Capturing More Volatile EPA Method 8270 Compounds

Problem: EPA Method 8270D is used to determine neutral, acidic, and basic semivolatile organic compounds that are soluble in methylene chloride, such as polynuclear aromatic hydrocarbons, chlorinated hydrocarbons and pesticides, phthalate esters, organophosphate esters, nitrosamines, haloethers, aldehydes, ethers, ketones, anilines, pyridines, quinolines, aromatic nitro compounds, and phenols, including nitrophenols. In most cases, EPA Method 8270 is not appropriate for the quantitation of multicomponent analytes, such as N-Nitrosodimethylamine, Pyridine, and N-Nitrosodiethylamine, because of limited sensitivity for those analytes.

N-nitrosodimethylamine can be difficult to separate from the solvent, and N-nitrosodiphenylamine can decompose in the gas chromatographic inlet and cannot be separated from diphenylamine. Pyridine may perform poorly at the GC injection port temperatures listed in the method. Lowering the injection port temperature may reduce the amount of degradation. However, the analyst must use caution in modifying the injection port temperature, as the performance of other analytes may be adversely affected. Therefore, if pyridine is to be determined in addition to other target analytes, it may be necessary to perform separate analyses. In addition, pyridine may be lost during the evaporative concentration of the sample extract.

EPA Method 8270 – Carbon Cartridge Kit

Solution: Using the Horizon Technology 8270 Carbon Cartridge Kit enables the capture of the more volatile 8270 compounds. The 8270 Carbon Cartridge Kit is designed for use with the Horizon Technology SPE-DEX® 4790 Automated Extractor System, and the Oasis® HLB (Hydrophilic-Lipophilic Balanced) solid phase extraction disk, developed by Horizon Technology and Waters Corporation. The SPEDEX ® 4790 system provides automatic extraction of liquid samples by solid phase extraction (SPE). Automating the sample preparation step through the use of SPE not only improves the quality and consistency of the results by minimizing operator to operator variation, but also offers the additional benefit of reduced solvent consumption by as much as 70 percent as compared to the EPA Method 8270D’s manually performed liquid-liquid extractions.

Since EPA Method 8270D has such an extensive analyte list of 243 semi-volatile organic compounds that range in volatility and polarity, the Oasis® HLB SPE disk is ideal as the sorbent used has both hydrophilic and lipophilic groups to maximize retention of these analytes. The 8270 Carbon Cartridge Kit is included down-stream of the SPE disk to scavenge the disk effluent of any analytes that were not retained by the disk. These analytes are typically volatile compounds such as nnitrosodimethylamine, N-nitrosomethylethylamine and methymethane sulfonate. The 8270 Carbon Cartridge is designed to accommodate the higher sample flow rates from the SPE disk without restrictions. In addition the disk effluent passes through the carbon cartridge in the back flush mode for fast extractions with reduced solvent usage. To date very good recoveries of 44 percent to 88 percent and 34 percent to 113 percent have been achieved for the more volatile compounds and the 8270D full list respectively.

For more information, go to www.horizontechinc.com