How to Extract Pesticides and Flame Retardants from Drinking Water: A Complete EPA Method 527.1 Protocol
- Apr 30
- 7 min read
Updated: 15 hours ago
Authors: Xiaohui Zhang, Michael Apsokardu
Study summary: A validated EPA Method 527.1 workflow using the Empore™ SDB-XC SPE Disk with the EZ-Trace SPE Workstation extracts 26 pesticides and flame retardants (including pyrethroids, organophosphates, and polybrominated diphenyl ethers) from 1 L drinking water samples. With 1.0 and 2.0 µg/L spike levels (n=4), 92% of analytes fell within EPA's 70-130% acceptable recovery range with average recovery of 102.7% (RSD 15.8%) and 102.6% (RSD 12.7%) respectively.
TL;DR: If you need an EPA Method 527.1-compliant workflow for analyzing pesticides and flame retardants (including BDE-47, BDE-99, BDE-100, BDE-153) in drinking water, the Empore™ SDB-XC Disk + EZ-Trace combination handles 26 target analytes with 92% within the EPA-acceptable recovery range. The EZ-Trace processes four samples simultaneously, significantly reducing prep time per batch.
Study at a Glance
Introduction: Why EPA Method 527.1 Matters
EPA Method 527.1 targets 26 semi-volatile organic compounds in drinking water designed to detect and quantify various pesticides and chemical additives in flame retardants. The method covers several chemistry classes of regulatory concern:
Pyrethroid pesticides — highly effective insecticides with low mammalian toxicity but known toxicity to aquatic organisms including fish
Organophosphate pesticides — common agricultural and household pest control compounds
Herbicides — including triazines and substituted urea compounds
Polybrominated biphenyls (PBBs) — used as flame retardant additives, known carcinogens
Polybrominated diphenyl ethers (PBDEs) — including BDE-47, BDE-99, BDE-100, and BDE-153, also known carcinogens
This application note demonstrates a validated workflow using the Empore™ SDB-XC polymeric SPE Disk combined with the EZ-Trace Extraction System to extract these 26 analytes from 1 L reagent grade water samples. Multiple extractions are performed simultaneously under negative pressure from a vacuum pump. Validation data is based on four replicate measurements (n=4) for each sample from the same lot of SDB-XC disks.
Key findings at a glance:
Average recovery: 102.7% (1 µg/L) and 102.6% (2 µg/L)
Recovery range compliance: 92% of analytes within 70-130%
Reproducibility: 96% of analytes had RSD ≤ 20%
Throughput: 4 simultaneous extractions via EZ-Trace
Validated on 1 L drinking water samples at 1 ppb and 2 ppb spike levels
Why Use the Empore™ SDB-XC Disk for EPA 527.1
The Empore™ SDB-XC Disk applies polymeric-based particle-loaded membrane technology to handle the chemically diverse analyte list of EPA 527.1, delivering practical advantages for high-throughput drinking water analysis:
Polymeric chemistry — broad retention across pyrethroids, organophosphates, herbicides, and brominated compounds
Disk format compatible with EZ-Trace — 4 simultaneous extractions reduce prep time
Clean and efficient extraction — minimizes matrix interferences in GC/MS analysis
Validated EPA 527.1 performance — 92% of compounds within EPA-acceptable recovery range
Materials
SPE Media
Empore™ SDB-XC Disk, 47 mm
CDS Catalog: #2240
Fisher Scientific: 13110020
VWR: 76333-136
Extraction System
Empore™ EZ-Trace SPE Vacuum System
CDS Catalog: #8000
VWR: 76449-580
Reference Standards and Reagents
EPA Method 527 internal standards — Sigma Aldrich (St. Louis, MO)
Target analytes and surrogate molecules — AccuStandard (New Haven, CT), pre-mixed solutions
GC-MS calibration standard decafluorotriphenylphosphine (DTFPP) — Restek
Buffering reagents (potassium dihydrogen citrate, L-ascorbic acid, EDTA trisodium) — Sigma Aldrich
Methanol and dichloromethane — Sigma Aldrich
Ethyl acetate — EMD Millipore (Darmstadt, Germany)
Water — treated in-house using a Milli-Q Water Treatment System
GC Parameters
Oven Temperature Program
Mass Spectrometer Parameters
Standard Preparation and Buffering
The primary dilution standard (PDS) is prepared at a concentration of 50 µg/L and refrigerated until use. Each 1 L reagent grade water sample is treated with the following buffering reagents to prevent microbial growth and analyte degradation:
Approximately 0.1 g L-ascorbic acid
0.35 g EDTA trisodium
9.4 g potassium dihydrogen citrate
Each sample is buffered to pH 3.8 before extraction.
