满足 EPA 1633 方法要求的更快、更稳定样品前处理方案
摘要
非饮用水基质中的 PFAS 分析在样品前处理环节面临特殊困难。地表水和废水中的痕量 PFAS 检测，既要求极低的本底污染，又要能够应对复杂基质。Resprep PFAS 固相萃取小柱可快速、稳定地处理非饮用水样品（如 EPA 1633 方法所涵盖的水质类型），其将弱阴离子交换（WAX）与碳层合二为一，可在同一小柱内同时完成萃取和净化。此外，对于悬浮物含量较高的样品，还可选用自带过滤助剂的小柱，有效防止上样时发生堵塞。
引言
饮用水中的 PFAS 分析方法已应用多年，但非饮用水基质的固相萃取（SPE）方法长期缺位，导致许多实验室在分析地表水和废水时只能套用饮用水的方法。为此，EPA 于 2024 年 1 月正式发布 EPA 1633 方法[1]，其中规定使用弱阴离子交换（WAX）小柱进行SPE萃取（需手动填装玻璃棉），并配合分散型碳进行净化。然而，手动填装玻璃棉和额外增加碳净化步骤，不仅耗时繁琐，还容易引入污染，而且不同操作人员填装玻璃棉的差异也会增大结果波动。
为简化样品前处理流程，实验室可选用 Resprep PFAS 小柱。该小柱为双吸附床层结构，同时装填 WAX 和碳吸附剂，将 SPE 萃取与碳净化合二为一。自带过滤助剂的规格则免去了手动填装玻璃棉的麻烦，且防堵效果更佳。
实验
样品前处理
精密度、准确度及方法检出限（MDL）考察所用样品均在聚丙烯瓶中制备：取 500 mL 去离子水，按照 EPA 1633 方法第 11.2.4 节加入 25 μL 萃取内标（EIS，Wellington 产品号MPFAC‑ HIF‑ES）。准确度和回收率实验设 4 个平行加标样，加入 200 μL 天然 PFAS 混合标准品（Wellington 产品号 EPA‑1633STK），加标后萃取前浓度范围为 100～2500 ng/L。MDL 测定设 7 个加标样，加入 20 μL 稀释 20 倍的天然标准品，加标后萃取前浓度范围为 0.5～12.5 ng/L。同时制备 7 个空白样用于 MDL 计算。MDL 样品在 3 天内完成前处理和上机测定。
将 Resprep PFAS SPE 小柱（150 mg WAX，30 μm；50 mg CarboPrep Plus 石墨化碳，货号28930）安装至 ThermoAutoTrace PFAS 自动固相萃取仪。按 EPA 1633 方法第 11.4 节所述步骤进行样品萃取（流程见图 1）。萃取完成后，向萃取液中加入 25 μL 非提取内标溶液（Wellington，MPFAC‑ HIF‑ IS）。
过滤助剂效果验证实验采用 ASTM 替代废水[2]，稀释 2.5 倍至悬浮物浓度约 100 mg/L。将 Resprep PFAS SPE 小柱（含 2000 mg 过滤助剂、150 mg WAX（30 μm）和 50 mg CarboPrep Plus碳，货号 28931）安装于 Resprep QR‑12 真空固相萃取装置（货号28298‑VM）上，并配用快速更换衬管（货号 28310‑VM），通过 Resprep 样品输送系统（货号 26250）将样品转移至 SPE 小柱。上样体积为 500 mL，记录各小柱在不堵塞情况下能通过的实际样品体积，并与仅装填 WAX 的小柱（货号 28292）以及按方法 1633 第 12.1.1 节所述手动填装玻璃棉至小柱一半高度的 WAX 小柱（货号 24324）进行对比。
分析条件
萃取后的样品按以下条件进行 LC‑MS/MS 分析。为避免进样器上游管路中残留的 PFAS 与样品共洗脱，在进样器前安装 PFAS 延迟柱至关重要。系统经充分空白检验，未检出 PFAS 本底污染。
EPA 1633 方法 PFAS 分析的仪器条件
仪器系统: Waters ACQUITY Premier LC/Xevo TQ Absolute Triple Quadrupole MS
色谱柱:
• PFAS 延迟柱 (cat.# 27854)
• 分析柱: Force C18, 1.8 µm x 50 mm x 2.1 mm (cat.# 9634252)
进样量: 3 µL
流动相 A: 水, 5 mM乙酸铵
流动相 B: 甲醇
流速: 0.4 mL/min
柱温: 40 °C
梯度:
| Time (min) | %B |
| 0 | 20 |
| 6 | 95 |
| 6.6 | 95 |
| 6.61 | 20 |
| 7.5 | 20 |
离子源: 电喷雾 ESI
离子化方式: ESI-
扫描模式: MRM
标准曲线按方法 1633 表 4 所列浓度配制，拟合方式选择使相对标准误差百分比（%RSE）最小的曲线。
方法检出限 (MDL)
依据 EPA《方法检出限的定义与测定程序（修订版 2）》[3]，通过对 7 个空白样和 7 个低浓度加标样的测定结果计算 MDL。将加标样和空白样测定值的标准偏差分别乘以 Student’s t值（3.143），取两者中较大者作为该化合物的 MDL。
准确度与精密度
准确度和精密度通过对 4 个平行加标样的测定进行评估。计算各加标样的准确度（回收率），并与 EPA 1633 方法表 5 中的回收率要求进行比对。同时，计算加标样测定结果的相对标准偏差（RSD），并与表 5 中的精密度要求进行比较。同位素稀释内标的回收率根据加标样测定结果计算，并与方法 1633 表 6 中的回收率范围进行比对。
结果与讨论
方法性能验证实验
所有目标化合物均获得良好色谱峰形，代表性图谱见图 2。各天然 PFAS 目标物的 MDL、空白值、准确度和精密度结果汇总于表 I。计算所得的 MDL 均低于 EPA 1633 方法表 9 中所列的报告限；加标回收率在 77%～125% 之间，满足方法表 5 的要求；精密度良好，RSD 均≤25%。同位素稀释内标的回收率也在方法表 6 规定的范围内，结果见表II。
LC_EV0599
Peaks
| Peaks | tR (min) | Conc. (ng/L) | Precursor 1 | Product 1 | Product 2 | Precursor 2 | Product 1 | |
|---|---|---|---|---|---|---|---|---|
| 1. | Perfluoro-n-[1,2,3,4- 13C3]butanoic acid (13C3-PFBA) | 1.485 | 5 | 216 | 172 | – | – | – |
| 2. | Perfluoro-n-[1,2,3,4- 13C4]butanoic acid (13C4-PFBA) | 1.487 | 10 | 217 | 172 | – | – | – |
| 3. | Perfluorobutanoic acid (PFBA) | 1.489 | 10 | 213 | 169 | – | – | – |
| 4. | Perfluoro-3-methoxypropanoic acid (PFMPA) | 2.007 | 5 | 229 | 85 | – | – | – |
| 5. | 3-Perfluoropropyl propanoic acid (3:3FTCA) | 2.7 | 12.5 | 241 | 177 | 117 | – | – |
| 6. | Perfluoro-n-[1,2,3,4,5- 13C5]pentanoic acid (13C5-PFPeA) | 2.765 | 5 | 268 | 223 | – | – | – |
| 7. | Perfluoropentanoic acid (PFPeA) | 2.768 | 5 | 263 | 219 | 69 | – | – |
| 8. | Perfluorobutane sulfonate (PFBS) | 3.006 | 2.5 | 299 | 80 | 99 | – | – |
| 9. | Sodium perfluoro-1-[2,3,4- 13C3]butanesulfonate (13C3-PFBS) | 3.007 | 2.5 | 302 | 80 | 99 | – | – |
| 10. | Perfluoro-4-methoxybutanoic acid (PFMBA) | 3.071 | 5 | 279 | 85 | – | – | – |
| 11. | Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA) | 3.333 | 5 | 315 | 135 | 83 | – | – |
| 12. | Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | 3.493 | 5 | 295 | 201 | 85 | – | – |
| 13. | 1H,1H,2H,2H-perfluorohexane sulfonate (4:2 FTS) | 3.545 | 10 | 327 | 307 | 81 | – | – |
| 14. | Sodium 1H,1H,2H,2H-perfluoro-1-[1,2- 13C2]hexane sulfonate (13C2-4:2FTS) | 3.55 | 5 | 329 | 81 | 309 | – | – |
| 15. | Perfluorohexanoic acid (PFHxA) | 3.608 | 2.5 | 313 | 269 | 119 | – | – |
| 16. | Perfluoro-n-[1,2,3,4,6- 13C2]hexanoic acid (13C2-PFHxA) | 3.609 | 2.5 | 315 | 270 | 119 | – | – |
| 17. | Perfluoro-n-[1,2,3,4,6- 13C5]hexanoic acid (13C5-PFHxA) | 3.61 | 2.5 | 318 | 273 | 120 | – | – |
| 18. | Perfluoropentane sulfonate (PFPeS) | 3.718 | 2.5 | 349 | 80 | 99 | – | – |
| 19. | 2,3,3,3-Tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy13C3-propanoic acid (13C3-HFPO-DA) | 3.79 | 10 | 287 | 169 | 185 | – | – |
| 20. | Hexafluoropropylene oxide (HFPO-DA) | 3.795 | 10 | 285 | 169 | 185 | – | – |
| 21. | Perfluoroheptanoic acid (PFHpA) | 4.174 | 2.5 | 363 | 319 | 169 | – | – |
| 22. | Perfluoro-n-[1,2,3,4- 13C4]heptanoic acid (13C4-PFHpA) | 4.174 | 2.5 | 367 | 322 | – | – | – |
| 23. | Perfluoro-1-hexane[18O2]sulfonic acid (18O2-PFHxS) | 4.218 | 2.5 | 403 | 84 | – | – | – |
| 24. | Sodium perfluoro-1-[1,2,3- 13C3]hexanesulfonate (13C3-PFHxS) | 4.218 | 2.5 | 402 | 80 | 99 | – | – |
| 25. | Perfluorohexane sulfonate (PFHxS) | 4.22 | 2.5 | 399 | 80 | 99 | – | – |
| 26. | <a class="cmpd_link" title="View compound information for 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)” title=”View compound information for 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)” href=”https://ez.restek.com/compound/view/en/919005-14-4/4,8-Dioxa-3H-perfluorononanoic acid”>4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | 4.232 | 10 | 377 | 251 | 85 | – | – |
| 27. | 2H,2H,3H,3H-Perfluorooctanoic acid (5:3FTCA) | 4.247 | 62.5 | 341 | 237 | 217 | – | – |
| 28. | 1H,1H,2H,2H-perfluorooctane sulfonate (6:2 FTS) | 4.58 | 10 | 427 | 407 | 81 | – | – |
| 29. | Sodium 1H,1H,2H,2H-perfluoro-1-[1,2-13C2]-octane sulfonate (13C2-6:2FTS) | 4.581 | 5 | 429 | 81 | 409 | – | – |
| 30. | Perfluoro-n-[ 13C8]octanoic acid (13C8-PFOA) | 4.598 | 2.5 | 421 | 376 | – | – | – |
| 31. | Perfluorooctanoic acid (PFOA) | 4.601 | 2.5 | 413 | 369 | 169 | – | – |
| 32. | Perfluoro-n-[ 13C4]octanoic acid (13C4-PFOA) | 4.601 | 2.5 | 417 | 172 | – | – | – |
| 33. | Perfluoroheptane sulfonate (PFHpS) | 4.621 | 2.5 | 449 | 80 | 99 | – | – |
| 34. | Perfluorononanoic acid (PFNA) | 4.944 | 2.5 | 463 | 419 | 219 | – | – |
| 35. | Perfluoro-n-[ 13C5]nonanoic acid (13C5-PFNA) | 4.944 | 1.25 | 468 | 423 | – | – | – |
| 36. | Perfluoro-n-[ 13C9]nonanoic acid (13C9-PFNA) | 4.944 | 1.25 | 472 | 427 | – | – | – |
| 37. | Perfluorooctane sulfonate (PFOS) | 4.949 | 2.5 | 499 | 80 | 99 | – | – |
| 38. | Sodium perfluoro-[ 13C4]octanesulfonate (13C4-PFOS) | 4.95 | 2.5 | 503 | 80 | 99 | – | – |
| 39. | Sodium perfluoro-[ 13C8]octanesulfonate (13C8-PFOS) | 4.95 | 2.5 | 507 | 80 | 99 | – | – |
| 40. | 3-Perfluoroheptyl propanoic acid (7:3FTCA) | 5.046 | 62.5 | 441 | 317 | 337 | – | – |
| 41. | 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS) | 5.114 | 10 | 531 | 351 | – | 533 | 353 |
| 42. | Perfluorodecanoic acid (PFDA) | 5.237 | 2.5 | 513 | 469 | 219 | – | – |
| 43. | Perfluoro-n-[1,2,3,4,5,6- 13C2]decanoic acid (13C2-PFDA) | 5.237 | 1.25 | 515 | 470 | – | – | – |
| 44. | Perfluoro-n-[1,2,3,4,5,6- 13C6]decanoic acid (13C6-PFDA) | 5.237 | 1.25 | 519 | 474 | – | – | – |
| 45. | 1H,1H,2H,2H-perfluorodecane sulfonate (8:2 FTS) | 5.238 | 10 | 527 | 507 | 81 | – | – |
| 46. | Sodium 1H,1H,2H,2H-perfluoro-1-[1,2- 13C2]-decane sulfonate (13C2-8:2FTS) | 5.238 | 5 | 529 | 81 | 509 | – | – |
| 47. | Perfluorononanesulfonic acid (PFNS) | 5.239 | 2.5 | 549 | 80 | 99 | – | – |
| 48. | N-methyl-d 3-perfluoro-1-octanesulfonamidoacetic acid (D3-NMeFOSAA) | 5.361 | 5 | 573 | 419 | – | – | – |
| 49. | N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | 5.366 | 2.5 | 570 | 419 | 483 | – | – |
| 50. | Perfluorodecanesulfonic acid (PFDS) | 5.475 | 2.5 | 599 | 80 | 99 | – | – |
| 51. | Perfluoroundecanoic acid (PFUnA) | 5.486 | 2.5 | 563 | 519 | 269 | – | – |
| 52. | Perfluoro-n-[1,2,3,4,5,6,7- 13C7]undecanoic acid (13C7-PFUnA) | 5.486 | 1.25 | 570 | 525 | – | – | – |
| 53. | N-ethyl-d 5-perfluoro-1-octanesulfonamidoacetic acid (D5-NEtFOSAA) | 5.487 | 5 | 589 | 419 | – | – | – |
| 54. | N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | 5.487 | 2.5 | 584 | 419 | 526 | – | – |
| 55. | 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | 5.59 | 10 | 631 | 451 | – | 633 | 453 |
| 56. | Perfluorooctanesulfonamide (PFOSA) | 5.669 | 2.5 | 498 | 78 | 478 | – | – |
| 57. | Perfluoro-1-[ 13C8]octanesulfonamide (13C8-PFOSA) | 5.669 | 2.5 | 506 | 78 | – | – | – |
| 58. | Perfluorododecanoic acid (PFDoA) | 5.691 | 2.5 | 613 | 569 | 319 | – | – |
| 59. | Perfluoro-n-[1,2- 13C2]dodecanoic acid (13C2-PFDoA) | 5.692 | 1.25 | 615 | 570 | – | – | – |
| 60. | Perfluorododecanesulfonic acid (PFDoS) | 5.861 | 2.5 | 699 | 80 | 99 | – | – |
| 61. | Perfluorotridecanoic acid (PFTrDA) | 5.876 | 2.5 | 663 | 619 | 169 | – | – |
| 62. | Perfluorotetradecanoic acid (PFTeDA) | 6.031 | 2.5 | 713 | 669 | 169 | – | – |
| 63. | Perfluoro-n-[1,2- 13C2]tetradecanoic acid (13C2-PFTeDA) | 6.031 | 1.25 | 715 | 670 | – | – | – |
| 64. | N-methyl perfluorooctanesulfonamide (NMeFOSA) | 6.158 | 2.5 | 512 | 219 | 169 | – | – |
| 65. | N-methyl-D 3-perfluoro-1-octanesulfonamide (D3-NMeFOSA) | 6.159 | 2.5 | 515 | 219 | – | – | – |
| 66. | N-methyl perfluorooctanesulfonamidoethanol (NMeFOSE) | 6.166 | 25 | 616 | 59 | – | – | – |
| 67. | N-methyl-D 7-perfluorooctanesulfonamidoethanol (D7-NMeFOSE) | 6.167 | 25 | 623 | 59 | – | – | – |
| 68. | N-ethyl-D 5-perfluoro-1-octanesulfonamide (D5-NEtFOSA) | 6.295 | 2.5 | 531 | 219 | – | – | – |
| 69. | N-ethyl perfluorooctanesulfonamide (NEtFOSA) | 6.296 | 2.5 | 526 | 219 | 169 | – | – |
| 70. | N-ethyl perfluorooctanesulfonamidoethanol (NEtFOSE) | 6.298 | 25 | 630 | 59 | – | – | – |
| 71. | N-ethyl-D 9-perfluorooctanesulfonamidoethanol (D9-NEtFOSE) | 6.298 | 25 | 639 | 59 | – | – | – |
Conditions
| Column | Force C18 (cat.# 9634252) | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dimensions: | 50 mm x 2.1 mm ID | ||||||||||||||||||||||||
| Particle Size: | 1.8 µm | ||||||||||||||||||||||||
| Pore Size: | 100 Å | ||||||||||||||||||||||||
| Temp.: | 40 °C | ||||||||||||||||||||||||
| Standard/Sample | |||||||||||||||||||||||||
| Inj. Vol.: | 3 µL | ||||||||||||||||||||||||
| Mobile Phase | |||||||||||||||||||||||||
| A: | Water, 5 mM ammonium acetate | ||||||||||||||||||||||||
| B: | Methanol | ||||||||||||||||||||||||
| |||||||||||||||||||||||||
| Max Pressure: | ~400 bar |
| Detector | Waters Xevo TQ-S |
|---|---|
| Ion Mode: | ESI- |
| Mode: | MRM |
| Instrument | Waters ACQUITY Premier |
| Sample Preparation | Resprep PFAS cartridges (cat.# 28930) and a Thermo AutoTrace PFAS instrument were used for the following sample preparation procedure. 1. Spike 500 mL DI water with 200 µL of Wellington EPA-1633STK and 25 µL of Wellington MPFAC-HIF-ES. 2. Rinse cartridge with 15 mL of 1% ammonium hydroxide in methanol. 3. Rinse with 5 mL of 0.3 M formic acid in water. 4. Load sample onto SPE cartridge dropwise at 5 mL/min. 5. Rinse bottle with 5 mL DI water, load onto SPE cartridge dropwise at 5 mL/min, repeat. 6. Rinse bottle with 5 mL of 1:1 0.1 M formic acid:methanol and load onto SPE cartridge dropwise at 5 mL/min. 7. Flow nitrogen through cartridge for 15 minutes. 8. Rinse bottles with 5 mL of 1% ammonium hydroxide in methanol, elute into collection vessel. 9. Add 25 µL of concentrated acetic acid and 25 µL of Wellington MPFAC-HIF-IS. 10. Transfer aliquot to autosampler vial (cat. # 23243) and cap (cat. # 23244). |
| Notes | A PFAS delay column (cat.# 27854) was installed before the injector. |
表 I：天然 PFAS 的方法检出限、空白、精密度及准确度实验结果
| 化合物 | 简称 | MDL (ng/L) | 空白 (ng/L)* | 准确度(%) | %RSD |
| Perfluorobutanoic acid | PFBA | 0.34 | ND | 112 | 5 |
| Perfluoro-3-methoxypropanoic acid | PFMPA | 0.20 | ND | 109 | 6 |
| 3-Perfluoropropyl propanoic acid | 3:3FTCA | 0.31 | ND | 95 | 6 |
| Perfluoropentanoic acid | PFPeA | 0.26 | ND | 111 | 6 |
| Perfluorobutane sulfonate | PFBS | 0.19 | ND | 101 | 5 |
| Perfluoro-4-methoxybutanoic acid | PFMBA | 0.18 | ND | 111 | 6 |
| Perfluoro(2-ethoxyethane)sulfonic acid | PFEESA | 0.15 | ND | 94 | 5 |
| Nonafluoro-3,6-dioxaheptanoic acid | NFDHA | 0.46 | ND | 121 | 5 |
| 1H,1H,2H,2H-perfluorohexane sulfonate | 4:2 FTS | 0.36 | ND | 104 | 5 |
| 2H,2H,3H,3H-Perfluorooctanoic acid | 5:3FTCA | 1.48 | ND | 102 | 6 |
| Perfluorohexanoic acid | PFHxA | 0.08 | ND | 113 | 5 |
| Perfluoropentane sulfonate | PFPeS | 0.07 | ND | 122 | 4 |
| Hexafluoropropylene oxide dimer acid | HFPO-DA | 0.40 | ND | 114 | 12 |
| Perfluoroheptanoic acid | PFHpA | 0.08 | ND | 109 | 5 |
| Perfluorohexane sulfonate | PFHxS | 0.07 | ND | 104 | 7 |
| 4,8-Dioxa-3H-perfluorononanoic acid | ADONA | 0.39 | ND | 99 | 9 |
| 1H,1H,2H,2H-perfluorooctane sulfonate | 6:2 FTS | 0.37 | ND | 107 | 4 |
| 3-Perfluoroheptyl propanoic acid | 7:3FTCA | 2.32 | ND | 100 | 6 |
| Perfluoroheptane sulfonate | PFHpS | 0.76 | ND | 121 | 8 |
| Perfluorooctanoic acid | PFOA | 0.32 | ND | 104 | 2 |
| Perfluorooctane sulfonate | PFOS | 0.20 | ND | 112 | 7 |
| Perfluorooctanesulfonamide | PFOSA | 0.21 | ND | 81 | 11 |
| Perfluorononanoic acid | PFNA | 0.08 | ND | 114 | 5 |
| N-methyl perfluorooctanesulfonamide | NMeFOSA | 0.07 | ND | 104 | 13 |
| 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid | 9Cl-PF3ONS | 0.61 | ND | 85 | 11 |
| Perfluorononanesulfonic acid | PFNS | 0.25 | ND | 79 | 7 |
| Perfluorodecanoic acid | PFDA | 0.18 | ND | 117 | 8 |
| N-ethyl perfluorooctanesulfonamide | NEtFOSA | 0.14 | ND | 112 | 15 |
| 1H,1H,2H,2H-perfluorodecane sulfonate | 8:2 FTS | 0.91 | ND | 113 | 11 |
| Perfluoroundecanoic acid | PFUnA | 0.26 | ND | 125 | 12 |
| N-methyl perfluorooctanesulfonamidoacetic acid | NMeFOSAA | 0.15 | ND | 95 | 12 |
| N-ethyl perfluorooctanesulfonamidoacetic acid | NEtFOSAA | 0.23 | ND | 93 | 12 |
| Perfluorodecanesulfonic acid | PFDS | 0.25 | ND | 94 | 23 |
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid | 11Cl-PF3OUdS | 0.56 | ND | 77 | 25 |
| Perfluorododecanoic acid | PFDoA | 0.27 | ND | 118 | 15 |
| N-methyl perfluorooctanesulfonamidoethanol | NMeFOSE | 1.11 | ND | 106 | 9 |
| N-ethyl perfluorooctanesulfonamidoethanol | NEtFOSE | 1.10 | ND | 111 | 9 |
| Perfluorotridecanoic acid | PFTrDA | 0.33 | ND | 108 | 15 |
| Perfluorododecanesulfonic acid | PFDoS | 0.13 | ND | 89 | 12 |
| Perfluorotetradecanoic acid | PFTeDA | 0.32 | ND | 102 | 23 |
*ND = Not detected above MDL
表 II: 同位素稀释标准品的精密度与准确度实验结果
| 化合物 | 简称 | 准确度 (%) | %RSD |
| Perfluoro-n-[1,2,3,4- 13C4]butanoic acid | 13C4-PFBA | 88 | 4 |
| Perfluoro-n-[1,2,3,4,5- 13C5]pentanoic acid | 13C5-PFPeA | 88 | 5 |
| Sodium perfluoro-1-[2,3,4- 13C3]butanesulfonate | 13C3-PFBS | 97 | 3 |
| Sodium 1H,1H,2H,2H-perfluoro-1-[1,2- 13C2]hexane sulfonate | 13C2-4:2FTS | 95 | 8 |
| Perfluoro-n-[1,2,3,4,6- 13C5]hexanoic acid | 13C5-PFHxA | 122 | 2 |
| 2,3,3,3-Tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy13C3-propanoic acid | 13C3-HFPO-DA | 92 | 4 |
