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To automate or not to automate? Advantages of PAT: Part 1

To automate or not to automate? Advantages of PAT: Part 1

I have to admit that the technological world of process analysis seemed foreign for me for a while. When I first heard about process automation, I imagined futuristic robots that do the work, similar to modern science fiction films. Perhaps many people might have the same impression.

There is often a great deal of uncertainty about what the expression «we automate your process» actually means. In this blog series, I want to show you that process analytical technology (PAT) is less complicated than expected and offers several advantages for users.

What does process analytical technology (PAT) mean? 

I was once told in conversation:

«Process analytics is for everyone who believes that they don’t need it.»

There is definitely truth in this statement, and it certainly shows the abundance of application possibilities. At the same time, it should be considered that in the future, users of process analytical technology will not only invest in conventional measurement technologies (e.g., direct measurement, TDLAS, GC), but also increasingly in the determination of substance properties and material compositions.

Pollution (gases and aerosols) in ambient air are especially harmful to human health. These substances can continuously and reliably be monitored by process analyzers.

PAT serves to analyze, optimize, and ultimately control processes and their critical parameters. This control makes a major contribution to quality assurance and the overall process reliability at the manufacturer. Thinking back to some well-known chemical disasters (e.g. Minamata, Toulouse, or Tianjin) in which poisonous substances were released, causing immense damage to people and the environment, the importance regarding regular monitoring of critical parameters becomes abundantly clear. The list of analytes that can and must be monitored is long, ranging from contamination in wastewater due to municipal or industrial wastewater treatment plants, to pharmaceutical agents, to gases and aerosols in the ambient air.

From Lab to Process

Considering the history of manufacturing and other industrial processes, it is clear that the ultimate goal is to increase throughput in ever-shorter timeframes, with an eye on safety measures and minimization of costs where possible. Independence through automation and fast, reliable data transfer is a high priority.

In order to make the process economically viable along the entire value chain, the resulting products should be manufactured at the highest quality in a short time and with minimal raw material and energy usage. For 24/7 operations in particular, knowledge of the composition of the starting materials and intermediate products (or rather, any impurities) is essential for optimal process control and reliability.

How can reliable process monitoring be ensured around the clock? Very few companies have company laboratories with an actual 3-shift operation, and often send their samples to external laboratories. Additionally, the samples are sometimes taken with longer time intervals between them. This carries various risks.

On one hand, the time lost between the sampling event and receiving the results from the analysis is enormous. It is only possible to react to fluctuations and deviations from target concentrations or limit values ​​with a certain delay. On the other hand, working and environmental conditions are not comparable and can lead to changes in the sample. Oxidation, pressure or temperature changes, introduction of moisture, and many other factors can change a sample’s original properties during transport, waiting periods, and manual laboratory analysis.

Example trend graph comparing process deviations mitigated by manual control (grey) and fully automatic process control (orange) via PAT.

Process analyzers: automated operation around the clock

Analyses, which are usually carried out manually, are automated by using industrial process analyzers. The samples are automatically removed from critical points in the production process and processed further. The information obtained is used to control the process without any delay, as the data can be transferred immediately to a central computing system at the plant. Automated analysis right at the sample point allows for increased accuracy and reproducibility of the data.

In practice, this entails rerouting a partial stream from the process in question to be fed to the analyzer by means of valves, peristaltic pumps, or bypass lines. Each sample is therefore fresh and correlates to the current process conditions. Probes can also be integrated directly into the process for continuous inline measurement.

The analysis is performed using common titration, spectroscopy, ion chromatography, or electrochemical methods known from the laboratory, which are optimally integrated into the process analyzer for each individual application requirement. The methods can be used in combination, allowing several measuring points to be monitored in parallel with one system. Thanks to the process analyzers that are specifically configured and expandable for the application, the optimal conditions for stable process control are obtained.

Spectroscopic methods have become particularly well-established in recent years for process analysis and optimization purposes. In contrast to conventional analysis methods, near-infrared (NIR) spectroscopy shows a number of advantages, especially due to the analysis speed. Results can be acquired within a few seconds and transferred directly to the chemical control system so that production processes can be optimized quickly and reliably. Samples are analyzed in situ, completely without the use of chemicals, in a non-destructive manner, which means further added value for process safety.

