If you’re responsible for testing acrylamide in food samples, you already know the obstacles that come with analyzing this compound. Analysis can be difficult in general if there are background interferences, a multitude of analytes in a list, or if the analytes just don’t behave very well when it comes to running them on your analytical instrument.
Complex matrix effects
When extracting acrylamide from food samples, skipping or using an ineffective clean-up procedure can lead to significant issues during analysis. These problems arise because unwanted matrix components such as fats, lipids, and pigments can inhibit acrylamide detection. Matrix interference affects all analytical techniques, whether you’re using mass spectrometry or an absorbance spectrophotometer. Therefore, food samples must undergo a matrix clean-up before acrylamide analysis to ensure reliable results.
Challenging chemical properties
Acrylamide is very small molecule, with a molecular weight of just 71.01 g/mol. It’s also highly water soluble (log KOW -0.67), which makes it difficult to retain using reverse-phase chromatography. Additionally, acrylamide lacks a chromophore, which is a light absorbing group. As a result, ultraviolet (UV) detection is not an option. These properties make acrylamide particularly challenging to analyze using conventional methods.
Low concentration levels
The levels of acrylamide formed in food during cooking are typically very low, ranging from parts per billion (ppb) to parts per million (ppm). Detecting and accurately measuring such low concentrations requires highly sensitive instrumentation. Without the right system, results may be unreliable or fail to detect acrylamide altogether.
Lack of standardization across laboratories
Currently, there is no globally standardized method for analyzing acrylamide in food. Different laboratories use different methods and techniques, instruments and workflows, which makes it difficult to compare and interpret results.
Analytical techniques for acrylamide detection
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS): LC-MS/MS is the most widely used and popular technique. High performance liquid chromatography (HPLC) columns are often used for maximum reversed phase retention. HPLC columns packed with graphitized carbon or other highly retentive stationary phases help retain acrylamide despite its water solubility. This technique requires sample clean-up to minimize matrix effects caused by interfering components. Because acrylamide is such a small molecule, the MS/MS transitions occur at low masses, making the analysis vulnerable to interference from matrix components if not properly cleaned.
Liquid Chromatography-Mass Spectrometry (LC-MS): LC-MS is also commonly used for acrylamide analysis. The sample is first extracted and purified, then acrylamide is separated from other components using liquid chromatography and detected with mass spectrometry. Again, this can be difficult with the improper LC column because it is difficult to retain acrylamide by reversed phase HPLC. Without the tandem mass spectrometry of the LC-MS/MS, LC-MS sensitivity is limited making the removal of unwanted matrix interferences even more critical.
Gas Chromatography-Mass Spectrometry (GC-MS): GC-MS is another widely used technique, especially in laboratories where it has historically been favored for its cost-effectiveness. In this method, acrylamide must first be derivatized, meaning it is chemically modified into a more stable form, before separation using gas chromatography and detection using mass spectrometry. The derivatization process is labor-intensive and introduces another variable into the workflow, which could lead to loss of acrylamide and cause the reported result to be biased low.
Enzyme-Linked Immunosorbent Assay (ELISA): ELISA is a rapid and cost-effective method for acrylamide analysis. It uses antibodies that specifically bind to acrylamide to detect and quantify its presence in a sample. These methods can be much more challenging to set-up compared to MS methods to prevent cross reactivity. Cross-reactivity in ELISA testing occurs when an antibody binds to unintended sample components that are structurally similar to acrylamide. This non-specific binding can lead to false-positive results or reduced assay specificity. Not only that, but this technique is less sensitive than MS based techniques and is prone to interference from other components in the food matrix. To prevent matrix components from impacting precision and accuracy, the ELISA technique typically requires a cleanup step prior to analysis.
Why LC-MS/MS is the preferred method
Today, LC-MS/MS is becoming the preferred technique for analysis of acrylamide. With proper clean-up and removal of matrix interferences from the sample extract, it delivers greater precision, accuracy, sensitivity and acrylamide detection levels. In addition, LC-MS/MS is also applicable to many other food safety testing methods including pesticides, PFAS, and mycotoxins. This versatility makes it a valuable investment for laboratories conducting a wide range of analyses.
Download our technical poster: Application of a Novel Automated Sample Preparation Platform for the Determination of Acrylamide in Instant Coffee and Analysis Using UPLC-MS/MS Analysis
Related content/products/resources: