Analysis of EDB, 123-TCP, and DBCP
5Pages

Analysis of EDB, 123-TCP, and DBCP By USEPA Method 524.3 Eclipse 4760 Purge and Trap and the 4100 Autosampler Introduction Many laboratories analyze 1,2-Dibromoethane (EDB), 1,2,3-Trichloropropane (123-TCP), and 1,2-Dibromo3-chloropropane (DBCP) in drinking water by USEPA Method 504.1 or USEPA 8011. These methods require a micro-extraction step and analysis with dual column gas chromatography with dual electron capture detectors. These compounds may also be analyzed by USEPA Method 524.3 using purge and trap sample concentration followed by gas chromatographic separation with mass spectrometric detection (GC/MS) and selective ion monitoring (SIM). This approach is simpler since there is no sample prep and has the advantage of mass spec selectivity while yielding equivalent, if not better reporting limits than the GC/ECD method. Methodology Method 524.3 was followed using the instrumentation and conditions listed below. A seven-point calibration from 20 ppt to 2000 ppt was run. Initial demonstrations of capability (IDC) were run by analyzing seven replicates of 100 ppt and also 250 ppt standard. Seven replicates at 20 ppt were analyzed to determine the half range for the prediction interval of results (HRPIR). All standards and QC samples were prepared using the ascorbic acid/maleic acid preservative required by the method. Table 1. Instrument Configuration and Operating Conditions Purge-and-Trap Eclipse 4760 P & T Sample Concentrator 4100 Water/Soil Sample Processor Zero grade nitrogen #10 trap; Tenax® / Silica gel / CMS Zero grade helium Zero grade Helium at 45 mL/min Purge Time Sparge Mount Temperature Loop-based Time Settings Rinse Water Sample Temperature (purge) Soil Sample Transfer Sample Temperature (bake) Soil Oven Soil Lift Station Desorb Time Bake Time Ambient during purge 180 °C during desorb pre-heat 190 °C during desorb 210 °C during bake Water Management 120 °C during purge Ambient during desorb 240 °C during bake Transfer Line Temperature Six-port Valve Temperat

Analysis of EDB, 123-TCP, and DBCP Using USEPA Method 524.3 4100 Sample Processor Methods Blanks Only Restek Rtx-VMS 20 meter, 0.18 mm ID, 1.0 μm film Sample Type Waters Only Zero grade helium Needle Rinses Inlet Temperature Inlet Liner Agilent Ultra Inert, 1 mm straight taper Column Flow Rate Split Ratio Oven Program Rinse Water Hold at 40 °C for 1 min 18 °C/minute to 180 °C 40 °C/minute to 220 °C Hold at 220 °C for 3 min Total GC Run is 12.78 min Water Stir Time (min) Water Settle Time (sec) Soil Add Water to Vial (#loops) Soil Pre-Heat Stir Soil Pre-Heat/Purge Temp (°C) Soil Stir During...

Analysis of EDB, 123-TCP, and DBCP Using USEPA Method 524.3 Results and Discussion See Tables 2 through 6 for calibration data and USEPA Method 524.3 Quality Control data. The calibration must be validated by calculating the concentration of the analytes for each of the points used to generate the curve by use of the regression equations. Table 2. Calibration Data Analyte Table 3. Calibration Acceptance and Validation - 5 mL of 524.3 Standard [Results Signal 1] Table 4. Initial Demonstration of Capability at 100 ppt 100 ppt Table 5. Initial Demonstration of Capability at 250 ppt 250 ppt

Analysis of EDB, 123-TCP, and DBCP Using USEPA Method 524.3 Table 6. Minimum Reporting Level (MRL) Confirmation 20 ppt PIR 1 (4.0 ppt = True Value) Upper PIR Limit <= 150%

Analysis of EDB, 123-TCP, and DBCP Using USEPA Method 524.3 Conclusions This analysis by Method 524.3 using GC/MS SIM offers a fast, accurate alternative to Method 504.1 and 8011 and easily meets low reporting levels. The preservative for this method can build up in the purge and trap, so care must be taken to run cleaning blanks, rinsing the sparger between samples, and occasionally rinsing the sample pathway. References USEPA Method 524.3 Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry, Version 1.0 June 2009 USEPA Method 504.1...