The many advantages of PAT

Automation in the context of process analysis technology does not always have anything to do with futuristic robots. Instead, PAT offers companies a number of advantages:

 

  • Fully automatic, 24/7 monitoring of the process
  • Timely and automatic feedback of the analysis results to the system control for automatic process readjustment
  • Reduction in fluctuations of product quality
  • Increased process understanding to run production more efficiently
  • Independent of your own laboratory (or contract lab)
  • Complete digital traceability of analysis results
  • Total solution concepts including sample preconditioning, saving time and increasing safety

What’s next?

In our next post in this series, you will discover the role process analysis technology plays in digital transformation with regard to «Industry 4.0».

Want to learn more about the history of process analysis technology at Metrohm? Check out our previous blog post:

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), with contributions from Dr. Alyson Lanciki, Scientific Editor at Metrohm International Headquarters (Switzerland).

Tips and Tricks for IC Columns

Tips and Tricks for IC Columns

Monitoring and maintaining column performance

One of the basic requirements for ensuring reliable chromatographic analyses is a high-performance separation column. Ion chromatography (IC) users should regularly check the performance of their column. This way, if a drop in performance becomes apparent, steps can be taken in good time to restore or maintain the proper functioning of the column, reducing downtimes in sample throughput. In this blog post, we explain how you can assess column performance, which parameters you should monitor, and which measures you can take to ensure excellent column performance.

 

First-time use of a new separation column

When you use a column for the very first time, we recommend that you check its initial performance. The Certificate of Analysis (CoA), which you receive with every purchase of a Metrohm column, is your source of reference here. Record a chromatogram and use the analysis conditions specified in the CoA: these include flow rate, temperature, eluent (mobile phase), analyte concentration, sample loop size, and suppression.

You can evaluate the column’s performance by comparing some of the result parameters with the values listed in the CoA (e.g. retention time, theoretical plates, asymmetry, resolution, and peak height).

Regular monitoring of column performance

Columns that are already in use should be monitored regularly, too! We recommend carrying out these tests with check standards under the application conditions you normally use, because performance varies depending on the type of analysis and associated analysis conditions as well as the instrumental setup. If a reduction in performance is observed, the requirements of the application are crucial to determine whether it can still be used.

Below, we explain how to determine your column performance based on five performance indicators. You will also find out how you can prevent or rectify a decline in performance.

Click to jump directly to a topic:

 

Backpressure

Monitor the backpressure: When you use your new column for the first time, save the backpressure value under the analysis conditions of your application as a reference («common variable» in MagIC Net). Then use the user-defined results to monitor the difference between the initial backpressure and the one displayed during the current determination.

If you identify an increase in the backpressure in comparison with the saved initial value, this indicates that particles have been deposited in either the guard column or separation column. If the measured increase is greater than 1 MPa, action must be taken. First, you should check which of the columns is affected (guard vs. separation). If the guard column is contaminated, it should be replaced, as this is its primary function. If the separation column is affected, remove it from the system, turn it around and reinstall, and then rinse it for several hours in this reversed flow direction. If this doesn’t help, we strongly recommend that you consider replacing the column. This will be essential if the maximum permitted backpressure for the column is reached.

Retention time

To track changes in the retention time (which signal a decrease in column performance), the retention time of the last analyte peak is monitored in the chromatogram. Sulfate, for example, is suitable for this, as it usually elutes right at the end of standard anion chromatograms. Here too, work with a common variable in MagIC Net to save the initial value.

Unstable retention times can be caused by carbon dioxide introduced from the ambient air or from air bubbles present in the eluent. Luckily, these problems can be resolved easily (see Table 1).

Table 1. Preventing and correcting performance loss in IC columns (click to enlarge).

The column may also have lost some capacity. This capacity loss can be caused by the presence of high-valency ions which are difficult to remove due to their strong attraction to the stationary phase. The column should then be regenerated in accordance with the column leaflet to remove any contamination. If this doesn’t lead to any improvement, then consider replacing the column depending on the requirements of the application, particularly in the event of progressive capacity loss.

Capacity loss can also occur if the functional groups are permanently detached from the stationary phase. In such a case, the column cannot be regenerated and must be replaced.

Resolution

Monitor the chromatographic resolution by comparing measurements from a predefined check standard with an initial reference value. If the resolution is R > 1.5, the signal is considered baseline-separated (see illustration below). However, in cases involving highly concentrated matrices and for peaks that are more widely spread, the resolution value must be higher to ensure baseline separation.

If a loss of resolution occurs, first make sure that it is not caused by the eluent or the IC system. Once these have been ruled out, it is possible that the adsorptive effect of contaminations in the guard column or separation column may be responsible. A contaminated guard column should be replaced. If the cause of the problem is found to be the separation column, this should be regenerated in accordance with the column leaflet to free it from any organic or inorganic contamination. If the loss of resolution progresses, a column replacement is inevitable.

Theoretical plates

Save the initial number of theoretical plates in MagIC Net as a common variable, as mentioned earlier for other parameters. Usually, the last eluting peak is used – in anion chromatograms, sulfate would yet again prove to be a suitable candidate. Theoretical plates also depend on the analyte concentration. Therefore, it is ideal to monitor this parameter during check standard measurements and not during sample measurements. You can track the development of any changes to the number of theoretical plates via the user-defined results in MagIC Net.

A decrease in the theoretical plates can suggest dead volume in the IC system (see Table 1). A low number of theoretical plates may also be observed if the column has been overloaded by a high salt concentration in the sample matrix, for instance. If the theoretical plates decrease by more than 20%, this indicates that column performance is declining. Depending on the requirements of the application, action may need to be taken.

If the guard column is the reason for the drop in performance, it should be replaced. If the problem is with the separation column, we recommend regenerating the column in accordance with the column leaflet to eliminate any organic or inorganic contamination. If this doesn’t help, you should consider replacing the column, particularly if a trend toward lower theoretical plates is observed.

Asymmetry

Determine the initial asymmetry of the analytes by measuring a predefined check standard under the analysis conditions of your application. Save it as a common variable, then track the user-defined results to observe the development of asymmetry over time. The maximum acceptable values for the asymmetry vary depending on the analyte. For example, calcium and magnesium peaks initially present relatively high asymmetry values.

Asymmetry is defined as the distance from the centerline of the peak to the descending side of the peak (B in the figure below) divided by the distance from the centerline of the peak to the ascending side of the peak (A in the figure below), where both distances are measured at 10% of the peak height. Some pharmacopoeia may use other figures – please check to be sure of the requirements in your country.

AS > 1 means a peak has tailing, and AS < 1 equates to peak fronting. Optimum chromatography is achieved with peak asymmetries as close as possible to 1. As a general rule, column performance is considered in decline when the asymmetry is AS > 2 or AS < 0.5. Depending on the requirements of the application, measures have to be taken in this case in order to improve symmetry and to enable better integration.

The reason for high asymmetry values may be down to the ion chromatograph – due to dead volume, for example. If this is not the case, it is important to find out whether the asymmetry is caused by problems with the guard column or with the separation column. If the guard column causes the asymmetry, it should be replaced. If it is the separation column, it should first be regenerated in accordance with the column leaflet to remove any organic or inorganic contamination. If this doesn’t help, you should consider replacing the column. If a trend toward higher asymmetry values can be observed, replacement is unavoidable.

In summary, there are many ways in which you can estimate the performance of the column and track concrete figures over its lifetime. Proper maintenance can extend the lifetime of the separation column, as well as always using a guard column for extra protection.

Need help choosing the right column for your application?

Look no further!

Try the Metrohm Column Finder here:

For further guidance about IC column maintenance, you can watch our tutorial videos here:

Post written by Dr. Alyson Lanciki, Scientific Editor at Metrohm International Headquarters, Herisau, Switzerland. Primary research and content contribution done by Stephanie Kappes.

Increase productivity and profitability in environmental analysis with IC

Increase productivity and profitability in environmental analysis with IC

Nearly every chemist begins his or her path under the guidance of trained professionals, learning the correct way to implement the scientific method and to handle themselves safely in the laboratory. I am no different; I obtained my doctorate in Analytical and Environmental Chemistry in 2010. Since 2003, I worked in the environmental analysis sector, investigating soil contamination due to heavy metals and chemical spills, water quality analysis, and especially performing studies relating to atmospheric chemistry. During these years, I’ve been exposed to several analytical technologies, varied laboratory sizes, and different sample preparation procedures.

A common theme runs throughout these different places—the hunt for more time and a bigger budget. However, with the right tools at your disposal, you can have your cake and eat it, too.

Environmental chemical analysis

The focus of environmental analysis lies in these three major sectors:

  • Air
  • Water
  • Soil

It is in our best interest to study these interconnected areas as thoroughly as possible, considering how our health and the future of our species heavily relates to and relies upon them.

Authorities and regulations

With that in mind, local and governmental authorities have developed and enforced several regulations for the good of public health.

One of the more well-known authorities on the subject is the United States Environmental Protection Agency (EPA). Under the Clean Air Act (enacted in 1970) and Clean Water Act (1972), as well as the requirement to report the use and disposal of toxic chemical substances (TRI reporting), several norms and standards have been developed over the intervening years to meet the stringent guidelines brought forth in these and other regulations.

