Table 1.
Limits of detection (LOD), limit of quantification (LOQ), and method blank detections for PFAS in biosolid samples. LOD/LOQ values for the analytes without a corresponding isotopically labelled standard were predicted using a structurally similar isotopically labelled standard. Detections and relative standard deviations (RSD) of PFAS in biosolid samples are expressed in ng/g. For analytes detected in the method blank, the signal of the detection must be at least three times greater than the signal detected in the method blank to be reported (bracketed next to LOQ value). Non-detections are listed as n.d., and n.r. means the signals observed are non-reportable because they are either below LOQ or below 3 × the method blanks
| LOD (ng/g) | LOQ [Adjusted] (ng/g) | Method blank detection (ppb) | Waste activated sludge (ng/g) | RSD (%) | Primary solids (ng/g) | RSD (%) | |
|---|---|---|---|---|---|---|---|
| Carboxylates | |||||||
| PFBA | 7.7 | 25.7 | - | n.d. | - | n.d. | - |
| PFPeA | 1.2 | 4.1 | - | < LOQ | 9 | n.d. | - |
| PFHxA | 0.6 | 2.1 | - | 6.5 | 8 | < LOQ | 46 |
| PFHpA | 0.5 | 1.5 [9.9] | 3.3 | n.r. | - | n.r. | - |
| PFOA | 0.5 | 1.7 [1.5] | 0.5 | 7.5 | 7 | 4.2 | 39 |
| PFNA | 1.0 | 3.5 | - | < LOQ | 8 | < LOQ | 61 |
| PFDA | 0.9 | 2.9 | - | 8.0 | 6 | 3.6 | 58 |
| PFUdA | 1.6 | 5.2 | - | 21.1 | 5 | 8.7 | 161 |
| PFDoA | 1.4 | 4.6 | - | 8.9 | 4 | n.d. | - |
| PFTrDA | 0.8 | 2.8 | - | 84.6 | 4 | n.d. | - |
| PFTeDA | 0.8 | 2.8 | - | n.d. | - | n.d. | - |
| Sulfonates | |||||||
| PFPrS | 0.6 | 1.9 | - | n.d. | - | n.d. | - |
| PFBS | 0.6 | 1.9 | - | n.d. | - | n.d. | - |
| PFPeS | 0.6 | 2.0 | - | n.d. | - | n.d. | - |
| PFHxS | 0.6 | 2.0 | - | < LOQ (n = 2) | - | n.d. | - |
| PFHpS | 0.9 | 3.0 | 1.0 | n.d. | - | n.d. | - |
| PFOS | 1.0 | 3.3 [9.0] | 3.0 | 30.6 | 6 | 15.3 | 44 |
| PFNS | 1.0 | 3.3 | - | n.d. | - | n.d. | - |
| PFDS | 1.0 | 3.3 | - | < LOQ | - | n.d. | - |
| Fluorotelomer Sulfonate | |||||||
| 4:2 FTS | 0.8 | 2.8 | - | n.d. | - | n.d. | - |
| 6:2 FTS | 0.8 | 2.6 | - | n.d. | - | n.d. | - |
| 8:2 FTS | 1.2 | 4.2 [278.1] | 92.7 | n.r. | - | n.r. | - |
| Sulfonamides | |||||||
| FBSA | 4.7 | 15.5 | - | n.d. | - | n.d. | - |
| FOSA | 4.7 | 15.5 | - | < LOQ | 8 | n.d. | - |
| N-EtFOSAA | 3.8 | 12.6 | - | < LOQ | 12 | n.d. | - |
| N-MeFOSAA | 2.8 | 9.3 | - | 48.3 | 9 | 33.8 | 23 |
| Σ PFAS | NA | NA | - | 215.4 | NA | 65.5 | NA |