Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D5175-91 – Standard Test Method Technical Guide
🔬 Scope and Applicability
This test method, designated D5175‑91 (Reapproved 2024), is applicable to the determination of organohalide pesticides and polychlorinated biphenyls (PCBs) in finished drinking water, drinking water during intermediate stages of treatment, and raw source water. The standard covers 18 specific analytes including alachlor, aldrin, chlordane, dieldrin, endrin, heptachlor, heptachlor epoxide, hexachlorobenzene, lindane, methoxychlor, toxaphene, and Aroclor products (1016, 1221, 1232, 1242, 1248, 1254, and 1260).
This method is restricted to use by analysts experienced in gas chromatography (GC) and interpretation of chromatograms. For compounds not listed, the analyst must demonstrate applicability by collecting precision and bias data on spiked samples and confirming results via gas chromatography/mass spectrometry (GC/MS) or GC analysis using dissimilar columns.
⚙️ Test Method and Analytics
The method utilizes microextraction followed by GC to identify and quantify organohalide pesticides and PCBs. Analytes that are not chromatographically separated (very similar retention times) cannot be individually identified and measured in the same calibration mixture or water sample unless an alternative technique for identification and quantitation exists. For multi‑component materials like chlordane, toxaphene, and Aroclor products, precision and bias statements reflect recovery from dosed water samples and may not apply to environmentally altered materials or complex mixtures of PCBs and organochlorine pesticides.
| 🟦 Analyte | 📏 CAS Number |
|---|---|
| Alachlor | 5972-60-8 |
| Aldrin | 309-00-2 |
| Chlordane | 57-74-9 |
| Dieldrin | 60-57-1 |
| Endrin | 72-20-8 |
| Heptachlor | 76-44-8 |
| Heptachlor Epoxide | 1024-57-3 |
| Hexachlorobenzene | 118-74-1 |
| Lindane | 58-89-9 |
| Methoxychlor | 72-43-5 |
Only Aroclor 1016 and 1254 were included in the interlaboratory test used to derive precision and bias statements. Data for other PCB products are likely to be similar.
📊 Detection Limits and Precision
Detection limits for most test method analytes are less than 1 µg/L. Actual detection limits are highly dependent on the characteristics of the sample matrix and the gas chromatography system. The applicable concentration range for precision and bias statements is detailed in Table 1 of the standard.
💡 Technical Note: Detection limits vary significantly with sample matrix and GC conditions. Analysts should optimize instrument parameters for each sample set and consider matrix effects when reporting results.
For chlordane, toxaphene, and Aroclor products (PCBs), which are multi‑component materials, precision and bias statements are based on recovery from dosed water samples. These statements may not apply to environmentally altered materials or to samples containing complex mixtures of PCBs and organochlorine pesticides.
⚡ Safety Note: Users must establish appropriate safety, health, and environmental practices. Specific hazard statements are provided in Section 9 of the standard. This method is restricted to experienced analysts; each analyst must demonstrate the ability to generate acceptable results using the procedure described in Section 13.
When using this test method to analyze unfamiliar samples for any or all listed analytes, analyte identifications and concentrations should be confirmed by at least one additional technique, such as GC/MS or GC analysis using dissimilar columns (different stationary phases).
❓ Frequently Asked Questions
🔍 What are the detection limits for this method?
Detection limits for most analytes are less than 1 µg/L, but they depend on the sample matrix and the GC system. Analysts must determine actual detection limits for their specific sample and instrument configuration.
💡 How are multi‑component materials like chlordane and toxaphene handled?
Precision and bias statements for these materials reflect recovery from dosed water samples. They may not apply to environmentally altered materials or complex mixtures of PCBs and organochlorine pesticides. Confirmation by alternative techniques is recommended.
⚡ What safety precautions are required?
Users must establish appropriate safety, health, and environmental practices. The standard includes specific hazard statements in Section 9. Analysts should be experienced in GC and must demonstrate proficiency as described in Section 13.
📌 How are analyte identifications confirmed?
For unfamiliar samples, analyte identifications should be confirmed using GC/MS or GC analysis with dissimilar columns (different stationary phases) to ensure correct identification and quantitation, especially when multiple analytes have similar retention times.