Validated EPA 527.1 SPE Procedure
1. Sample Spiking
Spike the first 1 L reagent water sample with 20 µL of PDS and 10 µL of surrogate. The resulting concentration of PDS in the water sample is 2 µg/L.
2. EZ-Trace Setup
Assemble all 4 disk adapter and glass filtration assemblies on the Empore™ EZ-Trace using a 47 mm Empore™ SDB-XC SPE disk in each.
3. Disk Conditioning
Wash each disk with 5 mL of 1:1 ethyl acetate / methylene chloride. Pull a small amount of solvent through the disk and soak for 1 minute. Draw the remainder through and allow the disk to dry.
Wash each disk with 10 mL of methanol and soak for 1 minute. Leave a layer of methanol remaining above the disk.
Condition each disk by adding two 10 mL aliquots of water. Do not let the disk dry — leave a layer of water above the disk.
4. Sample Loading
Add each 1 L water sample to a filtration reservoir. Under vacuum, filter as quickly as the vacuum will allow. Before all the water samples have filtered through their SPE disks, wash each bottle with 10 mL of water and add to the filtration reservoirs.
5. Disk Washing and Drying
Before disk drying, wash each SPE disk with another 5-10 mL of water to wash any salts off the disks. Dry the disks for 10 minutes under vacuum.
6. Elution
Rinse the sample bottle with 5 mL of ethyl acetate and add to the reservoir. Let the disk soak for 1 minute.
Repeat using 5 mL of dichloromethane.
Pre-rinse a filtration reservoir with 5 mL of 1:1 ethyl acetate / dichloromethane. Dry the combined eluant with 10 g of granular anhydrous sodium sulfate and collect in an evaporation vial. Rinse the collection tube and sodium sulfate each with a 5 mL portion of dichloromethane into the evaporation vial.
7. Concentration and Final Preparation
Dry the extract to just below 1 mL under a gentle stream of nitrogen (warm gently). Allow the eluate to come back to room temperature and adjust to the 1 mL mark with ethyl acetate. Transfer this solution to a 1 mL GC-MS vial. Add 10 µL of internal standard.
For the second sample: Repeat the procedure adding 40 µL of PDS to the sample (yielding 2 µg/L). For all samples, add 10 µL of surrogate. Determine the recovery of each analytical calibration standard using GC-MS.
Results and Discussion
The chromatogram of the 26 standards, 3 surrogates, and 3 internal standards under EPA Method 527.1 conditions is shown in Figure 1. The compounds are well-separated under the GC method described above.
Summary of Performance
For both reagent grade water samples, the average recovery was 103% with 16% and 13% RSD for 1 and 2 µg/L respectively. As allowed by EPA Method 527.1, the permissible recovery range is between 70 and 130% with RSD ≤20%. More than 92% of analytes were within the acceptable recovery limit, while more than 96% had sufficient RSDs.
Compound-Specific Observations
Notably high recoveries were observed for kepone and bromacil:
Kepone is noted by the EPA as being problematic for measurements under method 527.1
Bromacil shows high recoveries due to interferences from the SDB-XC disk
Other problematic analytes include esfenvalerate, fenvalerate, norflurazon, nitrophen, and parathion, which can exhibit matrix-induced enhanced chromatographic response causing recoveries greater than 100%. These analytes are susceptible to inlet adsorption and thermal degradation. This effect is typically exacerbated in pristine calibration solutions and less noticeable in dirtier water samples.
Dimethoate produced low recovery in the 2 µg/L sample. This compound is known to produce low recoveries, according to the EPA method.
Table 1 — Recovery Data for 26 EPA 527.1 Analytes
Conclusion
This application note demonstrates the validated performance of the Empore™ EZ-Trace combined with the Empore™ SDB-XC SPE Disk for EPA Method 527.1, performing 4 simultaneous extractions of 26 standard semi-volatile organic compounds. Recoveries were within EPA-acceptable limits for 92% of analytes, while 96% of analytes were within the acceptable RSD limit. For the five compounds known to produce high recoveries, their accuracy and precision were all within the limits set by the EPA method.