| Perfluoro-n-[1,2,3,4- 13C4]heptanoic acid | 13C4-PFHpA | 107 | 4 |
| Sodium perfluoro-1-[1,2,3- 13C3]hexanesulfonate | 13C3-PFHxS | 102 | 4 |
| Sodium 1H,1H,2H,2H-perfluoro-1-[1,2-13C2]-octane sulfonate | 13C2-6:2FTS | 83 | 5 |
| Perfluoro-n-[ 13C8]octanoic acid | 13C8-PFOA | 106 | 5 |
| Sodium perfluoro-[ 13C8]octanesulfonate | 13C8-PFOS | 77 | 7 |
| Perfluoro-1-[ 13C8]octanesulfonamide | 13C8-PFOSA | 94 | 11 |
| N-methyl-d 3-perfluoro-1-octanesulfonamidoacetic acid | D3-NMeFOSAA | 85 | 9 |
| N-ethyl-d 5-perfluoro-1-octanesulfonamidoacetic acid | D5-NEtFOSAA | 87 | 11 |
| Perfluoro-n-[ 13C9]nonanoic acid | 13C9-PFNA | 83 | 7 |
| Perfluoro-n-[1,2,3,4,5,6- 13C6]decanoic acid | 13C6-PFDA | 80 | 7 |
| Sodium 1H,1H,2H,2H-perfluoro-1-[1,2- 13C2]-decane sulfonate | 13C2-8:2FTS | 84 | 5 |
| N-methyl-D 7-perfluorooctanesulfonamidoethanol | D7-NMeFOSE | 108 | 13 |
| N-ethyl-D 9-perfluorooctanesulfonamidoethanol | D9-NEtFOSE | 88 | 17 |
| N-methyl-D 3-perfluoro-1-octanesulfonamide | D3-NMeFOSA | 84 | 8 |
| N-ethyl-D 5-perfluoro-1-octanesulfonamide | D5-NEtFOSA | 111 | 10 |
| Perfluoro-n-[1,2,3,4,5,6,7- 13C7]undecanoic acid | 13C7-PFUnA | 78 | 13 |
| Perfluoro-n-[1,2- 13C2]dodecanoic acid | 13C2-PFDoA | 45 | 24 |
| Perfluoro-n-[1,2- 13C2]tetradecanoic acid | 13C2-PFTeDA | 36 | 21 |
过滤与上样流畅性实验
Resprep PFAS 固相萃取小柱有带和不带预填充助滤剂两种规格可供选用。与使用手动填装玻璃棉相比，带助滤剂可实现更快、更一致的样品前处理结果。如图 3 所示，助滤剂还提供了另一个显著优势：它能够防止小柱堵塞，从而可以处理全量样品，节省了二次萃取的时间、人力和成本。在此对比中，只有带过滤助剂的 Resprep PFAS 小柱能够完全萃取 500 mL 含有 100mg/L 悬浮固体的替代废水基质。与玻璃棉（只能萃取不到一半的样品）以及单独使用 WAX（只能萃取不到十分之一的样品）相比，这是一个显著的改进。
结论
非饮用水基质给采用固相萃取（SPE）进行样品前处理的实验室带来了独特挑战。Resprep PFAS 小柱可使实验室更高效地处理复杂水质基质，同时满足甚至优于 EPA 1633 方法对 PFAS 分析的要求。更多相关产品、方法及技术资源，请访问 www.restek.com/PFAS 。
引用文献
- U.S. Environmental Protection Agency, Method 1633, Analysis of per- and polyfluoroalkyl substances (PFAS) in aqueous, solid, biosolids, and tissue samples by LC-MS/MS, January 2024. https://cfpub.epa.gov/si/si_public_record_report.cfm?Lab=CESER&dirEntryId=356428
- ASTM International, D5905-98(2018), Standard practice for the preparation of substitute wastewater, December 2018. https://www.astm.org/d5905-98r18.html
- U.S. Environmental Protection Agency, Definition and procedure for the determination of the method detection limit, Revision 2, December 2016. https://www.epa.gov/sites/default/files/2016-12/documents/mdl-procedure_rev2_12-13-2016.pdf
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