Seeing Through the Sham With AMS
Whether verifying the age of wine or tracking environmental goals, accelerator mass spectrometry is helping researchers understand the true nature of organic materials
Michael Mores | | 4 min read | Opinion
Economically-motivated adulteration is rampant in industries with valuable and vulnerable products, such as wine, whiskey, and essential oils. Buying and reselling old and/or rare formulations can bring high financial returns, presenting a lucrative opportunity for fraudsters who think nobody can tell the difference.
Not so fast. On the surface, a well-aged bottle of wine looks the same as one blended with other ingredients, such as juices and sweeteners. But there’s a niche science that is helping researchers (literally) see through the sham – accelerator mass spectrometry (AMS). For those unfamiliar, AMS is a method of detecting and measuring the amount of carbon-14 in a sample. Also known as radiocarbon dating, carbon-14 analysis allows researchers to verify whether a sample was formulated from its authentic source – or tampered with using synthetic ingredients.
Here’s how AMS works: Carbon-14 is either ingested or breathed in by a living organism – plants, animals, people. When the organism dies, the amount of carbon-14 in its system starts to decay over time. By measuring how much carbon-14 is left, you can calculate how long ago the organic ingredients within the sample died. This is how we can determine if wine is as well-aged as its label claims.
Researchers extract carbon from a sample through a chemical process called graphitization. This is typically done by heating samples to very high temperatures with acid, cupric oxide and silver wool. The heating process creates CO2 gas, which can then be trapped in a liquid nitrogen cooling line. The cupric oxide and wool absorb anything that’s not carbon. Then, you add the CO2 to iron powder and heat it and cool it again, creating a solid sample of carbon that resembles a fine-grain powder. From here, you can introduce the sample into the AMS system’s ion source.
The ion source accelerates the carbon before passing it through magnetic and electrostatic filters to separate it from nearby isotopes. Then, researchers can work their magic (well, science and math) to get the “percent modern carbon” or pMC. For reference, something that only recently died – like grapes from the last few years – would be close to 100 pMC. Something that has been dead for a long time – like crude oil – would be closer to 0 pMC. An 80 pMC, for example, tells you that old ingredients have been blended with new.
Though there are other ways to date organic materials, AMS is by far the quickest and most accurate – plus, it requires the smallest sample sizes. Other methods, like liquid scintillation counting (LSC), can take days or weeks depending on how old the material is. AMS, by comparison, can measure samples within hours.
As with many issues today, the food fraud problem was magnified by the pandemic. An increase in online sales and decrease in vetting because of various restrictions has led to an uptick in fraudulent activity. Now, manufacturers and suppliers are cracking down on what has become – in the case of wine – a billion-dollar problem. But the issue is not just financial: it’s environmental.
With the growing desire to go green, governments around the world – the US, Canada, Hungary, Poland, to name a few – are investing in biofuel to help reduce carbon emissions. In fact, in 2020, the US reinstated a biodiesel tax credit through 2022 (and likely beyond). The goal is to offset the higher price of biofuels compared with petroleum-derived fuel.
Unfortunately, this opens the door for more fraud – especially in light of the financial troubles many companies and governments have faced during the pandemic. AMS technology has already proved useful in confirming that organizations are using biofuel when they claim to be – ultimately ensuring that we are, in fact, moving towards a cleaner environment.
AMS technology may be famous for its carbon applications, but it doesn’t stop there. AMS can measure iodine, plutonium, aluminum, and more. For example, following the devastating 2011 earthquake, tsunami, and resulting nuclear meltdown in Japan, NEC’s AMS-based systems were able to detect the plumes of iodine and other harmful chemicals in the air in Seattle a few days later. From an environmental monitoring and protection perspective, this application is vital.
Nevertheless, AMS is a niche science. There are only about 150 AMS labs around the world – and not all of them are doing this type of research. How do we expand this science specialism to better support our world’s environmental goals and reduce fraud?
We start by making systems smaller, and we’re well on our way. Early AMS systems were 10–12 meters long. Today, the footprint is down to about 3–4 meters. Like other technologies, the form factor will likely continue to get smaller over time. And the infrastructure required to install and house these systems (and associated costs) will also decrease. We even envision a future with mobile AMS stations that can be moved site-to-site where analysis is needed.
Our goal is to make this science more accessible and cost-friendly to organizations and governments across the world; the applications are important and almost endless – and the stakes have never been higher.