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Fresh shrimp – made in Switzerland?

Fresh shrimp – made in Switzerland?

Shrimp from Rheinfelden

SwissShrimp AG, based in Rheinfelden, Switzerland, is the largest producer of shrimp in Europe. Michael Siragusa, a chemist and Technical Operations Manager, introduced us to the company during a visit and explained why a fully automatic IC system from Metrohm plays the main role in monitoring water quality in the breeding pools.

SwissShrimp, which are locally grown without antibiotics, shown in the packaging available in some grocery stores in Switzerland.

An ideal location

Shrimp farms are usually associated with tropical fields, especially in Southeast Asia. Often, one also thinks of the dubious reputation these farms have due to their large ecological footprint. The SwissShrimp project in Rheinfelden shows that shrimp can also be produced on a large scale in Switzerland without exhausting nature and entirely without the use of antibiotics. According to Plant Manager Michael Siragusa, many individual factors are decisive for the success of the project. One of the most important of these is that SwissShrimp AG, at its Rheinfelden site, can cover a large part of the enormous power requirements for heating the breeding pools, at very favorable conditions, using heat from the nearby Swiss Salinen AG (Swiss Salt Works).

Inconspicuous: SwissShrimp produces its shrimp in this hall located in the middle of a green meadow.
The Swiss saltworks evaporate brine for salt production. Its waste heat supplies a large part of the energy for heating SwissShrimpʹs breeding pools.

Large technical effort

There is a tropical climate in the companyʹs large, inconspicuous hall: Shrimp of the species Litopenaeus vannamei (Pacific white shrimp) are raised in a total of 16 pools, each measuring 40 x 5 x 0.50 meters, on two floors. At a constant water temperature of 28 degrees Celsius, these pools each have up to 200,000 shrimp, with the animals in one pool all at roughly the same stage of development. SwissShrimp sources the larvae from special, certified breeders in Europe or the USA. It takes around six months before shrimp of up to 14 cm in length have developed from tiny larvae, which are barely two millimeters in size.

Densely stocked: Each of the 16 pools holds up to 200,000 shrimp.

Until the shrimp grow to full size, they are fed automatically with a special, organic dry feed. The grain size and composition of this feed varies depending on the stage of development. The dense stocking of the pools means that cleaning the water requires a great deal of effort. In a total of eight water circuits, the entire volume in the breeding pools is cleaned mechanically, biologically, and chemically 20 times a day using the latest filter technology; three percent of this volume is replaced daily. 

Waste recycling: The feed for the shrimp is mainly made from fish waste. The composition and grain size is precisely matched to the different development stages of the shrimp.

An IC system from Metrohm controls the water quality

«Water treatment is essential for us. We purify the water in our pools about 20 times per day.

In order to allow the shrimp to grow and keep the biological equilibrium of the plant, we have to keep a close eye on the toxic parameters… ammonium, nitrite, and nitrate.

If we performed this monitoring by an alternative method…, the 10 to 20 determinations would take the whole day, every day

Michael Siragusa

Technical Operations Manager, SwissShrimp AG

When it comes to monitoring the water quality in the breeding pools, a fully automated IC system from Metrohm comes into play: In the SwissShrimp company laboratory, the water of each of the 8 water circuits is examined daily for concentrations of toxic pollutants such as nitrite, nitrate, and ammonium, which are introduced into the water by the excretions of the shrimp.

Download our free Application Notes below to learn more about ion chromatography and the analysis of nitrite, nitrate, and phosphate in seawater from a shrimp farm.

In the company laboratory: The water quality is monitored fully automatically with a 930 Compact IC Flex, 940 Professional IC Vario, and 858 Professional Sample Processor. In order for the shrimp to thrive, it is important to detect any deteriorations in water quality at an early stage so that corrective measures can be initiated in good time. Altogether, around 2000 multi-parameter analyses are carried out annually at this measuring station.

On the other hand, saltwater parameters important for the shrimp to thrive are measured. These include chloride, sodium, magnesium, calcium, and potassium. Given the sheer number of parameters that need to be monitored, the advantage of ion chromatography comes into effect: IC is a multi-parameter method, i.e. several different parameters can be determined with a single measurement. In addition, not only does the analysis run automatically, but sample preparation with the inline ultrafiltration and dilution steps is also integrated into this process. In fact, SwissShrimp does not need a full laboratory assistant position thanks to Metrohmʹs automated analysis system.

