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Easy moisture determination in fertilizers by near-infrared spectroscopy

Easy moisture determination in fertilizers by near-infrared spectroscopy

Blooms or bombs?

As the global population steadily increases, it is important that sufficient crops are produced each year to provide enough food, clothing, and other products. Crops such as corn, wheat, soy, and cotton receive nutrients from the soil they are grown in. Fertilizers play a crucial role in providing these crops with the nutrients they need to grow properly.

An important ingredient in the production of high quality, effective fertilizers is ammonium nitrate (NH4NO3), a good source of nitrogen and ammonium for plants.

Produced as small beads similar in appearance to kitchen salt, ammonium nitrate is cheap to buy and usually safe to handle – but storing it can be a problem. Over time, the compound absorbs moisture, which leads to clumping of the individual beads into a larger block. When such a large quantity of compacted ammonium nitrate is exposed to intense heat it can trigger an explosion.

Over the last century, ammonium nitrate has been involved in at least 30 disasters and terrorist attacks. One of the most recent occurrences was on the evening of August 4th, 2020 in Beirut, where an ammonium nitrate explosion killed at least 220 people and injured more than 5000. This blast is one of the largest industrial disasters ever linked to NH4NO3.

Moisture analysis methods for fertilizers

During the production process of ammonium nitrate it is important to control the moisture content. A low moisture content is preferable, but unnecessary excess drying leads to additional manufacturing costs.  Regulations for different fertilizers vary across the globe, but local legal limits ensure that the maximum amount of water present must not be exceeded.  Therefore,  rapid, reliable, and accurate methods for the determination of moisture is necessary. Out of those available, Karl Fischer titration is one of the most common; oven drying, for example, cannot be used with fertilizers containing ammonium nitrate.

Compared to these methods, near-infrared spectroscopy (NIRS) offers unique advantages. It is a secondary technique that generates reliable results within seconds without needing any sample preparation. NIRS is a non-destructive measurement technique and at the same time does not create any chemical waste.

Read our previous blog posts below to learn more about NIRS as a secondary technique.

NIRS analysis of solids

The most suitable NIR analyzer to measuring different parameters in fertilizer or ammonium nitrate pellets is the Metrohm DS2500 Solid Analyzer with Large Sample Cup.

Solid samples (e.g., granules and pellets) that are filled in the rotating DS2500 Large Sample Cup must be placed on the analyzer window. While scanning the sample, the Large Sample Cup will rotate in order to compensate for inhomogeneity.

As the DS2500 Solid Analyzer is a pre-dispersive system, the sample is illuminated with monochromatic light in order to keep the energy level as low as possible. Therefore, the instrument lid must be closed prior to starting the analysis so external light does not affect the results. The NIR radiation comes from below and is partially reflected by the sample to the detector, which is also located below the sample vessel plane. After 45 seconds, the measurement is completed, and a result is displayed. As this reflected light contains all the relevant sample information, this measurement technique is called diffuse reflection.

Advantages of using NIRS

The procedure for obtaining the NIR spectrum already highlights its simplicity regarding sample measurement and its speed. Several advantages of NIRS are listed below:

 

  • Fast technique with results in less than 1 minute.
  • No sample preparation required – solids and liquids can be used in pure form.
  • Low cost per sample – no chemicals or solvents needed.
  • Environmentally friendly technique – no waste generated.
  • Non-destructive – precious samples can be reused after analysis.
  • Multiple component analysis – prediction of different constituents in parallel.
  • Easy to operate – inexperienced users are immediately successful.

Overall, near-infrared spectroscopy is a robust alternative technique for the determination of both chemical and physical parameters in solids and liquids. It is a fast method which can also be successfully implemented for routine analysis by staff without any higher laboratory education.

Related Applications

Specialty chemicals have to fulfill multiple quality requirements. One of these quality parameters, which can be found in almost all certificates of analysis and specifications, is the moisture content. The standard method for the determination of moisture content is Karl Fischer titration.

This method requires reproducible sample preparation, chemicals, and waste disposal. Alternatively, near-infrared spectroscopy can be used for the determination of moisture content. With this technique, samples can be analyzed without any preparation and without using any chemicals.

More information about the application details can be found below!

Moisture content is one of the most commonly measured properties of fertilizers. Globally, regulations for different fertilizers vary, but local legal limits ensure that the maximum amount of water must not be exceeded. A number of analytical techniques are available for this purpose. Next to gravimetric methods, Karl Fischer titration is often used for accurate moisture determination.

Compared to these methods, near-infrared spectroscopy offers unique advantages: it generates reliable results within seconds, and at the same time does not create chemical waste. This Application Note explains how NIRS can offer fast, reagent-free analysis of moisture content in various fertilizer products.

