USGS-NWQL: O-4433-06:  Wastewater Compounds in Water by CLLE and GC-MS

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Determination of Wastewater Compounds in Whole Water by Continuous Liquid-Liquid Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry
Current Revision
2007 Revision (of 2006 release)
Continuous Liquid-Liquid Extractor with Gas Chromatography with Mass Spectrometry Detection
Method Subcategory
Method Source
Zaugg, S.D., Smith, S.G., and Schroeder, M.P., 2006, Determination of wastewater compounds in whole water by continuous liquid-liquid extraction and capillary-column gas chromatography/mass spectrometry: U.S. Geological Survey Techniques and Methods, book 5, chap. B4, 30 p.
Brief Method Summary
A method for the determination of 69 compounds typically found in domestic and industrial wastewater is described. The method was developed in response to increasing concern over the impact of endocrine-disrupting chemicals on aquatic organisms in wastewater. This method also is useful for evaluating the effects of combined sanitary and storm-sewer overflow on the water quality of urban streams. The method focuses on the determination of compounds that are indicators of wastewater or have endocrine-disrupting potential. These compounds include the alkylphenol ethoxylate nonionic surfactants, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Wastewater compounds in whole-water samples were extracted using continuous liquid-liquid extractors and methylene chloride solvent, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-water samples fortified at 0.5 microgram per liter averaged 72 percent ? 8 percent relative standard deviation. The concentration of 21 compounds is always reported as estimated because method recovery was less than 60 percent, variability was greater than 25 percent relative standard deviation, or standard reference compounds were prepared from technical mixtures. Initial method detection limits averaged 0.18 microgram per liter. Samples were preserved by adding 60 grams of sodium chloride and stored at 4 degrees Celsius. The laboratory established a sample holding-time limit prior to sample extraction of 14 days from the date of collection.
Scope and Application
This method is suitable for the determination of microgram-per-liter concentrations of compounds in whole wastewater and environmental water samples. The method is applicable to compounds that are efficiently partitioned from the water phase into the DCM organic phase, and are sufficiently volatile and thermally stable for gas chromatography. The method includes many compounds that typically are associated with industrial and household wastewater, as well as some that are known or suspected endocrine-disrupting compounds.
Applicable Concentration Range
Variable and dependant upon analyte
Organic compounds that have gas chro¬matographic retention times and characteristic ions with a mass identical to those of the com¬pounds of interest might interfere. There might be unknown compounds that interfere because of the complex nature of wastewater.
Sample-collection protocols and cleaning procedures for field equipment must be followed to reduce the possibility of interferences and to minimize potential contamination. Many method compounds are widespread in the environment and have been detected in laboratory reagent-water-blank samples. Samples and collection equipment that are handled improperly also might become contaminated with soaps, caffeine, and fragrances. Precautions are necessary to avoid and minimize the potential for contami¬nation during sample collection because some method compounds are contained in commonly used products.
Quality Control Requirements
Laboratory quality-control data includes reagent blank and spike samples, surrogate standards, and continuous calibration verifications to determine if corrective actions are necessary. Standard reference material and instrumental checks provide external verification of method performance and are considered quality-assurance samples.
Sample Handling
Glass bottles; amber, 1,000-mL, 33-mm neck, baked at 450°C for 2 hours, fitted with Teflon-lined screw caps. Immediately treat sample with 60 ± 10 g NaCl and store at 4oC.
Collect whole-water samples in 1-L amber glass pesticide bottles before shipping at 4oC to the laboratory, preferably by express overnight mail. Fill the bottle to the neck, and leave sufficient headspace (about 30-40 mL) for the addition of 60 g NaCl upon arrival at the laboratory. Field-sampling procedures need to follow those typically used to collect samples for trace organic compound determinations with specific instructions for the collection of wastewater compounds.
Some of the compounds that are determined by this method are found in commonly used products, such as coffee, tea, cola, soap, and insecticide repellent. Project personnel need to be careful to avoid potential contamination of samples from such sources by avoiding consumption or contact with these materials immediately prior to and during sampling procedures. Limit or avoid contact with any fragranced materials, including colognes, scented-detergents, shampoos, and conditioners. If samples are suspected of containing untreated sewage or biohazards, special shipping, handling, and processing requirements need to be followed prior to shipping. Clean the outside of the bottle thoroughly with isopropyl alcohol and secure the lid tightly before wrapping in four high-capacity 3M sorbent pads. Finally, enclose the wrapped bottle in three resealable plastic bags (two bags are necessary and one bag is precaution¬ary).
The probability of sample contamination with compounds determined by this method is higher than for other NWQL methods. For this reason, routinely prepare field blanks for analysis to monitor for potential sample contamination.
Maximum Holding Time
14 days
Relative Cost
Greater than $400
Sample Preparation Methods