Feasibility of a Selective Epoxidation Technique for Use in Quantification of Peracetic Acid in Air Samples Collected on Sorbent Tubes-Dataset

Data Collection Methods

1. Preparation of Peracetic Acid Solutions
   • Peracetic acid solutions were prepared using 32% peracetic acid in acetic acid (Sigma Aldrich) solution diluted to 1 mL with deionized H₂O (18 MΩ cm).
   • Concentration range: 0.041-3.27 M.

2. PAA Solution Experiments
   • PAA solutions were prepared as described above.
   • 1 mL of acetonitrile (ACN), 2 µL of PAA solution, and 100 µL cyclohexene were combined in a clean 7-mL clear glass vial.
   • After 24-hour reaction at room temperature, 1.5 mL of 0.178 mM 1-bromohexane in n-hexane solution was added to extract the epoxide product.

3. Control Solution Experiments
   • Control experiments were performed using cyclohexene oxide aliquots of the same concentration as the PAA samples. These were prepared using cyclohexene oxide (CHO) (98%, Sigma Aldrich) diluted to 1 mL in acetonitrile.
   • Five mL of acetonitrile, 2 µL of CHO solution, and 100 µL cyclohexene were combined in clean, 16-mL glass vials.
   • Samples were processed using same procedure as above after 24-hour reaction period, and data were compared to that of analogous PAA product samples (also prepared in 5 mL of acetonitrile).

4. Contaminant Reactivity Experiments
   • A 100-ppb PAA solution was prepared as described above.
   • Hydrogen peroxide solutions (1000 and 10000 ppb) were prepared using a 30% (w/w) hydrogen peroxide solution purchased from Sigma Aldrich and deionized H₂O (18 MΩ cm).
   • Acetic acid solutions (1000 and 10000 ppb) were prepared using glacial acetic (Sigma Aldrich) and deionized H₂O (18 MΩ cm).
   • 1 mL of ACN, varying quantities of PAA and HP/AA, and 100 µL cyclohexene were combined in a clean 7-mL glass vial.
   • Samples reacted for 24 hours, after which time they were processed as described above.

5. PAA Chamber Creation and Sorbent Tube Sampling
   • A Teflon chamber containing PAA-spiked air was prepared by introducing 2 µL of the prepared PAA solution of known concentration in 80 L of 50% relative humidity air.
   • Using 350-mg XAD-7 sorbent tubes (SKC Inc.) and SKC personal sampling pumps, the PAA-containing air was sampled for 4 hours at 250 mL/min.

6. Sample Processing
   • After sampling, the sorbent from the tube was treated with 1 mL ACN (Sigma Aldrich) and 100 µL cyclohexene (Sigma Aldrich) in a clean 7-mL clear glass vial.
   • After 24-hour reaction at room temperature,1.5 mL of 0.178 mM 1-bromohexane (Sigma Aldrich) in n-hexane (Sigma Aldrich) solution was added to the sorbent to extract epoxide product.

7. Vial Experiments Containing Sorbent for Calibration Curve
   • PAA solutions were prepared as described above.
   • The sorbent from a fresh 350-mg XAD-7 sorbent tube, 1 mL of ACN, and 2 µL of PAA solution of known concentration were combined in a clean 7-mL glass vial.
   • 100 µL cyclohexene was added to vial, and the sample was vortexed.
   • Following 24-hour reaction at room temperature, sample was processed as described above.

8. Fortified Sampler Experiments
   • PAA solutions were prepared as described above.
   • A Teflon chamber was filled with 80 L of clean air at 50% relative humidity.
   • A 350-mg XAD-7 sorbent tube was loaded with 2 µL of PAA solution of known concentration.
   • The spiked tube was attached to the sampling pump and to the Teflon chamber.
   • Clean air from the chamber was pulled across the spiked sorbent tube for 4 hours at 250 mL/min.
   • Sample was processed as described above.

9. Sorbent Capacity Experiments
   • A 2000-ppb PAA solution was prepared as described above.
   • 2 µL of the solution was added to the Teflon chamber, which was subsequently filled.
   • A second sorbent tube, a 175-mg XAD-7 tube, was added behind the 350-mg XAD-7 tube in the sampling train.
   • Sampling proceeded as described above.
   • Each tube was processed separately as described above.

10. Sorbent Tube Storage Experiments
    • Chamber was prepared and sampled as described above.
    • Following sampling, sorbent tubes were sealed on both ends, wrapped in foil to prevent light exposure, and were stored in 1 of 2 ways:
      1. At room temperature (approx. 25˚C) for 72 hours.
      2. At -20˚C for 72 hours.
    • Tube was processed as described above following storage, except 5 mL of acetonitrile were used instead of 1 mL.

11. Stability and Variable Sampling Time Experiments
    • Chambers were prepared as described above.
    • Two treatments conducted:
      1. PAA-spiked chamber was sampled at 250 mL/min of PAA-spiked gas for 4 hours, with the sorbent tube being replaced with a fresh tube at the end of each 1-hour period. Each of the 4 resulting sorbent tubes were processed separately as described above.
      2. PAA-spiked chamber was sampled at 1 L/min for 15 minutes (total volume = 15 L). Samples processed as described above.