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METHODS FOR THE ANALYSIS OF ALKYLPHENOL ETHOXYLATES AND DERIVATIVES
MedinaVera, M, L H. Wright, AND M S. Lumpkin. METHODS FOR THE ANALYSIS OF ALKYLPHENOL ETHOXYLATES AND DERIVATIVES. Presented at American Chemical Society 221st National Meeting, San Diego, CA, April 1-5, 2001.
1) Develop methods of ecological exposure (e.g. rapid , sensitive analytical screening methods for a select list of antibiotics widely used in agriculture primarily in CAFOs (confined animal feeding operations).
2) Do Measurements & Provide data for multicompartment models of fate and transport.
3) Study biomagnification of specific chemicals and toxic metals.
4) Study specific pharmaceuticals:
*Determine the routes of entry and the impact of environmental factors such as rainfall on the movement and survivorability of selected antimicrobials in the environment.
*Determine if the entry of agriculture based antibiotics into the environment contributes to resistance in bacterial populations.
*Determine the contribution from municipal waste water treatment plants to antibiotic loading in the environment.
5) Develop methods for the analysis of alkylphenol ethoxylates and derivatives.
Alkylphenol ethoxylates and their derivatives are well known for their harmful impact in wildlife. These compounds are being phased-out and banned in most European Countries. Their use has increased in the U.S. resulting in their addition to the Priority Testing List, TSCA (1997). The compounds are used in pulp and paper manufacturing, textiles manufacturing, plastic and elastomer manufacturing (e.g. nonylphenol in the form of tris-nonylphenol phosphite, octylphenol), household, industrial and institutional cleaning (e.g. Triton X-100), oil extraction and production, agriculture (as adjuvants for active ingredients in pesticides), metal processing, paint and protective coating, leather manufacturing, building and construction, food and beverages sectors, and as spermicides in contraceptive foams, jellies and creams (e.g. nonoxynol-9). Alkylphenol ethoxylates are partially degraded in sewage treatment plants. The main degradation products formed in sewage treatment plants or in rivers are alkylphenol ethoxylates with fewer ethoxylate groups, alkylphenoxy carboxylic acids and alkylphenols.
Studies suggest that these compounds persist in rivers, sediment and groundwater (1-3). Alkylphenol like compounds are also concentrated by organisms (4) such as fish and birds. The objective of this work is to compile and develop analytical methods for the characterization and quantitation of alkylphenol ethoxylates, alkylphenols and derivatives in several environmental matrices.
To adequately understand pathways of exposure, fate & transport of alkylphenol ethoxylates and their derivatives, it is necessary to characterize exposure accurately. This can only be done by using valid methods that are sensitive and reliable. It is already known that some data gaps exist for alkylphenols ethoxylates, alkylphenols, and their carboxylic derivatives in water, sediment and biota. Alkylphenol ethoxylates can be released to the environment through wastewater treatment systems and agricultural runoff. Most analytical efforts focus on the analysis of alkylphenols exclusively without considering the need for quantitating the ethoxylates and carboxylic components. The breakdown products of alkylphenols ethoxylates are generally ten times more toxic (e.g Daphnia) than the original compounds. In the United Kingdom, alkylphenols ethoxylates are believed to be mainly responsible for the production of female egg-yolk protein on the male Rainbow Trout. Compounds such as nonylphenoxy acetic acid have been confirmed to affect the hormonal control in adult male trout. Research shows that these compounds persist in rivers, sediments and groundwater and that they can be accumulated by fish and birds. The measurement of these compounds has become such an important issue that countries like Denmark have set water quality criterion for nonylphenol and nonylphenol ethoxylates. These compounds have been found to be estrogen mimickers. Humans are exposed directly to them through contaminated waters, absorption through the skin from shampoos, spermicidal lubricants, etc, and by inhalation and ingestion of pesticide sprays, and contaminated food. To assess the exposure to these compounds a multimedia approach which measures degradation products of alkylphenol ethoxylates is necessary.
Preparation of standards
Nonyl- and t-octylphenol and mixtures of their polyethoxylate homologs were obtained from commercial sources. No commercial source could be located for the alkylphenol polyethoxylate carboxylates, which result from oxidation of the terminal oxyethanol unit. These derivatives were obtained via custom synthesis (Organix, Inc. , Woburn, Mass., and Gateway Chemical Technology, St. Louis, Mo.).
Sample Isolation methods being tested
Solid Phase Extraction cartridges are being used for the extraction of aqueous samples. Fresh water samples are collected from a control site and an agricultural impacted area in the Neuse River Basin. One liter amber bottles are used for the collection. The collected fresh water samples are passed through a conditioned SPE cartridge and eluted with solvent. Several cartridges are being tested. SPE cartridges are conditioned by passing thru High Purity water (2 mL), and then 2 mL of methanol. The samples are eluted by using methanol or acetonitrile. The extract is then analyzed by HPLC.
Accelerated Solvent Extraction (ASE) is being used for the extraction of solids. Five grams of dry sediment samples are packed into the ASE cartridge. Sediment samples were collected from the same area as the water samples. The top layer of sediment (4 cm) is sieved, dried, and stored on glass jars (4 0C) before extraction. Several programs are being tested to optimize the extraction. The solvents used include dichloromethane and methanol.
Both normal and reverse phase HPLC experiments are being conducted using a Hewlett-Packard HP-1090 chromatograph equipped with a diode array detector and a fluorescence detector. Several reverse phase columns were tested. Normal phase experiments were primarily conducted using an Zorbax amine column. Future tests include a HPLC/MS method.
The lack of commercial sources to obtain the necessary standards confirms the lack of analytical methods for alkylphenol ethoxylates. The goals of this methods development effort are 1) reducing solvent use, 2) streamlining sample handling, and 3)simplifying analysis. Chromatographic analyses have been done for nonyl- and t-octylphenol and mixtures of their polyethoxylate homologs. Normal phase chromatography provided better resolution of the homologs than reverse phase chromatography on the basic HPLC/UV/Fluorescence system. HPLC/MS (HP1100) and Capillary electrophoresis (CE 3D) methods are being optimized to improve the resolution and sensitivity. A new promising water sampling technique that combines SPE principles and ASE technology is being tested as a possible method that would reduce sample handling, solvent used, and extraction times.
This work has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review process and approved for presentation and publication. Mention of tradenames or commercial products does not constitute endorsement or recommendation for use.