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«Analyze This»: 2020 in review

«Analyze This»: 2020 in review

I wanted to end 2020 by thanking all of you for making «Analyze This» – the Metrohm blog for chemists such a success! For our 60th blog post, I’d like to look back and focus on the wealth of interesting topics we have published this year. There is truly something for everyone: it doesn’t matter whether your lab focuses on titration or spectroscopic techniques, or analyzes water samples or illicit substances – we’ve got you covered! If you’re looking to answer your most burning chemical analysis questions, we have FAQs and other series full of advice from the experts. Or if you’re just in the mood to learn something new in a few minutes, there are several posts about the chemical world to discover.

We love to hear back from you as well. Leaving comments on your favorite blog posts or contacting us through social media are great ways to voice your opinion—we at Metrohm are here for you!

Finally, I wish you and your families a safe, restful holiday season. «Analyze This» will return on January 11, 2021, so subscribe if you haven’t already done so, and bookmark this page for an overview of all of our articles grouped by topic!

Stay healthy, and stay curious.

Best wishes,

Dr. Alyson Lanciki, Scientific Editor, Metrohm AG

Quickly jump directly to any section by clicking a topic:

Customer Stories

We are curious by nature, and enjoy hearing about the variety of projects where our products are being used! For some examples of interesting situations where Metrohm analytical equipment is utilized, read on.

From underwater archaeological research to orbiting Earth on the International Space Station, Metrohm is there! We assist on all types of projects, like brewing top quality beers and even growing antibiotic-free shrimp – right here in Switzerland.

Interested in being featured? Contact your local Metrohm dealer for details!

Titration

Metrohm is the global market leader in analytical instruments for titration. Who else is better then to advise you in this area? Our experts are eager to share their knowledge with you, and show this with the abundance of topics they have contributed this year to our blog.

For more in-depth information about obtaining the most accurate pH measurements, take a look at our FAQ about pH calibration or read about avoiding the most common mistakes in pH measurement. You may pick up a few tips!

Choose the best electrode for your needs and keep it in top condition with our best practices, and then learn how to standardize titrant properly. Better understand what to consider during back-titration, check out thermometric titration and its advantages and applications, or read about the most common challenges and how to overcome them when carrying out complexometric titrations

If you are interested in improving your conductivity measurements, measuring dissolved oxygen, or the determination of oxidation in edible fats and oils, check out these blog posts and download our free Application Notes and White Papers!

Finally, this article about comprehensive water analysis with a combination of titration and ion chromatography explains the many benefits for laboratories with large sample loads. The history behind the TitrIC analysis system used for these studies can be found in a separate blog post.

Karl Fischer Titration

Metrohm and Karl Fischer titration: a long history of success. Looking back on more than half a century of experience in KFT, Metrohm has shaped what coulometric and volumetric water analysis are today.

Aside from the other titration blog posts, our experts have also written a 2-part series including 20 of the most frequently asked questions for KFT arranged into three categories: instrument preparation and handling, titration troubleshooting, and the oven technique. Our article about how to properly standardize Karl Fischer titrant will take you step by step through the process to obtain correct results.

For more specific questions, read about the oven method for sample preparation, or which is the best technique to choose when measuring moisture in certain situations: Karl Fischer titration, near-infrared spectroscopy, or both?

Ion Chromatography (IC)

Ion chromatography has been a part of the Metrohm portfolio since the late 1980s. From routine IC analysis to research and development, and from stand-alone analyzers to fully automated systems, Metrohm has provided IC solutions for all situations. If you’re curious about the backstory of R&D, check out the ongoing series about the history of IC at Metrohm.

Metrohm IC user sitting at a laboratory bench.

Common questions for users are answered in blog posts about IC column tips and tricks and Metrohm inline ultrafiltration. Clear calculations showing how to increase productivity and profitability in environmental analysis with IC perfectly complement our article about comprehensive water analysis using IC and titration together for faster sample throughput.

On the topic of foods and beverages, you can find out how to determine total sulfite faster and easier than ever, measure herbicides in drinking water, or even learn how Metrohm IC is used in Switzerland to grow shrimp!

Near-Infrared Spectroscopy (NIRS)

Metrohm NIRS analyzers for the lab and for process analysis enable you to perform routine analysis quickly and with confidence – without requiring sample preparation or additional reagents and yielding results in less than a minute. Combining visible (Vis) and near-infrared (NIR) spectroscopy, these analyzers are capable of performing qualitative analysis of various materials and quantitative analysis of a number of physical and chemical parameters in one run.

Our experts have written all about the benefits of NIR spectroscopy in a 4-part series, which includes an explanation of the advantages of NIRS over conventional wet chemical analysis methods, differences between NIR and IR spectroscopy, how to implement NIRS in your laboratory workflow, and examples of how pre-calibrations make implementation even quicker.

