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Food packaging is rarely completely inert. From plastic wrapping to greaseproof cardboard, the materials used to package our groceries can often contain microplastics or unfriendly chemicals such as per- and polyfluoroalkyl substances (PFAS) and bisphenol A (BPA). These substances can leach from food packaging materials into the food they encase, potentially contaminating the diets of millions.
To monitor this kind of hazardous chemical migration in real-time, researchers are continually adapting and developing new analytical techniques.
Condensed phase–membrane introduction mass spectrometry (CP-MIMS) is an on-line analysis technique that does not require extensive sample preparation or chromatographic separation. Instead, through the use of a semi-permeable hollow fiber membrane, only compounds with certain physicochemical properties are allowed to pass through the membrane and reach the MS ion source. While this technique is known to be a useful strategy for the continuous real-time monitoring of dynamic processes, it has not been a routine part of food and beverage analysis.
Speaking at the 11th International Symposium on Recent Advances in Food Analysis (RAFA), Dr. Maurizio Piergiovanni, a researcher in the University of Parma’s Department of Chemical, Life and Environmental Sustainability Sciences, presented for the first time a CP-MIMS method for the monitoring of bisphenols released from food packaging. The research demonstrated the use of a CP-MIMS probe coupled to an electrospray source to detect bisphenols A, E, F and S in drinking water and food simulants, as well as to monitor in real-time the migration of bisphenols from plastic packaging. To learn more about this technique and how it can be applied to food analysis, Technology Networks caught up with Piergiovanni and his collaborator, Dr. Nicolò Riboni, at the event.
Alexander Beadle (AB):
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
Can you tell me a little more about the history of CP-MIMS and what this technique entails?
Researcher
University of Parma
Dr. Maurizio Piergiovanni holds a master's degree in industrial chemistry from the University of Bologna and obtained his PhD at the University of Urbino, where he worked on the development of an interface for coupling liquid chromatography and electron ionization mass spectrometry, called Liquid-EI. His research interests include the development of MS-based methods for food safety, food characterization and metabolomics.
This [MIMS] technique is honestly not so new, but it’s not so famous – it was not used so much over time. It was developed more or less 50 years ago, and it was used mainly to couple to electron ionization (EI). This membrane separated the high vacuum of the EI and allowed analysis in real-time with basically no sample preparation.
Its “second life” – the condensed phase–MIMS (CP-MIMS) – was developed by Dr. Chris Gill at Vancouver Island University, where he used liquid chromatography and electrospray ionization to extend its power and potential and gain the means to [directly analyze] liquid samples. From that moment, he was mostly the only one working [on it].
[CP-MIMS] functioning is based on a membrane, which is made of mostly polydimethylsiloxane – silicon, basically – which is put inside the sample and behaves as a passive level of separation. It selectively allows only a restricted range of compounds to permeate over it, so only small molecules with a restricted range of polarity and a restricted range of dimensions are allowed to permeate, so no polymers and no salts, for instance, which are the worst enemy of electrospray ionization.
So it’s in all one step. The sample preparation required is very, very easy because, in most cases, there is no sample preparation. So, [it’s] easy, cheap, fast and with good performances, but of course, it has some limitations. No qualitative, non-targeted analysis – so only targeted analysis [is possible] – and the range of compounds it is suitable for is not so broad.
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
In your research presentation, you mentioned that this method has good sustainability credentials. Can you expand on that a bit further?
MP:
Researcher
University of Parma
Dr. Maurizio Piergiovanni holds a master's degree in industrial chemistry from the University of Bologna and obtained his PhD at the University of Urbino, where he worked on the development of an interface for coupling liquid chromatography and electron ionization mass spectrometry, called Liquid-EI. His research interests include the development of MS-based methods for food safety, food characterization and metabolomics.
Most other methods involve the use of solid phase extraction (SPE), which uses a disposable cartridge, and solvents and has various steps of preparation. All of these steps involve the use of time, energy and solvents and they produce waste. Also, for SPE, the volume of the sample needed is not low.
So, imagine you can avoid all of this stuff and perform analysis without doing anything. For this kind of application [the detection of bisphenols in drinking water and food simulants], there is no sample preparation. We are also validating our method now with beverages; we’re working with orange juice. In this case, a brief centrifugation is required, but that’s the only step. So, it’s very straightforward.
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
Regarding the membrane, do you have to refresh it after a certain number of uses?
MP:
Researcher
University of Parma
Dr. Maurizio Piergiovanni holds a master's degree in industrial chemistry from the University of Bologna and obtained his PhD at the University of Urbino, where he worked on the development of an interface for coupling liquid chromatography and electron ionization mass spectrometry, called Liquid-EI. His research interests include the development of MS-based methods for food safety, food characterization and metabolomics.
This is a good question. It depends, of course, on the sample. Working on tap water and food simulants, it lasts for more than 100 analyses. For real matrices, it lasts a little bit less. But, to the best of my experience, it lasts almost 100 analyses. The cleaning process is very easy – it’s just a rinse in distilled water, so there is no need to perform any kind of complicated preparation to the membrane; there is no need to change it until it doesn’t work. And in most cases, with the quality control samples, you can always have an idea of if it is still performing well.