In the world of water analysis, one of the most common methods you will hear about is EPA Method 300. The methods 300.0 and 300.1 give detailed instructions to chemical analysts regarding measurement of common anions (Part A) and inorganic disinfection byproducts (Part B) in water via ion chromatography.

Meet the family! The Metohm 940 Professional IC Vario TWO/SeS/PP, 930 Compact IC Flex Oven/SeS/PP/Deg, and Eco IC.

Heavier workloads = less time per sample

A growing list of aqueous contaminants and increasingly stringent regulatory requirements require labs to process more samples in less time, without sacrificing accuracy.

The nature of the samples measured in environmental laboratories is such that sample preparation is required—this always involves filtering the samples, and in many cases diluting them as well. This procedure is the only way to prevent damage to the analysis system and to achieve accurate results.

However, sample preparation is an expensive step, as it involves a significant amount work as well as costly consumables.

Time to crunch the numbers!

A 30 day study was performed on a Metrohm IC system with automatic ultrafiltration and dilution by an environmental analysis laboratory in the US. This lab, like many others, processes a high volume of samples, including some with a limited shelf life. Reliability is therefore a particularly important criterion when it comes to buying a new system.

Economic considerations also play a key role: a new system should pay for itself as quickly as possible; it needs to be generating a return on investment after a year at the latest.

So, how did we perform in the study? We tested several parameters, including:

(Click to jump directly to the relevant section.)

(Ultra)filtration

All aqueous environmental samples must be filtered prior to analysis. This prevents particles from the sample contaminating or blocking the separation column, significantly extending its lifetime. The high volume of samples at the lab involved in this study drove material cost down to only $1 USD per syringe filter. However, since each individual sample requires a new filter, with 14,300 samples a year this still amounts to $14,300 – just for filtration materials!

The integrated ultrafiltration in the ion chromatography system from Metrohm only needs one filter change per day, saving this laboratory over $12,000 per year. What’s more, the ultrafiltration process is fully automated.

Compared to manual filtration, this saves three minutes of working time per sample. With labor costs of $18 per hour, this again corresponds to savings of around $13,000 per year.

The Metrohm inline ultrafiltration cell.
Overall, using ultrafiltration saves over $25,000 in annual expenditure – a significant return on investment (ROI).
Yearly cost savings estimated by switching from manual filtration to automatic inline ultrafiltration (click to enlarge).
For even more information about this time-saver, read our earlier blog post about how to determine when it is time to exchange the ultrafiltration membrane:

Suppression

Suppression reduces the conductivity of the eluent, resulting in a more sensitive conductivity detection of the analyte. This makes it possible to achieve particularly low limits of detection and quantification.

The instrument previously used at this laboratory (from a different supplier) employed membrane-based suppressors. These suppressors have to be replaced every three months, costing approximately $1,200 each time. The Metrohm Suppressor Module (MSM), on the other hand, is a one-off purchase because it utilizes ion exchanger particles in a robust micro-packed bed for suppression instead of membranes. The three suppression cartridges of the MSM alternate between suppression, rinsing, and regeneration, thereby ensuring continuous suppression at all times.

The regeneration reagents are inexpensive, averaging $52 per 1,000 samples, resulting in total annual costs of $750 for 14,300 samples. This is much cheaper than the cost of replacing a membrane suppressor multiple times!

The Metrohm Suppressor Module (MSM) high-capacity version.
Yearly cost savings estimated by switching from membrane suppressors to the packed bed MSM. (click to enlarge).
Want to learn even more about suppression in anion chromatography? Download our free brochure here:

Separation Columns

With Metrohm columns, the environmental laboratory in this study achieved better separation of the analytes and a much longer column service life – on average, 7,000 injections compared to 1,200 with the previous columns. There appear to be two factors that are key to the reduced wear on the separation column:

1. The Metrohm ion chromatograph provides measuring signals that are four to five times stronger. This makes it possible to reduce the injection volume by a factor of five.

2. Additionally, Metrohm Inline Ultrafiltration removes particles down to a size of 0.2 μm, whereas manual filtration with syringe filters can only remove particles down to 20 μm.

Selection of Metrohm separation columns in various lengths with intelligent chips (top) and protective guard columns (bottom).
Overall, using Metrohm separation columns saves nearly $18,000 in one year for a high-throughput environmental analysis laboratory.
Yearly cost savings estimated by switching from using Metrohm separation columns compared to the competition (click to enlarge).
Looking for a specific column for your analysis challenges? Check out our Column Finder here!

