Determination of nonylphenol and nonylphenol ethoxylates in powdered milk infant formula by HPLC-FL
Linear nonylphenol (4-n-NP), nonylphenol isomers (NP), and NP short chain ethoxylated derivates (NPEO1 and NPEO2) show a wellreported endocrine disrupting activity due to their ability to mimic natural estrogens of living organisms. In this work, two methodologies were developed for the simultaneous extraction and determination of NP, 4-n-NP, long and short chain nonylphenol ethoxylates in commercial powdered milk infant formula using high performance liquid chromatography with fluorescence detection (HPLC-FL). Separation was performed on an Eclipse XDB-C8 column (3 μm and 4.6 × 150 mm) in isocratic mode at 1 mL/min using a mixture of ACN-H 2O (6535). In the first approach, milk powder was reconstituted according to the indications of the manufacturer. A saponification step was carried out to remove triacylglycerols and, subsequently, the obtained solution was solid-phase extracted. Following this procedure, quantitative recovery and high selectivity were achieved for 4-n-NP, whereas several interferences appeared at the retention times of NPEOx, thus increasing limits of detection for these compounds. The second approach consisted of a simple ultrasonic-assisted extraction of the milk powder (non-reconstituted sample) and subsequent determination by HPLC-FL. Different organic solvents were tested for the extraction, and among them acetonitrile (ACN) provided the best results. Quantitative recoveries were obtained for all the analytes in a single extraction step of 15 min using only 1 mL of ACN. Additionally, this approach was more selective than the reconstituted milk-based procedure. The limits of detection achieved ranged from 0.010 μg/g to 0.085 μg/g depending upon the analyte. Copyright © 2010 Publishing Technology.
| Main Authors: | , , |
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| Format: | journal article biblioteca |
| Language: | eng |
| Published: |
2011
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| Online Access: | http://hdl.handle.net/20.500.12792/2718 |
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