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
Most of the work you presented was done on bisphenols, specifically bisphenol A. Why was that?
MP:
Researcher
University of Parma
Dr. Maurizio Piergiovanni holds a master's degree in industrial chemistry from the University of Bologna and obtained his PhD at the University of Urbino, where he worked on the development of an interface for coupling liquid chromatography and electron ionization mass spectrometry, called Liquid-EI. His research interests include the development of MS-based methods for food safety, food characterization and metabolomics.
Because it is one of the hottest topics. Our interest as analytical chemists was directed at the technique, of course, but one of the hottest topics right now is BPA because the European Food Safety Authority decreased the maximum tolerable daily intake of BPA by 20,000 times in 2023 – from 4 micrograms per kilo to 0.2 nanograms per kilo body weight. It was a huge reduction, and it increased the attention towards bisphenol A. It is quite a hot topic, and I think that this could be a cutting-edge technique for this topic.
AB:
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
Speaking of big topics, you also mentioned that you are working on a similar technique for monitoring PFAS?
MP:
Researcher
University of Parma
Dr. Maurizio Piergiovanni holds a master's degree in industrial chemistry from the University of Bologna and obtained his PhD at the University of Urbino, where he worked on the development of an interface for coupling liquid chromatography and electron ionization mass spectrometry, called Liquid-EI. His research interests include the development of MS-based methods for food safety, food characterization and metabolomics.
Yes, we’re also extending this potential to PFAS determination. It’s quite different because the molecules are very different. They’re more polar, so it’s more difficult to convince them to permeate [through the membrane].
Researcher
University of Parma
Dr. Nicolò Riboni is a researcher in the University of Parma’s Department of Chemistry, Life Sciences and Environmental Sustainability. His main research interests are the development of novel materials for sample pretreatments, data analysis and the development of analytical methods for the analysis of targeted compounds at ultra-trace levels.
There is also the problem of contamination because PFAS are present everywhere. You have to isolate the contaminants from the “real” PFAS contained in the packaging, for example, and so on.
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
How exactly do you adapt your approach to monitor PFAS? Do you change the structure of the membrane or is it functionalized in some way?
MP:
Researcher
University of Parma
Dr. Maurizio Piergiovanni holds a master's degree in industrial chemistry from the University of Bologna and obtained his PhD at the University of Urbino, where he worked on the development of an interface for coupling liquid chromatography and electron ionization mass spectrometry, called Liquid-EI. His research interests include the development of MS-based methods for food safety, food characterization and metabolomics.
This [altering the membrane] would be ideal, but currently, there is no alternative to the PDMS [polydimethylsiloxane] membrane. The only other material used now is Nafion [the brand name for a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer]. But, in the literature, authors have demonstrated that it does not provide any good advantage, especially comparing the price, which is 80 times higher.
So, the best [strategy] for us was to find a partner focusing on these polymers and these membranes to prepare some custom-made membranes for us. So, currently, we are going to work with the PDMS and we are trying to work over external factors.
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
How do you see the future of this research area developing?
Researcher
University of Parma
Dr. Maurizio Piergiovanni holds a master's degree in industrial chemistry from the University of Bologna and obtained his PhD at the University of Urbino, where he worked on the development of an interface for coupling liquid chromatography and electron ionization mass spectrometry, called Liquid-EI. His research interests include the development of MS-based methods for food safety, food characterization and metabolomics.
Firstly, I hope so many other people try to use it! This is my expectation, because I think it has really good potential. From my point of view, it’s important to be open to future modifications of the technique and the hardware. Most of the time, what you see these days is a major trend moving towards software applications, and increasing the information collected within each analysis from a software point of view. But there is also still the possibility to work on instrumentation and to provide improvements on it.
NR:
Researcher
University of Parma
Dr. Nicolò Riboni is a researcher in the University of Parma’s Department of Chemistry, Life Sciences and Environmental Sustainability. His main research interests are the development of novel materials for sample pretreatments, data analysis and the development of analytical methods for the analysis of targeted compounds at ultra-trace levels.
Changing the immediate membrane, that will be another interesting part. We want to try different materials – some materials may be more suitable for other classes of compounds, like PFAS and so on. Developing these kinds of “modified” membranes could be very, very interesting. In the application of such membranes, maybe they will also require different parameters to work and that could be a very interesting point, I think.
MP:
Researcher
University of Parma
Dr. Maurizio Piergiovanni holds a master's degree in industrial chemistry from the University of Bologna and obtained his PhD at the University of Urbino, where he worked on the development of an interface for coupling liquid chromatography and electron ionization mass spectrometry, called Liquid-EI. His research interests include the development of MS-based methods for food safety, food characterization and metabolomics.
We also just want to use this opportunity to thank our project, because the funding was crucial for supporting me as a scientist of course, but also for supporting all of the research activities. This is the OnFoods project, a partnership for the sustainable development of food and nutrition, funded under the Italian National Recovery and Resilience Plan (NRRP), which supports many of our activities in food research and also many other projects being presented here at RAFA.