A comparison between NIRS and the Karl Fischer titration method for moisture analysis is made in a dedicated article.

A 2-part FAQ about NIRS has also been written in a collaboration between our laboratory and process analysis colleagues, covering all kinds of questions related to both worlds.

Raman Spectroscopy

This latest addition to the Metrohm family expands the Metrohm portfolio to include novel, portable instruments for materials identification and verification. We offer both Metrohm Raman as well as B&W Tek products to cover a variety of needs and requirements.

Here you can find out some of the history of Raman spectroscopy including the origin story behind Mira, the handheld Raman instrument from Metrohm Raman. For a real-world situation involving methamphetamine identification by law enforcement and first responders, read about Mira DS in action – detecting drugs safely in the field.

Mira - handheld Raman keeping you safe in hazardous situations.

Are you looking for an easier way to detect food fraud? Our article about Misa describes its detection capabilities and provides several free Application Notes for download.

Process Analytics

We cater to both: the laboratory and the production floor. The techniques and methods for laboratory analysis are also available for automated in-process analysis with the Metrohm Process Analytics brand of industrial process analyzers.

Learn about how Metrohm became pioneers in the process world—developing the world’s first online wet chemistry process analyzer, and find out how Metrohm’s modular IC expertise has been used to push the limits in the industrial process optimization.

Additionally, a 2-part FAQ has been written about near-infrared spectroscopy by both laboratory and process analysis experts, which is helpful when starting out or even if you’re an advanced user.

Finally, we offer a 3-part series about the advantages of process analytical technology (PAT) covering the topics of process automation advantages, digital networking of production plants, and error and risk minimization in process analysis.

Voltammetry (VA)

Voltammetry is an electrochemical method for the determination of trace and ultratrace concentrations of heavy metals and other electrochemically active substances. Both benchtop and portable options are available with a variety of electrodes to choose from, allowing analysis in any situation.

A 5-part series about solid-state electrodes covers a range of new sensors suitable for the determination of «heavy metals» using voltammetric methods. This series offers information and example applications for the Bi drop electrode, scTrace Gold electrode (as well as a modified version), screen-printed electrodes, and the glassy carbon rotating disc electrode.

Come underwater with Metrohm and Hublot in our blog post as they try to find the missing pieces of the ancient Antikythera Mechanism in Greece with voltammetry.

If you’d like to learn about the combination of voltammetry with ion chromatography and the expanded application capabilities, take a look at our article about combined analysis techniques.

Electrochemistry (EC)

Electrochemistry plays an important role in groundbreaking technologies such as battery research, fuel cells, and photovoltaics. Metrohm’s electrochemistry portfolio covers everything from potentiostats/galvanostats to accessories and software.

Our two subsidiaries specializing in electrochemistry, Metrohm Autolab (Utrecht, Netherlands) and Metrohm DropSens (Asturias, Spain) develop and produce a comprehensive portfolio of electrochemistry equipment.

This year, the COVID-19 pandemic has been at the top of the news, and with it came the discussion of testing – how reliable or accurate was the data? In our blog post about virus detection with screen-printed electrodes, we explain the differences between different testing methods and their drawbacks, the many benefits of electrochemical testing methods, and provide a free informative White Paper for interested laboratories involved in this research.

Our electrochemistry instruments have also gone to the International Space Station as part of a research project to more efficiently recycle water on board spacecraft for long-term missions.

The History of…

Stories inspire people, illuminating the origins of theories, concepts, and technologies that we may have become to take for granted. Metrohm aims to inspire chemists—young and old—to be the best and never stop learning. Here, you can find our blog posts that tell the stories behind the scenes, including the Metrohm founder Bertold Suhner.

Bertold Suhner, founder of Metrohm.

For more history behind the research and development behind Metrohm products, take a look at our series about the history of IC at Metrohm, or read about how Mira became mobile. If you are more interested in process analysis, then check out the story about the world’s first process analyzer, built by Metrohm Process Analytics.

Need something lighter? Then the 4-part history of chemistry series may be just what you’re looking for.

Specialty Topics

Some articles do not fit neatly into the same groups as the rest, but are nonetheless filled with informative content! Here you can find an overview of Metrohm’s free webinars, grouped by measurement technique.

If you work in a regulated industry such as pharmaceutical manufacturing or food and beverage production, don’t miss our introduction to Analytical Instrument Qualification and what it can mean for consumer safety!

Industry-focused

Finally, if you are more interested in reading articles related to the industry you work in, here are some compilations of our blog posts in various areas including pharmaceutical, illicit substances, food and beverages, and of course water analysis. More applications and information can be found on our website.

Food and beverages
All of these products can be measured for total sulfite content.

