PromoChrom Extraction and Organomation Evaporation for EPA PFAS Methods

Per- and polyfluoroalkyl substances (PFAS) have become a major focus in environmental testing due to their persistence and potential health impacts. Efficient sample preparation is crucial for accurate PFAS analysis. This post explores how PromoChrom's extraction equipment and Organomation's blowdown evaporators work synergistically to optimize sample preparation for EPA Methods 537.1, 533, and ISO 21675, and walks you through the entire sample preparation process.

The Optimal Equipment to Prepare Water Samples for PFAS Analysis

PromoChrom SPE-03 Automated Extraction System

The PromoChrom SPE-03 8-Channel automated solid phase extraction (SPE) system is an ideal solution for PFAS extraction:

- Processes up to 8 samples simultaneously, significantly increasing throughput

- Compatible with both SPE cartridges and disks, offering flexibility for different sample types

- Automates all extraction steps, including bottle rinsing, ensuring consistency and reducing human error

- Positive pressure design ensures consistent flow rates across all channels

- Compact footprint saves valuable lab space

Organomation Nitrogen Blowdown Evaporators

Organomation's nitrogen blowdown evaporators complement the SPE-03 perfectly:

- The N-EVAP nitrogen evaporator is the sample concentrator most commonly cited in EPA methods due to the it's flexibility and ease of use

- However, environmental labs tasks with processing large batches of PFAS water samples typically rely on Organomation’s MULTIVAP evaporator

The Sample Prep Process for PFAS Analysis of Water Samples

Let's walk through the typical process for PFAS sample preparation and analysis using this equipment:

1. Sample Loading: Up to 8 water samples (typically 250-500 mL) are loaded onto the SPE-03 system.

2. Cartridge Conditioning: The SPE cartridges are automatically conditioned with methanol and water.

3. Sample Processing: The samples are passed through the SPE cartridges, allowing PFAS compounds to bind to the sorbent material.

4. Washing: The cartridges are washed to remove interfering compounds.

5. Elution: PFAS compounds are eluted from the cartridges using a small volume of methanol (typically 4-5 mL).

6. Container Rinsing: The SPE-03 rinses the original sample containers and uses this rinsate to elute the cartridges, maximizing PFAS recovery.

7. Transfer to Evaporator: The methanol extracts are transferred to evaporation tubes in the N-EVAP.

8. Evaporation Setup: The water bath is set to 60-65°C, and a gentle nitrogen flow is applied.

9. Controlled Evaporation: The extracts are evaporated down to a small volume (typically 1 mL) or near-dryness, depending on the specific method requirements.

10. Reconstitution: If evaporated to dryness, the samples are reconstituted with a small volume of methanol/water mixture.

11. Final Transfer: The concentrated extracts are transferred to autosampler vials.

12. LC-MS/MS Analysis: The samples are analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) following the specific parameters outlined in EPA Methods 537.1, 533, or ISO 21675.

Benefits To Combining PromoChrom and Organomation Equipment

Increased Throughput: Automation of both extraction and evaporation steps significantly reduces hands-on time.

Improved Reproducibility: Consistent extraction and evaporation conditions lead to more reliable results.

Versatility: The equipment can be easily adapted for different PFAS methods and sample types.

Quality Control: Both systems help meet the stringent QC requirements of EPA and ISO methods.

Optimized Recovery: The SPE-03's container rinsing feature and N-EVAP's controlled evaporation maximize PFAS recovery and prevent sample loss.

Distinguishing SPE Cartridge Drying from Sample Concentration

It's important to note that while the PromoChrom SPE-03 system incorporates a nitrogen air purge function to dry the SPE cartridge, this feature is distinct from the sample concentration process.

The nitrogen purge in the SPE-03 serves primarily to remove residual moisture from the sorbent bed after the washing step and before elution. This drying step is crucial for ensuring efficient elution of analytes and preventing water from interfering with subsequent analytical procedures.

However, it does not concentrate the sample itself. Sample concentration typically occurs after elution, often using separate equipment such as the Organomation N-EVAP or similar evaporation systems. Research has shown that the evaporation step is critical for PFAS analysis and requires careful control of parameters such as temperature and gas flow rate to prevent loss of volatile PFAS compounds.

For instance, studies recommend keeping water bath temperatures below 65°C and using gentle nitrogen flow to create a vortex effect without aggressive evaporation that could lead to analyte loss. This post-extraction concentration step is where the actual reduction in sample volume occurs, increasing the concentration of target analytes for improved detection limits in subsequent analyses.

The Gold Standard in PFAS Sample Prep

The combination of PromoChrom's SPE-03 and Organomation's N-EVAP creates a powerful, efficient sample preparation workflow for PFAS analysis. This tandem approach not only meets the requirements of EPA Methods 537.1, 533, and ISO 21675 but also enhances laboratory productivity and result quality. The automated extraction process, followed by controlled evaporation, ensures consistent and reliable sample preparation, crucial for accurate PFAS quantification.

As PFAS testing demands continue to grow, investing in such optimized workflows becomes increasingly valuable for environmental testing laboratories. By streamlining the sample preparation process from extraction through evaporation and into analysis, laboratories can handle higher sample volumes while maintaining the precision and accuracy required for these critical environmental analyses.