Learn more here about Metrohm Inline Sample Preparation (MISP) for difficult sample matrices:

In the profit zone starting this year

The operation in Rheinfelden did not begin until 2018, and SwissShrimp is not yet operating profitably. However, production is expected to increase to 60 tons annually by the end of 2021. This is when the project, costing 25 million francs, would generate a profit for the first time. The company is currently investing in marketing in order to achieve this goal, because it is not yet well known that the best shrimp to be purchased in Switzerland come from Rheinfelden.

No frozen goods

Shrimp from Rheinfelden are a delicacy and are marketed as such, but only in Switzerland so far. Around 70 to 80 kilograms of shrimp currently leave the company every day, delivered only on order. The fresh shrimp are delivered directly to end customers and select markets of the two major Swiss retailers, Migros and Coop, via Priority Mail within 24 hours in special transport boxes specially developed for SwissShrimp with integrated Peltier cooling elements. On-site collection by the customer after ordering is also possible.

Fresh shrimp, grown daily on the northern border of Switzerland.

To learn more about the production of shrimp in Rheinfelden, visit the SwissShrimp website.

Further free Application Notes for the analysis of several ions in seawater via ion chromatography can be found on the Metrohm website.

Visit our website

to learn more about how automated IC analysis can help save valuable time in your lab

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

Exposing secrets of ancient Greek civilization through chemistry

Exposing secrets of ancient Greek civilization through chemistry

This week, learn the story of how analytical instrumentation from Metrohm helps underwater archaeology locate hidden treasures beneath the seafloor.

 

Antikythera Mechanism: a machine lost to time

One of the most fascinating items ever salvaged from an ancient shipwreck is the so-called «Antikythera Mechanism». More than 2000 years old, this magnificent piece of mechanical engineering forced the scientific community to rewrite the history of science as it became clear that its unknown maker must have possessed knowledge and skills that were believed to simply not exist in the 1st century BC.

Figure 1. Digital reconstruction of the Antikythera Mechanism.

The Antikythera Mechanism was a complex and highly precise lunar and solar calendar that could also predict solar and lunar eclipses as well as the future dates of the Panhellenic Games. The complexity and precision of this machine inspired not only scientists but also Hublot, the Swiss brand famous for their luxury watches. Not only did Hublot recreate the Antikythera Mechanism in a wristwatch but they also started their own underwater archaeology program. This project of Hublot is fascinating—and we from Metrohm are part of it on every dive.

 The device was retrieved from an ancient shipwreck (70 BC) found off the coast of the Greek island of Antikythera in 1901. Since then, researchers have tried to get to the bottom of its mysteries. Dated to approximately 100 BC, the Antikythera Mechanism was a shockingly complex piece of machinery, the likes of which were not seen elsewhere for at least another millennium.

One of the challenges faced by underwater archeology is the fact that the cargo and debris of ancient shipwrecks is often randomly scattered across vast areas on the seafloor and also often covered by sediments. Because only fragments of the mechanism have been found and recovered, retrieving the missing pieces of the Antikythera Mechanism would be a scientific sensation.

Figure 2. Location where the Antikythera Mechanism was found in 1901 at a shipwreck in Greece.

As divers can only operate for very limited time spans at depths below 50 meters, drones are needed to investigate larger areas on the seafloor at such depths. Hublot’s engineers have built drones for this purpose, known as «Bubblots», and have equipped them with miniaturized voltammetric measuring stands from Metrohm.

«With a metal detector, all you get is «beep-beep-beep», which means there is metal around. However, in a bronze statue, there is copper, there is tin, and you have to detect the oxides of them, the exact kind of material you are facing. We have decided for Metrohm, because you are the most competent for the measuring technology we need in our drones.»

Mathias Buttet

R&D Director, Hublot

The Bubblots are utilized to perform real-time analyses of the seawater for unusual concentrations of dissolved metal salts typically associated with corroding bronze artefacts. Thus, the systematic and highly selective investigation of larger areas of seafloor for historical bronze artefacts becomes feasible.

Figure 3. Hublot’s underwater drones, known as «Bubblots», and the voltammetric measuring stand from Metrohm.

