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EPA Method 8270, EPA Method 8260 (now 8260D, formerly 8260C), and EPA Method 624 (now 624.1) are the three gas chromatography/mass spectrometry (GC/MS) methods that show up most often in environmental water and soil testing scopes of work, laboratory RFPs, and NPDES or RCRA permit conditions. All three run on the same underlying technology — GC/MS, in two cases with purge-and-trap sample introduction — but they belong to different EPA regulatory programs, carry different approval status, and are not interchangeable on a compliance sample even when they measure overlapping analyte lists. For a lab manager, procurement officer, or research administrator writing a testing contract, choosing (or verifying) the right method is a compliance decision, not just a technical one: specify the wrong one and the data may not be legally usable for the permit or program that required the sample in the first place.
This guide explains what each method actually measures, how the SW-846 program (8270, 8260) differs from the Clean Water Act Part 136 program (624), and what to require from a contract laboratory before you sign a testing agreement.
EPA Method 8270: semivolatile organic compounds by GC/MS
EPA Method 8270 (“Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry”) is a SW-846 method used to identify and quantify semivolatile organic compounds — a broad target list that typically includes polynuclear aromatic hydrocarbons (PAHs), phthalate esters, nitrosamines, phenols, chlorinated hydrocarbons, and other base/neutral and acid-extractable organics — in solid waste matrices: groundwater, soil, sediment, sludge, and other waste. The current published revision is Method 8270E, issued by EPA as part of the SW-846 Update VI methods package (finalized 2018) alongside the current volatile organics method, 8260D.
SW-846 methods, including 8270, are published as guidance, not as promulgated regulation in the way a Clean Water Act analytical method is. EPA describes SW-846 as providing performance-based, generally reliable procedures that a laboratory can modify (within documented limits) to fit a given matrix or program, provided the lab demonstrates the modification still meets the method’s quality control acceptance criteria. That flexibility is useful, but it also means “we ran Method 8270” is not by itself a complete specification — a buyer should confirm the target analyte list, reporting limits, and any matrix-specific modifications the lab applied.
EPA Method 8260, 8260C, and 8260D: volatile organic compounds by GC/MS
EPA Method 8260 (“Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry”) is the SW-846 counterpart to 8270 for volatile rather than semivolatile organics — compounds such as benzene, toluene, ethylbenzene and xylenes (BTEX), chlorinated solvents (e.g., trichloroethylene, tetrachloroethylene), and other purgeable organics. Samples are introduced by purge-and-trap rather than direct injection, which is what distinguishes the volatiles methods (8260, 624) from the semivolatiles method (8270) at the sample-prep level.
The revision letter matters for procurement purposes:
- EPA Method 8260C was the prior published revision, in wide use for years and still referenced in some older permits, waste profiles, and state program requirements.
- EPA Method 8260D is the current published revision, issued alongside 8270E under the SW-846 Update VI package. It updated quality control and calibration provisions relative to 8260C.
Because SW-846 methods are performance-based guidance, a state agency, waste facility, or accreditation body may or may not have moved every program requirement over to the D revision on the same timeline. When you specify “Method 8260” in an RFP or waste-acceptance requirement, confirm which revision the governing program actually requires or accepts, and confirm the laboratory’s accreditation scope lists that specific revision — not just the method number.
EPA Method 624 and 624.1: the Clean Water Act analog
EPA Method 624 (“Purgeables”) sits in a different regulatory program entirely. It is one of the analytical methods promulgated under the Clean Water Act at 40 CFR Part 136, the regulation that specifies which test methods are legally approved for compliance monitoring under the National Pollutant Discharge Elimination System (NPDES) — wastewater discharge permits, publicly owned treatment works (POTW) monitoring, and related Clean Water Act reporting. Method 624 measures purgeable (volatile) organic compounds by GC/MS, the same general chemistry as SW-846 Method 8260, but it is a different, separately promulgated method with its own method-specific quality control requirements, and it is the one a discharger is generally required to cite when a permit or the Part 136 table requires it — not an SW-846 method run under similar conditions.
EPA updated the Part 136 methods table to include Method 624.1, a capillary-column GC/MS version of the original packed-column-era method, as part of its periodic Clean Water Act methods update process. As with the SW-846 revision question above, the practical procurement point is the same: confirm which version (624 or 624.1) your permit, delegated state program, or receiving laboratory’s NELAP/state certification actually covers, rather than assuming any GC/MS purgeables result satisfies a Part 136 citation.
Why the regulatory program — not just the chemistry — decides which method you can specify
The single most common procurement mistake with this group of methods is treating 8260 and 624 as interchangeable because they measure an overlapping list of volatile organics with the same instrument technique. They are not interchangeable for compliance purposes:
- SW-846 methods (8270, 8260) generally apply under RCRA (hazardous waste characterization, corrective action, site investigation) and CERCLA/Superfund site work, and are performance-based guidance a lab can adapt within documented limits.
- Part 136 methods (624, 624.1) generally apply under the Clean Water Act for NPDES discharge monitoring and related wastewater compliance reporting, and are prescribed, promulgated methods with less latitude for lab-specific modification.
If a sample is being collected to satisfy an NPDES permit condition, the permit (or the state program administering it) typically dictates a Part 136-approved method by citation — running 8260 instead of 624 on that sample, even if the numeric result would be similar, does not automatically satisfy the permit’s method requirement. Conversely, a RCRA waste characterization program will typically expect an SW-846 method, not a Part 136 method. Confirm which regulatory driver applies to the specific sample before writing the method into a testing contract or purchase order — not after results come back.