Read on for more technical details…

To learn more about how Karl Fischer titration and NIRS complement each other for the analysis of moisture in different products, read our blog post!

For more information

About spectroscopy solutions provided by Metrohm, visit our website!

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

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

Real World Raman: Simplifying Incoming Raw Material Inspection

Real World Raman: Simplifying Incoming Raw Material Inspection

Raw material identification and verification (RMID) is a complicated process for a very important reason: it confirms the quality of the raw materials used in the manufacture of products that you put on and in your body. The complexity of RMID spans the spectrum from analytical techniques and instruments to the testing process, then to the governmental norms and standards that regulate all aspects of RMID including system suitability, extent of sampling, method validation, electronic records, and many others.

With Mira P and Mira Cal P, Metrohm Raman simplifies RMID.

Warehouse verification of incoming materials with mobile Raman in regulated industries involves performing RMID directly at the loading dock. Therefore, chemical analyses that historically would be performed in a laboratory by trained chemists can now be performed very quickly and with great success by nontechnical professionals.

Beginning with System Suitability…

Producers of handheld Raman instruments for RMID must provide suitable calibration and validation routines. Calibration of Mira P with the Calibrate/Verify Accessory (CVA) accomplishes instrument calibration as well as system and performance verification, then summarizes these tests in the System Suitability Test (SST) report for Mira P. CVA ensures that Mira P performs as intended and that users can trust in the generated data quality. Upon completion of the SST, users are assured that all measurements are in accordance with agreed standards.

For more information about instrument calibration, system verification, and performance validation for Metrohm Instant Raman Analyzers (Mira), download our free White Paper!

Moving on to Sampling Flexibility…

RMID methods must accommodate a number of factors to create the most accurate and robust solution for the task. Specific consideration must be given to:

  1. The sampling strategy: how to collect the best quality data, given specific conditions
  2. Sample presentation: including morphology, packaging, and chemical nature

Handheld Raman is recognized as a particularly well-suited technique for RMID, as it offers portable, onsite, no-contact analysis of solid and liquid samples.

RMID for Regulated Industries Part I: General Considerations outlines basic applications of handheld Raman, including sampling considerations and types of evaluation. Metrohm Raman simplifies sampling with Smart Tips for every sample type.

Followed by Method Development…

From Training and Validation Set building and specific recommendations for collecting best quality spectra to dedicated software routines that automatically determine optimal model parameters, Mira P streamlines development of methods for RMID with handheld Raman.

Successful development of a method relies on the inclusion of spectra in libraries and training sets used for RMID. Careful planning in the design phase of the model leads to an easy data collection phase. This data can then be used to determine the best model parameters for robust method development. With Mira Cal P and ModelExpert, even non-technical users can implement accurate, effective RMID methods.

Download our free Application Note AN-RS-031 for more information about Simplified RMID Model Building with Mira Cal P and Model Expert!

And Method Implementation…

Implementation of handheld Raman in RMID, where the majority of materials testing is performed in the receiving area, is a logical step for such a powerful technique. It has become widespread due to some very real advantages.

Massive time savings: acquisition times of less than a minute, coupled with instant, obvious results, permits very high-throughput

Faster turnaround: delivers materials to production sooner

Reduced resources: less demand for laboratory and warehouse personnel and lab consumables, costs, and workloads

Guided Workflows: predefined workflows on Mira P make sampling simple and efficient

With Full Compliance and Utter Confidence.

Just as Mira P has built-in routines to ensure instrument integrity, Mira Cal P is designed to protect customer data integrity and simplify compliance with worldwide norms and standards. All RMID customers require data to be complete, consistent, and accurate, and MiraCal P goes beyond this with full transparency and traceability.

MiraCal P analytical software from Metrohm Raman gives you peace of mind, as it ensures all data processing adheres to several standards. More information about data integrity can be found in our free flyer.

RMID is a complex process. Learn more about how handheld Raman can provide the simplest, most efficient and accurate RMID experience possible.

Learn more about

Handheld Raman spectrometers and SERS analyzers for the lab and the process

Post written by Dr. Melissa J. Gelwicks, Applications Chemist, Metrohm Raman, Laramie, Wyoming, USA.

Analysis of prebiotics with IC-PAD: Improving AOAC 2001.02

Analysis of prebiotics with IC-PAD: Improving AOAC 2001.02

Our diet is critical for our health. In the past several years, interest has increased in food additives and dietary supplements such as prebiotics like β-galactooligosaccharides (GOSs). The determination of total GOS contents in food and supplements is essential to fulfill strict food labeling and safety requirements. The most widely used method for total GOS determination is based on enzymatic hydrolysis to break down the complex molecules into simple carbohydrates prior to their chromatographic analysis. This article outlines the advantage of using an improvement to AOAC Method 2001.02 using ion chromatography with amperometric detection (IC-PAD) and full sample automation after enzymatic hydrolysis.