Oxidation stability is an estimate of how quickly a fat or oil will become rancid. It is a standard parameter of quality control in the production of oils and fats in the food industry or for the incoming goods inspection in processing facilities. To learn more about how to determine if your edible oils are rancid, read our blog post.

Determining total sulfite in foods and beverages has never been faster or easier than with our IC method. Read on about how to perform this notoriously frustrating analysis and get more details in our free LC/GC The Column article available for download within.

Measuring the true sodium content in foodstuff directly and inexpensively is possible using thermometric titration, which is discussed in more detail here. To find out the best way to determine moisture content in foods, our experts have written a blog post about the differences between Karl Fischer titration and near-infrared spectroscopy methods.

To determine if foods, beverages, spices, and more are adulterated, you no longer have to wait for the lab. With Misa, it is possible to measure a variety of illicit substances in complex matrices within minutes, even on the go.

All of these products can be measured for total sulfite content.

Making high quality products is a subject we are passionate about. This article discusses improving beer brewing practices and focuses on the tailor-made system built for Feldschlösschen, Switzerland’s largest brewer.

Pharmaceutical / healthcare

Like the food sector, pharmaceutical manufacturing is a very tightly regulated industry. Consumer health is on the line if quality drops.

Ensuring that the analytical instruments used in the production processes are professionally qualified is a must, especially when auditors come knocking. Find out more about this step in our blog post about Analytical Instrument Qualification (AIQ).

Moisture content in the excipients, active ingredients, and in the final product is imperative to measure. This can be accomplished with different analytical methods, which we compare and contrast for you here.

The topic of virus detection has been on the minds of everyone this year. In this blog post, we discuss virus detection based on screen-printed electrodes, which are a more cost-effective and customizable option compared to other conventional techniques.

Water analysis

Water is our business. From trace analysis up to high concentration determinations, Metrohm has you covered with a variety of analytical measurement techniques and methods developed by the experts.

Learn how to increase productivity and profitability in environmental analysis laboratories with IC with a real life example and cost calculations, or read about how one of our customers in Switzerland uses automated Metrohm IC to monitor the water quality in shrimp breeding pools.

If heavy metal analysis is what you are interested in, then you may find our 5-part series about trace analysis with solid-state electrodes very handy.

Unwanted substances may find their way into our water supply through agricultural practices. Find out an easier way to determine herbicides in drinking water here!

Water is arguably one of the most important ingredients in the brewing process. Determination of major anions and cations along with other parameters such as alkalinity are described in our blog post celebrating International Beer Day.

All of these products can be measured for total sulfite content.
Illicit / harmful substances

When you are unsure if your expensive spices are real or just a colored powder, if your dairy products have been adulterated with melamine, or fruits and vegetables were sprayed with illegal pesticides, it’s time to test for food fraud. Read our blog post about simple, fast determination of illicit substances in foods and beverages for more information.

Detection of drugs, explosives, and other illegal substances can be performed safely by law enforcement officers and first responders without the need for a lab or chemicals with Mira DS. Here you can read about a real life training to identify a methamphetamine laboratory.

Drinking water regulations are put in place by authorities out of concern for our health. Herbicides are important to measure in our drinking water as they have been found to be carcinogenic in many instances.

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

How to determine if your edible oils are rancid

How to determine if your edible oils are rancid

Rancidity is the process through which oils and fats become partially or completely oxidized after exposure to moisture, air, or even light. Though not always that obvious, foods can go rancid long before they become old. For oils, whose antioxidant properties are highly valued, such as for olive oil, this is especially problematic. A simple (and free) test for rancidity of oils can be performed at home using your own analytical instruments: your senses of smell and taste.

  1.  Pour a few milliliters of the oil into a shallow bowl or cup, and breathe in the scent.
  2.  If the smell is slightly sweet (like adhesive paste), or gives off a fermented odor, then the oil is probably rancid.
  3.  A taste test should be performed to be sure, since some oils may have a naturally sweet scent.
  4.  Ensure the oil sample is at room temperature, then sip a small amount into your mouth without swallowing. Similar to tasting wine, slurp air across the oil in your mouth, then exhale to determine if the oil has flavor.
  5.  If the oil has no flavor, it is most likely rancid. Do not consume it!

Once food has turned rancid, there is no way to go back and fix it. So, if you find out by means of the sensory test that the oil is rancid, it is already too late. For those of us who would rather skip this step to avoid having rancid food in our mouths, the possibility to accurately predict the future oxidation behavior of edible oils would be great. In fact, this is exactly what the Rancimat from Metrohm can do if you follow our tips and tricks in this article.

Rancimat to the rescue!

With the 892 Rancimat and the 893 Biodiesel Rancimat, Metrohm offers two instruments for the simple and reliable determination of the oxidation stability of natural fats and oils and of biodiesel, respectively. The method, also known as the Rancimat method or Rancimat test, is the same in both cases. It is based on a simple principle of reaction kinetics, according to which the rate of a chemical reaction (here the oxidation of fatty acids) can be accelerated by increasing the temperature.

