Determining PFAS (per- and polyfluoroalkyl substances) in soil typically involves advanced techniques like liquid chromatography-tandem mass spectrometry (LC-MS/MS) for sensitive and accurate detection. For both soil and plants, recent methods involve solid-phase extraction (SPE) paired with high-resolution mass spectrometry (HRMS), which allows detailed profiling of PFAS, including newer and emerging compounds. Another innovative approach is the use of enhanced sorbent materials that selectively capture PFAS, making extraction from environmental matrices more efficient and reducing interference from complex organic compounds found in soil and plant matter.

Determining PFAS (per- and polyfluoroalkyl substances) in soil and plants is challenging due to their complex chemical nature and environmental persistence. While gas chromatography (GC) has been commonly used, it’s limited in detecting PFAS due to the thermal stability requirements, so advanced methods generally rely on liquid chromatography and mass spectrometry. Here are some emerging techniques beyond GC:

1. Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS)

- Description: UHPLC-MS/MS has become a preferred method for PFAS detection due to its high sensitivity and specificity, which can detect PFAS down to parts per trillion (ppt) levels in soil and plant matrices.

- Advantages: Faster analysis time and increased resolution compared to traditional HPLC methods. It can separate and identify a wide range of PFAS compounds in complex samples.

2. Direct Injection Mass Spectrometry (DI-MS)

- Description: This method bypasses complex sample preparation, allowing for direct injection of samples into a mass spectrometer, which can be particularly useful for real-time analysis and monitoring.

- Advantages: Minimal sample prep, reduced time, and potential for in-field applications. However, it might require further refinement to handle high-matrix soil samples effectively.

3. Accelerated Solvent Extraction (ASE) Coupled with Liquid Chromatography-Mass Spectrometry (LC-MS)

- Description: ASE uses heated solvents under pressure to extract PFAS from soil and plant matrices, providing higher extraction efficiency. This is followed by LC-MS for quantification and identification.

- Advantages: Efficient for complex environmental matrices like soil, improving extraction rates while reducing the amount of solvent needed.

4. Solid Phase Microextraction (SPME) for PFAS in Plants and Soil

- Description: SPME is a solvent-free extraction technique, which allows the selective isolation of PFAS compounds from soil and plant samples before analysis with LC-MS/MS.

- Advantages: It’s less labor-intensive and minimizes contamination risks, making it suitable for PFAS studies focused on soil-plant interactions.

5. High-Resolution Mass Spectrometry (HRMS) for Non-Targeted Analysis

- Description: HRMS can detect a broad range of known and unknown PFAS compounds, ideal for discovering emerging PFAS contaminants in soil and plant systems.

- Advantages: HRMS allows for a more comprehensive profile of PFAS in samples, which can be critical for understanding PFAS fate and transport in soil and its interactions with microplastics.

6. Emerging Field-Sensitive Sensors and Spectroscopy Approaches

- While less common for precise quantification, field-portable PFAS sensors using methods like Surface-Enhanced Raman Spectroscopy (SERS) are under development. These could offer initial screening in the field, particularly in studies on PFAS-microplastic interactions in soil systems.

Combining these methods can be beneficial, especially given the potential interactions between microplastics and PFAS in soil, which may influence the mobility and bioavailability of these compounds in plant systems.

For comprehensive insights into advanced methods for PFAS detection in soil and plants, conducting a literature search on databases like the Directory of Open Access Journals (DOAJ) and Web of Science using targeted keywords can be highly effective. Keywords such as ‘PFAS detection in soil’, ‘PFAS in plants’, ‘microplastics and PFAS interactions’, ‘LC-MS/MS for PFAS’, and ‘soil PFAS extraction techniques’ may yield relevant peer-reviewed articles. This approach will help in identifying the latest methodologies and scientific developments, supporting your research on the mobilization and immobilization of PFAS and microplastics in soil ecosystems.