What are GOSs?

GOSs are chains of galactose units with an optional glucose end. They are often naturally present in small amounts in various foods and beverages.

Initially discovered as major constituents of human breast milk (present up to 12 g/L), GOSs are added as a prebiotic supplement to infant formulas. They show bifidogenic effects, meaning they support growth and well-being of non-pathogenic gut bacteria.

GOS supplements are available either raw, or as concentrated powders or syrups, and are subsequently used by food manufacturers to enrich consumer products or sold as supplements.

GOS labeling requirements

The ongoing growth of global prebiotic and GOS markets is a result of increasing consumer awareness regarding healthy eating. Similarly, increased demand regarding food quality has led to stricter, more comprehensive rules for food labeling and safety (e.g., EU 1169/2011 and  EU 2015/2283). The determination of total GOS contents in food, supplements, or raw products is thus essential to fulfill such requirements.

Studies about GOS health effects recommend maximum doses under 30 g per day, though this is much stricter for infant formulas. Otherwise, there are no other limits regarding GOS content in food or as nutritional supplements.

AOAC 2001.02

The most widely used method to measure total GOSs in food products is the standard method AOAC 2001.02. This method is based on the extraction of GOS from a sample followed by enzymatic hydrolysis of the oligosaccharides into monosaccharides and their subsequent analyses with high performance anion exchange chromatography with pulsed amperometric detection.

Figure 1. Schematic for determination of total GOS contents using ion chromatography with pulsed amperometric detection (IC-PAD) according to AOAC 2001.02, and an optimized method from Metrohm (in green). Chromatography for anions in AOAC is referred as HPAEC (high performance anion exchange chromatography) but is simplified here to the generic term of IC.

In AOAC, chromatography for anions is referred to as HPAEC (high performance anion exchange chromatography) but here we will simplify this to the generic term of IC.

The key to AOAC 2001.02 is the comparison of a control solution with one which has been treated and hydrolyzed with an enzyme (β-galactosidase). The enzyme catalyzes the splitting of glycosidic bonds and hydrolyzes GOSs and lactose into glucose and galactose. The concentration differences of free galactose and lactose determined in these two solutions is used to calculate the total GOSs (Figure 1).

Improvements to the AOAC Method

The sample preparation for AOAC 2001.02 is rather complex: one shortcoming is the incubation of the reference solution with the deactivated enzyme (which is rather expensive) to determine the initial carbohydrate concentrations (Figure 1) rather than using the pure extract. Another critical point is the sample dilution procedure, which is supposed to be done in acetonitrile, while standards are based on ultrapure water.

Here, the focus was to simplify the entire procedure to increase the ease of use and the overall efficiency of the method.

The improved method for total GOS content analysis uses the extract for measuring of the initial glucose, galactose, and lactose concentrations (Figure 1 Assay 1). However, the deactivated enzyme was not used, and instead comparisons were made to see if its presence had any effect on the results. This step was eliminated after proving results equivalent to AOAC 2001.02 Assay 1 (with the deactivated enzyme), but chemical expenses and additional manual work are reduced. The total GOS content is therefore calculated from the analyte concentrations in Assay 1 (without any enzyme) and Assay 2 (extract with the active enzyme) (Figure 2).

Figure 2. Overlaid chromatograms of Bimuno (prebiotic supplement), untreated (black) and treated with enzyme (orange).

Want to know more details about the application? Download our free Application Note AN-P-087 about total GOS analysis in foods with ion chromatography!

Aside from the enzyme usage, the official AOAC method for analysis of total GOSs suggests that standards be prepared in ultrapure water (UPW) while samples are to be diluted with 20% acetonitrile. A control experiment was performed to compare results between:

  • Dilutions in UPW evaluated with UPW calibration (“UPW option”)
  • Dilutions in acetonitrile evaluated with UPW calibration (AOAC 2001.02)
  • Dilutions in acetonitrile evaluated with acetonitrile calibration (“ACN option”)

Reproducibility of total GOS contents was compared among the three options, with the UPW and AOAC preparation options exhibiting similar results. The ACN option resulted in lower total GOS contents than the others. Additionally, the acetonitrile did not seem to lend a stabilizing effect to the samples. This supports the improvement of the AOAC method by performing sample dilutions with UPW instead of acetonitrile, saving unnecessary reagents and limiting the chemical imprint of the analysis.