Dilution

If the determination indicates that the analyte concentration is too high, i.e., outside the permissible determination range, the sample must be diluted and reanalyzed.

This is the situation for around 30% of the samples at the laboratory involved in this study. Manual dilution takes the lab staff at least three minutes per sample. With labor costs of approximately $18 USD per hour, this adds up to annual costs of $3,800.

Automatic Inline Dilution eliminates this expense: the analysis system dilutes the relevant samples fully automatically and then measures them again. This makes the laboratory much more efficient: the daily sample throughput increases, and samples with a limited shelf life are always analyzed in good time.

Yearly cost savings estimated by switching from manual dilution practices to automatic inline dilution from Metrohm (click to enlarge).
Find out more about the many different Metrohm Inline Sample Preparation options available here:

Robustness

Significant cost savings weren’t the only benefit of the Metrohm analysis system – the 30 day comparison study also revealed a number of other advantages. The company was impressed with the robustness of the instrument and with its ability to measure the entire range of samples processed in their laboratory.

Its stable calibration also made it possible to reduce the calibration frequency: the new system only needs calibrating every two to three weeks instead of every two to three days.

The most impressive features, though, were the high measuring sensitivity and the large linear range of the detector. Thanks to the latter, only 2% of the samples remain outside the measuring range and have to be diluted – compared to 30% with the old system.

Final Results

The 30 day test proved to the lab in question that the Metrohm IC with the integrated automatic inline sample preparation techniques saves both material and labor costs. Furthermore, it also offers a number of improvements in terms of analysis performance compared to the systems previously used on site.

The most significant savings are those for labor and material costs as a result of using ultrafiltration, followed by those resulting from the longer service life of the separation column.

 

For the final savings calculation over an entire year, download our white paper on the subject below.

Want to learn more?

Download our free White Paper:

High productivity and profitability in environmental IC analysis

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

Determining the total sulfite in food and beverages: faster and easier than ever

Determining the total sulfite in food and beverages: faster and easier than ever

The chances are good that if you’re reading this, you are an analytical chemist or somehow connected to the food science sector. Maybe you have had the lucky experience of measuring sulfite (SO32-) before in the laboratory. I certainly have, and the adventure regarding tedious sample preparation and proper measurement of such a finicky analyte still haunts me today, years later.

Why sulfite?

Sulfite is a preservative added to a vast range of foods and beverages to prevent browning or oxidation. Some individuals are sensitive to sulfite additives and may experience a range of allergic reactions. Therefore, both the U.S. Food and Drug Administration (FDA) and European Union (EU) laws require that the presence of sulfites be declared on food labels when the concentration exceeds 10 mg/L.

To put this into perspective, an Olympic size swimming pool can hold about 2,500,000 liters, meaning anything beyond 25 kilograms (the average mass of one young child!) would need to be reported.

So, which foods contain sulfite?

Many foods and beverages contain sulfite – whether added to prolong the freshness, or occurring naturally as a byproduct from processes like fermentation. Typically, the first things that come to mind are wine, beer, or dried fruit snacks. However, many pickled and otherwise preserved items such as sauerkraut, canned fruits and vegetables, and even frozen foods contain significant levels of sulfites. Processed meats, several condiments, and some prepared doughs are also high on the list of offenders, so beware at your next picnic!

If you think you may be sensitive to sulfites, don’t forget to check the nutrition facts, and try to avoid such foodstuffs.

How is sulfite usually measured?

Several analytical methods exist to measure sulfite in food and beverages, however they suffer from repeatability issues, and can be quite cumbersome to perform.

Traditionally, the optimized Monier-Williams (OMW) AOAC Official Method 990.28 was used for quantification of sulfite in most foodstuffs, but the method detection limit now lies at the regulatory labeling threshold. Automated discrete analysis methods have been reported for sulfite analysis, but they are limited by their strong dependence on sample matrix type. Therefore these methods are less than ideal for laboratories where sulfite analysis is required for a wide variety of food and beverage products.

Methods based on ion chromatography (IC) with conductivity detection exhibit a lack of selectivity combined with an extended analysis time due to separation challenges. A newer method developed by AOAC (Method 990.31) focuses on the use of ion-exclusion chromatography followed by electrochemical (amperometric) detection of samples.

Another issue arises concerning the sensitivity of the detector. After a few injections, fouling from contaminants rapidly decreases the electrode sensitivity. Frequent reconditioning of the working electrode is necessary due to a rising background and baseline noise, and can be accomplished in a couple of ways. Manual polishing and utilizing pulsed amperometric detection (PAD) pulse sequences are the most common choices to recondition the surface of the working electrode, while other methods opt for disposable electrodes to avoid this step altogether.

What has improved?

Metrohm has filed a patent for an innovative, fast, and accurate ion chromatographic (IC) method based on direct current (DC) mode electrochemical detection. It works with the implementation of a unique working electrode conditioning function (patent pending) in the newest version of chromatographic software (MagIC Net 3.3) offered by Metrohm. A great diversity of food and beverage products were analyzed with sulfite recovery values near 100% in all cases. Using a single, robust chromatographic method, any sample can be treated identically, saving time and making laboratory work much easier.

Sample of garlic analyzed for sulfite content (spiked: red, unspiked: black). Recovery was calculated at 100%.
(Click to enlarge)

No matter what type of sample (solid, liquid), the preparation steps are nearly identical, and much simpler to perform than ever before. Additionally, the retention time of sulfite in the method does not shift. This saves even more time for analysts as they do not have to reprocess data. Since the electrode is automatically reconditioned after each analysis, results are both reliable and reproducible. Waste from disposable electrodes is reduced, as well as costs incurred by the materials and excess working hours which would generally be spent performing other manual steps. This is truly a win-win situation for food analysis!

Benefits to QC laboratories and beyond

In real terms, this improved method allows for up to 10x the throughput of samples compared to conventional methods. Previously, the contract laboratories involved in this study could measure 5 samples, with 2 analysts per 8-hour shift (15 samples per 24 hours, if you like). With our patent-pending technique, at 10 minutes per sample, including fully automatic regeneration of the electrode surface, this allows for up to 144 samples to be analyzed every day.

Whether you work in the food and beverage industry, wastewater analysis, or in daily analytical laboratory work, you can appreciate the numerous benefits this method offers. Robustness, reproducibility, time savings, cost savings, and a simpler procedure for sample preparation across the board – are you interested? With our expertise in ion chromatography as well as electrochemistry, among other techniques, Metrohm is able to offer such cutting edge methods for the most challenging applications.

Want to learn more?

Download our free Application Note:

Sulfite determination in food and beverages applying amperometric detection

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

Special thanks are given to Miguel Espinosa, Product Manager Ion Chromatography, at Metrohm Hispania (Madrid, Spain) for his assistance in providing the laboratory data for the study.

When do I have to exchange the filtration membrane with Inline Ultrafiltration?

When do I have to exchange the filtration membrane with Inline Ultrafiltration?

Inline sample preparation is a powerful tool to make your ion chromatography analysis more efficient. Inline Ultrafiltration is an easy add-on that works for many samples. Use it for any type of sample which contains particles, like surface water, groundwater, or wastewater.

Inline Ultrafiltration by Metrohm

Ion chromatography is equipped with Inline Ultrafiltration in many branches to save time and money, e.g.:

  • Water
  • Environmental
  • Pharmaceutical
  • Food/beverage
  • Chemical
This combination increases filtration effectiveness and sample throughput. Consumables such as syringe filters are not necessary, and the workload for sample preparation in the laboratory is significantly reduced.

How often is optimal?

Customers often ask me about how often the membrane in an Ultrafiltration cell needs to be exchanged. There is no strict limit to the number of injections per membrane filter. This number strongly depends on the level of contamination of the samples.

The optimal point in time can be easily determined using our intelligent software. MagIC Net allows you to automatically integrate a check standard measurement after a certain number of samples. When the membrane filter begins to clog, the check standard data will deviate from its accepted value. MagIC Net automatically evaluates this value, and a warning message will inform you that it is time to check the system and to exchange the membrane.

Add this feature to any MagIC Net method. Define the monitoring period for the desired result.

In any case that the limit value is exceeded, a warning message will pop-up in the software. The data file is highlighted in red in the database, and the respective result is also displayed in red.

Ultimate flexibility for your needs

Monitoring the check standard is useful for several analytical methods. In this example, I explained how to use it to automatically control the performance of the Inline Ultrafiltration. Of course, the MagIC Net software has many more options for flexible methods with feedback. Contact your Metrohm representative if you want to learn more.

For more information

about inline sample preparation techniques for ion chromatography, visit our website!

Metrohm Inline Sample Preparation (MISP)

Post written by Dr. Katinka Ruth, Senior Application Specialist Ion Chromatography at Metrohm International Headquarters, Herisau, Switzerland.