|AVILES, MARIA DE LA PAZ|
Submitted to: Society of Environmental Toxicology and Chemistry (SETAC)
Publication Type: Abstract Only
Publication Acceptance Date: 11/18/2002
Publication Date: N/A
Technical Abstract: Nonylphenol (NP) and octylphenol (OP) and their respective lower alkyl ethoxylates (APnEOs) have been found to accumulate in several aquatic organisms. Evidence suggests that these compounds can exhibit estrogenic effects in some organisms. While techniques exist to examine the occurrence of these compounds in river water and in sediment samples, methods for biota are scarce. Most of these methods involve GC/MS, for which the sensitivity progressively decreases with increasing ethoxy substitutions. HPLC with fluorescence detection is another tehcnique which allows for the determination of NP and NPnEO up to n=5 and higher, but it cannot easily distinguish OPs from NPs. HPLC with tandem mass spectrometry provides both the specificity and the sensitivity to analyze for all these compounds. We have developed a LC/ESI-MS/MS method that uses ammonium adducts in positive mode and M-H ions in negative mode. Using this method, we have been able to quantitate all of the natural APnEOs (n = 0 to 5), the internal standards, n-NP, n-NP3EO and a series (n = 0 to 4) of 13C-labelled NPnEOs. Matrix effects from fish samples resulted in as much as a 50% reduction in signal for NP and OP in the negative mode. To correct this problem, other techniques were examined such as comparing APCI and ESI interfaces, using 13C-labelled internal standards, and employing additional cleanup steps, namely C18 solid-phase extraction in different solvents. These methods have been successfully applied to walleye from St. Paul Metro, carp from Cuyahoga River, and osprey egg from Delaware Bay. Quantification limits were 12ng/g for NP and OP and 4 ng/g for APnEOs in osprey eggs and 21ng/g for NP and OP and 6ng/g for APnEOS for fish samples.