Results

Overall, the satisfying variability, target and spike recoveries (Application Note AN-P-087), together with the interference tests proved the modified method as valuable and robust. With limits of detection (LODs) of 0.1 mg/L (galactose) and 0.2 mg/L (glucose, lactose) in solution, even low total GOS contents can be determined with high precision.

Summary

As a multicomponent method, ion chromatography with amperometric detection is a very selective, sensitive, and robust analysis method for carbohydrates without any additional derivatization steps. In combination with enzymatic treatment, even more complex carbohydrates can be quantified.

This research presents an update to the standard AOAC method for total GOS determination in foodstuffs. With the same principle (enzymatic hydrolysis of complex GOS molecules followed by chromatographic analysis of simple carbohydrates), analytical method efficiency was improved in favor of laboratory time and running costs. Additional automation steps (e.g., Metrohm Inline Dilution and automatic calibrations) can further improve the method efficiency.

Want more information about the simplified method for total GOSs via IC-PAD? More details about the improvement of AOAC method 2001.02 by reducing manual laboratory work and eliminating expensive reagents can be found in our article published in The Column from LC/GC (2021): Improving on AOAC 2001.02: GOS Determination in Foods Using HPAEC–PAD.

Read our article in LC/GC The Column (2021)

Improving on AOAC 2001.02: GOS Determination in Foods Using HPAEC–PAD

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

Multiparameter analysis in fertilizers by thermometric titration

Multiparameter analysis in fertilizers by thermometric titration

Agriculture without fertilizers is no longer possible – without them, today’s estimated global population of 7.9 billion people could not be supported. Fertilizers provide plants with much needed nutrients for optimal growth. The ideal fertilizer depends not only on the crop, but the soil as well. To achieve the best results, knowledge of the fertilizer composition is essential.

To learn more about the origins of industrial fertilizers, read about the Haber-Bosch process in our series about the History of Chemistry.

Different fertilizers for different needs

Fertilizers can be classified in various ways, one of which being their origin. Fertilizers derived from plants and/or animals, such as dung or manure, are usually called «organic fertilizers», while fertilizers obtained from mineral salts or ores are called «inorganic fertilizers».

 The most often used classification of inorganic fertilizers is based on their nutrient composition. Classification by nutrient composition allows farmers to select the optimal fertilizer for their soil and crops. Single nutrient or straight fertilizers deliver only one nutrient. Examples are ammonium nitrate or single superphosphate. More common are multi-nutrient fertilizers consisting of two or more nutrients. Examples here include monoammonium phosphate or NPK (nitrogen-phosphate-potassium) fertilizers.

Nutrients for plants

The macronutrients nitrogen, phosphorus, and potassium are the main nutrients required by the plant for its growth. Other secondary nutrients such as sulfur and calcium, or micronutrients like boron are also essential but required in smaller quantities.

Why analyze the fertilizer composition?

Selecting the ideal fertilizer composition is essential for proper plant growth. Crops will suffer from a deficiency in nutrients, however adding an abundance of them can be detrimental, resulting in fertilizer burn for example.

Furthermore, releasing too much fertilizers at once can lead to undesirable environmental pollution. Fertilizer producers are therefore required to specify the amount of nutrients within their products, and various norms from ISO, EN, and AOAC exist for the standardized determination of these nutrients.

Thermometric titration for fertilizer analysis

Traditionally the main nutrients in fertilizers are determined by analytical methods such as gravimetry, photometry, or ICP-OES. These methods require either time-consuming sample preparation or the use of expensive analysis equipment. Thermometric titration provides an inexpensive alternative solution for the analysis of potassium, phosphorus, sulfur, ammoniacal nitrogen, and urea without any time-consuming steps.

Using thermometric titration to analyze fertilizer composition has several benefits: 

  • Analysis of multiple parameters with one device
  • Automation possibility for analyzing multiple samples a day
  • Rapid results for each parameter with titration times under 5 minutes

Want to learn more about the analysis of fertilizers with thermometric titration? Download our free White Paper on this topic: Multiparameter analysis in fertilizers – Fast and easy via thermometric titration. 

What is thermometric titration?

Thermometric titration (TET) is based on the principle of enthalpy change. Each chemical reaction is associated with a change in enthalpy that in turn causes a temperature change. This temperature change during a titration can be measured with a highly sensitive thermistor in order to determine the endpoint of the titration.

If you would like to read more about the basic principles of thermometric titration, click below for our previous  blog post «Thermometric titration – the missing piece of the puzzle».

Metrohm’s maintenance-free Thermoprobe used for fast and reliable indication of thermometric titration endpoints.

How are the analyses performed?

In this section I will explain how the analyses for various macronutrients in fertilizers are done using thermometric titration.

