TTO Volatile Organic Compounds in Wastewater Analysis by EPA 624.1
Summary
EPA 624.1 is used to determine the concentrations of Volatile Organic Compounds (VOCs) in wastewater.
Technique
EPA 624.1 is performed by purging low-solubility VOCs from the sample, trapping those VOCs in a sorbent tube, and then desorbing the VOCs from the sorbent tube and into a capillary gas chromatography column that is interfaced to a mass spectrometer (GC/MS).
Holding Time
All samples must be analyzed within 14 days of collection. Samples not analyzed within this period must be discarded and replaced.
Container and Preservative
Collect all samples in (2) 40-mL clear glass vials fitted with fluoropolymer-lined screw caps containing 0.25 to 0.5 mL of 1+1 hydrochloric acid (HCl), attaining a pH of 2. Fill each vial in such a manner that no air bubbles pass through the sample as the bottle is being filled, and so that no air bubbles are entrapped in it after sealing (zero headspace). Ice or refrigerate samples at ≤6 °C from the time of collection until analysis, but do NOT freeze. If residual chlorine is present, add a dechlorinating agent (e.g., 80 mg/L sodium thiosulfate, ascorbic acid, or sodium sulfite) and gently mix prior to sealing the vials.
Shipping/Transport Instructions
Samples must be chilled to >0°C to ≤6 °C at collection and kept at >0 °C to ≤6 °C until analyzed. Field samples must be packaged for shipment with sufficient ice to ensure that they will be >0 °C to ≤6 °C upon arrival at the laboratory.
Analytes and Reporting
Limits Analytes routinely reported are listed below.
| Analyte | CAS Number | Reporting Limit |
| Chloromethane (Methyl chloride) | 74-87-3 | 1 µg/L |
| Vinyl chloride | 75-01-4 | 1 µg/L |
| Bromomethane (Methyl bromide) | 74-83-9 | 1 µg/L |
| Chloroethane | 75-00-3 | 1 µg/L |
| Acrolein | 107-02-8 | 5 µg/L |
| 1,1-Dichloroethene | 75-35-4 | 1 µg/L |
| Methylene chloride (DCM) | 75-09-2 | 1 µg/L |
| Acrylonitrile | 107-13-1 | 5 µg/L |
| trans-1,2-Dichloroethene | 156-60-5 | 1 µg/L |
| 1,1-Dichloroethane | 75-34-3 | 1 µg/L |
| Chloroform | 67-66-3 | 1 µg/L |
| 1,1,1-Trichloroethane | 71-55-6 | 1 µg/L |
| Carbon tetrachloride | 56-23-5 | 1 µg/L |
| 1,2-Dichloroethane (EDC) | 107-06-2 | 1 µg/L |
| Benzene | 71-43-2 | 1 µg/L |
| Trichloroethene (TCE) | 79-01-6 | 1 µg/L |
| 1,2-Dichloropropane | 78-87-5 | 1 µg/L |
| 2-Chloroethyl vinyl ether | 110-75-8 | 1 µg/L |
| Bromodichloromethane | 75-27-4 | 1 µg/L |
| cis-1,3-Dichloropropene | 10061-01-5 | 1 µg/L |
| Toluene | 108-88-3 | 1 µg/L |
| trans-1,3-Dichloropropene | 10061-02-6 | 1 µg/L |
| 1,1,2-Trichloroethane | 79-00-5 | 1 µg/L |
| Tetrachloroethene (PCE) | 127-18-4 | 1 µg/L |
| Dibromochloromethane | 124-48-1 | 1 µg/L |
| Chlorobenzene | 108-90-7 | 1 µg/L |
| Ethylbenzene | 100-41-4 | 1 µg/L |
| Bromoform | 75-25-2 | 1 µg/L |
| 1,1,2,2-Tetrachloroethane | 79-34-5 | 1 µg/L |
| 1,3-Dichlorobenzene | 541-73-1 | 1 µg/L |
| 1,4-Dichlorobenzene | 106-46-7 | 1 µg/L |
| 1,2-Dichlorobenzene | 95-50-1 | 1 µg/L |