Analytical Methods, Fish Tissue Mass and Suitable Container Materials
These tables detail the recommended aliquot weights, suggested method for analysis and appropriate container materials for various analyses. Check the suggested method document or consult with the analytical laboratory supervisor to ensure appropriate weights and containers are used.
| Analysis | Tissue mass (g)* | Suggested Method | Suitable Container Material |
|---|---|---|---|
| Arsenic | 20-50 | EPA Method 1632A | Fluoropolymer (FEP, PTFE), conventional or linear polyethylene, polycarbonate or polypropylene |
| Cadmium | 20-50 | EPA Method 200.8, Rev. 5.4, with sample preparation by SW-846 Method 3050B, or other suitable strong acid digestion procedure applicable to tissues | Plastic or glass |
| Lead | 20-50 | EPA Method 200.8, Rev. 5.4, with sample preparation by SW-846 Method 3050B, or other suitable strong acid digestion procedure applicable to tissues | Plastic or glass |
| Mercury† | 1-5 | EPA Method 1631E, with preparation by the appendix in EPA Method 1631B | Fluoropolymer or glass container for collection of samples, polyethylene and/or polypropylene labware may be used for digestion |
| Selenium | 20-50 | EPA Method 200.8, Rev. 5.4, with sample preparation by SW-846 Method 3050B, or other suitable strong acid digestion procedure applicable to tissues | Plastic or glass |
| Tributyltin | 1-5 | EPA Method 8323 | Glass |
*Mass suitable for at least two analyses, in case QC issues arise, and to ensure that the sample aliquot analyzed is reasonably representative of the available tissue sample. Smaller masses may be used but would result in higher detection limits. (Additional mass may be required for additional QC purposes for any of these methods other than 1613B, 1614A, 1633, and 1668C.)
†Method 1631E is used for total mercury, but the assumption is that it is all (or mostly) methylmercury. This is a conservative assumption and costs less than analyzing only for methylmercury. Method 7473 could be used for mercury analysis, but QC limits would need to be provided by the jurisdiction since Method 7473 does not contain firm QC limits. Method 1631E (with fish sample preparation procedure 1633B) contains firm QC requirements and has been widely validated and used across many studies and laboratories.
| Analysis | Tissue mass (g)* | Suggested Method | Suitable Container Material |
|---|---|---|---|
| Amphetamine (pharmaceutical)‡ | EPA Method 1694 | Amber glass container with fluoropolymer-lined lid | |
| Aroclors | 25-30 | EPA Method 1656A or Method 8082A with extraction methods of 3540 or 3541 | Glass |
| BDE-47 | 25-30 | EPA Method 1614A | Glass container with fluoropolymer-lined lid |
| Dioxins/furans | 20-30 | EPA Method 1613B | Glass container with fluoropolymer-lined lid |
| Organochlorine pesticides | 25-30 | EPA Method 1656A or SW-846 Method 8081 with extraction methods of 3540 or 3541 | Glass |
| Organophosphorus pesticides | 25-30 | EPA Method 1657A or Method 8141B with extraction methods of 3540 or 3541 | Glass container with fluoropolymer-lined lid |
| Oxyfluorfen§ | |||
| PAHs | 10-20 | SW-846 Method 8310, with sample preparation by SW-846 Method 3540 or 3541 | Glass |
| PCB congeners | 25-30 | EPA Method 1668C or EPA Method 1628 | Glass container with fluoropolymer-lined lid |
| PFAS | 5-10 | EPA Method 1633A | HDPE with linerless HDPE or polypropylene caps, do not use PTFE-lined caps |
‡Amphetamines are controlled substances and a laboratory must have a license to possess controlled substances in order to perform the test.
§There is not an EPA approved method for oxyfluorfen analysis. A research paper describes a QuEChERS multi-residue GC-MS/MS method developed for determining pesticides in tissue (Camara et al., 2020). Method SW-846 8151A does not list oxyfluorfen or tissue, but this could be used as a basis for a method for tissue analysis.
| Analysis | Tissue mass (g)* | Suggested Method | Suitable Container Material |
|---|---|---|---|
| Cyanotoxins (microcystins, BMAA, DABA) | For microcystins, method using 2-methoxy-3-methyl-4-phenylbutyric acid (MMPB) procedure is under development. |
Quality Control
Ensure the sample mass is sufficient for laboratory duplicates, matrix spikes, and matrix spike duplicates so that the QC requirements of the program can be met. Additionally, the processing laboratory is responsible for preparing extra extractions to allow for reanalysis if the sample is lost or if quality control limits are not met. Regularly calibrate the balances used to weigh the whole fish and fillet fish tissue during various stages of homogenization and aliquot preparation. Verify the calibrations at the beginning of each day on which the balances are used.