Thermometric titration system consisting of a 859 Titrotherm fully equipped with a Thermoprobe, titration stand and buret, and the tiamo software for the multiparameter analysis of fertilizers.
Phosphorus

Phosphorus is an essential macronutrient for photosynthesis and optimal crop growth, as it provides the energy to extract other nutrients from the soil. Historically, total phosphorus content is determined by gravimetric analysis. Alternatively, spectrophotometric analysis or ICP-OES may be used for the determination. These methods all require time-consuming sample preparation steps or regular calibrations.

The thermometric titration of phosphorus is based on the gravimetric determination, but without long drying times to achieve constant weight. An appropriate aliquot of sample is added to the titration vessel and 5 mL of pH 10 buffer (ammonium chloride / ammonia) as well as 5 mL of an oxalate solution (to precipitate any interfering calcium) are added. The solution is then made up to 30 mL with deionized water and titrated with a magnesium nitrate titrant until after the exothermic endpoint.

Figure 1. Exothermic titration curve of the phosphate determination in an NPK fertilizer (blue = titration curve, pink = second derivative showing the endpoint).

For more detailed information about thermometric titration of phosphorus, download one of the following free application documents:

Ammoniacal nitrogen and urea

Nitrogen is an essential macronutrient as it is a component of amino acids (protein building blocks) and nucleic acid (building blocks of DNA). In inorganic fertilizers, nitrogen is usually present as ammonium, nitrate, or urea. Ammonia is usually determined after alkaline distillation by acid-base back-titration, while other nitrogen species are usually first converted to ammonia via digestion prior to analysis.

With thermometric titration, a different approach is used. Ammonium ions as well as urea react exothermically with hypochlorite in a redox reaction. This reaction is further catalyzed in the presence of bromide ions in a slightly alkaline solution. 

Figure 2. Exothermic titration curve of ammoniacal nitrogen and urea in an NPK fertilizer (blue = titration curve, pink = second derivative showing the endpoint). The first endpoint (left) corresponds to ammonia and the second one (right) to urea.

To analyze ammoniacal nitrogen and urea, an appropriate aliquot of sample is added to the titration vessel and then 10 mL of a bromide/bicarbonate solution is added. The solution is then made up to 50 mL with deionized water and titrated with hypochlorite until after the exothermic endpoint.

For more detailed information about thermometric titration of ammonium and urea, check out the following free application notes:

Potassium

Potassium is an essential macronutrient for crops, needed for regulating their water and making them more resistant to droughts. Historically, potassium content is determined by gravimetric analysis. More recently, ICP-OES is used for this determination, but the instrumentation is very expensive.

The thermometric titration of potassium is based on the precipitation of potassium with sodium tetraphenyl borate (STPB). It is a quick titration and for this reason has already been integrated in various Chinese standards on fertilizers (HG/T 2321 for potassium dihydrogen phosphate, GB/T 20784 for potassium nitrate, and GB/T 37918 for potassium chloride).

An appropriate aliquot of sample is added to the titration vessel. The solution is then made up to 30 mL with deionized water and titrated with STPB until after the exothermic endpoint is reached.

Figure 3. Exothermic titration curve of the potassium determination in potash (blue = titration curve, pink = second derivative showing the endpoint).

For more detailed information about thermometric titration of potassium, download our free application notes:

Sulfur

Sulfur is a secondary macronutrient and plays an important role in chloroplast growth as well as acting as a catalyst for nitrogen uptake. Sulfur is usually provided in the form of sulfate. Sulfuric acid also influences the wet phosphoric acid production process, and therefore knowledge of its content is crucial.

Conventionally, sulfur is determined by gravimetry. The same precipitation reaction with barium is also used for the thermometric titration, without time-consuming drying to weight.

For the analysis, an appropriate aliquot of sample is added to the titration vessel and acidified (if necessary). The solution is then made up to 30 mL with deionized water and titrated with barium chloride until after the exothermic endpoint. For improved method sensitivity, the samples can be spiked with a standard sulfuric acid solution.

Figure 4. Exothermic titration curve of the sulfate determination in an NPK fertilizer spiked with a known amount of sulfuric acid for better endpoint recognition (blue = titration curve, pink = second derivative showing the endpoint).

For more detailed information about thermometric titration of sulfur, download our free application documents:

Summary

Thermometric titration is an inexpensive analysis method without the need for costly maintenance or calibrations. It provides a rapid and robust solution for the determination of multiple parameters in fertilizers. If you wish to learn more about thermometric titration and its potential to solve application challenges do not hesitate to contact your local Metrohm representative!

For more information, read our White Paper

Multiparameter analysis in fertilizers – Fast and easy via thermometric titration

Post written by Lucia Meier, Technical Editor at Metrohm International Headquarters, Herisau, Switzerland.