Voltammetry to the rescue

Due to its selectivity regarding different metals and their oxidation states, voltammetry is ideally suited for such investigations, as it is also very fast and robust technique. In the case of Hublot’s drones, results are obtained in a few seconds and this information can be immediately processed.

«We use this Metrohm instrument for voltammetric measurements. We take a water sample and do a live measurement of the aspirated water. The voltammetric measurement takes only a few seconds. This is enough to give us an idea of the different metals present in the solution. This allows us to do highly selective measurements very fast to cover different regions of the archaeological site.»

Sébastien Recalcati

Materials Engineer, Hublot

For a selection of free Metrohm Application Notes related to voltammetric measurements in seawater, visit our website!

Figure 4. The 910 PSTAT mini from Metrohm used in the study.
Figure 5. One of Metrohm’s disposable screen printed electrodes (SPEs) utilized in Hublot’s drone analysis of the seafloor.

Giving the Antikythera Mechanism a second life

The maker of this mechanism was far ahead of his time. He must have had skills and possessed scientific knowledge that are mind-boggling even today. The watchmakers from Hublot were inspired by this to a very special project: they rebuilt the Antikythera Mechanism in a wristwatch.

«The original Antikythera Mechanism has the size of a shoe box. Reducing the size of the mechanism and putting it into a wrist watch was not so easy. Because the Antikythera Mechanism was not a clock, it was a machine with a driving crank to show the position of the moon and the sun in relation to the stars at any given date. The absolute dream is to find the missing parts of the machine. But the debris is hidden below the seafloor, covered by sediments, one meter, sometimes two meters.»

Mathias Buttet

R&D Director, Hublot

Figure 6. The Antikythera Mechanism miniaturized and captured in a Hublot wristwatch.

We are glad to support Hublot’s archaeological mission with our analytical instruments and our expertise in chemical analysis. Metrohm wishes the Hublot team all the best.

Visit our website to learn more

about this fascinating project and to discover more related applications from Metrohm

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

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.

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.

Subscribe to the blog below so you don’t miss out!

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.

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.

Upgrade your lab skills online

Upgrade your lab skills online

At the moment, times are strange, as many people are kept home to keep each other safe and healthy. Some of you are still able to work in your office or laboratories, but others are trying to find constructive ways to keep focused and stay connected.

During this time, one way to keep your skills sharp, or even to learn new ones, is by watching informative webinars. Level up in your laboratory expertise!

Below, we have a selection of some excellent free webinars from Metrohm to keep you on top of your game – no matter which technique you use. Application examples, practical information on handling, care, and troubleshooting, and more – our webinars provide very useful information dealing with various techniques and industries.

We offer several on-demand webinars about subjects such as the fundamentals of titration, troubleshooting, and the synergy between titration and near-infrared spectroscopy (also see our related blog post on this topic).

This important segment of titration is especially important for accurate moisture determinations.

On-demand webinars available include fundamentals and troubleshooting, as well as others for more in-depth knowledge.

NIRS is a fast, nondestructive, reagent-free technique, used in several markets (e.g., pharmaceuticals, petrochemicals, polymers, and personal care).

We have many interesting webinars not only focused on these industries, but also for quality control, process analytical technology (PAT),  and about the combination with the primary method of titration (also see our related blog post on this topic).

Raman spectroscopy is a handy tool for quick, reagent-free identification of raw materials, illicit substances, and hazardous chemicals – even from a distance.

Watch this webinar to learn how accurate, reliable, and portable screening tools can help to detect substandard and falsified medical products.

Aside from providing information about how Metrohm ion chromatography (IC) can be used for multiple applications in different markets, we also offer free webinars about sample preparation and automatic calibration to help save you valuable time when you’re back in the lab!

The measurement of pH is one of the most commonly performed determinations in chemical analysis. Why not learn some of the basics, or perhaps some troubleshooting techniques with our free webinars to impress your colleagues? If you are looking to avoid the most common mistakes in pH measurement, be sure to check out our blog post as well.

Our electrochemistry webinars cover a variety of topics to enhance your knowledge in this area. From corrosion analysis to electrocatalysis research, we have you covered.

If you’re more interested in screen-printed electrodes (SPEs) and biosensing applications, we have something for you, too!

I hope you find these webinars informative. If you’re interested in further educational opportunities from Metrohm, check out the Metrohm Academy. Stay safe, stay healthy, and always keep learning!

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