Organic Carbon: analytical methods, detection limits, and holding times - USEPA/SuRGE GitHub Wiki
- Total organic carbon (toc) will be measured in all years.
- Dissolved organic carbon (doc) will be measured in the 2021 - 2023 field seasons.
- toc samples collected in 2020 were analyzed by MASI, an outside contract laboratory.
- toc and doc collected by ADA field crew will be analyzed at the ADA General Parameters Laboratory.
- All other toc and doc samples will be analyzed in CIN.
Analyte detection and reporting limits vary by lab, and sometimes by year (e.g. annual reassessment). Separate values are provided below for ADA, CIN, and MASI. ADA and MASI clearly report limits in the data reports. CIN included minimum detection limits in data reports. Reporting limit assumed to be equal to lowest standard and was provided by Sonia O'Dell via email [9/29/2022].
Please note that the analyte names and units used below are consistent with the SuRGE chemistry data objects, but may differ from those in the data files provided by the laboratories. See Wiki page Chemistry units, names, and data sources for the official list of analyte names and units to be used in the SuRGE data objects.
| Analyte | Analyte Container and volume | Analytical method | Year | Detection limit | Reporting Limit | Preservation and Holding times | Lab |
|---|---|---|---|---|---|---|---|
| toc | 40ml glass TOC bottle | Shimadzu TOC-L/ASI-L | 2016 - 2023 | 0.1 mg_l | 0.5 mg_l | 4oC + 2 drops 50% H2SO4. 28 days | CIN |
| doc | 40ml glass TOC bottle | Shimadzu TOC-L/ASI-L | 2016 - 2023 | 0.1 mg_l | 0.5 mg_l | 4oC + 2 drops 50% H2SO4. 28 days | CIN |
| toc | 40ml glass TOC bottle | Teledyne Tekmar Fusion Analyzer | 2020 | 0.08 mg_l | 2.0 mg_l | 4oC + 2 drops 50% H3PO4. 28 days | MASI |
| toc | 40mL glass VOA vials with a Teflon-lined septum cap to prevent carbon contamination. | Determination of Various Fraction of Carbon in Aqueous Samples Using Shimadzu TOC-VCSH analyzer. K-GCRD-SOP-1165-0. | 2021 | 0.102 mg_l MDL determination on 1/6/2021 |
0.5 mg_l | Not filtered, not acidified. Stored @ 4oC up to 7 days | ADA |
| doc | 40mL glass VOA vials with a Teflon-lined septum cap to prevent carbon contamination. | Determination of Various Fraction of Carbon in Aqueous Samples Using Shimadzu TOC-VCSH analyzer. K-GCRD-SOP-1165-0. | 2021 | 0.102 mg_l MDL determination on 1/6/2021 |
0.5 mg_l | Filtered, not acidified. Stored @ 4oC up to 7 days | ADA |
| toc | 40mL glass VOA vials with a Teflon-lined septum cap to prevent carbon contamination. | Determination of Various Fraction of Carbon in Aqueous Samples Using Shimadzu TOC-VCSH analyzer. K-GCRD-SOP-1165-0. | 2022 | 0.049 mg_l MDL determination on 10/25/2021 |
0.5 mg_l | Not filtered, not acidified. Stored @ 4oC up to 7 days | ADA |
| doc | 40mL glass VOA vials with a Teflon-lined septum cap to prevent carbon contamination. | Determination of Various Fraction of Carbon in Aqueous Samples Using Shimadzu TOC-VCSH analyzer. K-GCRD-SOP-1165-0. | 2022 | 0.049 mg_l MDL determination on 10/25/2021 |
0.5 mg_l | Filtered, not acidified. Stored @ 4oC up to 7 days | ADA |
| toc | 40mL glass VOA vials with a Teflon-lined septum cap to prevent carbon contamination. | Determination of Various Fraction of Carbon in Aqueous Samples Using Shimadzu TOC-VCSH analyzer. K-GCRD-SOP-1165-0. | 2023 | 0.096 mg_l MDL determination on 10/17/2022 |
0.5 mg_l | Not filtered, not acidified. Stored @ 4oC up to 7 days | ADA |
| doc | 40mL glass VOA vials with a Teflon-lined septum cap to prevent carbon contamination. | Determination of Various Fraction of Carbon in Aqueous Samples Using Shimadzu TOC-VCSH analyzer. K-GCRD-SOP-1165-0. | 2023 | 0.096 mg_l MDL determination on 10/17/2022 |
0.5 mg_l | Filtered, not acidified. Stored @ 4oC up to 7 days | ADA |