Unmatched flexibility in online ion analysis: The 2060 IC Process Analyzer

Unmatched flexibility in online ion analysis: The 2060 IC Process Analyzer

When discussing chemical analysis, the first thing that comes to mind is a chemist working in the laboratory analyzing a sample.

However, in the industrial process world chemical analysis is a much more complicated affair. In the metalworking industry for example, corrosion is a complex problem. The conventional approach (offline analysis systems) is costly, and a more proactive approach is needed for prevention, identification, and manufacturing of high quality metalworking products. Therefore, a more comprehensive sample monitoring and analysis approach is necessary in order to comply with such requirements.

While offline analysis systems depend upon an analyst to collect and process samples, an online analysis system allows for continuous monitoring of multiple parameters in real time without being dependent on an analyst.

Need to refresh your knowledge about the differences between online, inline, and atline analysis? Read our blog post: «We are pioneers: Metrohm Process Analytics».

The implementation of Process Analytical Technologies (PAT) provides a detailed representation in real time of the actual conditions within a process. As a complete solution provider, Metrohm Process Analytics offers the best solutions for online chemical analysis. We seek to optimize process analysis by developing flexible, modular process analyzers that allow multiple analyses of different analytes from a representative sample taken directly at the process site.

Want to learn more about PAT? Check out our article series here: «To automate or not to automate? Advantages of PAT – Part 1».

2060 IC Process Analyzer

With more than 40 years of experience with online process analysis, Metrohm Process Analytics has always been committed to innovation. In 2001, the first modular IC system was developed at Metrohm and it was a success. In the past several years Metrohm Process Analytics focused on implementing more modular flexibility in their products, which resulted in the introduction of the next generation of Process Ion Chromatographs: the 2060 IC Process Analyzer (Figure 1) in 2019. It is built using two 930 Compact IC Flex systems and is in full synergy with the Metrohm process analyzer portfolio (such as the 2060 Process Analyzer).

Figure 1. The 2060 IC Process Analyzer from Metrohm Process Analytics. Pictured here is the touchscreen human interface, the analytical wet part (featuring additional sample preparation modules – top inlay, and the integrated IC – bottom inlay), and a reagent cabinet.

For more background behind the development of IC solutions for the process world, check out our previous blog posts featuring the past of the 2060 IC Process Analyzer:

Using the 2060 platform, modularity is taken to the next step. Configurations of up to four wet part cabinets allow numerous combinations of multiple analysis modules for multiparameter measurements on multiple process streams, making this analyzer unequal to any other on the market.

This modular architecture gives the additional possibility to place separate cabinets in different locations around a production site for a wide angle view of the process. For example, the 2060 IC Process Analyzer can be set up at different locations to prevent corrosion on the water steam cycles in fossil and nuclear power plants.

The 2060 IC Process Analyzer is managed using flexible software enabling straightforward efficient control and programming options. With multiple types of detectors available from Metrohm, high precision analysis of a wide spectrum of analytes is possible in parallel.

The inclusion of an optional (pressureless) ultrapure water system for autonomous operation and reliable trace analysis also benefits users by providing continuous eluent production possibilities for unattended operation (Figure 2).

Finally, the well-known Metrohm Inline Sample Preparation (MISP) techniques are an added bonus for process engineers for repeatable, fully automated preparation of challenging sample matrices.

Figure 2. Continuous eluent production integrated in the 2060 IC Process Analyzer.

Top applications

The collection of samples and process data, including corrosion prevention and control indicators, is critical for efficient plant management in many industries. In order to prevent unscheduled plant shutdowns, accidents, and damage to company assets, process engineers rely on their colleagues in the lab to pinpoint corrosion problems. One of the most effective ways to bridge laboratory analyses to the process environment is to employ real-time analysis monitoring.

Figure 3. Product and process optimization differences between offline, atline, online, and inline analysis.

Optimal online corrosion management

Be it quantifying the harmful corrosive ions (e.g., chlorides, sulfates, or organic acids), measuring corrosion inhibitors (e.g., ammonia, amines, and film-forming amines), or detecting corrosion products, the 2060 IC Process Analyzer is the ideal solution for 24/7 unattended analysis.

In a nuclear power plant, this analyzer can measure a number of analytes including inorganic anions, organic cations, and aliphatic amines to ensure a thorough understanding of corrosive indications without needing multiple instruments.

Figure 4. Water sample from the primary circuit of a pressurized water reactor containing 2 g/L H3BO3 and 3.3 mg/L LiOH spiked with 2 μg/L anions (preconcentration volume: 2000 μL).
Figure 5. Simulated sample from the primary circuit of a pressurized water reactor containing 2 g/L H3BO3 and 3.3 mg/L LiOH spiked with 2 μg/L nickel, zinc, calcium, and magnesium (preconcentration volume: 1000 μL).