The CDS Empore™ EZ-Trace combined with the Empore™ SDB-XC SPE disk provides a clean and efficient screening method while still producing high analyte recoveries for the compounds listed by EPA Method 527.1, making it well-suited for drinking water laboratories monitoring pesticides and flame retardants under regulatory compliance frameworks.
Frequently Asked Questions
What is EPA Method 527.1 used for?
EPA Method 527.1 is the U.S. EPA's targeted method for detecting and quantifying 26 semi-volatile organic compounds in drinking water, including pyrethroid pesticides, organophosphate pesticides, herbicides, polybrominated biphenyls (PBBs), and polybrominated diphenyl ethers (PBDEs) used in flame retardants. The method combines solid-phase extraction (SPE) with gas chromatography/mass spectrometry (GC/MS) for analysis.
What recovery does the Empore SDB-XC Disk achieve for EPA 527.1?
In a validated workflow using 1 L reagent grade water samples (n=4 replicates), the Empore SDB-XC Disk with EZ-Trace achieved an average recovery of 102.7% (RSD 15.8%) at 1 µg/L spike level and 102.6% (RSD 12.7%) at 2 µg/L spike level. Over 92% of the 26 target analytes fell within the EPA-acceptable 70-130% recovery range, and over 96% had acceptable RSDs (≤20%).
Why use SDB-XC instead of C18 for EPA 527.1?
SDB-XC is a polymeric-based SPE sorbent, well-suited for extracting the diverse chemistry of EPA 527.1 target analytes (pyrethroids, organophosphates, herbicides, polybrominated compounds). The polymer-based chemistry provides broad-spectrum retention across the full pH range and handles compounds that may not retain well on silica-based C18 phases.
What product SKUs are needed for EPA 527.1 with Empore?
The validated workflow uses:
Empore™ SDB-XC SPE Disk, 47 mm — catalog #2240; Fisher Scientific 13110020; VWR 76333-136
Empore™ EZ-Trace SPE Workstation — catalog #8000; VWR 76449-580
The EZ-Trace allows four extractions to run simultaneously, significantly reducing preparation time per batch.
What sample preparation is needed before SPE for EPA 527.1?
Each 1 L water sample must be treated with approximately 0.1 g L-ascorbic acid, 0.35 g EDTA trisodium, and 9.4 g potassium dihydrogen citrate, and buffered to pH 3.8 to prevent microbial growth and analyte degradation. The sample is then spiked with surrogates and the primary dilution standard before SPE extraction.
Which compounds in EPA 527.1 are problematic and why?
Several EPA 527.1 analytes are known to exhibit unusual recoveries:
Kepone — noted by EPA itself as problematic
Bromacil — shows high recoveries due to interferences from the SDB-XC disk
Esfenvalerate, fenvalerate, norflurazon, nitrophen, and parathion — can show matrix-induced enhanced chromatographic response with recoveries above 100%, due to inlet adsorption and thermal degradation
Dimethoate — known to produce low recoveries per EPA documentation
How many samples can be processed simultaneously with EZ-Trace?
The Empore EZ-Trace SPE vacuum system allows four extractions to be performed simultaneously, significantly reducing sample preparation time compared to single-disk processing. This makes it ideal for laboratories processing multiple drinking water samples under EPA 527.1.
What flame retardant compounds does EPA 527.1 target?
EPA Method 527.1 includes several brominated flame retardant compounds:
BDE-47 (2,2',4,4'-Tetrabromodiphenyl Ether)
BDE-99 (2,2',4,4',5-Pentabromodiphenyl Ether)
BDE-100 (2,2',4,4',6-Pentabromodiphenyl Ether)
BDE-153 (2,2',4,4',5,5'-Hexabromodiphenyl Ether)
Hexabromobiphenyl
These polybrominated diphenyl ethers (PBDEs) are known carcinogens and are commonly used as additives in flame retardant materials.
References
Environmental Protection Agency. Method 527.1. Determination of Selected Pesticides and Flame Retardants in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS), 2005.
Pepich, B. V.; Prakash, B.; Domino, M. M.; and Dattilio, T. A. Development of U.S. EPA Method 527 for the analysis of selected pesticides and flame retardants in UCMR Survey. Environ. Sci. Tech., 2005.
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