Procurement checklist: what to require from a contract laboratory
Before signing a testing agreement or issuing a purchase order for 8270, 8260, or 624/624.1 analysis, request documentation on each of the following rather than accepting a method number alone:
- Accreditation scope, by method and matrix. ISO/IEC 17025 accreditation (see our ISO/IEC 17025 guide) and, for regulatory compliance samples, state or NELAP certification should explicitly list the specific method and revision (8270E, 8260D, 624.1, etc.) and the matrix (drinking water, wastewater, soil) you need — a lab’s general accreditation does not guarantee every method and matrix combination is in scope.
- Documented detection and reporting limits. Ask for the laboratory’s current method detection limit (MDL) and reporting limit (RL) study for the exact analyte list you need, and compare those limits against your regulatory action level or data quality objective before you buy — a lower headline price is not useful if the lab’s reporting limits are too high to be usable against your permit limit.
- QA/QC program details. Method blanks, laboratory control samples, matrix spike/matrix spike duplicate recovery ranges, and surrogate recovery criteria should be part of the standard data package, not a special request. Confirm the lab’s current proficiency-testing status for these methods — see our guide to proficiency testing and external quality assessment.
- Holding times and preservation. Volatile organic analyses (8260, 624/624.1) carry short holding times relative to most other analyte groups — commonly cited as on the order of days to roughly two weeks from collection to analysis for properly preserved aqueous samples — and require specific preservation (e.g., zero-headspace vials, acid preservation) confirmed at sample receipt. Confirm the lab’s sample receipt and rejection criteria before shipping, and require a documented chain of custody for any sample tied to a regulatory or legal outcome.
- Instrumentation and column documentation. If you are evaluating a lab’s capability rather than just its accreditation certificate, ask what GC/MS platform, detector, and column configuration it runs these methods on; see our guides to gas chromatography columns and detectors and GC detector types if your lab is instead building or buying this capability in-house.
- Data deliverable format. Confirm the lab can deliver results in the electronic data deliverable (EDD) format your program or LIMS requires, and that calibration records are traceable — see our calibration certificate guide for what a defensible calibration record should contain.
- Waste and sample disposal. Ask how the lab manages disposal of extracted samples and standards, particularly for hazardous-waste-characterization work; see our lab waste disposal guide.
If you are building this capability in-house rather than contracting it out, the equipment side of the decision (GC/MS system selection, column selection, and total cost of ownership) is covered in our GC and HPLC column selection guide and general vendor selection criteria framework; instrument and consumable pricing context is in our gas chromatograph cost guide.
8270 vs. 8260 vs. 624/624.1 at a glance
| Method | Measures | Regulatory program | Typical matrices | Current revision |
|---|---|---|---|---|
| EPA Method 8270 | Semivolatile organics (PAHs, phenols, phthalates, and related base/neutral/acid extractables) | SW-846 (RCRA/CERCLA, performance-based guidance) | Groundwater, soil, sediment, sludge, waste | 8270E |
| EPA Method 8260 | Volatile organics (BTEX, chlorinated solvents, other purgeables) | SW-846 (RCRA/CERCLA, performance-based guidance) | Groundwater, soil, waste, air in some applications | 8260D (8260C is the prior revision) |
| EPA Method 624 / 624.1 | Purgeable (volatile) organics | Clean Water Act, 40 CFR Part 136 (promulgated, prescribed method) | Wastewater, NPDES-regulated discharges, drinking water in some programs | 624.1 (capillary-column update to 624) |
Frequently asked questions
What is EPA Method 8270 used for?
EPA Method 8270 is used to identify and quantify semivolatile organic compounds — including PAHs, phthalates, phenols, and other base/neutral/acid-extractable organics — in groundwater, soil, sediment, sludge, and other solid waste matrices, most commonly for RCRA hazardous waste characterization, site investigation, and CERCLA/Superfund work.
What is the difference between EPA Method 8260 and EPA Method 624?
Both measure volatile (purgeable) organic compounds by GC/MS and use similar purge-and-trap sample introduction, but they belong to different EPA regulatory programs. Method 8260 is an SW-846 method, generally used for RCRA/CERCLA waste and site-investigation work, published as performance-based guidance. Method 624 (now 624.1) is promulgated under the Clean Water Act at 40 CFR Part 136 and is the method generally required for NPDES wastewater discharge compliance monitoring. A permit or program that cites Part 136 method 624 is generally not satisfied by an 8260 result, even though the underlying chemistry is similar.
What is EPA Method 8260C, and is it still valid?
EPA Method 8260C is the prior published SW-846 revision for volatile organics by GC/MS, superseded by the current revision, 8260D, issued under the SW-846 Update VI methods package. Whether 8260C is still accepted depends on the specific program or permit citing it; confirm which revision your regulatory driver and your laboratory’s accreditation scope currently require before specifying either one in a contract.
Is EPA Method 8270 the same as EPA Method 8260?
No. They are companion SW-846 GC/MS methods that together cover most of the organic target compound list used in RCRA and CERCLA work, but they measure different compound classes: 8270 covers semivolatile organics (typically extracted and analyzed by direct injection), and 8260 covers volatile organics (introduced by purge-and-trap). Many site investigations and waste characterizations require both methods run in parallel to cover the full analyte scope.
Does ISO/IEC 17025 accreditation guarantee a lab is approved to run these methods on my samples?
Not by itself. ISO/IEC 17025 accreditation certifies a laboratory’s general management system and technical competence, but the specific methods, revisions, and matrices covered are listed in that lab’s accreditation scope — a separate, checkable document. For regulatory compliance samples (e.g., NPDES discharge monitoring), also confirm the lab holds current state or NELAP certification for the specific method and matrix, not general ISO/IEC 17025 accreditation alone.