Providing quick, reliable results, this system gives valuable insight into the status of corrosion processes within a plant by continuous comparison of results with control values. By correlating the results with specific events, effective corrective action can quickly be undertaken to prevent or minimize plant downtime.

For more information about the determination of anions and cations in the primary circuit of nuclear power plants with the 2060 IC Process Analyzer, download our free Application Notes below.

Online drinking water analysis

In drinking water plants and beverage bottling companies, determination of disinfection byproducts (DBPs) like bromate is crucial due to their carcinogenic properties. The carcinogen bromate (BrO3) has a recommended concentration limit of 10 μg/L of in drinking water set by the World Health Organization.

Nowadays, ion chromatography has been proven to be the best routine analysis method for water analysis, due to its possibility of automated sample preparation, various separation mechanisms, and different types of detectors. Some of the analytical standards that support this include: EPA 300.1EPA 321.8, ASTM D6581, ISO 11206, and ISO 15061.

The 2060 IC Process Analyzer can monitor trace levels of bromate in drinking water online, meaning higher throughput, less time spent performing manual laboratory tests, and better quality drinking water.

Figure 6. Drinking water sample, spiked with 10 μg/L each of chlorite, bromate, chlorate, 40 μg/L each of nitrate, bromide, 100 μg/L phosphate, and 500 μg/L dichloroacetate.
Figure 7. Analysis of a mineral water sample spiked with 0.5 μg/L bromate.

To learn more about the online analysis of bromate in drinking water with the 2060 IC Process Analyzer, download our free Application Note.

Monitoring aerosols and gases in air

Approximately 92% of the world population lives in places where the World Health Organization air quality guideline levels are not met. Air pollution can exacerbate preexisting health conditions and shorten lifespans. It has even been suggested as a link to infertility causes. Hence, understanding the impact of air pollution and air constituents on the environment and our wellbeing is of great significance.

Air pollution is caused not only by gaseous compounds, but also by aerosols and particulate matter (PM). These extremely fine particles enter and damage the lungs; from them, ultrafine particles can spread across the body through the blood cells and cause symptoms of inflammation. While these risks are being debated and researched actively around the world, it is still not known which compounds actually cause harm.

As a result, there is a great need for more specific data on long-term measurements. Fast analytical methods and real-time measurements of concentrations of chemical compounds in ambient air are important and should make it possible to better understand the circumstances and effects.

For optimal air quality monitoring, the gas and aerosol composition of the surrounding air has to be analyzed practically simultaneously as well as continuously, which is possible via inline analysis with ion chromatography.

Metrohm Process Analytics offers the 2060 MARGA (Monitor for AeRosols and Gases in ambient Air) which thanks to its dual-channel ion chromatograph, can automatically analyze the ions from the collected gas and aerosol samples.

If you want to learn more background behind the development of the 2060 MARGA, check out our previous blog post: History of Metrohm IC – Part 5.

For a full list of free downloadable 2060 IC applications, visit our website and check out the Metrohm Application Finder!

Free Application Notes

For the 2060 IC Process Analyzer

Post written by Andrea Ferreira, Technical Writer at Metrohm Applikon, Schiedam, The Netherlands.

Supercharge your battery research – Part 1

Supercharge your battery research – Part 1

Replacing traditional fuel-powered vehicles with battery-powered options is essential to reduce carbon dioxide (CO2) emissions. This greenhouse gas results from the combustion of fossil fuels, therefore limiting its input into the atmosphere will also influence global warming. Battery research therefore focuses on discovering new materials with higher energy and power density as well as a more efficient energy storage.

Various critical parameters need to be determined to develop viable new batteries. In this first of two blog posts, I want to highlight a few of the analytical parameters which can be determined using high precision analytical instruments from Metrohm and provide some free downloads in this research area.

What’s in a lithium battery?

Today, lithium ion batteries are the most common rechargeable batteries available on the market. A battery consists of an anode (negative pole) and cathode (positive pole). An electrolyte facilitates charge transfer in the form of lithium ions between these two poles. Meanwhile a separator placed between anode and cathode prevents short-circuits. An example cross section can be seen in Figure 1.

Figure 1. Cross-section illustration of a lithium ion battery. While the battery is being charged, lithium ions migrate from the cathode to the anode (from right to left), and during discharging they move from the anode to the cathode (from left to right).

