Within our research lab we have access to PFOA in powder form and PFOS in 100microgram/L methanol solution. We want to make a PFAS contaminated water to test a PFAS treatment technology. Does anyone have a method we could use to create a "real world" simulation of PFAS contaminated water from these products?
OK, First of all you may have to decide what concentration of PFOA and PFOS you are going to work with. What is the volume of water you are going to use for your experiments etc. then you have to calculate accordingly.
As you have powder form PFOA you can easily prepare your stock solution in MeOH with higher concentration using small volume of MeOH like 5 or 10 mL.
You have to calculate the mass of the PFOA taking its percentage purity in to consideration.
Then you can dilute (like 1:10 ) your stock solution in 10 mL of MeOH to prepare working solution, and that you can use to prepare your your desired experimental water sample depending on what concentration of PFOA you want to work with.
However, your PFOS stock solution is diluted 100 ug/L that means 100 ppb solution. As such you can only work with PFOS low concentrations (
Creating a PFAS-Contaminated Water Simulation
1. Prepare PFOA Stock Solution:
- Weigh out an appropriate amount of PFOA powder to create a concentrated stock solution (e.g., 1,000 mg/L).
- Dissolve the PFOA powder in deionized water until fully dissolved and the solution is homogeneous.
2. Prepare PFOS Stock Solution:
- Start with a 100 μg/L PFOS in methanol solution.
- Evaporate the methanol to isolate the PFOS compound.
- Redissolve the PFOS in deionized water to create a concentrated stock solution (e.g., 1,000 mg/L).
3. Mix PFOA and PFOS Stock Solutions:
- Combine the prepared PFOA and PFOS stock solutions in appropriate proportions, reflecting typical ratios found in real-world PFAS-contaminated waters, such as those impacted by Aqueous Film-Forming Foams (AFFF).
4. Dilute to Target Concentrations:
- Dilute the mixed PFOA and PFOS solution with deionized water to achieve the desired PFAS concentrations suitable for testing treatment technologies.
- Target concentrations can vary widely, from low parts per trillion (ng/L) to high parts per million (mg/L), depending on contamination levels.
5. Verify PFAS Concentrations:
- Analyze samples using methods like LC-MS/MS to confirm actual PFOA and PFOS concentrations.
- Adjust the solution as necessary to meet desired PFAS levels for accurate treatment technology evaluation.
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