As the alternative protein industry continues to grow rapidly, ensuring food safety and nutritional quality remains paramount. Elemental analysis using inductively coupled plasma mass spectrometry (ICP-MS) plays a critical role in evaluating both toxic and essential metal constituents throughout the production process.
To explore how ICP-MS is applied in this quickly evolving space, Yuri Tanaka, Product Marketing Manager at Agilent Technologies, provides expert insights into applications, regulatory challenges, sample preparation, instrument selection, and emerging trends.
What are the key applications of ICP-MS in alternative protein testing?
ICP-MS can be used in the research and development (R&D) of alternative proteins to monitor and control their metal constituents before the product is finalized. ICP-MS reveals the elemental composition of a sample and is frequently used in food analysis to detect toxic metal contaminants at parts per billion (ppb) levels.
Concentrations of lead, cadmium, mercury, arsenic, and other harmful elements in food are strictly regulated by various legislative bodies, including the European Union. By implementing testing at multiple stages, the source of contamination can be identified and eliminated, resulting in healthier food products.
In addition to screening contaminants, ICP-MS can provide a profile of important metal-based nutrients such as iron, calcium, and zinc. These constituents should also be considered during the development of alternative proteins intended to substitute traditional animal proteins.
What are the main challenges in trace metals analysis of alternative proteins?
Although food samples are generally not high in matrix, they can be complex with unexpected interferences, such as various chloride-based polyatomic ions arising from salt components. Particularly in the case of plant-based foods, some plants can retain more rare earth elements (REE) from soil, which can cause spectral interferences known as “doubly charged ion interference.”
Additionally, while regulations such as the United States Food and Drug Administration (US FDA) Elemental Analysis Manual (EAM) 4.5 or methods from the AOAC (Association of Official Analytical Collaboration) stipulate general requirements, fine-tuning of digestion procedures is often left up to the labs and analysts. When developing alternative proteins sourced from novel ingredients, traditional microwave digestion procedures may need to be modified for optimal safety and efficiency.
Furthermore, due to the novel nature of alternative proteins, finding suitable Certified Reference Materials of similar origin and composition to validate analysis methods may also be a significant challenge.
How is ICP-MS typically integrated into broader alternative protein testing workflows?
To perform effective ICP-MS analyses of solid foods such as alternative proteins, it is essential to incorporate a microwave digestion system in the sample preparation process. Analysis of solid samples by ICP-MS requires acid digestion assisted by heat. Some liquid samples also need acid digestion to fully dissolve suspended particulate matter. Compared to traditional digestion methods using hot plates and sand baths, microwave-assisted digestion provides a modern solution to ICP-MS sample preparation. Methods can be tailored with multiple stages, each adjustable for pressure, temperature, and duration. This approach provides enhanced safety and reproducibility in laboratory settings.
As businesses expand, labs often reach a point at which manually tracking and inputting samples into worksheets becomes impractical. This is where laboratory information management systems (LIMS) come into play. LIMS can be used to register sample details well in advance of their run, including any additional information that may be unrelated to the ICP-MS analyses, such as a product batch number. Many large-scale laboratories mark their samples with barcodes that correspond to entries in their LIMS so that any sample can be tracked and identified.
ICP-MS systems can also be paired and interfaced with a variety of other technologies and techniques to further expand the potential for analysis. For elements such as arsenic and mercury, where toxicity can vary greatly depending on the species, speciation analysis is possible using gas chromatography (GC) or high-performance liquid chromatography (HPLC) systems to separate the different targets before ionization in the plasma.
Alternatively, labs that are running GC or HPLC methods and seek to achieve greater detection limits, as well as elemental and isotopic data, may consider using ICP-MS as an ultra-high-sensitivity detector with an expansive dynamic range. These techniques are known as GC-ICP-MS and HPLC-ICP-MS.
What regulatory and technological advancements are shaping the future of ICP-MS in food testing?
The US FDA currently does not have overarching limits on heavy metal concentrations in all food products, but has recently been taking steps to implement more regulations, starting with baby food, as part of the "Closer to Zero" initiative.
Continuing in this direction, regulation of heavy metals in more food types is likely to follow, meaning the alternative protein industry may soon be impacted as well. This will add yet another method to introduce a compliance checkbox to tick, which can slow down work in already busy food labs.
To minimize the time sink of introducing metal analysis into a food lab, automation systems and workflows have been developed, including switching valve systems and auto-dilutors, which simplify sample preparation and free analysts' time.
Regarding the various interferences that may arise, ICP with triple quadrupole MS (ICP-QQQ) can provide multiple options to avoid and divert interferences. By filtering which ions enter the collision reaction chamber with the first quadrupole, reactions with various gases can be effectively controlled, maximizing the potential of reaction chemistry.
When labs are selecting an ICP-MS system for food or alternative protein analysis, what key performance indicators or features should they prioritize?
The major decision to make when selecting an ICP-MS system is evaluating whether your lab would benefit from the expanded capabilities of a triple-quadrupole unit over a simpler single-quadrupole ICP-MS. Lab managers should consider whether they will need to accurately measure low-level phosphorus, sulfur, arsenic, selenium, or lead isotopes, among other important elements.
Phosphorus and sulphur have been difficult to analyze at trace levels with conventional single-quadrupole ICP-MS due to intense polyatomic interferences, even when using helium in the collision-reaction cell.
Arsenic and selenium face interferences from doubly charged rare earth elements neodymium, samarium, and gadolinium, which similarly persist through the helium mode. In addition to similar polyatomic interferences, several lead isotopes face isobaric interferences from other elements that cannot be eliminated with kinetic discrimination.
The comprehensive solution to these types of interferences is the use of oxygen mass-shift mode with a triple-quadrupole ICP-MS, which can shift the target ions to a mass unaffected by these interferences.
What advice would you offer to laboratories just beginning to implement trace metal testing to prepare for emerging food regulations?
Introducing a new type of testing to any laboratory can be complicated and stressful, but there are steps that can be taken to mitigate these challenges. Firstly, the team should carefully review the regulations and methods, which may vary based on country and region, such as FDA EAM 4.7 in the USA, GB 5009.268-2025 in China, or BIS 10500 in India. Including necessary quality control (QC) steps in standard operating procedures from the beginning will ensure the lab delivers reliable results consistently.
Metal analysis can be challenging for analysts accustomed to working with organics, but hardware and software are designed for ease of use. Suppliers, including Agilent, should ensure that customers receive full support and relevant training.