The anode is made from graphite containing intercalated lithium applied to a copper foil, while the cathode consists of metal oxides dotted with lithium ions applied to an aluminum foil. The most common transition metals used in cathode materials are cobalt, nickel, manganese, or iron. The electrolyte is an anhydrous aprotic solvent containing a lithium salt (e.g., lithium hexafluorophosphate) to facilitate charge transfer. The separator is prepared from a porous material, acting as an insulator to prevent short-circuits. The composition of all of these components has a significant influence on the battery characteristics.

After this brief overview about the composition of a lithium battery, let’s take a look at selected key parameters and how they can be analyzed.

Water content in battery raw materials

Lithium-ion batteries should be free of water (concentration of H2O less than 20 mg/kg), because water reacts with the conducting salt (e.g., LiPF6) to form toxic hydrofluoric acid. Sensitive coulometric Karl Fischer titration is the ideal method for determining water content at trace levels. Water determination for solids is carried out using the Karl Fischer oven method – the residual moisture in the sample is evaporated and transferred to the titration cell where it is subsequently titrated. The working principle and advantages of the KF oven method are described in more detail in our blog post «Oven method for sample preparation in Karl Fischer titration».

For more details on how to carry out the water determination in one of the following battery components, download our free Application Bulletin AB-434:

 

  • raw materials for the manufacture of lithium-ion batteries
  • electrode coating preparations (slurry) for anode and cathode coating
  • the coated anode and cathode foils as well as in separator foils and in packed foil layers
  • electrolytes for lithium-ion batteries

Transition metal composition of cathode materials

The cathode of a lithium-ion battery is usually made from metal oxides derived from cobalt, nickel, manganese, iron, or aluminum. To produce the cathode, solutions containing the desired metal salts are used. For an optimized production process, the exact content of the metals present in the solution must be known. Additionally, the metal composition within the obtained cathode material should be determined. Potentiometric titration is a suitable technique to determine the metal content in starting solutions and the finished cathode materials.

The following mixtures of metals or metal oxides can be analyzed potentiometrically:

  • Nickel, cobalt, and manganese in solutions
  • Nickel, cobalt, and manganese in cathode materials such as cobalt tetraoxide (Co3O4), lithium manganite, or lithium cobaltite

For more details about the potentiometric analysis of a mixture of nickel, cobalt, and manganese download our free Application Note AN-T-218.

Analysis of lithium salts

Potentiometric titration is also ideally suited for determining the purity of lithium salts. For lithium hydroxide and lithium carbonate, the purity is determined using an aqueous acid-base titration. It is also possible to determine carbonate impurity within lithium hydroxide using this method.

For more details about performing the assay of lithium hydroxide and lithium carbonate, download our free Application Note AN-T-215.

For the assay of lithium chloride and lithium nitrate, the lithium is directly titrated using the precipitation reaction between lithium and fluoride in ethanolic solutions. For more details about how to carry out the assay of lithium chloride, download Application Note AN-T-181 and for lithium nitrate download AN-T-216.

The knowledge of other cations which might be present in lithium salts (and their concentration) is also of interest. Various cations (e.g., sodium, ammonium, or calcium) can be determined using ion chromatography (IC). IC is an efficient and precise multi-parameter method to quantify anions and cations over a wide concentration range.

The chromatogram in Figure 2 shows the separation of lithium, sodium, and calcium in a lithium ore processing stream.

Figure 2. Ion chromatogram of the lithium ore processing stream (1: lithium, 23.8 g/L; 2: sodium, 1.55 g/L; 3: calcium, 0.08 g/L).

For more information on how this analysis was carried out, download our free Application Note AN-C-189.

Eluated ions and decomposition products

In the development and optimization of lithium-ion batteries, one of the items of special interest is the content of ions (e.g., lithium, fluoride, and hexafluorophosphate) in the electrolyte or in eluates of different components. Ion chromatography allows the determination of decomposition products in electrolyte, or anions and cations eluated for example from finished batteries. Additionally, any sample preparation steps that might be required (e.g., preconcentration, dilution, filtration) can be automated with the Metrohm Inline Sample Preparation («MISP») techniques.

For more detailed information about selected IC applications for battery research, check out our Application Notes:

  • Cations in lithium hexafluorophosphate (AN-C-037)
  • Trace cations in lithium hexafluorophosphate (AN-CS-011)
  • Anions in electrolyte (AN-N-012)
  • Decomposition products of lithium hexaflurophosphate (AN-S-372)

Summary

This blog post contains only part of the analyses for battery research which are possible using Metrohm’s analytical instruments. Part 2 will deal with the electrochemical characterization of batteries and their raw materials. Don’t want to miss out? Subscribe to the blog at the bottom of the page.

If you want to see a complete overview about the analyses which are possible with our portfolio, have a look at our brochure on Battery research and production.

Battery research

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Post written by Lucia Meier, Technical Editor at Metrohm International Headquarters, Herisau, Switzerland.