This document describes a routine method for the quantitative determination of 4-nonylphenol (NP), 4-nonylphenol monoethoxylate (NP1EO), and 4-nonylphenol diethoxylate (NP2EO) in sludge samples. A Soxtec® extraction procedure was used to enrich the target compounds from the solid matrix. Quantitative determinations were performed by high-speed gas chromatography/mass spectrometry using a short apolar fused silica column. Derivatization allows NP1EO and NP2EO to be analyzed by gas chromatography. The relative standard deviation was close to 5% for the analysis of 10 different sludges analyzed seven times each. Recoveries were determined for a sludge reference material and were higher than 90%. The experimental limits of quantification were 2, 5, and 5 µg/g of dry matter (µg/g DM), respectively, for NP, NP1EO, and NP2EO. Good agreement was observed between results obtained with this method and those obtained by our previous method, which used normal-phase liquid chromatography with an aminosilica column. This method was applied to the determination of alkylphenols and alkylphenol mono- and diethoxylates in sewage sludge by high-speed gas chromatography/mass spectrometry.
The document outlines a specific procedure for the quantitative determination of 4-nonylphenol (NP), 4-nonylphenol monoethoxylate (NP1EO), and 4-nonylphenol diethoxylate (NP2EO) in sludge samples. The method utilizes Soxtec extraction followed by derivatization with Sigma-Sil-A to enable analysis via gas chromatography/mass spectrometry.
| GC/MS System | Agilent 6890/5973 MSD |
|---|---|
| Column Type | 20-m x 0.10-mm id x 0.10 um RTX5 capillary column |
| Inlet Temperature | 300 °C |
| Source Temperature | 250 °C |
| Quadrupole Temperature | 150 °C |
| Transfer Line Temperature | 250 °C |
| Carrier Gas Flow | 0.3 mL/min |
The experimental limits of quantification were 2, 5, and 5 µg/g of dry matter respectively.
Recoveries determined for a sludge reference material were higher than 90%.
The monitoring ions chosen for NP1EO in SIM mode are 251, 265, and 336.