Application Notes
EPA Method 502.2: VOCs in Water by Purge & Trap (PID/ELCD)
Sixty regulated VOCs are determined in water by purge and trap GC with PID/ELCD detection.
EPA Method 502.2: Volatile Organic Compounds in Water by Purge and Trap (PID/ELCD), Alltech Application Note #ANE001, October 18, 1995.
The requirements set forth in EPA Method 502.2 for determining 60 regulated volatile organic compounds in raw and finished drinking water by purge and trap gas chromatography were described.
A method detection limit of 0.5 µg/L must be achieved for each analyte. Quantitative results for at least 80% of the analytes must not differ from the actual concentration in a performance evaluation sample by more than 20-40% depending on the actual concentration.
Water samples must be collected and prepared to ensure analyte stability for up to 14 days after sampling. The GC response must be calibrated with at least 3 different levels, the calibration solution must contain two internal standards and the calibration response stability must be verified daily. Reagent blanks must also be analyzed. Conditions for the purge and trap analysis are specified.
The GC system must be equipped with a photoionization (PID) detector in sequence with an electrolytic conductivity (ELCD) detector. The PID detects the aromatic and unsaturated VOCs while the RLCD detects the halogenated VOCs.
Both the AT-502.2 (Part No. 13794) and AT-624 (Part No. 13800) columns can be used for this determination. Example chromatograms obtained using the AT-502.2 column (105m x 0.53mm x 3.0µm) are shown with all of the halogenated compounds identified using the ELCD along with some of the nonhalogenated compounds and all of the nonhalogenated compounds along with some of the halogenated compounds identified using the PID.
The column temperature was held at 40°C for 10 min and raised to 220°C over 45 minutes at 4°C/min. The carrier gas was He. The purge and trap device was a Tekmar LSC 2000. Purging was done for 1 min with He at 40mL/min and desorbing for 4 min at 200°C. The separation took around 50 minutes.
Key Analyte(s)
1,1,1,2-tetrachloroethane1,1,1,2-tetrachloroethane is a chlorinated solvent most often measured by GC/ECD, ELCD and GC/MS.
1,1,1-trichloroethane1,1,1-trichloroethane is a chlorinated solent most often measured by GC/ECD, ELCD and GC/MS.
1,1,2,2-tetrachloroethane1,1,2,2-tetrachloroethane is a chlorinated solvent most often measured by GC/ECD, ELCD and GC/MS.
1,1,2-trichloroethane1,1,2-trichloroethane is a chlorinated liquid used in the manufacture of other chlorinated hydrocarbons. It is most often measured using GC/ECD, ELCD and GC/MS.
1,1-dichloroethane1,1-dichloroethane is a chlorinated liquid used in the manufacture of other chlorinated hydrocarbons. It is most often measured using GC/ECD, ELCD and GC/MS.
1,1-dichloroethene1,1-dichloroethene is a chlorinated liquid used in the manufacture of plastics. It is most often measured using GC/ECD, ELCD and GC/MS.
1,1-dichloropropene1,1-dichloropropene is a chlorinated volatile solvent that is an impurity in 1,2-dichloropropane production. It is most often measured using GC/ECD, ELCD and GC/MS.
1,2,3-trichlorobenzene1,2,3-trichlorobenzene is a chlorinated solid used in the manufacture of pesticides and plastics. It is most often measured using GC/ECD, ELCD and GC/MS.
1,2,3-trichloropropane1,2,3-trichloropropane is a chlorinated liquid used as a solvent and degreasing agent. It is most often measured using GC/ECD, ELCD and GC/MS.
More AnalytesEquipment
Alltech Heliflex® AT-502.2 Capillary ColumnsAlltech Heliflex® AT-502.2 capillary column are a line of intermediate polarity fused silica GC columns manufactured and sold by Alltech Associates designed to separate early eluting volatile organics at above ambient temperature.
Technique
GC/PID, GC/ELCD
Source
