material for electrodes in a flow-through cell. However, stainless steel worked perfectly. The measuring cell still needed to be insulated, however, insulation alone was not sufficient. Active thermostating was required to achieve a temperature stability of better than 0.01 °C. That stability was measured with a thermocouple, and recorded on the Labograph. Later on, with more sophisticated tools the stability was determined to be better than 0.001 °C.

Even after all of this hard work, the initial system baseline stability was still not good enough. As it turned out, several components of the IC system needed to be thermally stabilized. Additionally, the different brand of HPLC pump was not optimal for the development of the Metrohm ion chromatograph.

The Metrohm 690 Ion Chromatograph.

The first decision was to put the conductivity detector project to the side, and start building an ion chromatograph. Thus, the first Metrohm IC (the 690 Ion Chromatograph) was developed. The 690 IC consisted of: a foam polymer housing for perfect thermal insulation, the electronic and detector block, as well as a pulse dampener, a sample injector, and separation column. All capillary connections consisted of HPLC capillaries at the time (made from stainless steel). The inadequate HPLC pump was replaced and upgraded with a Metrohm IC Pump, and the Labograph was almost immediately followed by an integrator, which completed the IC system.

Despite the general consensus in the 1980s that ion chromatography was only robust while using metal-free instruments, Metrohm was able to run anion, cation, and ion-exclusion chromatography on stainless steel-based systems. Even determinations of heavy metals were performed without issues.

Conductivity detection with «electronic suppression»

A drawback of non-suppressed IC is the relatively high inherent baseline noise, due to high conductivity levels from the mobile phase. Parameters which add to this baseline noise include temperature induced fluctuations, pump noise, and electronic noise.

The temperature influence on baseline noise was minimized thanks to the near perfect thermal stabilization of the detector. The quality of the high pressure pump is important to stabilize the baseline, however, under standard running conditions it does not add much to the baseline noise. Finally, after optimizing these points, it was clear that the electronic noise was the most important parameter on which to focus. Each electronic component influences temperature fluctuations and also adds some amount of noise.

Internal view of the Metrohm 690 IC. The conductivity detector is highlighted.

The thermostated detector block consisted of an aluminum block for thermostating, a built-in measuring cell, and an electronic preamplifier. This preamplifier guaranteed that the measured analog conductivity signal was insensitive to external fields when guided to the main electronics.

Auto Zero function for background compensation purposes during measurement.

The Auto Zero function measured the actual conductivity at initialization of the function and was subtracted from the signal throughout the chromatogram. This can be called background compensation. The «electronic suppression» designation is given due to an electronic setup which additionally reduced the electronic noise. The idea behind this is as simple as it was effective. The electronics were set to measure the actual conductivity signal as well as the measured background conductivity through two parallel paths with identical electronic components. Subtraction of the two signals was done just prior to the output to the external A/D converter. Under an assumption that the same components should add the same noise and exhibit similar thermal behavior, both signals are influenced in the same manner. Therefore, the noise level was minimized even further.

Additionally, the apparent noise level was improved using the optimal output window (called «Full-scale») in units of [µS/cm]. The Metrohm Application Note AN-C-032 describes this effect. At that time, this noise level of approximately 2 nS/cm was similar to or better than analyses performed with chemical suppression.

Separation column developments

At market launch in late 1987, Metrohm offered a total of six IC separation columns: two suitable for anions, one for monovalent cations, one for divalent cations, and one for organic acids (ion-exclusion). At that time, the group of Prof. Dr. Schomburg (Institut für Kohlenforschung, Mühlheim/Ruhr, DE) studied the preparation of HPLC phases by coating polymer materials on to e.g. silica. One of the phases used was poly(butadiene/maleic acid) on a silica material, which was found to be able to separate mono- and divalent cations in a single isocratic run. Metrohm acquired the technology and started column production in Herisau, Switzerland.

The so-called «Schomburg column» or later «Super-Sep Cation column» was the very first column on the market allowing the simultaneous separation of alkali and alkaline earth metal cations. Even the current Metrosep C 4 and Metrosep C 6 columns’ roots date back to the Schomburg column.

Data handling capabilities

In the first months on the market, only the Labograph (a chart recorder) was available for the new IC. This was of course not really acceptable. Nevertheless, results achieved by cutting out and physically weighing the peaks were quite correct. The first integrator (Shimadzu C-R5A) was a tabletop integrator with LCD display (2 lines), storage capabilities (2 chromatograms in the instrument, and 5 chromatograms per external card), and a thermo-printer for documentation.

Top: Metrohm 690 Ion Chromatograph with Labograph on the left, and separation columns in the foreground.
Bottom: Metrohm 690 Ion Chromatograph with the Shimadzu C-R5A tabletop integrator on the left.

In 1991, the first PC-based data acquisition and handling software (714 IC-Metrodata) was developed, consisting of a data acquisition box and the DOS-based integration software. Five years later in 1996, the software of the 714 IC-Metrodata was updated to a Windows version. Then in 2000, the new IC Net software was released together with the 762 IC Interface and 771 IC Compact interface for both data acquisition and remote control capabilities.

The 690 IC featuring the 714 IC-Metrodata, ushering scientists into a new era of peak integration possibilities.

What’s next?

Stay tuned for the next installment in this series, covering the 1990s and early 2000s. During this time, Metrohm developed modular IC, the Metrohm Suppressor Module (MSM), as well as some outstanding separation columns. Subscribe to the blog below so you don’t miss out!

Download our free Monograph for more information

Practical Ion Chromatography – An Introduction

References

[1] Small, H.; Stevens, T.S.; W.C. Baumann. Novel ion exchange chromatographic method using conductimetric detection. Anal. Chem. 1975, 47 (11), 1801–1809. https://doi.org/10.1021/ac60361a017

[2]  Gjerde, D. T.; Fritz, J. S.; Schmuckler, G. Anion Chromatography with Low-Conductivity Eluents. J. Chromatogr. A 1979, 186, 509–519. https://doi.org/10.1016/S0021-9673(00)95271-3

Post written by Dr. Markus Läubli, Manager Marketing Support IC at Metrohm International Headquarters, Herisau, Switzerland.