The 892 Rancimat (L) and the 893 Biodiesel Rancimat (R) from Metrohm (click to enlarge image).

How does it work?

During the determination, a stream of air is passed through the sample at a constant temperature (e.g. 110 °C according to standard EN 14214 for biodiesel). Any oxidation products that develop are transferred by the air stream to a measuring vessel, where they are detected by the change in conductivity of an absorption solution. In addition to the temperature (both the accuracy and stability of which are guaranteed by the Rancimat system), the preparation of the measurement and the condition of the accessories also influence the quality and reproducibility of the results. In this blog post, we have compiled some practical experience in using the Rancimat to help you.

Oxidation stability: practical tips and tricks from the experts

Remove foreign particles from the reaction vessel

Foreign particles in the reaction vessel can catalyze reactions in the sample, leading to measurement results which are not reproducible. Remove foreign objects such as packaging remains from the reaction vessels using a strong gas stream (preferably nitrogen).

Weigh sample with a plastic spatula

Weigh the sample directly into the reaction vessel. Make sure that the maximum filling height does not exceed 3.5 cm. An error of ±10% in the sample weight has no influence on the final result.

Metal spatulas should not be used for weighing, as the metal ions could catalytically accelerate oxidation.

Reaction vessel lid

The green reaction vessel lid (see following image, article number: 6.2753.100) must seal the reaction vessel tightly. If this is no longer possible, the lid must be replaced. Leaky reaction vessel lids lead to incorrect and non-reproducible measurement results!

Tip: to make it easier to seal or to remove the lid, a fine film of silicone oil can be applied with a finger to the upper outer edge of the reaction vessel, to a height of about 1 cm.

Position and stability of the air tube

The stable, vertical positioning of the air tube (article number: 6.2418.100 or 6.2418.130) in the reaction vessel increases the reproducibility of the measurement results.

The air tube should protrude straight down into the vessel as illustrated in the following graphic representation (click image to enlarge).

Absorbent solution in the measuring vessel

Deionized water is used as the absorption solution with the Rancimat. Prior to beginning the analysis, the electrical conductivity of the water in the measuring vessel should not exceed 5 µS/cm.

If this value is higher, check the filters of the water system, and also ensure that there are no other sources of contamination.

Need replacement measuring vessels?

We’ve got you covered.

Positioning of the cannula for air supply

The PTFE (polytetrafluoroethylene) cannula for the air supply into the absorption solution (article number: 6.1819.080) must be aligned properly so that no air passes over the electrodes of the conductivity measuring cell, as shown in the graphic (click image to enlarge).

Air bubbles at the electrodes lead to noisy measurement curves that are difficult to evaluate.

Is it time to start the determination yet?

First, the temperature of the heating block (which is defined in the method) must be reached and stabilize before the reaction vessel is inserted into the instrument.

The sample identification data is then entered in the  StabNet software by the operator.

After connecting all of the tubing for the air supply, the reaction vessel can be inserted into the heating block. The sample measurement begins immediately after pressing the button on the Rancimat.

Cleaning: important for reproducible results

To obtain reliable analysis results, cleaning all accessories is of the utmost importance.

Both the reaction vessel and the inlet tube are disposable items. You can dispose of these materials immediately after cooling down. The rest of the accessories can be cleaned with a laboratory dishwasher (or equivalent) at maximum temperature and maximum drying time.

If you use glass or polycarbonate materials for the measuring vessels, you can of course also clean them in the same manner. The same applies to the measuring vessel lid with integrated conductivity electrode, the transparent silicone tubing, or the black Iso-Versinic tube, as well as the reaction vessel lid.

Tip: the silicone or Iso-Versinic tubing should be washed in a vertical position inside of the dishwasher to ensure it is thoroughly cleaned inside.

After washing, the transfer tubes and the reaction vessel lids should be heated at 80 °C for at least two hours in a drying cabinet, since the materials of these accessories absorb reaction products. This step further reduces the possibility of carryover to the next measurement which leads to unstable measurement results.

Maintenance

Depending on the use of the Rancimat, a regular visual control of the air filter on the back of the instrument is recommended. A clogged filter will lead to fluctuating air flows. The molecular sieve may also need a regular change depending on the instrument usage.

I hope that these tips have given you some helpful suggestions which will save you a little time and troubleshooting when using the Rancimat for determination of the oxidation stability of edible oils and other products. Good luck with your determinations!

Want to learn more?

Rancimat test: Quality control of natural fats and oils in cosmetics

Post written by Simon Lüthi, PM Titration (Meters & Measuring Instruments) at Metrohm International Headquarters, Herisau, Switzerland.